1 /*
2 This is a version (aka dlmalloc) of malloc/free/realloc written by
3 Doug Lea and released to the public domain, as explained at
4 http://creativecommons.org/publicdomain/zero/1.0/ Send questions,
5 comments, complaints, performance data, etc to dl@cs.oswego.edu
6
7 * Version 2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea
8 Note: There may be an updated version of this malloc obtainable at
9 ftp://gee.cs.oswego.edu/pub/misc/malloc.c
10 Check before installing!
11
12 * Quickstart
13
14 This library is all in one file to simplify the most common usage:
15 ftp it, compile it (-O3), and link it into another program. All of
16 the compile-time options default to reasonable values for use on
17 most platforms. You might later want to step through various
18 compile-time and dynamic tuning options.
19
20 For convenience, an include file for code using this malloc is at:
21 ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.6.h
22 You don't really need this .h file unless you call functions not
23 defined in your system include files. The .h file contains only the
24 excerpts from this file needed for using this malloc on ANSI C/C++
25 systems, so long as you haven't changed compile-time options about
26 naming and tuning parameters. If you do, then you can create your
27 own malloc.h that does include all settings by cutting at the point
28 indicated below. Note that you may already by default be using a C
29 library containing a malloc that is based on some version of this
30 malloc (for example in linux). You might still want to use the one
31 in this file to customize settings or to avoid overheads associated
32 with library versions.
33
34 * Vital statistics:
35
36 Supported pointer/size_t representation: 4 or 8 bytes
37 size_t MUST be an unsigned type of the same width as
38 pointers. (If you are using an ancient system that declares
39 size_t as a signed type, or need it to be a different width
40 than pointers, you can use a previous release of this malloc
41 (e.g. 2.7.2) supporting these.)
42
43 Alignment: 8 bytes (minimum)
44 This suffices for nearly all current machines and C compilers.
45 However, you can define MALLOC_ALIGNMENT to be wider than this
46 if necessary (up to 128bytes), at the expense of using more space.
47
48 Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes)
49 8 or 16 bytes (if 8byte sizes)
50 Each malloced chunk has a hidden word of overhead holding size
51 and status information, and additional cross-check word
52 if FOOTERS is defined.
53
54 Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead)
55 8-byte ptrs: 32 bytes (including overhead)
56
57 Even a request for zero bytes (i.e., malloc(0)) returns a
58 pointer to something of the minimum allocatable size.
59 The maximum overhead wastage (i.e., number of extra bytes
60 allocated than were requested in malloc) is less than or equal
61 to the minimum size, except for requests >= mmap_threshold that
62 are serviced via mmap(), where the worst case wastage is about
63 32 bytes plus the remainder from a system page (the minimal
64 mmap unit); typically 4096 or 8192 bytes.
65
66 Security: static-safe; optionally more or less
67 The "security" of malloc refers to the ability of malicious
68 code to accentuate the effects of errors (for example, freeing
69 space that is not currently malloc'ed or overwriting past the
70 ends of chunks) in code that calls malloc. This malloc
71 guarantees not to modify any memory locations below the base of
72 heap, i.e., static variables, even in the presence of usage
73 errors. The routines additionally detect most improper frees
74 and reallocs. All this holds as long as the static bookkeeping
75 for malloc itself is not corrupted by some other means. This
76 is only one aspect of security -- these checks do not, and
77 cannot, detect all possible programming errors.
78
79 If FOOTERS is defined nonzero, then each allocated chunk
80 carries an additional check word to verify that it was malloced
81 from its space. These check words are the same within each
82 execution of a program using malloc, but differ across
83 executions, so externally crafted fake chunks cannot be
84 freed. This improves security by rejecting frees/reallocs that
85 could corrupt heap memory, in addition to the checks preventing
86 writes to statics that are always on. This may further improve
87 security at the expense of time and space overhead. (Note that
88 FOOTERS may also be worth using with MSPACES.)
89
90 By default detected errors cause the program to abort (calling
91 "abort()"). You can override this to instead proceed past
92 errors by defining PROCEED_ON_ERROR. In this case, a bad free
93 has no effect, and a malloc that encounters a bad address
94 caused by user overwrites will ignore the bad address by
95 dropping pointers and indices to all known memory. This may
96 be appropriate for programs that should continue if at all
97 possible in the face of programming errors, although they may
98 run out of memory because dropped memory is never reclaimed.
99
100 If you don't like either of these options, you can define
101 CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
102 else. And if if you are sure that your program using malloc has
103 no errors or vulnerabilities, you can define INSECURE to 1,
104 which might (or might not) provide a small performance improvement.
105
106 It is also possible to limit the maximum total allocatable
107 space, using malloc_set_footprint_limit. This is not
108 designed as a security feature in itself (calls to set limits
109 are not screened or privileged), but may be useful as one
110 aspect of a secure implementation.
111
112 Thread-safety: NOT thread-safe unless USE_LOCKS defined non-zero
113 When USE_LOCKS is defined, each public call to malloc, free,
114 etc is surrounded with a lock. By default, this uses a plain
115 pthread mutex, win32 critical section, or a spin-lock if if
116 available for the platform and not disabled by setting
117 USE_SPIN_LOCKS=0. However, if USE_RECURSIVE_LOCKS is defined,
118 recursive versions are used instead (which are not required for
119 base functionality but may be needed in layered extensions).
120 Using a global lock is not especially fast, and can be a major
121 bottleneck. It is designed only to provide minimal protection
122 in concurrent environments, and to provide a basis for
123 extensions. If you are using malloc in a concurrent program,
124 consider instead using nedmalloc
125 (http://www.nedprod.com/programs/portable/nedmalloc/) or
126 ptmalloc (See http://www.malloc.de), which are derived from
127 versions of this malloc.
128
129 System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
130 This malloc can use unix sbrk or any emulation (invoked using
131 the CALL_MORECORE macro) and/or mmap/munmap or any emulation
132 (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
133 memory. On most unix systems, it tends to work best if both
134 MORECORE and MMAP are enabled. On Win32, it uses emulations
135 based on VirtualAlloc. It also uses common C library functions
136 like memset.
137
138 Compliance: I believe it is compliant with the Single Unix Specification
139 (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
140 others as well.
141
142 * Overview of algorithms
143
144 This is not the fastest, most space-conserving, most portable, or
145 most tunable malloc ever written. However it is among the fastest
146 while also being among the most space-conserving, portable and
147 tunable. Consistent balance across these factors results in a good
148 general-purpose allocator for malloc-intensive programs.
149
150 In most ways, this malloc is a best-fit allocator. Generally, it
151 chooses the best-fitting existing chunk for a request, with ties
152 broken in approximately least-recently-used order. (This strategy
153 normally maintains low fragmentation.) However, for requests less
154 than 256bytes, it deviates from best-fit when there is not an
155 exactly fitting available chunk by preferring to use space adjacent
156 to that used for the previous small request, as well as by breaking
157 ties in approximately most-recently-used order. (These enhance
158 locality of series of small allocations.) And for very large requests
159 (>= 256Kb by default), it relies on system memory mapping
160 facilities, if supported. (This helps avoid carrying around and
161 possibly fragmenting memory used only for large chunks.)
162
163 All operations (except malloc_stats and mallinfo) have execution
164 times that are bounded by a constant factor of the number of bits in
165 a size_t, not counting any clearing in calloc or copying in realloc,
166 or actions surrounding MORECORE and MMAP that have times
167 proportional to the number of non-contiguous regions returned by
168 system allocation routines, which is often just 1. In real-time
169 applications, you can optionally suppress segment traversals using
170 NO_SEGMENT_TRAVERSAL, which assures bounded execution even when
171 system allocators return non-contiguous spaces, at the typical
172 expense of carrying around more memory and increased fragmentation.
173
174 The implementation is not very modular and seriously overuses
175 macros. Perhaps someday all C compilers will do as good a job
176 inlining modular code as can now be done by brute-force expansion,
177 but now, enough of them seem not to.
178
179 Some compilers issue a lot of warnings about code that is
180 dead/unreachable only on some platforms, and also about intentional
181 uses of negation on unsigned types. All known cases of each can be
182 ignored.
183
184 For a longer but out of date high-level description, see
185 http://gee.cs.oswego.edu/dl/html/malloc.html
186
187 * MSPACES
188 If MSPACES is defined, then in addition to malloc, free, etc.,
189 this file also defines mspace_malloc, mspace_free, etc. These
190 are versions of malloc routines that take an "mspace" argument
191 obtained using create_mspace, to control all internal bookkeeping.
192 If ONLY_MSPACES is defined, only these versions are compiled.
193 So if you would like to use this allocator for only some allocations,
194 and your system malloc for others, you can compile with
195 ONLY_MSPACES and then do something like...
196 static mspace mymspace = create_mspace(0,0); // for example
197 #define mymalloc(bytes) mspace_malloc(mymspace, bytes)
198
199 (Note: If you only need one instance of an mspace, you can instead
200 use "USE_DL_PREFIX" to relabel the global malloc.)
201
202 You can similarly create thread-local allocators by storing
203 mspaces as thread-locals. For example:
204 static __thread mspace tlms = 0;
205 void* tlmalloc(size_t bytes) {
206 if (tlms == 0) tlms = create_mspace(0, 0);
207 return mspace_malloc(tlms, bytes);
208 }
209 void tlfree(void* mem) { mspace_free(tlms, mem); }
210
211 Unless FOOTERS is defined, each mspace is completely independent.
212 You cannot allocate from one and free to another (although
213 conformance is only weakly checked, so usage errors are not always
214 caught). If FOOTERS is defined, then each chunk carries around a tag
215 indicating its originating mspace, and frees are directed to their
216 originating spaces. Normally, this requires use of locks.
217
218 ------------------------- Compile-time options ---------------------------
219
220 Be careful in setting #define values for numerical constants of type
221 size_t. On some systems, literal values are not automatically extended
222 to size_t precision unless they are explicitly casted. You can also
223 use the symbolic values MAX_SIZE_T, SIZE_T_ONE, etc below.
224
225 WIN32 default: defined if _WIN32 defined
226 Defining WIN32 sets up defaults for MS environment and compilers.
227 Otherwise defaults are for unix. Beware that there seem to be some
228 cases where this malloc might not be a pure drop-in replacement for
229 Win32 malloc: Random-looking failures from Win32 GDI API's (eg;
230 SetDIBits()) may be due to bugs in some video driver implementations
231 when pixel buffers are malloc()ed, and the region spans more than
232 one VirtualAlloc()ed region. Because dlmalloc uses a small (64Kb)
233 default granularity, pixel buffers may straddle virtual allocation
234 regions more often than when using the Microsoft allocator. You can
235 avoid this by using VirtualAlloc() and VirtualFree() for all pixel
236 buffers rather than using malloc(). If this is not possible,
237 recompile this malloc with a larger DEFAULT_GRANULARITY. Note:
238 in cases where MSC and gcc (cygwin) are known to differ on WIN32,
239 conditions use _MSC_VER to distinguish them.
240
241 DLMALLOC_EXPORT default: extern
242 Defines how public APIs are declared. If you want to export via a
243 Windows DLL, you might define this as
244 #define DLMALLOC_EXPORT extern __declspec(dllexport)
245 If you want a POSIX ELF shared object, you might use
246 #define DLMALLOC_EXPORT extern __attribute__((visibility("default")))
247
248 MALLOC_ALIGNMENT default: (size_t)(2 * sizeof(void *))
249 Controls the minimum alignment for malloc'ed chunks. It must be a
250 power of two and at least 8, even on machines for which smaller
251 alignments would suffice. It may be defined as larger than this
252 though. Note however that code and data structures are optimized for
253 the case of 8-byte alignment.
254
255 MSPACES default: 0 (false)
256 If true, compile in support for independent allocation spaces.
257 This is only supported if HAVE_MMAP is true.
258
259 ONLY_MSPACES default: 0 (false)
260 If true, only compile in mspace versions, not regular versions.
261
262 USE_LOCKS default: 0 (false)
263 Causes each call to each public routine to be surrounded with
264 pthread or WIN32 mutex lock/unlock. (If set true, this can be
265 overridden on a per-mspace basis for mspace versions.) If set to a
266 non-zero value other than 1, locks are used, but their
267 implementation is left out, so lock functions must be supplied manually,
268 as described below.
269
270 USE_SPIN_LOCKS default: 1 iff USE_LOCKS and spin locks available
271 If true, uses custom spin locks for locking. This is currently
272 supported only gcc >= 4.1, older gccs on x86 platforms, and recent
273 MS compilers. Otherwise, posix locks or win32 critical sections are
274 used.
275
276 USE_RECURSIVE_LOCKS default: not defined
277 If defined nonzero, uses recursive (aka reentrant) locks, otherwise
278 uses plain mutexes. This is not required for malloc proper, but may
279 be needed for layered allocators such as nedmalloc.
280
281 LOCK_AT_FORK default: not defined
282 If defined nonzero, performs pthread_atfork upon initialization
283 to initialize child lock while holding parent lock. The implementation
284 assumes that pthread locks (not custom locks) are being used. In other
285 cases, you may need to customize the implementation.
286
287 FOOTERS default: 0
288 If true, provide extra checking and dispatching by placing
289 information in the footers of allocated chunks. This adds
290 space and time overhead.
291
292 INSECURE default: 0
293 If true, omit checks for usage errors and heap space overwrites.
294
295 USE_DL_PREFIX default: NOT defined
296 Causes compiler to prefix all public routines with the string 'dl'.
297 This can be useful when you only want to use this malloc in one part
298 of a program, using your regular system malloc elsewhere.
299
300 MALLOC_INSPECT_ALL default: NOT defined
301 If defined, compiles malloc_inspect_all and mspace_inspect_all, that
302 perform traversal of all heap space. Unless access to these
303 functions is otherwise restricted, you probably do not want to
304 include them in secure implementations.
305
306 ABORT default: defined as abort()
307 Defines how to abort on failed checks. On most systems, a failed
308 check cannot die with an "assert" or even print an informative
309 message, because the underlying print routines in turn call malloc,
310 which will fail again. Generally, the best policy is to simply call
311 abort(). It's not very useful to do more than this because many
312 errors due to overwriting will show up as address faults (null, odd
313 addresses etc) rather than malloc-triggered checks, so will also
314 abort. Also, most compilers know that abort() does not return, so
315 can better optimize code conditionally calling it.
316
317 PROCEED_ON_ERROR default: defined as 0 (false)
318 Controls whether detected bad addresses cause them to bypassed
319 rather than aborting. If set, detected bad arguments to free and
320 realloc are ignored. And all bookkeeping information is zeroed out
321 upon a detected overwrite of freed heap space, thus losing the
322 ability to ever return it from malloc again, but enabling the
323 application to proceed. If PROCEED_ON_ERROR is defined, the
324 static variable malloc_corruption_error_count is compiled in
325 and can be examined to see if errors have occurred. This option
326 generates slower code than the default abort policy.
327
328 DEBUG default: NOT defined
329 The DEBUG setting is mainly intended for people trying to modify
330 this code or diagnose problems when porting to new platforms.
331 However, it may also be able to better isolate user errors than just
332 using runtime checks. The assertions in the check routines spell
333 out in more detail the assumptions and invariants underlying the
334 algorithms. The checking is fairly extensive, and will slow down
335 execution noticeably. Calling malloc_stats or mallinfo with DEBUG
336 set will attempt to check every non-mmapped allocated and free chunk
337 in the course of computing the summaries.
338
339 ABORT_ON_ASSERT_FAILURE default: defined as 1 (true)
340 Debugging assertion failures can be nearly impossible if your
341 version of the assert macro causes malloc to be called, which will
342 lead to a cascade of further failures, blowing the runtime stack.
343 ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
344 which will usually make debugging easier.
345
346 MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32
347 The action to take before "return 0" when malloc fails to be able to
348 return memory because there is none available.
349
350 HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES
351 True if this system supports sbrk or an emulation of it.
352
353 MORECORE default: sbrk
354 The name of the sbrk-style system routine to call to obtain more
355 memory. See below for guidance on writing custom MORECORE
356 functions. The type of the argument to sbrk/MORECORE varies across
357 systems. It cannot be size_t, because it supports negative
358 arguments, so it is normally the signed type of the same width as
359 size_t (sometimes declared as "intptr_t"). It doesn't much matter
360 though. Internally, we only call it with arguments less than half
361 the max value of a size_t, which should work across all reasonable
362 possibilities, although sometimes generating compiler warnings.
363
364 MORECORE_CONTIGUOUS default: 1 (true) if HAVE_MORECORE
365 If true, take advantage of fact that consecutive calls to MORECORE
366 with positive arguments always return contiguous increasing
367 addresses. This is true of unix sbrk. It does not hurt too much to
368 set it true anyway, since malloc copes with non-contiguities.
369 Setting it false when definitely non-contiguous saves time
370 and possibly wasted space it would take to discover this though.
371
372 MORECORE_CANNOT_TRIM default: NOT defined
373 True if MORECORE cannot release space back to the system when given
374 negative arguments. This is generally necessary only if you are
375 using a hand-crafted MORECORE function that cannot handle negative
376 arguments.
377
378 NO_SEGMENT_TRAVERSAL default: 0
379 If non-zero, suppresses traversals of memory segments
380 returned by either MORECORE or CALL_MMAP. This disables
381 merging of segments that are contiguous, and selectively
382 releasing them to the OS if unused, but bounds execution times.
383
384 HAVE_MMAP default: 1 (true)
385 True if this system supports mmap or an emulation of it. If so, and
386 HAVE_MORECORE is not true, MMAP is used for all system
387 allocation. If set and HAVE_MORECORE is true as well, MMAP is
388 primarily used to directly allocate very large blocks. It is also
389 used as a backup strategy in cases where MORECORE fails to provide
390 space from system. Note: A single call to MUNMAP is assumed to be
391 able to unmap memory that may have be allocated using multiple calls
392 to MMAP, so long as they are adjacent.
393
394 HAVE_MREMAP default: 1 on linux, else 0
395 If true realloc() uses mremap() to re-allocate large blocks and
396 extend or shrink allocation spaces.
397
398 MMAP_CLEARS default: 1 except on WINCE.
399 True if mmap clears memory so calloc doesn't need to. This is true
400 for standard unix mmap using /dev/zero and on WIN32 except for WINCE.
401
402 USE_BUILTIN_FFS default: 0 (i.e., not used)
403 Causes malloc to use the builtin ffs() function to compute indices.
404 Some compilers may recognize and intrinsify ffs to be faster than the
405 supplied C version. Also, the case of x86 using gcc is special-cased
406 to an asm instruction, so is already as fast as it can be, and so
407 this setting has no effect. Similarly for Win32 under recent MS compilers.
408 (On most x86s, the asm version is only slightly faster than the C version.)
409
410 malloc_getpagesize default: derive from system includes, or 4096.
411 The system page size. To the extent possible, this malloc manages
412 memory from the system in page-size units. This may be (and
413 usually is) a function rather than a constant. This is ignored
414 if WIN32, where page size is determined using getSystemInfo during
415 initialization.
416
417 USE_DEV_RANDOM default: 0 (i.e., not used)
418 Causes malloc to use /dev/random to initialize secure magic seed for
419 stamping footers. Otherwise, the current time is used.
420
421 NO_MALLINFO default: 0
422 If defined, don't compile "mallinfo". This can be a simple way
423 of dealing with mismatches between system declarations and
424 those in this file.
425
426 MALLINFO_FIELD_TYPE default: size_t
427 The type of the fields in the mallinfo struct. This was originally
428 defined as "int" in SVID etc, but is more usefully defined as
429 size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set
430
431 NO_MALLOC_STATS default: 0
432 If defined, don't compile "malloc_stats". This avoids calls to
433 fprintf and bringing in stdio dependencies you might not want.
434
435 REALLOC_ZERO_BYTES_FREES default: not defined
436 This should be set if a call to realloc with zero bytes should
437 be the same as a call to free. Some people think it should. Otherwise,
438 since this malloc returns a unique pointer for malloc(0), so does
439 realloc(p, 0).
440
441 LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
442 LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H
443 LACKS_STDLIB_H LACKS_SCHED_H LACKS_TIME_H default: NOT defined unless on WIN32
444 Define these if your system does not have these header files.
445 You might need to manually insert some of the declarations they provide.
446
447 DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS,
448 system_info.dwAllocationGranularity in WIN32,
449 otherwise 64K.
450 Also settable using mallopt(M_GRANULARITY, x)
451 The unit for allocating and deallocating memory from the system. On
452 most systems with contiguous MORECORE, there is no reason to
453 make this more than a page. However, systems with MMAP tend to
454 either require or encourage larger granularities. You can increase
455 this value to prevent system allocation functions to be called so
456 often, especially if they are slow. The value must be at least one
457 page and must be a power of two. Setting to 0 causes initialization
458 to either page size or win32 region size. (Note: In previous
459 versions of malloc, the equivalent of this option was called
460 "TOP_PAD")
461
462 DEFAULT_TRIM_THRESHOLD default: 2MB
463 Also settable using mallopt(M_TRIM_THRESHOLD, x)
464 The maximum amount of unused top-most memory to keep before
465 releasing via malloc_trim in free(). Automatic trimming is mainly
466 useful in long-lived programs using contiguous MORECORE. Because
467 trimming via sbrk can be slow on some systems, and can sometimes be
468 wasteful (in cases where programs immediately afterward allocate
469 more large chunks) the value should be high enough so that your
470 overall system performance would improve by releasing this much
471 memory. As a rough guide, you might set to a value close to the
472 average size of a process (program) running on your system.
473 Releasing this much memory would allow such a process to run in
474 memory. Generally, it is worth tuning trim thresholds when a
475 program undergoes phases where several large chunks are allocated
476 and released in ways that can reuse each other's storage, perhaps
477 mixed with phases where there are no such chunks at all. The trim
478 value must be greater than page size to have any useful effect. To
479 disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
480 some people use of mallocing a huge space and then freeing it at
481 program startup, in an attempt to reserve system memory, doesn't
482 have the intended effect under automatic trimming, since that memory
483 will immediately be returned to the system.
484
485 DEFAULT_MMAP_THRESHOLD default: 256K
486 Also settable using mallopt(M_MMAP_THRESHOLD, x)
487 The request size threshold for using MMAP to directly service a
488 request. Requests of at least this size that cannot be allocated
489 using already-existing space will be serviced via mmap. (If enough
490 normal freed space already exists it is used instead.) Using mmap
491 segregates relatively large chunks of memory so that they can be
492 individually obtained and released from the host system. A request
493 serviced through mmap is never reused by any other request (at least
494 not directly; the system may just so happen to remap successive
495 requests to the same locations). Segregating space in this way has
496 the benefits that: Mmapped space can always be individually released
497 back to the system, which helps keep the system level memory demands
498 of a long-lived program low. Also, mapped memory doesn't become
499 `locked' between other chunks, as can happen with normally allocated
500 chunks, which means that even trimming via malloc_trim would not
501 release them. However, it has the disadvantage that the space
502 cannot be reclaimed, consolidated, and then used to service later
503 requests, as happens with normal chunks. The advantages of mmap
504 nearly always outweigh disadvantages for "large" chunks, but the
505 value of "large" may vary across systems. The default is an
506 empirically derived value that works well in most systems. You can
507 disable mmap by setting to MAX_SIZE_T.
508
509 MAX_RELEASE_CHECK_RATE default: 4095 unless not HAVE_MMAP
510 The number of consolidated frees between checks to release
511 unused segments when freeing. When using non-contiguous segments,
512 especially with multiple mspaces, checking only for topmost space
513 doesn't always suffice to trigger trimming. To compensate for this,
514 free() will, with a period of MAX_RELEASE_CHECK_RATE (or the
515 current number of segments, if greater) try to release unused
516 segments to the OS when freeing chunks that result in
517 consolidation. The best value for this parameter is a compromise
518 between slowing down frees with relatively costly checks that
519 rarely trigger versus holding on to unused memory. To effectively
520 disable, set to MAX_SIZE_T. This may lead to a very slight speed
521 improvement at the expense of carrying around more memory.
522 */
523
524 /* Version identifier to allow people to support multiple versions */
525 #ifndef DLMALLOC_VERSION
526 #define DLMALLOC_VERSION 20806
527 #endif /* DLMALLOC_VERSION */
528
529 #ifndef DLMALLOC_EXPORT
530 #define DLMALLOC_EXPORT extern
531 #endif
532
533 #ifndef WIN32
534 #ifdef _WIN32
535 #define WIN32 1
536 #endif /* _WIN32 */
537 #ifdef _WIN32_WCE
538 #define LACKS_FCNTL_H
539 #define WIN32 1
540 #endif /* _WIN32_WCE */
541 #endif /* WIN32 */
542 #ifdef WIN32
543 #define WIN32_LEAN_AND_MEAN
544 #include <windows.h>
545 #include <tchar.h>
546 #define HAVE_MMAP 1
547 #define HAVE_MORECORE 0
548 #define LACKS_UNISTD_H
549 #define LACKS_SYS_PARAM_H
550 #define LACKS_SYS_MMAN_H
551 #define LACKS_STRING_H
552 #define LACKS_STRINGS_H
553 #define LACKS_SYS_TYPES_H
554 #define LACKS_ERRNO_H
555 #define LACKS_SCHED_H
556 #ifndef MALLOC_FAILURE_ACTION
557 #define MALLOC_FAILURE_ACTION
558 #endif /* MALLOC_FAILURE_ACTION */
559 #ifndef MMAP_CLEARS
560 #ifdef _WIN32_WCE /* WINCE reportedly does not clear */
561 #define MMAP_CLEARS 0
562 #else
563 #define MMAP_CLEARS 1
564 #endif /* _WIN32_WCE */
565 #endif /*MMAP_CLEARS */
566 #endif /* WIN32 */
567
568 #if defined(DARWIN) || defined(_DARWIN)
569 /* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
570 #ifndef HAVE_MORECORE
571 #define HAVE_MORECORE 0
572 #define HAVE_MMAP 1
573 /* OSX allocators provide 16 byte alignment */
574 #ifndef MALLOC_ALIGNMENT
575 #define MALLOC_ALIGNMENT ((size_t)16U)
576 #endif
577 #endif /* HAVE_MORECORE */
578 #endif /* DARWIN */
579
580 #ifndef LACKS_SYS_TYPES_H
581 #include <sys/types.h> /* For size_t */
582 #endif /* LACKS_SYS_TYPES_H */
583
584 /* The maximum possible size_t value has all bits set */
585 #define MAX_SIZE_T (~(size_t)0)
586
587 #ifndef USE_LOCKS /* ensure true if spin or recursive locks set */
588 #define USE_LOCKS ((defined(USE_SPIN_LOCKS) && USE_SPIN_LOCKS != 0) || \
589 (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0))
590 #endif /* USE_LOCKS */
591
592 #if USE_LOCKS /* Spin locks for gcc >= 4.1, older gcc on x86, MSC >= 1310 */
593 #if ((defined(__GNUC__) && \
594 ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) || \
595 defined(__i386__) || defined(__x86_64__))) || \
596 (defined(_MSC_VER) && _MSC_VER>=1310))
597 #ifndef USE_SPIN_LOCKS
598 #define USE_SPIN_LOCKS 1
599 #endif /* USE_SPIN_LOCKS */
600 #elif USE_SPIN_LOCKS
601 #error "USE_SPIN_LOCKS defined without implementation"
602 #endif /* ... locks available... */
603 #elif !defined(USE_SPIN_LOCKS)
604 #define USE_SPIN_LOCKS 0
605 #endif /* USE_LOCKS */
606
607 #ifndef ONLY_MSPACES
608 #define ONLY_MSPACES 0
609 #endif /* ONLY_MSPACES */
610 #ifndef MSPACES
611 #if ONLY_MSPACES
612 #define MSPACES 1
613 #else /* ONLY_MSPACES */
614 #define MSPACES 0
615 #endif /* ONLY_MSPACES */
616 #endif /* MSPACES */
617 #ifndef MALLOC_ALIGNMENT
618 #define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *)))
619 #endif /* MALLOC_ALIGNMENT */
620 #ifndef FOOTERS
621 #define FOOTERS 0
622 #endif /* FOOTERS */
623 #ifndef ABORT
624 #define ABORT abort()
625 #endif /* ABORT */
626 #ifndef ABORT_ON_ASSERT_FAILURE
627 #define ABORT_ON_ASSERT_FAILURE 1
628 #endif /* ABORT_ON_ASSERT_FAILURE */
629 #ifndef PROCEED_ON_ERROR
630 #define PROCEED_ON_ERROR 0
631 #endif /* PROCEED_ON_ERROR */
632
633 #ifndef INSECURE
634 #define INSECURE 0
635 #endif /* INSECURE */
636 #ifndef MALLOC_INSPECT_ALL
637 #define MALLOC_INSPECT_ALL 0
638 #endif /* MALLOC_INSPECT_ALL */
639 #ifndef HAVE_MMAP
640 #define HAVE_MMAP 1
641 #endif /* HAVE_MMAP */
642 #ifndef MMAP_CLEARS
643 #define MMAP_CLEARS 1
644 #endif /* MMAP_CLEARS */
645 #ifndef HAVE_MREMAP
646 #ifdef linux
647 #define HAVE_MREMAP 1
648 #define _GNU_SOURCE /* Turns on mremap() definition */
649 #else /* linux */
650 #define HAVE_MREMAP 0
651 #endif /* linux */
652 #endif /* HAVE_MREMAP */
653 #ifndef MALLOC_FAILURE_ACTION
654 #define MALLOC_FAILURE_ACTION errno = ENOMEM;
655 #endif /* MALLOC_FAILURE_ACTION */
656 #ifndef HAVE_MORECORE
657 #if ONLY_MSPACES
658 #define HAVE_MORECORE 0
659 #else /* ONLY_MSPACES */
660 #define HAVE_MORECORE 1
661 #endif /* ONLY_MSPACES */
662 #endif /* HAVE_MORECORE */
663 #if !HAVE_MORECORE
664 #define MORECORE_CONTIGUOUS 0
665 #else /* !HAVE_MORECORE */
666 #define MORECORE_DEFAULT sbrk
667 #ifndef MORECORE_CONTIGUOUS
668 #define MORECORE_CONTIGUOUS 1
669 #endif /* MORECORE_CONTIGUOUS */
670 #endif /* HAVE_MORECORE */
671 #ifndef DEFAULT_GRANULARITY
672 #if (MORECORE_CONTIGUOUS || defined(WIN32))
673 #define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */
674 #else /* MORECORE_CONTIGUOUS */
675 #define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
676 #endif /* MORECORE_CONTIGUOUS */
677 #endif /* DEFAULT_GRANULARITY */
678 #ifndef DEFAULT_TRIM_THRESHOLD
679 #ifndef MORECORE_CANNOT_TRIM
680 #define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
681 #else /* MORECORE_CANNOT_TRIM */
682 #define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
683 #endif /* MORECORE_CANNOT_TRIM */
684 #endif /* DEFAULT_TRIM_THRESHOLD */
685 #ifndef DEFAULT_MMAP_THRESHOLD
686 #if HAVE_MMAP
687 #define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
688 #else /* HAVE_MMAP */
689 #define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
690 #endif /* HAVE_MMAP */
691 #endif /* DEFAULT_MMAP_THRESHOLD */
692 #ifndef MAX_RELEASE_CHECK_RATE
693 #if HAVE_MMAP
694 #define MAX_RELEASE_CHECK_RATE 4095
695 #else
696 #define MAX_RELEASE_CHECK_RATE MAX_SIZE_T
697 #endif /* HAVE_MMAP */
698 #endif /* MAX_RELEASE_CHECK_RATE */
699 #ifndef USE_BUILTIN_FFS
700 #define USE_BUILTIN_FFS 0
701 #endif /* USE_BUILTIN_FFS */
702 #ifndef USE_DEV_RANDOM
703 #define USE_DEV_RANDOM 0
704 #endif /* USE_DEV_RANDOM */
705 #ifndef NO_MALLINFO
706 #define NO_MALLINFO 0
707 #endif /* NO_MALLINFO */
708 #ifndef MALLINFO_FIELD_TYPE
709 #define MALLINFO_FIELD_TYPE size_t
710 #endif /* MALLINFO_FIELD_TYPE */
711 #ifndef NO_MALLOC_STATS
712 #define NO_MALLOC_STATS 0
713 #endif /* NO_MALLOC_STATS */
714 #ifndef NO_SEGMENT_TRAVERSAL
715 #define NO_SEGMENT_TRAVERSAL 0
716 #endif /* NO_SEGMENT_TRAVERSAL */
717
718 /*
719 mallopt tuning options. SVID/XPG defines four standard parameter
720 numbers for mallopt, normally defined in malloc.h. None of these
721 are used in this malloc, so setting them has no effect. But this
722 malloc does support the following options.
723 */
724
725 #define M_TRIM_THRESHOLD (-1)
726 #define M_GRANULARITY (-2)
727 #define M_MMAP_THRESHOLD (-3)
728
729 /* ------------------------ Mallinfo declarations ------------------------ */
730
731 #if !NO_MALLINFO
732 /*
733 This version of malloc supports the standard SVID/XPG mallinfo
734 routine that returns a struct containing usage properties and
735 statistics. It should work on any system that has a
736 /usr/include/malloc.h defining struct mallinfo. The main
737 declaration needed is the mallinfo struct that is returned (by-copy)
738 by mallinfo(). The malloinfo struct contains a bunch of fields that
739 are not even meaningful in this version of malloc. These fields are
740 are instead filled by mallinfo() with other numbers that might be of
741 interest.
742
743 HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
744 /usr/include/malloc.h file that includes a declaration of struct
745 mallinfo. If so, it is included; else a compliant version is
746 declared below. These must be precisely the same for mallinfo() to
747 work. The original SVID version of this struct, defined on most
748 systems with mallinfo, declares all fields as ints. But some others
749 define as unsigned long. If your system defines the fields using a
750 type of different width than listed here, you MUST #include your
751 system version and #define HAVE_USR_INCLUDE_MALLOC_H.
752 */
753
754 /* #define HAVE_USR_INCLUDE_MALLOC_H */
755
756 #ifdef HAVE_USR_INCLUDE_MALLOC_H
757 #include "/usr/include/malloc.h"
758 #else /* HAVE_USR_INCLUDE_MALLOC_H */
759 #ifndef STRUCT_MALLINFO_DECLARED
760 /* HP-UX (and others?) redefines mallinfo unless _STRUCT_MALLINFO is defined */
761 #define _STRUCT_MALLINFO
762 #define STRUCT_MALLINFO_DECLARED 1
763 struct mallinfo {
764 MALLINFO_FIELD_TYPE arena; /* non-mmapped space allocated from system */
765 MALLINFO_FIELD_TYPE ordblks; /* number of free chunks */
766 MALLINFO_FIELD_TYPE smblks; /* always 0 */
767 MALLINFO_FIELD_TYPE hblks; /* always 0 */
768 MALLINFO_FIELD_TYPE hblkhd; /* space in mmapped regions */
769 MALLINFO_FIELD_TYPE usmblks; /* maximum total allocated space */
770 MALLINFO_FIELD_TYPE fsmblks; /* always 0 */
771 MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
772 MALLINFO_FIELD_TYPE fordblks; /* total free space */
773 MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
774 };
775 #endif /* STRUCT_MALLINFO_DECLARED */
776 #endif /* HAVE_USR_INCLUDE_MALLOC_H */
777 #endif /* NO_MALLINFO */
778
779 /*
780 Try to persuade compilers to inline. The most critical functions for
781 inlining are defined as macros, so these aren't used for them.
782 */
783
784 #ifndef FORCEINLINE
785 #if defined(__GNUC__)
786 #define FORCEINLINE __inline __attribute__ ((always_inline))
787 #elif defined(_MSC_VER)
788 #define FORCEINLINE __forceinline
789 #endif
790 #endif
791 #ifndef NOINLINE
792 #if defined(__GNUC__)
793 #define NOINLINE __attribute__ ((noinline))
794 #elif defined(_MSC_VER)
795 #define NOINLINE __declspec(noinline)
796 #else
797 #define NOINLINE
798 #endif
799 #endif
800
801 #ifdef __cplusplus
802 extern "C" {
803 #ifndef FORCEINLINE
804 #define FORCEINLINE inline
805 #endif
806 #endif /* __cplusplus */
807 #ifndef FORCEINLINE
808 #define FORCEINLINE
809 #endif
810
811 #if !ONLY_MSPACES
812
813 /* ------------------- Declarations of public routines ------------------- */
814
815 #ifndef USE_DL_PREFIX
816 #define dlcalloc calloc
817 #define dlfree free
818 #define dlmalloc malloc
819 #define dlmemalign memalign
820 #define dlposix_memalign posix_memalign
821 #define dlrealloc realloc
822 #define dlrealloc_in_place realloc_in_place
823 #define dlvalloc valloc
824 #define dlpvalloc pvalloc
825 #define dlmallinfo mallinfo
826 #define dlmallopt mallopt
827 #define dlmalloc_trim malloc_trim
828 #define dlmalloc_stats malloc_stats
829 #define dlmalloc_usable_size malloc_usable_size
830 #define dlmalloc_footprint malloc_footprint
831 #define dlmalloc_max_footprint malloc_max_footprint
832 #define dlmalloc_footprint_limit malloc_footprint_limit
833 #define dlmalloc_set_footprint_limit malloc_set_footprint_limit
834 #define dlmalloc_inspect_all malloc_inspect_all
835 #define dlindependent_calloc independent_calloc
836 #define dlindependent_comalloc independent_comalloc
837 #define dlbulk_free bulk_free
838 #endif /* USE_DL_PREFIX */
839
840 /*
841 malloc(size_t n)
842 Returns a pointer to a newly allocated chunk of at least n bytes, or
843 null if no space is available, in which case errno is set to ENOMEM
844 on ANSI C systems.
845
846 If n is zero, malloc returns a minimum-sized chunk. (The minimum
847 size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
848 systems.) Note that size_t is an unsigned type, so calls with
849 arguments that would be negative if signed are interpreted as
850 requests for huge amounts of space, which will often fail. The
851 maximum supported value of n differs across systems, but is in all
852 cases less than the maximum representable value of a size_t.
853 */
854 DLMALLOC_EXPORT void* dlmalloc(size_t);
855
856 /*
857 free(void* p)
858 Releases the chunk of memory pointed to by p, that had been previously
859 allocated using malloc or a related routine such as realloc.
860 It has no effect if p is null. If p was not malloced or already
861 freed, free(p) will by default cause the current program to abort.
862 */
863 DLMALLOC_EXPORT void dlfree(void*);
864
865 /*
866 calloc(size_t n_elements, size_t element_size);
867 Returns a pointer to n_elements * element_size bytes, with all locations
868 set to zero.
869 */
870 DLMALLOC_EXPORT void* dlcalloc(size_t, size_t);
871
872 /*
873 realloc(void* p, size_t n)
874 Returns a pointer to a chunk of size n that contains the same data
875 as does chunk p up to the minimum of (n, p's size) bytes, or null
876 if no space is available.
877
878 The returned pointer may or may not be the same as p. The algorithm
879 prefers extending p in most cases when possible, otherwise it
880 employs the equivalent of a malloc-copy-free sequence.
881
882 If p is null, realloc is equivalent to malloc.
883
884 If space is not available, realloc returns null, errno is set (if on
885 ANSI) and p is NOT freed.
886
887 if n is for fewer bytes than already held by p, the newly unused
888 space is lopped off and freed if possible. realloc with a size
889 argument of zero (re)allocates a minimum-sized chunk.
890
891 The old unix realloc convention of allowing the last-free'd chunk
892 to be used as an argument to realloc is not supported.
893 */
894 DLMALLOC_EXPORT void* dlrealloc(void*, size_t);
895
896 /*
897 realloc_in_place(void* p, size_t n)
898 Resizes the space allocated for p to size n, only if this can be
899 done without moving p (i.e., only if there is adjacent space
900 available if n is greater than p's current allocated size, or n is
901 less than or equal to p's size). This may be used instead of plain
902 realloc if an alternative allocation strategy is needed upon failure
903 to expand space; for example, reallocation of a buffer that must be
904 memory-aligned or cleared. You can use realloc_in_place to trigger
905 these alternatives only when needed.
906
907 Returns p if successful; otherwise null.
908 */
909 DLMALLOC_EXPORT void* dlrealloc_in_place(void*, size_t);
910
911 /*
912 memalign(size_t alignment, size_t n);
913 Returns a pointer to a newly allocated chunk of n bytes, aligned
914 in accord with the alignment argument.
915
916 The alignment argument should be a power of two. If the argument is
917 not a power of two, the nearest greater power is used.
918 8-byte alignment is guaranteed by normal malloc calls, so don't
919 bother calling memalign with an argument of 8 or less.
920
921 Overreliance on memalign is a sure way to fragment space.
922 */
923 DLMALLOC_EXPORT void* dlmemalign(size_t, size_t);
924
925 /*
926 int posix_memalign(void** pp, size_t alignment, size_t n);
927 Allocates a chunk of n bytes, aligned in accord with the alignment
928 argument. Differs from memalign only in that it (1) assigns the
929 allocated memory to *pp rather than returning it, (2) fails and
930 returns EINVAL if the alignment is not a power of two (3) fails and
931 returns ENOMEM if memory cannot be allocated.
932 */
933 DLMALLOC_EXPORT int dlposix_memalign(void**, size_t, size_t);
934
935 /*
936 valloc(size_t n);
937 Equivalent to memalign(pagesize, n), where pagesize is the page
938 size of the system. If the pagesize is unknown, 4096 is used.
939 */
940 DLMALLOC_EXPORT void* dlvalloc(size_t);
941
942 /*
943 mallopt(int parameter_number, int parameter_value)
944 Sets tunable parameters The format is to provide a
945 (parameter-number, parameter-value) pair. mallopt then sets the
946 corresponding parameter to the argument value if it can (i.e., so
947 long as the value is meaningful), and returns 1 if successful else
948 0. To workaround the fact that mallopt is specified to use int,
949 not size_t parameters, the value -1 is specially treated as the
950 maximum unsigned size_t value.
951
952 SVID/XPG/ANSI defines four standard param numbers for mallopt,
953 normally defined in malloc.h. None of these are use in this malloc,
954 so setting them has no effect. But this malloc also supports other
955 options in mallopt. See below for details. Briefly, supported
956 parameters are as follows (listed defaults are for "typical"
957 configurations).
958
959 Symbol param # default allowed param values
960 M_TRIM_THRESHOLD -1 2*1024*1024 any (-1 disables)
961 M_GRANULARITY -2 page size any power of 2 >= page size
962 M_MMAP_THRESHOLD -3 256*1024 any (or 0 if no MMAP support)
963 */
964 DLMALLOC_EXPORT int dlmallopt(int, int);
965
966 /*
967 malloc_footprint();
968 Returns the number of bytes obtained from the system. The total
969 number of bytes allocated by malloc, realloc etc., is less than this
970 value. Unlike mallinfo, this function returns only a precomputed
971 result, so can be called frequently to monitor memory consumption.
972 Even if locks are otherwise defined, this function does not use them,
973 so results might not be up to date.
974 */
975 DLMALLOC_EXPORT size_t dlmalloc_footprint(void);
976
977 /*
978 malloc_max_footprint();
979 Returns the maximum number of bytes obtained from the system. This
980 value will be greater than current footprint if deallocated space
981 has been reclaimed by the system. The peak number of bytes allocated
982 by malloc, realloc etc., is less than this value. Unlike mallinfo,
983 this function returns only a precomputed result, so can be called
984 frequently to monitor memory consumption. Even if locks are
985 otherwise defined, this function does not use them, so results might
986 not be up to date.
987 */
988 DLMALLOC_EXPORT size_t dlmalloc_max_footprint(void);
989
990 /*
991 malloc_footprint_limit();
992 Returns the number of bytes that the heap is allowed to obtain from
993 the system, returning the last value returned by
994 malloc_set_footprint_limit, or the maximum size_t value if
995 never set. The returned value reflects a permission. There is no
996 guarantee that this number of bytes can actually be obtained from
997 the system.
998 */
999 DLMALLOC_EXPORT size_t dlmalloc_footprint_limit(void);
1000
1001 /*
1002 malloc_set_footprint_limit();
1003 Sets the maximum number of bytes to obtain from the system, causing
1004 failure returns from malloc and related functions upon attempts to
1005 exceed this value. The argument value may be subject to page
1006 rounding to an enforceable limit; this actual value is returned.
1007 Using an argument of the maximum possible size_t effectively
1008 disables checks. If the argument is less than or equal to the
1009 current malloc_footprint, then all future allocations that require
1010 additional system memory will fail. However, invocation cannot
1011 retroactively deallocate existing used memory.
1012 */
1013 DLMALLOC_EXPORT size_t dlmalloc_set_footprint_limit(size_t bytes);
1014
1015 #if MALLOC_INSPECT_ALL
1016 /*
1017 malloc_inspect_all(void(*handler)(void *start,
1018 void *end,
1019 size_t used_bytes,
1020 void* callback_arg),
1021 void* arg);
1022 Traverses the heap and calls the given handler for each managed
1023 region, skipping all bytes that are (or may be) used for bookkeeping
1024 purposes. Traversal does not include include chunks that have been
1025 directly memory mapped. Each reported region begins at the start
1026 address, and continues up to but not including the end address. The
1027 first used_bytes of the region contain allocated data. If
1028 used_bytes is zero, the region is unallocated. The handler is
1029 invoked with the given callback argument. If locks are defined, they
1030 are held during the entire traversal. It is a bad idea to invoke
1031 other malloc functions from within the handler.
1032
1033 For example, to count the number of in-use chunks with size greater
1034 than 1000, you could write:
1035 static int count = 0;
1036 void count_chunks(void* start, void* end, size_t used, void* arg) {
1037 if (used >= 1000) ++count;
1038 }
1039 then:
1040 malloc_inspect_all(count_chunks, NULL);
1041
1042 malloc_inspect_all is compiled only if MALLOC_INSPECT_ALL is defined.
1043 */
1044 DLMALLOC_EXPORT void dlmalloc_inspect_all(void(*handler)(void*, void *, size_t, void*),
1045 void* arg);
1046
1047 #endif /* MALLOC_INSPECT_ALL */
1048
1049 #if !NO_MALLINFO
1050 /*
1051 mallinfo()
1052 Returns (by copy) a struct containing various summary statistics:
1053
1054 arena: current total non-mmapped bytes allocated from system
1055 ordblks: the number of free chunks
1056 smblks: always zero.
1057 hblks: current number of mmapped regions
1058 hblkhd: total bytes held in mmapped regions
1059 usmblks: the maximum total allocated space. This will be greater
1060 than current total if trimming has occurred.
1061 fsmblks: always zero
1062 uordblks: current total allocated space (normal or mmapped)
1063 fordblks: total free space
1064 keepcost: the maximum number of bytes that could ideally be released
1065 back to system via malloc_trim. ("ideally" means that
1066 it ignores page restrictions etc.)
1067
1068 Because these fields are ints, but internal bookkeeping may
1069 be kept as longs, the reported values may wrap around zero and
1070 thus be inaccurate.
1071 */
1072 DLMALLOC_EXPORT struct mallinfo dlmallinfo(void);
1073 #endif /* NO_MALLINFO */
1074
1075 /*
1076 independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
1077
1078 independent_calloc is similar to calloc, but instead of returning a
1079 single cleared space, it returns an array of pointers to n_elements
1080 independent elements that can hold contents of size elem_size, each
1081 of which starts out cleared, and can be independently freed,
1082 realloc'ed etc. The elements are guaranteed to be adjacently
1083 allocated (this is not guaranteed to occur with multiple callocs or
1084 mallocs), which may also improve cache locality in some
1085 applications.
1086
1087 The "chunks" argument is optional (i.e., may be null, which is
1088 probably the most typical usage). If it is null, the returned array
1089 is itself dynamically allocated and should also be freed when it is
1090 no longer needed. Otherwise, the chunks array must be of at least
1091 n_elements in length. It is filled in with the pointers to the
1092 chunks.
1093
1094 In either case, independent_calloc returns this pointer array, or
1095 null if the allocation failed. If n_elements is zero and "chunks"
1096 is null, it returns a chunk representing an array with zero elements
1097 (which should be freed if not wanted).
1098
1099 Each element must be freed when it is no longer needed. This can be
1100 done all at once using bulk_free.
1101
1102 independent_calloc simplifies and speeds up implementations of many
1103 kinds of pools. It may also be useful when constructing large data
1104 structures that initially have a fixed number of fixed-sized nodes,
1105 but the number is not known at compile time, and some of the nodes
1106 may later need to be freed. For example:
1107
1108 struct Node { int item; struct Node* next; };
1109
1110 struct Node* build_list() {
1111 struct Node** pool;
1112 int n = read_number_of_nodes_needed();
1113 if (n <= 0) return 0;
1114 pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
1115 if (pool == 0) die();
1116 // organize into a linked list...
1117 struct Node* first = pool[0];
1118 for (i = 0; i < n-1; ++i)
1119 pool[i]->next = pool[i+1];
1120 free(pool); // Can now free the array (or not, if it is needed later)
1121 return first;
1122 }
1123 */
1124 DLMALLOC_EXPORT void** dlindependent_calloc(size_t, size_t, void**);
1125
1126 /*
1127 independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
1128
1129 independent_comalloc allocates, all at once, a set of n_elements
1130 chunks with sizes indicated in the "sizes" array. It returns
1131 an array of pointers to these elements, each of which can be
1132 independently freed, realloc'ed etc. The elements are guaranteed to
1133 be adjacently allocated (this is not guaranteed to occur with
1134 multiple callocs or mallocs), which may also improve cache locality
1135 in some applications.
1136
1137 The "chunks" argument is optional (i.e., may be null). If it is null
1138 the returned array is itself dynamically allocated and should also
1139 be freed when it is no longer needed. Otherwise, the chunks array
1140 must be of at least n_elements in length. It is filled in with the
1141 pointers to the chunks.
1142
1143 In either case, independent_comalloc returns this pointer array, or
1144 null if the allocation failed. If n_elements is zero and chunks is
1145 null, it returns a chunk representing an array with zero elements
1146 (which should be freed if not wanted).
1147
1148 Each element must be freed when it is no longer needed. This can be
1149 done all at once using bulk_free.
1150
1151 independent_comallac differs from independent_calloc in that each
1152 element may have a different size, and also that it does not
1153 automatically clear elements.
1154
1155 independent_comalloc can be used to speed up allocation in cases
1156 where several structs or objects must always be allocated at the
1157 same time. For example:
1158
1159 struct Head { ... }
1160 struct Foot { ... }
1161
1162 void send_message(char* msg) {
1163 int msglen = strlen(msg);
1164 size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
1165 void* chunks[3];
1166 if (independent_comalloc(3, sizes, chunks) == 0)
1167 die();
1168 struct Head* head = (struct Head*)(chunks[0]);
1169 char* body = (char*)(chunks[1]);
1170 struct Foot* foot = (struct Foot*)(chunks[2]);
1171 // ...
1172 }
1173
1174 In general though, independent_comalloc is worth using only for
1175 larger values of n_elements. For small values, you probably won't
1176 detect enough difference from series of malloc calls to bother.
1177
1178 Overuse of independent_comalloc can increase overall memory usage,
1179 since it cannot reuse existing noncontiguous small chunks that
1180 might be available for some of the elements.
1181 */
1182 DLMALLOC_EXPORT void** dlindependent_comalloc(size_t, size_t*, void**);
1183
1184 /*
1185 bulk_free(void* array[], size_t n_elements)
1186 Frees and clears (sets to null) each non-null pointer in the given
1187 array. This is likely to be faster than freeing them one-by-one.
1188 If footers are used, pointers that have been allocated in different
1189 mspaces are not freed or cleared, and the count of all such pointers
1190 is returned. For large arrays of pointers with poor locality, it
1191 may be worthwhile to sort this array before calling bulk_free.
1192 */
1193 DLMALLOC_EXPORT size_t dlbulk_free(void**, size_t n_elements);
1194
1195 /*
1196 pvalloc(size_t n);
1197 Equivalent to valloc(minimum-page-that-holds(n)), that is,
1198 round up n to nearest pagesize.
1199 */
1200 DLMALLOC_EXPORT void* dlpvalloc(size_t);
1201
1202 /*
1203 malloc_trim(size_t pad);
1204
1205 If possible, gives memory back to the system (via negative arguments
1206 to sbrk) if there is unused memory at the `high' end of the malloc
1207 pool or in unused MMAP segments. You can call this after freeing
1208 large blocks of memory to potentially reduce the system-level memory
1209 requirements of a program. However, it cannot guarantee to reduce
1210 memory. Under some allocation patterns, some large free blocks of
1211 memory will be locked between two used chunks, so they cannot be
1212 given back to the system.
1213
1214 The `pad' argument to malloc_trim represents the amount of free
1215 trailing space to leave untrimmed. If this argument is zero, only
1216 the minimum amount of memory to maintain internal data structures
1217 will be left. Non-zero arguments can be supplied to maintain enough
1218 trailing space to service future expected allocations without having
1219 to re-obtain memory from the system.
1220
1221 Malloc_trim returns 1 if it actually released any memory, else 0.
1222 */
1223 DLMALLOC_EXPORT int dlmalloc_trim(size_t);
1224
1225 /*
1226 malloc_stats();
1227 Prints on stderr the amount of space obtained from the system (both
1228 via sbrk and mmap), the maximum amount (which may be more than
1229 current if malloc_trim and/or munmap got called), and the current
1230 number of bytes allocated via malloc (or realloc, etc) but not yet
1231 freed. Note that this is the number of bytes allocated, not the
1232 number requested. It will be larger than the number requested
1233 because of alignment and bookkeeping overhead. Because it includes
1234 alignment wastage as being in use, this figure may be greater than
1235 zero even when no user-level chunks are allocated.
1236
1237 The reported current and maximum system memory can be inaccurate if
1238 a program makes other calls to system memory allocation functions
1239 (normally sbrk) outside of malloc.
1240
1241 malloc_stats prints only the most commonly interesting statistics.
1242 More information can be obtained by calling mallinfo.
1243 */
1244 DLMALLOC_EXPORT void dlmalloc_stats(void);
1245
1246 /*
1247 malloc_usable_size(void* p);
1248
1249 Returns the number of bytes you can actually use in
1250 an allocated chunk, which may be more than you requested (although
1251 often not) due to alignment and minimum size constraints.
1252 You can use this many bytes without worrying about
1253 overwriting other allocated objects. This is not a particularly great
1254 programming practice. malloc_usable_size can be more useful in
1255 debugging and assertions, for example:
1256
1257 p = malloc(n);
1258 assert(malloc_usable_size(p) >= 256);
1259 */
1260 size_t dlmalloc_usable_size(void*);
1261
1262 #endif /* ONLY_MSPACES */
1263
1264 #if MSPACES
1265
1266 /*
1267 mspace is an opaque type representing an independent
1268 region of space that supports mspace_malloc, etc.
1269 */
1270 typedef void* mspace;
1271
1272 /*
1273 create_mspace creates and returns a new independent space with the
1274 given initial capacity, or, if 0, the default granularity size. It
1275 returns null if there is no system memory available to create the
1276 space. If argument locked is non-zero, the space uses a separate
1277 lock to control access. The capacity of the space will grow
1278 dynamically as needed to service mspace_malloc requests. You can
1279 control the sizes of incremental increases of this space by
1280 compiling with a different DEFAULT_GRANULARITY or dynamically
1281 setting with mallopt(M_GRANULARITY, value).
1282 */
1283 DLMALLOC_EXPORT mspace create_mspace(size_t capacity, int locked);
1284
1285 /*
1286 destroy_mspace destroys the given space, and attempts to return all
1287 of its memory back to the system, returning the total number of
1288 bytes freed. After destruction, the results of access to all memory
1289 used by the space become undefined.
1290 */
1291 DLMALLOC_EXPORT size_t destroy_mspace(mspace msp);
1292
1293 /*
1294 create_mspace_with_base uses the memory supplied as the initial base
1295 of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
1296 space is used for bookkeeping, so the capacity must be at least this
1297 large. (Otherwise 0 is returned.) When this initial space is
1298 exhausted, additional memory will be obtained from the system.
1299 Destroying this space will deallocate all additionally allocated
1300 space (if possible) but not the initial base.
1301 */
1302 DLMALLOC_EXPORT mspace create_mspace_with_base(void* base, size_t capacity, int locked);
1303
1304 /*
1305 mspace_track_large_chunks controls whether requests for large chunks
1306 are allocated in their own untracked mmapped regions, separate from
1307 others in this mspace. By default large chunks are not tracked,
1308 which reduces fragmentation. However, such chunks are not
1309 necessarily released to the system upon destroy_mspace. Enabling
1310 tracking by setting to true may increase fragmentation, but avoids
1311 leakage when relying on destroy_mspace to release all memory
1312 allocated using this space. The function returns the previous
1313 setting.
1314 */
1315 DLMALLOC_EXPORT int mspace_track_large_chunks(mspace msp, int enable);
1316
1317
1318 /*
1319 mspace_malloc behaves as malloc, but operates within
1320 the given space.
1321 */
1322 DLMALLOC_EXPORT void* mspace_malloc(mspace msp, size_t bytes);
1323
1324 /*
1325 mspace_free behaves as free, but operates within
1326 the given space.
1327
1328 If compiled with FOOTERS==1, mspace_free is not actually needed.
1329 free may be called instead of mspace_free because freed chunks from
1330 any space are handled by their originating spaces.
1331 */
1332 DLMALLOC_EXPORT void mspace_free(mspace msp, void* mem);
1333
1334 /*
1335 mspace_realloc behaves as realloc, but operates within
1336 the given space.
1337
1338 If compiled with FOOTERS==1, mspace_realloc is not actually
1339 needed. realloc may be called instead of mspace_realloc because
1340 realloced chunks from any space are handled by their originating
1341 spaces.
1342 */
1343 DLMALLOC_EXPORT void* mspace_realloc(mspace msp, void* mem, size_t newsize);
1344
1345 /*
1346 mspace_calloc behaves as calloc, but operates within
1347 the given space.
1348 */
1349 DLMALLOC_EXPORT void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
1350
1351 /*
1352 mspace_memalign behaves as memalign, but operates within
1353 the given space.
1354 */
1355 DLMALLOC_EXPORT void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
1356
1357 /*
1358 mspace_independent_calloc behaves as independent_calloc, but
1359 operates within the given space.
1360 */
1361 DLMALLOC_EXPORT void** mspace_independent_calloc(mspace msp, size_t n_elements,
1362 size_t elem_size, void* chunks[]);
1363
1364 /*
1365 mspace_independent_comalloc behaves as independent_comalloc, but
1366 operates within the given space.
1367 */
1368 DLMALLOC_EXPORT void** mspace_independent_comalloc(mspace msp, size_t n_elements,
1369 size_t sizes[], void* chunks[]);
1370
1371 /*
1372 mspace_footprint() returns the number of bytes obtained from the
1373 system for this space.
1374 */
1375 DLMALLOC_EXPORT size_t mspace_footprint(mspace msp);
1376
1377 /*
1378 mspace_max_footprint() returns the peak number of bytes obtained from the
1379 system for this space.
1380 */
1381 DLMALLOC_EXPORT size_t mspace_max_footprint(mspace msp);
1382
1383
1384 #if !NO_MALLINFO
1385 /*
1386 mspace_mallinfo behaves as mallinfo, but reports properties of
1387 the given space.
1388 */
1389 DLMALLOC_EXPORT struct mallinfo mspace_mallinfo(mspace msp);
1390 #endif /* NO_MALLINFO */
1391
1392 /*
1393 malloc_usable_size(void* p) behaves the same as malloc_usable_size;
1394 */
1395 DLMALLOC_EXPORT size_t mspace_usable_size(const void* mem);
1396
1397 /*
1398 mspace_malloc_stats behaves as malloc_stats, but reports
1399 properties of the given space.
1400 */
1401 DLMALLOC_EXPORT void mspace_malloc_stats(mspace msp);
1402
1403 /*
1404 mspace_trim behaves as malloc_trim, but
1405 operates within the given space.
1406 */
1407 DLMALLOC_EXPORT int mspace_trim(mspace msp, size_t pad);
1408
1409 /*
1410 An alias for mallopt.
1411 */
1412 DLMALLOC_EXPORT int mspace_mallopt(int, int);
1413
1414 #endif /* MSPACES */
1415
1416 #ifdef __cplusplus
1417 } /* end of extern "C" */
1418 #endif /* __cplusplus */
1419
1420 /*
1421 ========================================================================
1422 To make a fully customizable malloc.h header file, cut everything
1423 above this line, put into file malloc.h, edit to suit, and #include it
1424 on the next line, as well as in programs that use this malloc.
1425 ========================================================================
1426 */
1427
1428 /* #include "malloc.h" */
1429
1430 /*------------------------------ internal #includes ---------------------- */
1431
1432 #ifdef _MSC_VER
1433 #pragma warning( disable : 4146 ) /* no "unsigned" warnings */
1434 #endif /* _MSC_VER */
1435 #if !NO_MALLOC_STATS
1436 #include <stdio.h> /* for printing in malloc_stats */
1437 #endif /* NO_MALLOC_STATS */
1438 #ifndef LACKS_ERRNO_H
1439 #include <errno.h> /* for MALLOC_FAILURE_ACTION */
1440 #endif /* LACKS_ERRNO_H */
1441 #ifdef DEBUG
1442 #if ABORT_ON_ASSERT_FAILURE
1443 #undef assert
1444 #define assert(x) if(!(x)) ABORT
1445 #else /* ABORT_ON_ASSERT_FAILURE */
1446 #include <assert.h>
1447 #endif /* ABORT_ON_ASSERT_FAILURE */
1448 #else /* DEBUG */
1449 #ifndef assert
1450 #define assert(x)
1451 #endif
1452 #define DEBUG 0
1453 #endif /* DEBUG */
1454 #if !defined(WIN32) && !defined(LACKS_TIME_H)
1455 #include <time.h> /* for magic initialization */
1456 #endif /* WIN32 */
1457 #ifndef LACKS_STDLIB_H
1458 #include <stdlib.h> /* for abort() */
1459 #endif /* LACKS_STDLIB_H */
1460 #ifndef LACKS_STRING_H
1461 #include <string.h> /* for memset etc */
1462 #endif /* LACKS_STRING_H */
1463 #if USE_BUILTIN_FFS
1464 #ifndef LACKS_STRINGS_H
1465 #include <strings.h> /* for ffs */
1466 #endif /* LACKS_STRINGS_H */
1467 #endif /* USE_BUILTIN_FFS */
1468 #if HAVE_MMAP
1469 #ifndef LACKS_SYS_MMAN_H
1470 /* On some versions of linux, mremap decl in mman.h needs __USE_GNU set */
1471 #if (defined(linux) && !defined(__USE_GNU))
1472 #define __USE_GNU 1
1473 #include <sys/mman.h> /* for mmap */
1474 #undef __USE_GNU
1475 #else
1476 #include <sys/mman.h> /* for mmap */
1477 #endif /* linux */
1478 #endif /* LACKS_SYS_MMAN_H */
1479 #ifndef LACKS_FCNTL_H
1480 #include <fcntl.h>
1481 #endif /* LACKS_FCNTL_H */
1482 #endif /* HAVE_MMAP */
1483 #ifndef LACKS_UNISTD_H
1484 #include <unistd.h> /* for sbrk, sysconf */
1485 #else /* LACKS_UNISTD_H */
1486 #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && \
1487 !defined(__DragonFly__)
1488 extern void* sbrk(ptrdiff_t);
1489 #endif /* FreeBSD etc */
1490 #endif /* LACKS_UNISTD_H */
1491
1492 /* Declarations for locking */
1493 #if USE_LOCKS
1494 #ifndef WIN32
1495 #if defined (__SVR4) && defined (__sun) /* solaris */
1496 #include <thread.h>
1497 #elif !defined(LACKS_SCHED_H)
1498 #include <sched.h>
1499 #endif /* solaris or LACKS_SCHED_H */
1500 #if (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0) || !USE_SPIN_LOCKS
1501 #include <pthread.h>
1502 #endif /* USE_RECURSIVE_LOCKS ... */
1503 #elif defined(_MSC_VER)
1504 #ifndef _M_AMD64
1505 /* These are already defined on AMD64 builds */
1506 #ifdef __cplusplus
1507 extern "C" {
1508 #endif /* __cplusplus */
1509 LONG __cdecl _InterlockedCompareExchange(LONG volatile *Dest, LONG Exchange, LONG Comp);
1510 LONG __cdecl _InterlockedExchange(LONG volatile *Target, LONG Value);
1511 #ifdef __cplusplus
1512 }
1513 #endif /* __cplusplus */
1514 #endif /* _M_AMD64 */
1515 #pragma intrinsic (_InterlockedCompareExchange)
1516 #pragma intrinsic (_InterlockedExchange)
1517 #define interlockedcompareexchange _InterlockedCompareExchange
1518 #define interlockedexchange _InterlockedExchange
1519 #elif defined(WIN32) && defined(__GNUC__)
1520 #define interlockedcompareexchange(a, b, c) __sync_val_compare_and_swap(a, c, b)
1521 #define interlockedexchange __sync_lock_test_and_set
1522 #endif /* Win32 */
1523 #else /* USE_LOCKS */
1524 #endif /* USE_LOCKS */
1525
1526 #ifndef LOCK_AT_FORK
1527 #define LOCK_AT_FORK 0
1528 #endif
1529
1530 /* Declarations for bit scanning on win32 */
1531 #if defined(_MSC_VER) && _MSC_VER>=1300
1532 #ifndef BitScanForward /* Try to avoid pulling in WinNT.h */
1533 #ifdef __cplusplus
1534 extern "C" {
1535 #endif /* __cplusplus */
1536 unsigned char _BitScanForward(unsigned long *index, unsigned long mask);
1537 unsigned char _BitScanReverse(unsigned long *index, unsigned long mask);
1538 #ifdef __cplusplus
1539 }
1540 #endif /* __cplusplus */
1541
1542 #define BitScanForward _BitScanForward
1543 #define BitScanReverse _BitScanReverse
1544 #pragma intrinsic(_BitScanForward)
1545 #pragma intrinsic(_BitScanReverse)
1546 #endif /* BitScanForward */
1547 #endif /* defined(_MSC_VER) && _MSC_VER>=1300 */
1548
1549 #ifndef WIN32
1550 #ifndef malloc_getpagesize
1551 # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */
1552 # ifndef _SC_PAGE_SIZE
1553 # define _SC_PAGE_SIZE _SC_PAGESIZE
1554 # endif
1555 # endif
1556 # ifdef _SC_PAGE_SIZE
1557 # define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
1558 # else
1559 # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
1560 extern size_t getpagesize();
1561 # define malloc_getpagesize getpagesize()
1562 # else
1563 # ifdef WIN32 /* use supplied emulation of getpagesize */
1564 # define malloc_getpagesize getpagesize()
1565 # else
1566 # ifndef LACKS_SYS_PARAM_H
1567 # include <sys/param.h>
1568 # endif
1569 # ifdef EXEC_PAGESIZE
1570 # define malloc_getpagesize EXEC_PAGESIZE
1571 # else
1572 # ifdef NBPG
1573 # ifndef CLSIZE
1574 # define malloc_getpagesize NBPG
1575 # else
1576 # define malloc_getpagesize (NBPG * CLSIZE)
1577 # endif
1578 # else
1579 # ifdef NBPC
1580 # define malloc_getpagesize NBPC
1581 # else
1582 # ifdef PAGESIZE
1583 # define malloc_getpagesize PAGESIZE
1584 # else /* just guess */
1585 # define malloc_getpagesize ((size_t)4096U)
1586 # endif
1587 # endif
1588 # endif
1589 # endif
1590 # endif
1591 # endif
1592 # endif
1593 #endif
1594 #endif
1595
1596 /* ------------------- size_t and alignment properties -------------------- */
1597
1598 /* The byte and bit size of a size_t */
1599 #define SIZE_T_SIZE (sizeof(size_t))
1600 #define SIZE_T_BITSIZE (sizeof(size_t) << 3)
1601
1602 /* Some constants coerced to size_t */
1603 /* Annoying but necessary to avoid errors on some platforms */
1604 #define SIZE_T_ZERO ((size_t)0)
1605 #define SIZE_T_ONE ((size_t)1)
1606 #define SIZE_T_TWO ((size_t)2)
1607 #define SIZE_T_FOUR ((size_t)4)
1608 #define TWO_SIZE_T_SIZES (SIZE_T_SIZE<<1)
1609 #define FOUR_SIZE_T_SIZES (SIZE_T_SIZE<<2)
1610 #define SIX_SIZE_T_SIZES (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
1611 #define HALF_MAX_SIZE_T (MAX_SIZE_T / 2U)
1612
1613 /* The bit mask value corresponding to MALLOC_ALIGNMENT */
1614 #define CHUNK_ALIGN_MASK (MALLOC_ALIGNMENT - SIZE_T_ONE)
1615
1616 /* True if address a has acceptable alignment */
1617 #define is_aligned(A) (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
1618
1619 /* the number of bytes to offset an address to align it */
1620 #define align_offset(A)\
1621 ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
1622 ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
1623
1624 /* -------------------------- MMAP preliminaries ------------------------- */
1625
1626 /*
1627 If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
1628 checks to fail so compiler optimizer can delete code rather than
1629 using so many "#if"s.
1630 */
1631
1632
1633 /* MORECORE and MMAP must return MFAIL on failure */
1634 #define MFAIL ((void*)(MAX_SIZE_T))
1635 #define CMFAIL ((char*)(MFAIL)) /* defined for convenience */
1636
1637 #if HAVE_MMAP
1638
1639 #ifndef WIN32
1640 #define MUNMAP_DEFAULT(a, s) munmap((a), (s))
1641 #define MMAP_PROT (PROT_READ|PROT_WRITE)
1642 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
1643 #define MAP_ANONYMOUS MAP_ANON
1644 #endif /* MAP_ANON */
1645 #ifdef MAP_ANONYMOUS
1646 #define MMAP_FLAGS (MAP_PRIVATE|MAP_ANONYMOUS)
1647 #define MMAP_DEFAULT(s) mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
1648 #else /* MAP_ANONYMOUS */
1649 /*
1650 Nearly all versions of mmap support MAP_ANONYMOUS, so the following
1651 is unlikely to be needed, but is supplied just in case.
1652 */
1653 #define MMAP_FLAGS (MAP_PRIVATE)
1654 static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
1655 #define MMAP_DEFAULT(s) ((dev_zero_fd < 0) ? \
1656 (dev_zero_fd = open("/dev/zero", O_RDWR), \
1657 mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
1658 mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
1659 #endif /* MAP_ANONYMOUS */
1660
1661 #define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s)
1662
1663 #else /* WIN32 */
1664
1665 /* Win32 MMAP via VirtualAlloc */
win32mmap(size_t size)1666 static FORCEINLINE void* win32mmap(size_t size) {
1667 void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
1668 return (ptr != 0)? ptr: MFAIL;
1669 }
1670
1671 /* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
win32direct_mmap(size_t size)1672 static FORCEINLINE void* win32direct_mmap(size_t size) {
1673 void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN,
1674 PAGE_READWRITE);
1675 return (ptr != 0)? ptr: MFAIL;
1676 }
1677
1678 /* This function supports releasing coalesed segments */
win32munmap(void * ptr,size_t size)1679 static FORCEINLINE int win32munmap(void* ptr, size_t size) {
1680 MEMORY_BASIC_INFORMATION minfo;
1681 char* cptr = (char*)ptr;
1682 while (size) {
1683 if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
1684 return -1;
1685 if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
1686 minfo.State != MEM_COMMIT || minfo.RegionSize > size)
1687 return -1;
1688 if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
1689 return -1;
1690 cptr += minfo.RegionSize;
1691 size -= minfo.RegionSize;
1692 }
1693 return 0;
1694 }
1695
1696 #define MMAP_DEFAULT(s) win32mmap(s)
1697 #define MUNMAP_DEFAULT(a, s) win32munmap((a), (s))
1698 #define DIRECT_MMAP_DEFAULT(s) win32direct_mmap(s)
1699 #endif /* WIN32 */
1700 #endif /* HAVE_MMAP */
1701
1702 #if HAVE_MREMAP
1703 #ifndef WIN32
1704 #define MREMAP_DEFAULT(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
1705 #endif /* WIN32 */
1706 #endif /* HAVE_MREMAP */
1707
1708 /**
1709 * Define CALL_MORECORE
1710 */
1711 #if HAVE_MORECORE
1712 #ifdef MORECORE
1713 #define CALL_MORECORE(S) MORECORE(S)
1714 #else /* MORECORE */
1715 #define CALL_MORECORE(S) MORECORE_DEFAULT(S)
1716 #endif /* MORECORE */
1717 #else /* HAVE_MORECORE */
1718 #define CALL_MORECORE(S) MFAIL
1719 #endif /* HAVE_MORECORE */
1720
1721 /**
1722 * Define CALL_MMAP/CALL_MUNMAP/CALL_DIRECT_MMAP
1723 */
1724 #if HAVE_MMAP
1725 #define USE_MMAP_BIT (SIZE_T_ONE)
1726
1727 #ifdef MMAP
1728 #define CALL_MMAP(s) MMAP(s)
1729 #else /* MMAP */
1730 #define CALL_MMAP(s) MMAP_DEFAULT(s)
1731 #endif /* MMAP */
1732 #ifdef MUNMAP
1733 #define CALL_MUNMAP(a, s) MUNMAP((a), (s))
1734 #else /* MUNMAP */
1735 #define CALL_MUNMAP(a, s) MUNMAP_DEFAULT((a), (s))
1736 #endif /* MUNMAP */
1737 #ifdef DIRECT_MMAP
1738 #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s)
1739 #else /* DIRECT_MMAP */
1740 #define CALL_DIRECT_MMAP(s) DIRECT_MMAP_DEFAULT(s)
1741 #endif /* DIRECT_MMAP */
1742 #else /* HAVE_MMAP */
1743 #define USE_MMAP_BIT (SIZE_T_ZERO)
1744
1745 #define MMAP(s) MFAIL
1746 #define MUNMAP(a, s) (-1)
1747 #define DIRECT_MMAP(s) MFAIL
1748 #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s)
1749 #define CALL_MMAP(s) MMAP(s)
1750 #define CALL_MUNMAP(a, s) MUNMAP((a), (s))
1751 #endif /* HAVE_MMAP */
1752
1753 /**
1754 * Define CALL_MREMAP
1755 */
1756 #if HAVE_MMAP && HAVE_MREMAP
1757 #ifdef MREMAP
1758 #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP((addr), (osz), (nsz), (mv))
1759 #else /* MREMAP */
1760 #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP_DEFAULT((addr), (osz), (nsz), (mv))
1761 #endif /* MREMAP */
1762 #else /* HAVE_MMAP && HAVE_MREMAP */
1763 #define CALL_MREMAP(addr, osz, nsz, mv) MFAIL
1764 #endif /* HAVE_MMAP && HAVE_MREMAP */
1765
1766 /* mstate bit set if continguous morecore disabled or failed */
1767 #define USE_NONCONTIGUOUS_BIT (4U)
1768
1769 /* segment bit set in create_mspace_with_base */
1770 #define EXTERN_BIT (8U)
1771
1772
1773 /* --------------------------- Lock preliminaries ------------------------ */
1774
1775 /*
1776 When locks are defined, there is one global lock, plus
1777 one per-mspace lock.
1778
1779 The global lock_ensures that mparams.magic and other unique
1780 mparams values are initialized only once. It also protects
1781 sequences of calls to MORECORE. In many cases sys_alloc requires
1782 two calls, that should not be interleaved with calls by other
1783 threads. This does not protect against direct calls to MORECORE
1784 by other threads not using this lock, so there is still code to
1785 cope the best we can on interference.
1786
1787 Per-mspace locks surround calls to malloc, free, etc.
1788 By default, locks are simple non-reentrant mutexes.
1789
1790 Because lock-protected regions generally have bounded times, it is
1791 OK to use the supplied simple spinlocks. Spinlocks are likely to
1792 improve performance for lightly contended applications, but worsen
1793 performance under heavy contention.
1794
1795 If USE_LOCKS is > 1, the definitions of lock routines here are
1796 bypassed, in which case you will need to define the type MLOCK_T,
1797 and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK
1798 and TRY_LOCK. You must also declare a
1799 static MLOCK_T malloc_global_mutex = { initialization values };.
1800
1801 */
1802
1803 #if !USE_LOCKS
1804 #define USE_LOCK_BIT (0U)
1805 #define INITIAL_LOCK(l) (0)
1806 #define DESTROY_LOCK(l) (0)
1807 #define ACQUIRE_MALLOC_GLOBAL_LOCK()
1808 #define RELEASE_MALLOC_GLOBAL_LOCK()
1809
1810 #else
1811 #if USE_LOCKS > 1
1812 /* ----------------------- User-defined locks ------------------------ */
1813 /* Define your own lock implementation here */
1814 /* #define INITIAL_LOCK(lk) ... */
1815 /* #define DESTROY_LOCK(lk) ... */
1816 /* #define ACQUIRE_LOCK(lk) ... */
1817 /* #define RELEASE_LOCK(lk) ... */
1818 /* #define TRY_LOCK(lk) ... */
1819 /* static MLOCK_T malloc_global_mutex = ... */
1820
1821 #elif USE_SPIN_LOCKS
1822
1823 /* First, define CAS_LOCK and CLEAR_LOCK on ints */
1824 /* Note CAS_LOCK defined to return 0 on success */
1825
1826 #if defined(__GNUC__)&& (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
1827 #define CAS_LOCK(sl) __sync_lock_test_and_set(sl, 1)
1828 #define CLEAR_LOCK(sl) __sync_lock_release(sl)
1829
1830 #elif (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
1831 /* Custom spin locks for older gcc on x86 */
x86_cas_lock(int * sl)1832 static FORCEINLINE int x86_cas_lock(int *sl) {
1833 int ret;
1834 int val = 1;
1835 int cmp = 0;
1836 __asm__ __volatile__ ("lock; cmpxchgl %1, %2"
1837 : "=a" (ret)
1838 : "r" (val), "m" (*(sl)), "0"(cmp)
1839 : "memory", "cc");
1840 return ret;
1841 }
1842
x86_clear_lock(int * sl)1843 static FORCEINLINE void x86_clear_lock(int* sl) {
1844 assert(*sl != 0);
1845 int prev = 0;
1846 int ret;
1847 __asm__ __volatile__ ("lock; xchgl %0, %1"
1848 : "=r" (ret)
1849 : "m" (*(sl)), "0"(prev)
1850 : "memory");
1851 }
1852
1853 #define CAS_LOCK(sl) x86_cas_lock(sl)
1854 #define CLEAR_LOCK(sl) x86_clear_lock(sl)
1855
1856 #else /* Win32 MSC */
1857 #define CAS_LOCK(sl) interlockedexchange(sl, (LONG)1)
1858 #define CLEAR_LOCK(sl) interlockedexchange (sl, (LONG)0)
1859
1860 #endif /* ... gcc spins locks ... */
1861
1862 /* How to yield for a spin lock */
1863 #define SPINS_PER_YIELD 63
1864 #if defined(_MSC_VER)
1865 #define SLEEP_EX_DURATION 50 /* delay for yield/sleep */
1866 #define SPIN_LOCK_YIELD SleepEx(SLEEP_EX_DURATION, FALSE)
1867 #elif defined (__SVR4) && defined (__sun) /* solaris */
1868 #define SPIN_LOCK_YIELD thr_yield();
1869 #elif !defined(LACKS_SCHED_H)
1870 #define SPIN_LOCK_YIELD sched_yield();
1871 #else
1872 #define SPIN_LOCK_YIELD
1873 #endif /* ... yield ... */
1874
1875 #if !defined(USE_RECURSIVE_LOCKS) || USE_RECURSIVE_LOCKS == 0
1876 /* Plain spin locks use single word (embedded in malloc_states) */
spin_acquire_lock(int * sl)1877 static int spin_acquire_lock(int *sl) {
1878 int spins = 0;
1879 while (*(volatile int *)sl != 0 || CAS_LOCK(sl)) {
1880 if ((++spins & SPINS_PER_YIELD) == 0) {
1881 SPIN_LOCK_YIELD;
1882 }
1883 }
1884 return 0;
1885 }
1886
1887 #define MLOCK_T int
1888 #define TRY_LOCK(sl) !CAS_LOCK(sl)
1889 #define RELEASE_LOCK(sl) CLEAR_LOCK(sl)
1890 #define ACQUIRE_LOCK(sl) (CAS_LOCK(sl)? spin_acquire_lock(sl) : 0)
1891 #define INITIAL_LOCK(sl) (*sl = 0)
1892 #define DESTROY_LOCK(sl) (0)
1893 static MLOCK_T malloc_global_mutex = 0;
1894
1895 #else /* USE_RECURSIVE_LOCKS */
1896 /* types for lock owners */
1897 #ifdef WIN32
1898 #define THREAD_ID_T DWORD
1899 #define CURRENT_THREAD GetCurrentThreadId()
1900 #define EQ_OWNER(X,Y) ((X) == (Y))
1901 #else
1902 /*
1903 Note: the following assume that pthread_t is a type that can be
1904 initialized to (casted) zero. If this is not the case, you will need to
1905 somehow redefine these or not use spin locks.
1906 */
1907 #define THREAD_ID_T pthread_t
1908 #define CURRENT_THREAD pthread_self()
1909 #define EQ_OWNER(X,Y) pthread_equal(X, Y)
1910 #endif
1911
1912 struct malloc_recursive_lock {
1913 int sl;
1914 unsigned int c;
1915 THREAD_ID_T threadid;
1916 };
1917
1918 #define MLOCK_T struct malloc_recursive_lock
1919 static MLOCK_T malloc_global_mutex = { 0, 0, (THREAD_ID_T)0};
1920
recursive_release_lock(MLOCK_T * lk)1921 static FORCEINLINE void recursive_release_lock(MLOCK_T *lk) {
1922 assert(lk->sl != 0);
1923 if (--lk->c == 0) {
1924 CLEAR_LOCK(&lk->sl);
1925 }
1926 }
1927
recursive_acquire_lock(MLOCK_T * lk)1928 static FORCEINLINE int recursive_acquire_lock(MLOCK_T *lk) {
1929 THREAD_ID_T mythreadid = CURRENT_THREAD;
1930 int spins = 0;
1931 for (;;) {
1932 if (*((volatile int *)(&lk->sl)) == 0) {
1933 if (!CAS_LOCK(&lk->sl)) {
1934 lk->threadid = mythreadid;
1935 lk->c = 1;
1936 return 0;
1937 }
1938 }
1939 else if (EQ_OWNER(lk->threadid, mythreadid)) {
1940 ++lk->c;
1941 return 0;
1942 }
1943 if ((++spins & SPINS_PER_YIELD) == 0) {
1944 SPIN_LOCK_YIELD;
1945 }
1946 }
1947 }
1948
recursive_try_lock(MLOCK_T * lk)1949 static FORCEINLINE int recursive_try_lock(MLOCK_T *lk) {
1950 THREAD_ID_T mythreadid = CURRENT_THREAD;
1951 if (*((volatile int *)(&lk->sl)) == 0) {
1952 if (!CAS_LOCK(&lk->sl)) {
1953 lk->threadid = mythreadid;
1954 lk->c = 1;
1955 return 1;
1956 }
1957 }
1958 else if (EQ_OWNER(lk->threadid, mythreadid)) {
1959 ++lk->c;
1960 return 1;
1961 }
1962 return 0;
1963 }
1964
1965 #define RELEASE_LOCK(lk) recursive_release_lock(lk)
1966 #define TRY_LOCK(lk) recursive_try_lock(lk)
1967 #define ACQUIRE_LOCK(lk) recursive_acquire_lock(lk)
1968 #define INITIAL_LOCK(lk) ((lk)->threadid = (THREAD_ID_T)0, (lk)->sl = 0, (lk)->c = 0)
1969 #define DESTROY_LOCK(lk) (0)
1970 #endif /* USE_RECURSIVE_LOCKS */
1971
1972 #elif defined(WIN32) /* Win32 critical sections */
1973 #define MLOCK_T CRITICAL_SECTION
1974 #define ACQUIRE_LOCK(lk) (EnterCriticalSection(lk), 0)
1975 #define RELEASE_LOCK(lk) LeaveCriticalSection(lk)
1976 #define TRY_LOCK(lk) TryEnterCriticalSection(lk)
1977 #define INITIAL_LOCK(lk) (!InitializeCriticalSectionAndSpinCount((lk), 0x80000000|4000))
1978 #define DESTROY_LOCK(lk) (DeleteCriticalSection(lk), 0)
1979 #define NEED_GLOBAL_LOCK_INIT
1980
1981 static MLOCK_T malloc_global_mutex;
1982 static volatile LONG malloc_global_mutex_status;
1983
1984 /* Use spin loop to initialize global lock */
init_malloc_global_mutex()1985 static void init_malloc_global_mutex() {
1986 for (;;) {
1987 long stat = malloc_global_mutex_status;
1988 if (stat > 0)
1989 return;
1990 /* transition to < 0 while initializing, then to > 0) */
1991 if (stat == 0 &&
1992 interlockedcompareexchange(&malloc_global_mutex_status, (LONG)-1, (LONG)0) == 0) {
1993 InitializeCriticalSection(&malloc_global_mutex);
1994 interlockedexchange(&malloc_global_mutex_status, (LONG)1);
1995 return;
1996 }
1997 SleepEx(0, FALSE);
1998 }
1999 }
2000
2001 #else /* pthreads-based locks */
2002 #define MLOCK_T pthread_mutex_t
2003 #define ACQUIRE_LOCK(lk) pthread_mutex_lock(lk)
2004 #define RELEASE_LOCK(lk) pthread_mutex_unlock(lk)
2005 #define TRY_LOCK(lk) (!pthread_mutex_trylock(lk))
2006 #define INITIAL_LOCK(lk) pthread_init_lock(lk)
2007 #define DESTROY_LOCK(lk) pthread_mutex_destroy(lk)
2008
2009 #if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0 && defined(linux) && !defined(PTHREAD_MUTEX_RECURSIVE)
2010 /* Cope with old-style linux recursive lock initialization by adding */
2011 /* skipped internal declaration from pthread.h */
2012 extern int pthread_mutexattr_setkind_np __P ((pthread_mutexattr_t *__attr,
2013 int __kind));
2014 #define PTHREAD_MUTEX_RECURSIVE PTHREAD_MUTEX_RECURSIVE_NP
2015 #define pthread_mutexattr_settype(x,y) pthread_mutexattr_setkind_np(x,y)
2016 #endif /* USE_RECURSIVE_LOCKS ... */
2017
2018 static MLOCK_T malloc_global_mutex = PTHREAD_MUTEX_INITIALIZER;
2019
pthread_init_lock(MLOCK_T * lk)2020 static int pthread_init_lock (MLOCK_T *lk) {
2021 pthread_mutexattr_t attr;
2022 if (pthread_mutexattr_init(&attr)) return 1;
2023 #if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0
2024 if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) return 1;
2025 #endif
2026 if (pthread_mutex_init(lk, &attr)) return 1;
2027 if (pthread_mutexattr_destroy(&attr)) return 1;
2028 return 0;
2029 }
2030
2031 #endif /* ... lock types ... */
2032
2033 /* Common code for all lock types */
2034 #define USE_LOCK_BIT (2U)
2035
2036 #ifndef ACQUIRE_MALLOC_GLOBAL_LOCK
2037 #define ACQUIRE_MALLOC_GLOBAL_LOCK() ACQUIRE_LOCK(&malloc_global_mutex);
2038 #endif
2039
2040 #ifndef RELEASE_MALLOC_GLOBAL_LOCK
2041 #define RELEASE_MALLOC_GLOBAL_LOCK() RELEASE_LOCK(&malloc_global_mutex);
2042 #endif
2043
2044 #endif /* USE_LOCKS */
2045
2046 /* ----------------------- Chunk representations ------------------------ */
2047
2048 /*
2049 (The following includes lightly edited explanations by Colin Plumb.)
2050
2051 The malloc_chunk declaration below is misleading (but accurate and
2052 necessary). It declares a "view" into memory allowing access to
2053 necessary fields at known offsets from a given base.
2054
2055 Chunks of memory are maintained using a `boundary tag' method as
2056 originally described by Knuth. (See the paper by Paul Wilson
2057 ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
2058 techniques.) Sizes of free chunks are stored both in the front of
2059 each chunk and at the end. This makes consolidating fragmented
2060 chunks into bigger chunks fast. The head fields also hold bits
2061 representing whether chunks are free or in use.
2062
2063 Here are some pictures to make it clearer. They are "exploded" to
2064 show that the state of a chunk can be thought of as extending from
2065 the high 31 bits of the head field of its header through the
2066 prev_foot and PINUSE_BIT bit of the following chunk header.
2067
2068 A chunk that's in use looks like:
2069
2070 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2071 | Size of previous chunk (if P = 0) |
2072 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2073 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
2074 | Size of this chunk 1| +-+
2075 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2076 | |
2077 +- -+
2078 | |
2079 +- -+
2080 | :
2081 +- size - sizeof(size_t) available payload bytes -+
2082 : |
2083 chunk-> +- -+
2084 | |
2085 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2086 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
2087 | Size of next chunk (may or may not be in use) | +-+
2088 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2089
2090 And if it's free, it looks like this:
2091
2092 chunk-> +- -+
2093 | User payload (must be in use, or we would have merged!) |
2094 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2095 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
2096 | Size of this chunk 0| +-+
2097 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2098 | Next pointer |
2099 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2100 | Prev pointer |
2101 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2102 | :
2103 +- size - sizeof(struct chunk) unused bytes -+
2104 : |
2105 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2106 | Size of this chunk |
2107 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2108 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
2109 | Size of next chunk (must be in use, or we would have merged)| +-+
2110 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2111 | :
2112 +- User payload -+
2113 : |
2114 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2115 |0|
2116 +-+
2117 Note that since we always merge adjacent free chunks, the chunks
2118 adjacent to a free chunk must be in use.
2119
2120 Given a pointer to a chunk (which can be derived trivially from the
2121 payload pointer) we can, in O(1) time, find out whether the adjacent
2122 chunks are free, and if so, unlink them from the lists that they
2123 are on and merge them with the current chunk.
2124
2125 Chunks always begin on even word boundaries, so the mem portion
2126 (which is returned to the user) is also on an even word boundary, and
2127 thus at least double-word aligned.
2128
2129 The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
2130 chunk size (which is always a multiple of two words), is an in-use
2131 bit for the *previous* chunk. If that bit is *clear*, then the
2132 word before the current chunk size contains the previous chunk
2133 size, and can be used to find the front of the previous chunk.
2134 The very first chunk allocated always has this bit set, preventing
2135 access to non-existent (or non-owned) memory. If pinuse is set for
2136 any given chunk, then you CANNOT determine the size of the
2137 previous chunk, and might even get a memory addressing fault when
2138 trying to do so.
2139
2140 The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
2141 the chunk size redundantly records whether the current chunk is
2142 inuse (unless the chunk is mmapped). This redundancy enables usage
2143 checks within free and realloc, and reduces indirection when freeing
2144 and consolidating chunks.
2145
2146 Each freshly allocated chunk must have both cinuse and pinuse set.
2147 That is, each allocated chunk borders either a previously allocated
2148 and still in-use chunk, or the base of its memory arena. This is
2149 ensured by making all allocations from the `lowest' part of any
2150 found chunk. Further, no free chunk physically borders another one,
2151 so each free chunk is known to be preceded and followed by either
2152 inuse chunks or the ends of memory.
2153
2154 Note that the `foot' of the current chunk is actually represented
2155 as the prev_foot of the NEXT chunk. This makes it easier to
2156 deal with alignments etc but can be very confusing when trying
2157 to extend or adapt this code.
2158
2159 The exceptions to all this are
2160
2161 1. The special chunk `top' is the top-most available chunk (i.e.,
2162 the one bordering the end of available memory). It is treated
2163 specially. Top is never included in any bin, is used only if
2164 no other chunk is available, and is released back to the
2165 system if it is very large (see M_TRIM_THRESHOLD). In effect,
2166 the top chunk is treated as larger (and thus less well
2167 fitting) than any other available chunk. The top chunk
2168 doesn't update its trailing size field since there is no next
2169 contiguous chunk that would have to index off it. However,
2170 space is still allocated for it (TOP_FOOT_SIZE) to enable
2171 separation or merging when space is extended.
2172
2173 3. Chunks allocated via mmap, have both cinuse and pinuse bits
2174 cleared in their head fields. Because they are allocated
2175 one-by-one, each must carry its own prev_foot field, which is
2176 also used to hold the offset this chunk has within its mmapped
2177 region, which is needed to preserve alignment. Each mmapped
2178 chunk is trailed by the first two fields of a fake next-chunk
2179 for sake of usage checks.
2180
2181 */
2182
2183 struct malloc_chunk {
2184 size_t prev_foot; /* Size of previous chunk (if free). */
2185 size_t head; /* Size and inuse bits. */
2186 struct malloc_chunk* fd; /* double links -- used only if free. */
2187 struct malloc_chunk* bk;
2188 };
2189
2190 typedef struct malloc_chunk mchunk;
2191 typedef struct malloc_chunk* mchunkptr;
2192 typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */
2193 typedef unsigned int bindex_t; /* Described below */
2194 typedef unsigned int binmap_t; /* Described below */
2195 typedef unsigned int flag_t; /* The type of various bit flag sets */
2196
2197 /* ------------------- Chunks sizes and alignments ----------------------- */
2198
2199 #define MCHUNK_SIZE (sizeof(mchunk))
2200
2201 #if FOOTERS
2202 #define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
2203 #else /* FOOTERS */
2204 #define CHUNK_OVERHEAD (SIZE_T_SIZE)
2205 #endif /* FOOTERS */
2206
2207 /* MMapped chunks need a second word of overhead ... */
2208 #define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
2209 /* ... and additional padding for fake next-chunk at foot */
2210 #define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES)
2211
2212 /* The smallest size we can malloc is an aligned minimal chunk */
2213 #define MIN_CHUNK_SIZE\
2214 ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
2215
2216 /* conversion from malloc headers to user pointers, and back */
2217 #define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES))
2218 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
2219 /* chunk associated with aligned address A */
2220 #define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A)))
2221
2222 /* Bounds on request (not chunk) sizes. */
2223 #define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2)
2224 #define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
2225
2226 /* pad request bytes into a usable size */
2227 #define pad_request(req) \
2228 (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
2229
2230 /* pad request, checking for minimum (but not maximum) */
2231 #define request2size(req) \
2232 (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
2233
2234
2235 /* ------------------ Operations on head and foot fields ----------------- */
2236
2237 /*
2238 The head field of a chunk is or'ed with PINUSE_BIT when previous
2239 adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
2240 use, unless mmapped, in which case both bits are cleared.
2241
2242 FLAG4_BIT is not used by this malloc, but might be useful in extensions.
2243 */
2244
2245 #define PINUSE_BIT (SIZE_T_ONE)
2246 #define CINUSE_BIT (SIZE_T_TWO)
2247 #define FLAG4_BIT (SIZE_T_FOUR)
2248 #define INUSE_BITS (PINUSE_BIT|CINUSE_BIT)
2249 #define FLAG_BITS (PINUSE_BIT|CINUSE_BIT|FLAG4_BIT)
2250
2251 /* Head value for fenceposts */
2252 #define FENCEPOST_HEAD (INUSE_BITS|SIZE_T_SIZE)
2253
2254 /* extraction of fields from head words */
2255 #define cinuse(p) ((p)->head & CINUSE_BIT)
2256 #define pinuse(p) ((p)->head & PINUSE_BIT)
2257 #define flag4inuse(p) ((p)->head & FLAG4_BIT)
2258 #define is_inuse(p) (((p)->head & INUSE_BITS) != PINUSE_BIT)
2259 #define is_mmapped(p) (((p)->head & INUSE_BITS) == 0)
2260
2261 #define chunksize(p) ((p)->head & ~(FLAG_BITS))
2262
2263 #define clear_pinuse(p) ((p)->head &= ~PINUSE_BIT)
2264 #define set_flag4(p) ((p)->head |= FLAG4_BIT)
2265 #define clear_flag4(p) ((p)->head &= ~FLAG4_BIT)
2266
2267 /* Treat space at ptr +/- offset as a chunk */
2268 #define chunk_plus_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
2269 #define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
2270
2271 /* Ptr to next or previous physical malloc_chunk. */
2272 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~FLAG_BITS)))
2273 #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
2274
2275 /* extract next chunk's pinuse bit */
2276 #define next_pinuse(p) ((next_chunk(p)->head) & PINUSE_BIT)
2277
2278 /* Get/set size at footer */
2279 #define get_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot)
2280 #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
2281
2282 /* Set size, pinuse bit, and foot */
2283 #define set_size_and_pinuse_of_free_chunk(p, s)\
2284 ((p)->head = (s|PINUSE_BIT), set_foot(p, s))
2285
2286 /* Set size, pinuse bit, foot, and clear next pinuse */
2287 #define set_free_with_pinuse(p, s, n)\
2288 (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
2289
2290 /* Get the internal overhead associated with chunk p */
2291 #define overhead_for(p)\
2292 (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
2293
2294 /* Return true if malloced space is not necessarily cleared */
2295 #if MMAP_CLEARS
2296 #define calloc_must_clear(p) (!is_mmapped(p))
2297 #else /* MMAP_CLEARS */
2298 #define calloc_must_clear(p) (1)
2299 #endif /* MMAP_CLEARS */
2300
2301 /* ---------------------- Overlaid data structures ----------------------- */
2302
2303 /*
2304 When chunks are not in use, they are treated as nodes of either
2305 lists or trees.
2306
2307 "Small" chunks are stored in circular doubly-linked lists, and look
2308 like this:
2309
2310 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2311 | Size of previous chunk |
2312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2313 `head:' | Size of chunk, in bytes |P|
2314 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2315 | Forward pointer to next chunk in list |
2316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2317 | Back pointer to previous chunk in list |
2318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2319 | Unused space (may be 0 bytes long) .
2320 . .
2321 . |
2322 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2323 `foot:' | Size of chunk, in bytes |
2324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2325
2326 Larger chunks are kept in a form of bitwise digital trees (aka
2327 tries) keyed on chunksizes. Because malloc_tree_chunks are only for
2328 free chunks greater than 256 bytes, their size doesn't impose any
2329 constraints on user chunk sizes. Each node looks like:
2330
2331 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2332 | Size of previous chunk |
2333 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2334 `head:' | Size of chunk, in bytes |P|
2335 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2336 | Forward pointer to next chunk of same size |
2337 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2338 | Back pointer to previous chunk of same size |
2339 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2340 | Pointer to left child (child[0]) |
2341 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2342 | Pointer to right child (child[1]) |
2343 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2344 | Pointer to parent |
2345 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2346 | bin index of this chunk |
2347 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2348 | Unused space .
2349 . |
2350 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2351 `foot:' | Size of chunk, in bytes |
2352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2353
2354 Each tree holding treenodes is a tree of unique chunk sizes. Chunks
2355 of the same size are arranged in a circularly-linked list, with only
2356 the oldest chunk (the next to be used, in our FIFO ordering)
2357 actually in the tree. (Tree members are distinguished by a non-null
2358 parent pointer.) If a chunk with the same size an an existing node
2359 is inserted, it is linked off the existing node using pointers that
2360 work in the same way as fd/bk pointers of small chunks.
2361
2362 Each tree contains a power of 2 sized range of chunk sizes (the
2363 smallest is 0x100 <= x < 0x180), which is is divided in half at each
2364 tree level, with the chunks in the smaller half of the range (0x100
2365 <= x < 0x140 for the top nose) in the left subtree and the larger
2366 half (0x140 <= x < 0x180) in the right subtree. This is, of course,
2367 done by inspecting individual bits.
2368
2369 Using these rules, each node's left subtree contains all smaller
2370 sizes than its right subtree. However, the node at the root of each
2371 subtree has no particular ordering relationship to either. (The
2372 dividing line between the subtree sizes is based on trie relation.)
2373 If we remove the last chunk of a given size from the interior of the
2374 tree, we need to replace it with a leaf node. The tree ordering
2375 rules permit a node to be replaced by any leaf below it.
2376
2377 The smallest chunk in a tree (a common operation in a best-fit
2378 allocator) can be found by walking a path to the leftmost leaf in
2379 the tree. Unlike a usual binary tree, where we follow left child
2380 pointers until we reach a null, here we follow the right child
2381 pointer any time the left one is null, until we reach a leaf with
2382 both child pointers null. The smallest chunk in the tree will be
2383 somewhere along that path.
2384
2385 The worst case number of steps to add, find, or remove a node is
2386 bounded by the number of bits differentiating chunks within
2387 bins. Under current bin calculations, this ranges from 6 up to 21
2388 (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
2389 is of course much better.
2390 */
2391
2392 struct malloc_tree_chunk {
2393 /* The first four fields must be compatible with malloc_chunk */
2394 size_t prev_foot;
2395 size_t head;
2396 struct malloc_tree_chunk* fd;
2397 struct malloc_tree_chunk* bk;
2398
2399 struct malloc_tree_chunk* child[2];
2400 struct malloc_tree_chunk* parent;
2401 bindex_t index;
2402 };
2403
2404 typedef struct malloc_tree_chunk tchunk;
2405 typedef struct malloc_tree_chunk* tchunkptr;
2406 typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */
2407
2408 /* A little helper macro for trees */
2409 #define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
2410
2411 /* ----------------------------- Segments -------------------------------- */
2412
2413 /*
2414 Each malloc space may include non-contiguous segments, held in a
2415 list headed by an embedded malloc_segment record representing the
2416 top-most space. Segments also include flags holding properties of
2417 the space. Large chunks that are directly allocated by mmap are not
2418 included in this list. They are instead independently created and
2419 destroyed without otherwise keeping track of them.
2420
2421 Segment management mainly comes into play for spaces allocated by
2422 MMAP. Any call to MMAP might or might not return memory that is
2423 adjacent to an existing segment. MORECORE normally contiguously
2424 extends the current space, so this space is almost always adjacent,
2425 which is simpler and faster to deal with. (This is why MORECORE is
2426 used preferentially to MMAP when both are available -- see
2427 sys_alloc.) When allocating using MMAP, we don't use any of the
2428 hinting mechanisms (inconsistently) supported in various
2429 implementations of unix mmap, or distinguish reserving from
2430 committing memory. Instead, we just ask for space, and exploit
2431 contiguity when we get it. It is probably possible to do
2432 better than this on some systems, but no general scheme seems
2433 to be significantly better.
2434
2435 Management entails a simpler variant of the consolidation scheme
2436 used for chunks to reduce fragmentation -- new adjacent memory is
2437 normally prepended or appended to an existing segment. However,
2438 there are limitations compared to chunk consolidation that mostly
2439 reflect the fact that segment processing is relatively infrequent
2440 (occurring only when getting memory from system) and that we
2441 don't expect to have huge numbers of segments:
2442
2443 * Segments are not indexed, so traversal requires linear scans. (It
2444 would be possible to index these, but is not worth the extra
2445 overhead and complexity for most programs on most platforms.)
2446 * New segments are only appended to old ones when holding top-most
2447 memory; if they cannot be prepended to others, they are held in
2448 different segments.
2449
2450 Except for the top-most segment of an mstate, each segment record
2451 is kept at the tail of its segment. Segments are added by pushing
2452 segment records onto the list headed by &mstate.seg for the
2453 containing mstate.
2454
2455 Segment flags control allocation/merge/deallocation policies:
2456 * If EXTERN_BIT set, then we did not allocate this segment,
2457 and so should not try to deallocate or merge with others.
2458 (This currently holds only for the initial segment passed
2459 into create_mspace_with_base.)
2460 * If USE_MMAP_BIT set, the segment may be merged with
2461 other surrounding mmapped segments and trimmed/de-allocated
2462 using munmap.
2463 * If neither bit is set, then the segment was obtained using
2464 MORECORE so can be merged with surrounding MORECORE'd segments
2465 and deallocated/trimmed using MORECORE with negative arguments.
2466 */
2467
2468 struct malloc_segment {
2469 char* base; /* base address */
2470 size_t size; /* allocated size */
2471 struct malloc_segment* next; /* ptr to next segment */
2472 flag_t sflags; /* mmap and extern flag */
2473 };
2474
2475 #define is_mmapped_segment(S) ((S)->sflags & USE_MMAP_BIT)
2476 #define is_extern_segment(S) ((S)->sflags & EXTERN_BIT)
2477
2478 typedef struct malloc_segment msegment;
2479 typedef struct malloc_segment* msegmentptr;
2480
2481 /* ---------------------------- malloc_state ----------------------------- */
2482
2483 /*
2484 A malloc_state holds all of the bookkeeping for a space.
2485 The main fields are:
2486
2487 Top
2488 The topmost chunk of the currently active segment. Its size is
2489 cached in topsize. The actual size of topmost space is
2490 topsize+TOP_FOOT_SIZE, which includes space reserved for adding
2491 fenceposts and segment records if necessary when getting more
2492 space from the system. The size at which to autotrim top is
2493 cached from mparams in trim_check, except that it is disabled if
2494 an autotrim fails.
2495
2496 Designated victim (dv)
2497 This is the preferred chunk for servicing small requests that
2498 don't have exact fits. It is normally the chunk split off most
2499 recently to service another small request. Its size is cached in
2500 dvsize. The link fields of this chunk are not maintained since it
2501 is not kept in a bin.
2502
2503 SmallBins
2504 An array of bin headers for free chunks. These bins hold chunks
2505 with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
2506 chunks of all the same size, spaced 8 bytes apart. To simplify
2507 use in double-linked lists, each bin header acts as a malloc_chunk
2508 pointing to the real first node, if it exists (else pointing to
2509 itself). This avoids special-casing for headers. But to avoid
2510 waste, we allocate only the fd/bk pointers of bins, and then use
2511 repositioning tricks to treat these as the fields of a chunk.
2512
2513 TreeBins
2514 Treebins are pointers to the roots of trees holding a range of
2515 sizes. There are 2 equally spaced treebins for each power of two
2516 from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
2517 larger.
2518
2519 Bin maps
2520 There is one bit map for small bins ("smallmap") and one for
2521 treebins ("treemap). Each bin sets its bit when non-empty, and
2522 clears the bit when empty. Bit operations are then used to avoid
2523 bin-by-bin searching -- nearly all "search" is done without ever
2524 looking at bins that won't be selected. The bit maps
2525 conservatively use 32 bits per map word, even if on 64bit system.
2526 For a good description of some of the bit-based techniques used
2527 here, see Henry S. Warren Jr's book "Hacker's Delight" (and
2528 supplement at http://hackersdelight.org/). Many of these are
2529 intended to reduce the branchiness of paths through malloc etc, as
2530 well as to reduce the number of memory locations read or written.
2531
2532 Segments
2533 A list of segments headed by an embedded malloc_segment record
2534 representing the initial space.
2535
2536 Address check support
2537 The least_addr field is the least address ever obtained from
2538 MORECORE or MMAP. Attempted frees and reallocs of any address less
2539 than this are trapped (unless INSECURE is defined).
2540
2541 Magic tag
2542 A cross-check field that should always hold same value as mparams.magic.
2543
2544 Max allowed footprint
2545 The maximum allowed bytes to allocate from system (zero means no limit)
2546
2547 Flags
2548 Bits recording whether to use MMAP, locks, or contiguous MORECORE
2549
2550 Statistics
2551 Each space keeps track of current and maximum system memory
2552 obtained via MORECORE or MMAP.
2553
2554 Trim support
2555 Fields holding the amount of unused topmost memory that should trigger
2556 trimming, and a counter to force periodic scanning to release unused
2557 non-topmost segments.
2558
2559 Locking
2560 If USE_LOCKS is defined, the "mutex" lock is acquired and released
2561 around every public call using this mspace.
2562
2563 Extension support
2564 A void* pointer and a size_t field that can be used to help implement
2565 extensions to this malloc.
2566 */
2567
2568 /* Bin types, widths and sizes */
2569 #define NSMALLBINS (32U)
2570 #define NTREEBINS (32U)
2571 #define SMALLBIN_SHIFT (3U)
2572 #define SMALLBIN_WIDTH (SIZE_T_ONE << SMALLBIN_SHIFT)
2573 #define TREEBIN_SHIFT (8U)
2574 #define MIN_LARGE_SIZE (SIZE_T_ONE << TREEBIN_SHIFT)
2575 #define MAX_SMALL_SIZE (MIN_LARGE_SIZE - SIZE_T_ONE)
2576 #define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
2577
2578 struct malloc_state {
2579 binmap_t smallmap;
2580 binmap_t treemap;
2581 size_t dvsize;
2582 size_t topsize;
2583 char* least_addr;
2584 mchunkptr dv;
2585 mchunkptr top;
2586 size_t trim_check;
2587 size_t release_checks;
2588 size_t magic;
2589 mchunkptr smallbins[(NSMALLBINS+1)*2];
2590 tbinptr treebins[NTREEBINS];
2591 size_t footprint;
2592 size_t max_footprint;
2593 size_t footprint_limit; /* zero means no limit */
2594 flag_t mflags;
2595 #if USE_LOCKS
2596 MLOCK_T mutex; /* locate lock among fields that rarely change */
2597 #endif /* USE_LOCKS */
2598 msegment seg;
2599 void* extp; /* Unused but available for extensions */
2600 size_t exts;
2601 };
2602
2603 typedef struct malloc_state* mstate;
2604
2605 /* ------------- Global malloc_state and malloc_params ------------------- */
2606
2607 /*
2608 malloc_params holds global properties, including those that can be
2609 dynamically set using mallopt. There is a single instance, mparams,
2610 initialized in init_mparams. Note that the non-zeroness of "magic"
2611 also serves as an initialization flag.
2612 */
2613
2614 struct malloc_params {
2615 size_t magic;
2616 size_t page_size;
2617 size_t granularity;
2618 size_t mmap_threshold;
2619 size_t trim_threshold;
2620 flag_t default_mflags;
2621 };
2622
2623 static struct malloc_params mparams;
2624
2625 /* Ensure mparams initialized */
2626 #define ensure_initialization() (void)(mparams.magic != 0 || init_mparams())
2627
2628 #if !ONLY_MSPACES
2629
2630 /* The global malloc_state used for all non-"mspace" calls */
2631 static struct malloc_state _gm_;
2632 #define gm (&_gm_)
2633 #define is_global(M) ((M) == &_gm_)
2634
2635 #endif /* !ONLY_MSPACES */
2636
2637 #define is_initialized(M) ((M)->top != 0)
2638
2639 /* -------------------------- system alloc setup ------------------------- */
2640
2641 /* Operations on mflags */
2642
2643 #define use_lock(M) ((M)->mflags & USE_LOCK_BIT)
2644 #define enable_lock(M) ((M)->mflags |= USE_LOCK_BIT)
2645 #if USE_LOCKS
2646 #define disable_lock(M) ((M)->mflags &= ~USE_LOCK_BIT)
2647 #else
2648 #define disable_lock(M)
2649 #endif
2650
2651 #define use_mmap(M) ((M)->mflags & USE_MMAP_BIT)
2652 #define enable_mmap(M) ((M)->mflags |= USE_MMAP_BIT)
2653 #if HAVE_MMAP
2654 #define disable_mmap(M) ((M)->mflags &= ~USE_MMAP_BIT)
2655 #else
2656 #define disable_mmap(M)
2657 #endif
2658
2659 #define use_noncontiguous(M) ((M)->mflags & USE_NONCONTIGUOUS_BIT)
2660 #define disable_contiguous(M) ((M)->mflags |= USE_NONCONTIGUOUS_BIT)
2661
2662 #define set_lock(M,L)\
2663 ((M)->mflags = (L)?\
2664 ((M)->mflags | USE_LOCK_BIT) :\
2665 ((M)->mflags & ~USE_LOCK_BIT))
2666
2667 /* page-align a size */
2668 #define page_align(S)\
2669 (((S) + (mparams.page_size - SIZE_T_ONE)) & ~(mparams.page_size - SIZE_T_ONE))
2670
2671 /* granularity-align a size */
2672 #define granularity_align(S)\
2673 (((S) + (mparams.granularity - SIZE_T_ONE))\
2674 & ~(mparams.granularity - SIZE_T_ONE))
2675
2676
2677 /* For mmap, use granularity alignment on windows, else page-align */
2678 #ifdef WIN32
2679 #define mmap_align(S) granularity_align(S)
2680 #else
2681 #define mmap_align(S) page_align(S)
2682 #endif
2683
2684 /* For sys_alloc, enough padding to ensure can malloc request on success */
2685 #define SYS_ALLOC_PADDING (TOP_FOOT_SIZE + MALLOC_ALIGNMENT)
2686
2687 #define is_page_aligned(S)\
2688 (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
2689 #define is_granularity_aligned(S)\
2690 (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
2691
2692 /* True if segment S holds address A */
2693 #define segment_holds(S, A)\
2694 ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
2695
2696 /* Return segment holding given address */
segment_holding(mstate m,char * addr)2697 static msegmentptr segment_holding(mstate m, char* addr) {
2698 msegmentptr sp = &m->seg;
2699 for (;;) {
2700 if (addr >= sp->base && addr < sp->base + sp->size)
2701 return sp;
2702 if ((sp = sp->next) == 0)
2703 return 0;
2704 }
2705 }
2706
2707 /* Return true if segment contains a segment link */
has_segment_link(mstate m,msegmentptr ss)2708 static int has_segment_link(mstate m, msegmentptr ss) {
2709 msegmentptr sp = &m->seg;
2710 for (;;) {
2711 if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
2712 return 1;
2713 if ((sp = sp->next) == 0)
2714 return 0;
2715 }
2716 }
2717
2718 #ifndef MORECORE_CANNOT_TRIM
2719 #define should_trim(M,s) ((s) > (M)->trim_check)
2720 #else /* MORECORE_CANNOT_TRIM */
2721 #define should_trim(M,s) (0)
2722 #endif /* MORECORE_CANNOT_TRIM */
2723
2724 /*
2725 TOP_FOOT_SIZE is padding at the end of a segment, including space
2726 that may be needed to place segment records and fenceposts when new
2727 noncontiguous segments are added.
2728 */
2729 #define TOP_FOOT_SIZE\
2730 (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
2731
2732
2733 /* ------------------------------- Hooks -------------------------------- */
2734
2735 /*
2736 PREACTION should be defined to return 0 on success, and nonzero on
2737 failure. If you are not using locking, you can redefine these to do
2738 anything you like.
2739 */
2740
2741 #if USE_LOCKS
2742 #define PREACTION(M) ((use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
2743 #define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
2744 #else /* USE_LOCKS */
2745
2746 #ifndef PREACTION
2747 #define PREACTION(M) (0)
2748 #endif /* PREACTION */
2749
2750 #ifndef POSTACTION
2751 #define POSTACTION(M)
2752 #endif /* POSTACTION */
2753
2754 #endif /* USE_LOCKS */
2755
2756 /*
2757 CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
2758 USAGE_ERROR_ACTION is triggered on detected bad frees and
2759 reallocs. The argument p is an address that might have triggered the
2760 fault. It is ignored by the two predefined actions, but might be
2761 useful in custom actions that try to help diagnose errors.
2762 */
2763
2764 #if PROCEED_ON_ERROR
2765
2766 /* A count of the number of corruption errors causing resets */
2767 int malloc_corruption_error_count;
2768
2769 /* default corruption action */
2770 static void reset_on_error(mstate m);
2771
2772 #define CORRUPTION_ERROR_ACTION(m) reset_on_error(m)
2773 #define USAGE_ERROR_ACTION(m, p)
2774
2775 #else /* PROCEED_ON_ERROR */
2776
2777 #ifndef CORRUPTION_ERROR_ACTION
2778 #define CORRUPTION_ERROR_ACTION(m) ABORT
2779 #endif /* CORRUPTION_ERROR_ACTION */
2780
2781 #ifndef USAGE_ERROR_ACTION
2782 #define USAGE_ERROR_ACTION(m,p) ABORT
2783 #endif /* USAGE_ERROR_ACTION */
2784
2785 #endif /* PROCEED_ON_ERROR */
2786
2787
2788 /* -------------------------- Debugging setup ---------------------------- */
2789
2790 #if ! DEBUG
2791
2792 #define check_free_chunk(M,P)
2793 #define check_inuse_chunk(M,P)
2794 #define check_malloced_chunk(M,P,N)
2795 #define check_mmapped_chunk(M,P)
2796 #define check_malloc_state(M)
2797 #define check_top_chunk(M,P)
2798
2799 #else /* DEBUG */
2800 #define check_free_chunk(M,P) do_check_free_chunk(M,P)
2801 #define check_inuse_chunk(M,P) do_check_inuse_chunk(M,P)
2802 #define check_top_chunk(M,P) do_check_top_chunk(M,P)
2803 #define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
2804 #define check_mmapped_chunk(M,P) do_check_mmapped_chunk(M,P)
2805 #define check_malloc_state(M) do_check_malloc_state(M)
2806
2807 static void do_check_any_chunk(mstate m, mchunkptr p);
2808 static void do_check_top_chunk(mstate m, mchunkptr p);
2809 static void do_check_mmapped_chunk(mstate m, mchunkptr p);
2810 static void do_check_inuse_chunk(mstate m, mchunkptr p);
2811 static void do_check_free_chunk(mstate m, mchunkptr p);
2812 static void do_check_malloced_chunk(mstate m, void* mem, size_t s);
2813 static void do_check_tree(mstate m, tchunkptr t);
2814 static void do_check_treebin(mstate m, bindex_t i);
2815 static void do_check_smallbin(mstate m, bindex_t i);
2816 static void do_check_malloc_state(mstate m);
2817 static int bin_find(mstate m, mchunkptr x);
2818 static size_t traverse_and_check(mstate m);
2819 #endif /* DEBUG */
2820
2821 /* ---------------------------- Indexing Bins ---------------------------- */
2822
2823 #define is_small(s) (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
2824 #define small_index(s) (bindex_t)((s) >> SMALLBIN_SHIFT)
2825 #define small_index2size(i) ((i) << SMALLBIN_SHIFT)
2826 #define MIN_SMALL_INDEX (small_index(MIN_CHUNK_SIZE))
2827
2828 /* addressing by index. See above about smallbin repositioning */
2829 #define smallbin_at(M, i) ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
2830 #define treebin_at(M,i) (&((M)->treebins[i]))
2831
2832 /* assign tree index for size S to variable I. Use x86 asm if possible */
2833 #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
2834 #define compute_tree_index(S, I)\
2835 {\
2836 unsigned int X = S >> TREEBIN_SHIFT;\
2837 if (X == 0)\
2838 I = 0;\
2839 else if (X > 0xFFFF)\
2840 I = NTREEBINS-1;\
2841 else {\
2842 unsigned int K = (unsigned) sizeof(X)*__CHAR_BIT__ - 1 - (unsigned) __builtin_clz(X); \
2843 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
2844 }\
2845 }
2846
2847 #elif defined (__INTEL_COMPILER)
2848 #define compute_tree_index(S, I)\
2849 {\
2850 size_t X = S >> TREEBIN_SHIFT;\
2851 if (X == 0)\
2852 I = 0;\
2853 else if (X > 0xFFFF)\
2854 I = NTREEBINS-1;\
2855 else {\
2856 unsigned int K = _bit_scan_reverse (X); \
2857 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
2858 }\
2859 }
2860
2861 #elif defined(_MSC_VER) && _MSC_VER>=1300
2862 #define compute_tree_index(S, I)\
2863 {\
2864 size_t X = S >> TREEBIN_SHIFT;\
2865 if (X == 0)\
2866 I = 0;\
2867 else if (X > 0xFFFF)\
2868 I = NTREEBINS-1;\
2869 else {\
2870 unsigned int K;\
2871 _BitScanReverse((DWORD *) &K, (DWORD) X);\
2872 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
2873 }\
2874 }
2875
2876 #else /* GNUC */
2877 #define compute_tree_index(S, I)\
2878 {\
2879 size_t X = S >> TREEBIN_SHIFT;\
2880 if (X == 0)\
2881 I = 0;\
2882 else if (X > 0xFFFF)\
2883 I = NTREEBINS-1;\
2884 else {\
2885 unsigned int Y = (unsigned int)X;\
2886 unsigned int N = ((Y - 0x100) >> 16) & 8;\
2887 unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
2888 N += K;\
2889 N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
2890 K = 14 - N + ((Y <<= K) >> 15);\
2891 I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
2892 }\
2893 }
2894 #endif /* GNUC */
2895
2896 /* Bit representing maximum resolved size in a treebin at i */
2897 #define bit_for_tree_index(i) \
2898 (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
2899
2900 /* Shift placing maximum resolved bit in a treebin at i as sign bit */
2901 #define leftshift_for_tree_index(i) \
2902 ((i == NTREEBINS-1)? 0 : \
2903 ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
2904
2905 /* The size of the smallest chunk held in bin with index i */
2906 #define minsize_for_tree_index(i) \
2907 ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) | \
2908 (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
2909
2910
2911 /* ------------------------ Operations on bin maps ----------------------- */
2912
2913 /* bit corresponding to given index */
2914 #define idx2bit(i) ((binmap_t)(1) << (i))
2915
2916 /* Mark/Clear bits with given index */
2917 #define mark_smallmap(M,i) ((M)->smallmap |= idx2bit(i))
2918 #define clear_smallmap(M,i) ((M)->smallmap &= ~idx2bit(i))
2919 #define smallmap_is_marked(M,i) ((M)->smallmap & idx2bit(i))
2920
2921 #define mark_treemap(M,i) ((M)->treemap |= idx2bit(i))
2922 #define clear_treemap(M,i) ((M)->treemap &= ~idx2bit(i))
2923 #define treemap_is_marked(M,i) ((M)->treemap & idx2bit(i))
2924
2925 /* isolate the least set bit of a bitmap */
2926 #define least_bit(x) ((x) & -(x))
2927
2928 /* mask with all bits to left of least bit of x on */
2929 #define left_bits(x) ((x<<1) | -(x<<1))
2930
2931 /* mask with all bits to left of or equal to least bit of x on */
2932 #define same_or_left_bits(x) ((x) | -(x))
2933
2934 /* index corresponding to given bit. Use x86 asm if possible */
2935
2936 #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
2937 #define compute_bit2idx(X, I)\
2938 {\
2939 unsigned int J;\
2940 J = __builtin_ctz(X); \
2941 I = (bindex_t)J;\
2942 }
2943
2944 #elif defined (__INTEL_COMPILER)
2945 #define compute_bit2idx(X, I)\
2946 {\
2947 unsigned int J;\
2948 J = _bit_scan_forward (X); \
2949 I = (bindex_t)J;\
2950 }
2951
2952 #elif defined(_MSC_VER) && _MSC_VER>=1300
2953 #define compute_bit2idx(X, I)\
2954 {\
2955 unsigned int J;\
2956 _BitScanForward((DWORD *) &J, X);\
2957 I = (bindex_t)J;\
2958 }
2959
2960 #elif USE_BUILTIN_FFS
2961 #define compute_bit2idx(X, I) I = ffs(X)-1
2962
2963 #else
2964 #define compute_bit2idx(X, I)\
2965 {\
2966 unsigned int Y = X - 1;\
2967 unsigned int K = Y >> (16-4) & 16;\
2968 unsigned int N = K; Y >>= K;\
2969 N += K = Y >> (8-3) & 8; Y >>= K;\
2970 N += K = Y >> (4-2) & 4; Y >>= K;\
2971 N += K = Y >> (2-1) & 2; Y >>= K;\
2972 N += K = Y >> (1-0) & 1; Y >>= K;\
2973 I = (bindex_t)(N + Y);\
2974 }
2975 #endif /* GNUC */
2976
2977
2978 /* ----------------------- Runtime Check Support ------------------------- */
2979
2980 /*
2981 For security, the main invariant is that malloc/free/etc never
2982 writes to a static address other than malloc_state, unless static
2983 malloc_state itself has been corrupted, which cannot occur via
2984 malloc (because of these checks). In essence this means that we
2985 believe all pointers, sizes, maps etc held in malloc_state, but
2986 check all of those linked or offsetted from other embedded data
2987 structures. These checks are interspersed with main code in a way
2988 that tends to minimize their run-time cost.
2989
2990 When FOOTERS is defined, in addition to range checking, we also
2991 verify footer fields of inuse chunks, which can be used guarantee
2992 that the mstate controlling malloc/free is intact. This is a
2993 streamlined version of the approach described by William Robertson
2994 et al in "Run-time Detection of Heap-based Overflows" LISA'03
2995 http://www.usenix.org/events/lisa03/tech/robertson.html The footer
2996 of an inuse chunk holds the xor of its mstate and a random seed,
2997 that is checked upon calls to free() and realloc(). This is
2998 (probabalistically) unguessable from outside the program, but can be
2999 computed by any code successfully malloc'ing any chunk, so does not
3000 itself provide protection against code that has already broken
3001 security through some other means. Unlike Robertson et al, we
3002 always dynamically check addresses of all offset chunks (previous,
3003 next, etc). This turns out to be cheaper than relying on hashes.
3004 */
3005
3006 #if !INSECURE
3007 /* Check if address a is at least as high as any from MORECORE or MMAP */
3008 #define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
3009 /* Check if address of next chunk n is higher than base chunk p */
3010 #define ok_next(p, n) ((char*)(p) < (char*)(n))
3011 /* Check if p has inuse status */
3012 #define ok_inuse(p) is_inuse(p)
3013 /* Check if p has its pinuse bit on */
3014 #define ok_pinuse(p) pinuse(p)
3015
3016 #else /* !INSECURE */
3017 #define ok_address(M, a) (1)
3018 #define ok_next(b, n) (1)
3019 #define ok_inuse(p) (1)
3020 #define ok_pinuse(p) (1)
3021 #endif /* !INSECURE */
3022
3023 #if (FOOTERS && !INSECURE)
3024 /* Check if (alleged) mstate m has expected magic field */
3025 #define ok_magic(M) ((M)->magic == mparams.magic)
3026 #else /* (FOOTERS && !INSECURE) */
3027 #define ok_magic(M) (1)
3028 #endif /* (FOOTERS && !INSECURE) */
3029
3030 /* In gcc, use __builtin_expect to minimize impact of checks */
3031 #if !INSECURE
3032 #if defined(__GNUC__) && __GNUC__ >= 3
3033 #define RTCHECK(e) __builtin_expect(e, 1)
3034 #else /* GNUC */
3035 #define RTCHECK(e) (e)
3036 #endif /* GNUC */
3037 #else /* !INSECURE */
3038 #define RTCHECK(e) (1)
3039 #endif /* !INSECURE */
3040
3041 /* macros to set up inuse chunks with or without footers */
3042
3043 #if !FOOTERS
3044
3045 #define mark_inuse_foot(M,p,s)
3046
3047 /* Macros for setting head/foot of non-mmapped chunks */
3048
3049 /* Set cinuse bit and pinuse bit of next chunk */
3050 #define set_inuse(M,p,s)\
3051 ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
3052 ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
3053
3054 /* Set cinuse and pinuse of this chunk and pinuse of next chunk */
3055 #define set_inuse_and_pinuse(M,p,s)\
3056 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
3057 ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
3058
3059 /* Set size, cinuse and pinuse bit of this chunk */
3060 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
3061 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
3062
3063 #else /* FOOTERS */
3064
3065 /* Set foot of inuse chunk to be xor of mstate and seed */
3066 #define mark_inuse_foot(M,p,s)\
3067 (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
3068
3069 #define get_mstate_for(p)\
3070 ((mstate)(((mchunkptr)((char*)(p) +\
3071 (chunksize(p))))->prev_foot ^ mparams.magic))
3072
3073 #define set_inuse(M,p,s)\
3074 ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
3075 (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
3076 mark_inuse_foot(M,p,s))
3077
3078 #define set_inuse_and_pinuse(M,p,s)\
3079 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
3080 (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
3081 mark_inuse_foot(M,p,s))
3082
3083 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
3084 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
3085 mark_inuse_foot(M, p, s))
3086
3087 #endif /* !FOOTERS */
3088
3089 /* ---------------------------- setting mparams -------------------------- */
3090
3091 #if LOCK_AT_FORK
pre_fork(void)3092 static void pre_fork(void) { ACQUIRE_LOCK(&(gm)->mutex); }
post_fork_parent(void)3093 static void post_fork_parent(void) { RELEASE_LOCK(&(gm)->mutex); }
post_fork_child(void)3094 static void post_fork_child(void) { INITIAL_LOCK(&(gm)->mutex); }
3095 #endif /* LOCK_AT_FORK */
3096
3097 /* Initialize mparams */
init_mparams(void)3098 static int init_mparams(void) {
3099 #ifdef NEED_GLOBAL_LOCK_INIT
3100 if (malloc_global_mutex_status <= 0)
3101 init_malloc_global_mutex();
3102 #endif
3103
3104 ACQUIRE_MALLOC_GLOBAL_LOCK();
3105 if (mparams.magic == 0) {
3106 size_t magic;
3107 size_t psize;
3108 size_t gsize;
3109
3110 #ifndef WIN32
3111 psize = malloc_getpagesize;
3112 gsize = ((DEFAULT_GRANULARITY != 0)? DEFAULT_GRANULARITY : psize);
3113 #else /* WIN32 */
3114 {
3115 SYSTEM_INFO system_info;
3116 GetSystemInfo(&system_info);
3117 psize = system_info.dwPageSize;
3118 gsize = ((DEFAULT_GRANULARITY != 0)?
3119 DEFAULT_GRANULARITY : system_info.dwAllocationGranularity);
3120 }
3121 #endif /* WIN32 */
3122
3123 /* Sanity-check configuration:
3124 size_t must be unsigned and as wide as pointer type.
3125 ints must be at least 4 bytes.
3126 alignment must be at least 8.
3127 Alignment, min chunk size, and page size must all be powers of 2.
3128 */
3129 if ((sizeof(size_t) != sizeof(char*)) ||
3130 (MAX_SIZE_T < MIN_CHUNK_SIZE) ||
3131 (sizeof(int) < 4) ||
3132 (MALLOC_ALIGNMENT < (size_t)8U) ||
3133 ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) ||
3134 ((MCHUNK_SIZE & (MCHUNK_SIZE-SIZE_T_ONE)) != 0) ||
3135 ((gsize & (gsize-SIZE_T_ONE)) != 0) ||
3136 ((psize & (psize-SIZE_T_ONE)) != 0))
3137 ABORT;
3138 mparams.granularity = gsize;
3139 mparams.page_size = psize;
3140 mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
3141 mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
3142 #if MORECORE_CONTIGUOUS
3143 mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
3144 #else /* MORECORE_CONTIGUOUS */
3145 mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
3146 #endif /* MORECORE_CONTIGUOUS */
3147
3148 #if !ONLY_MSPACES
3149 /* Set up lock for main malloc area */
3150 gm->mflags = mparams.default_mflags;
3151 (void)INITIAL_LOCK(&gm->mutex);
3152 #endif
3153 #if LOCK_AT_FORK
3154 pthread_atfork(&pre_fork, &post_fork_parent, &post_fork_child);
3155 #endif
3156
3157 {
3158 #if USE_DEV_RANDOM
3159 int fd;
3160 unsigned char buf[sizeof(size_t)];
3161 /* Try to use /dev/urandom, else fall back on using time */
3162 if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
3163 read(fd, buf, sizeof(buf)) == sizeof(buf)) {
3164 magic = *((size_t *) buf);
3165 close(fd);
3166 }
3167 else
3168 #endif /* USE_DEV_RANDOM */
3169 #ifdef WIN32
3170 magic = (size_t)(GetTickCount() ^ (size_t)0x55555555U);
3171 #elif defined(LACKS_TIME_H)
3172 magic = (size_t)&magic ^ (size_t)0x55555555U;
3173 #else
3174 magic = (size_t)(time(0) ^ (size_t)0x55555555U);
3175 #endif
3176 magic |= (size_t)8U; /* ensure nonzero */
3177 magic &= ~(size_t)7U; /* improve chances of fault for bad values */
3178 /* Until memory modes commonly available, use volatile-write */
3179 (*(volatile size_t *)(&(mparams.magic))) = magic;
3180 }
3181 }
3182
3183 RELEASE_MALLOC_GLOBAL_LOCK();
3184 return 1;
3185 }
3186
3187 /* support for mallopt */
change_mparam(int param_number,int value)3188 static int change_mparam(int param_number, int value) {
3189 size_t val;
3190 ensure_initialization();
3191 val = (value == -1)? MAX_SIZE_T : (size_t)value;
3192 switch(param_number) {
3193 case M_TRIM_THRESHOLD:
3194 mparams.trim_threshold = val;
3195 return 1;
3196 case M_GRANULARITY:
3197 if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
3198 mparams.granularity = val;
3199 return 1;
3200 }
3201 else
3202 return 0;
3203 case M_MMAP_THRESHOLD:
3204 mparams.mmap_threshold = val;
3205 return 1;
3206 default:
3207 return 0;
3208 }
3209 }
3210
3211 #if DEBUG
3212 /* ------------------------- Debugging Support --------------------------- */
3213
3214 /* Check properties of any chunk, whether free, inuse, mmapped etc */
do_check_any_chunk(mstate m,mchunkptr p)3215 static void do_check_any_chunk(mstate m, mchunkptr p) {
3216 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
3217 assert(ok_address(m, p));
3218 }
3219
3220 /* Check properties of top chunk */
do_check_top_chunk(mstate m,mchunkptr p)3221 static void do_check_top_chunk(mstate m, mchunkptr p) {
3222 msegmentptr sp = segment_holding(m, (char*)p);
3223 size_t sz = p->head & ~INUSE_BITS; /* third-lowest bit can be set! */
3224 assert(sp != 0);
3225 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
3226 assert(ok_address(m, p));
3227 assert(sz == m->topsize);
3228 assert(sz > 0);
3229 assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE);
3230 assert(pinuse(p));
3231 assert(!pinuse(chunk_plus_offset(p, sz)));
3232 }
3233
3234 /* Check properties of (inuse) mmapped chunks */
do_check_mmapped_chunk(mstate m,mchunkptr p)3235 static void do_check_mmapped_chunk(mstate m, mchunkptr p) {
3236 size_t sz = chunksize(p);
3237 size_t len = (sz + (p->prev_foot) + MMAP_FOOT_PAD);
3238 assert(is_mmapped(p));
3239 assert(use_mmap(m));
3240 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
3241 assert(ok_address(m, p));
3242 assert(!is_small(sz));
3243 assert((len & (mparams.page_size-SIZE_T_ONE)) == 0);
3244 assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
3245 assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0);
3246 }
3247
3248 /* Check properties of inuse chunks */
do_check_inuse_chunk(mstate m,mchunkptr p)3249 static void do_check_inuse_chunk(mstate m, mchunkptr p) {
3250 do_check_any_chunk(m, p);
3251 assert(is_inuse(p));
3252 assert(next_pinuse(p));
3253 /* If not pinuse and not mmapped, previous chunk has OK offset */
3254 assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
3255 if (is_mmapped(p))
3256 do_check_mmapped_chunk(m, p);
3257 }
3258
3259 /* Check properties of free chunks */
do_check_free_chunk(mstate m,mchunkptr p)3260 static void do_check_free_chunk(mstate m, mchunkptr p) {
3261 size_t sz = chunksize(p);
3262 mchunkptr next = chunk_plus_offset(p, sz);
3263 do_check_any_chunk(m, p);
3264 assert(!is_inuse(p));
3265 assert(!next_pinuse(p));
3266 assert (!is_mmapped(p));
3267 if (p != m->dv && p != m->top) {
3268 if (sz >= MIN_CHUNK_SIZE) {
3269 assert((sz & CHUNK_ALIGN_MASK) == 0);
3270 assert(is_aligned(chunk2mem(p)));
3271 assert(next->prev_foot == sz);
3272 assert(pinuse(p));
3273 assert (next == m->top || is_inuse(next));
3274 assert(p->fd->bk == p);
3275 assert(p->bk->fd == p);
3276 }
3277 else /* markers are always of size SIZE_T_SIZE */
3278 assert(sz == SIZE_T_SIZE);
3279 }
3280 }
3281
3282 /* Check properties of malloced chunks at the point they are malloced */
do_check_malloced_chunk(mstate m,void * mem,size_t s)3283 static void do_check_malloced_chunk(mstate m, void* mem, size_t s) {
3284 if (mem != 0) {
3285 mchunkptr p = mem2chunk(mem);
3286 size_t sz = p->head & ~INUSE_BITS;
3287 do_check_inuse_chunk(m, p);
3288 assert((sz & CHUNK_ALIGN_MASK) == 0);
3289 assert(sz >= MIN_CHUNK_SIZE);
3290 assert(sz >= s);
3291 /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
3292 assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
3293 }
3294 }
3295
3296 /* Check a tree and its subtrees. */
do_check_tree(mstate m,tchunkptr t)3297 static void do_check_tree(mstate m, tchunkptr t) {
3298 tchunkptr head = 0;
3299 tchunkptr u = t;
3300 bindex_t tindex = t->index;
3301 size_t tsize = chunksize(t);
3302 bindex_t idx;
3303 compute_tree_index(tsize, idx);
3304 assert(tindex == idx);
3305 assert(tsize >= MIN_LARGE_SIZE);
3306 assert(tsize >= minsize_for_tree_index(idx));
3307 assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1))));
3308
3309 do { /* traverse through chain of same-sized nodes */
3310 do_check_any_chunk(m, ((mchunkptr)u));
3311 assert(u->index == tindex);
3312 assert(chunksize(u) == tsize);
3313 assert(!is_inuse(u));
3314 assert(!next_pinuse(u));
3315 assert(u->fd->bk == u);
3316 assert(u->bk->fd == u);
3317 if (u->parent == 0) {
3318 assert(u->child[0] == 0);
3319 assert(u->child[1] == 0);
3320 }
3321 else {
3322 assert(head == 0); /* only one node on chain has parent */
3323 head = u;
3324 assert(u->parent != u);
3325 assert (u->parent->child[0] == u ||
3326 u->parent->child[1] == u ||
3327 *((tbinptr*)(u->parent)) == u);
3328 if (u->child[0] != 0) {
3329 assert(u->child[0]->parent == u);
3330 assert(u->child[0] != u);
3331 do_check_tree(m, u->child[0]);
3332 }
3333 if (u->child[1] != 0) {
3334 assert(u->child[1]->parent == u);
3335 assert(u->child[1] != u);
3336 do_check_tree(m, u->child[1]);
3337 }
3338 if (u->child[0] != 0 && u->child[1] != 0) {
3339 assert(chunksize(u->child[0]) < chunksize(u->child[1]));
3340 }
3341 }
3342 u = u->fd;
3343 } while (u != t);
3344 assert(head != 0);
3345 }
3346
3347 /* Check all the chunks in a treebin. */
do_check_treebin(mstate m,bindex_t i)3348 static void do_check_treebin(mstate m, bindex_t i) {
3349 tbinptr* tb = treebin_at(m, i);
3350 tchunkptr t = *tb;
3351 int empty = (m->treemap & (1U << i)) == 0;
3352 if (t == 0)
3353 assert(empty);
3354 if (!empty)
3355 do_check_tree(m, t);
3356 }
3357
3358 /* Check all the chunks in a smallbin. */
do_check_smallbin(mstate m,bindex_t i)3359 static void do_check_smallbin(mstate m, bindex_t i) {
3360 sbinptr b = smallbin_at(m, i);
3361 mchunkptr p = b->bk;
3362 unsigned int empty = (m->smallmap & (1U << i)) == 0;
3363 if (p == b)
3364 assert(empty);
3365 if (!empty) {
3366 for (; p != b; p = p->bk) {
3367 size_t size = chunksize(p);
3368 mchunkptr q;
3369 /* each chunk claims to be free */
3370 do_check_free_chunk(m, p);
3371 /* chunk belongs in bin */
3372 assert(small_index(size) == i);
3373 assert(p->bk == b || chunksize(p->bk) == chunksize(p));
3374 /* chunk is followed by an inuse chunk */
3375 q = next_chunk(p);
3376 if (q->head != FENCEPOST_HEAD)
3377 do_check_inuse_chunk(m, q);
3378 }
3379 }
3380 }
3381
3382 /* Find x in a bin. Used in other check functions. */
bin_find(mstate m,mchunkptr x)3383 static int bin_find(mstate m, mchunkptr x) {
3384 size_t size = chunksize(x);
3385 if (is_small(size)) {
3386 bindex_t sidx = small_index(size);
3387 sbinptr b = smallbin_at(m, sidx);
3388 if (smallmap_is_marked(m, sidx)) {
3389 mchunkptr p = b;
3390 do {
3391 if (p == x)
3392 return 1;
3393 } while ((p = p->fd) != b);
3394 }
3395 }
3396 else {
3397 bindex_t tidx;
3398 compute_tree_index(size, tidx);
3399 if (treemap_is_marked(m, tidx)) {
3400 tchunkptr t = *treebin_at(m, tidx);
3401 size_t sizebits = size << leftshift_for_tree_index(tidx);
3402 while (t != 0 && chunksize(t) != size) {
3403 t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
3404 sizebits <<= 1;
3405 }
3406 if (t != 0) {
3407 tchunkptr u = t;
3408 do {
3409 if (u == (tchunkptr)x)
3410 return 1;
3411 } while ((u = u->fd) != t);
3412 }
3413 }
3414 }
3415 return 0;
3416 }
3417
3418 /* Traverse each chunk and check it; return total */
traverse_and_check(mstate m)3419 static size_t traverse_and_check(mstate m) {
3420 size_t sum = 0;
3421 if (is_initialized(m)) {
3422 msegmentptr s = &m->seg;
3423 sum += m->topsize + TOP_FOOT_SIZE;
3424 while (s != 0) {
3425 mchunkptr q = align_as_chunk(s->base);
3426 mchunkptr lastq = 0;
3427 assert(pinuse(q));
3428 while (segment_holds(s, q) &&
3429 q != m->top && q->head != FENCEPOST_HEAD) {
3430 sum += chunksize(q);
3431 if (is_inuse(q)) {
3432 assert(!bin_find(m, q));
3433 do_check_inuse_chunk(m, q);
3434 }
3435 else {
3436 assert(q == m->dv || bin_find(m, q));
3437 assert(lastq == 0 || is_inuse(lastq)); /* Not 2 consecutive free */
3438 do_check_free_chunk(m, q);
3439 }
3440 lastq = q;
3441 q = next_chunk(q);
3442 }
3443 s = s->next;
3444 }
3445 }
3446 return sum;
3447 }
3448
3449
3450 /* Check all properties of malloc_state. */
do_check_malloc_state(mstate m)3451 static void do_check_malloc_state(mstate m) {
3452 bindex_t i;
3453 size_t total;
3454 /* check bins */
3455 for (i = 0; i < NSMALLBINS; ++i)
3456 do_check_smallbin(m, i);
3457 for (i = 0; i < NTREEBINS; ++i)
3458 do_check_treebin(m, i);
3459
3460 if (m->dvsize != 0) { /* check dv chunk */
3461 do_check_any_chunk(m, m->dv);
3462 assert(m->dvsize == chunksize(m->dv));
3463 assert(m->dvsize >= MIN_CHUNK_SIZE);
3464 assert(bin_find(m, m->dv) == 0);
3465 }
3466
3467 if (m->top != 0) { /* check top chunk */
3468 do_check_top_chunk(m, m->top);
3469 /*assert(m->topsize == chunksize(m->top)); redundant */
3470 assert(m->topsize > 0);
3471 assert(bin_find(m, m->top) == 0);
3472 }
3473
3474 total = traverse_and_check(m);
3475 assert(total <= m->footprint);
3476 assert(m->footprint <= m->max_footprint);
3477 }
3478 #endif /* DEBUG */
3479
3480 /* ----------------------------- statistics ------------------------------ */
3481
3482 #if !NO_MALLINFO
internal_mallinfo(mstate m)3483 static struct mallinfo internal_mallinfo(mstate m) {
3484 struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
3485 ensure_initialization();
3486 if (!PREACTION(m)) {
3487 check_malloc_state(m);
3488 if (is_initialized(m)) {
3489 size_t nfree = SIZE_T_ONE; /* top always free */
3490 size_t mfree = m->topsize + TOP_FOOT_SIZE;
3491 size_t sum = mfree;
3492 msegmentptr s = &m->seg;
3493 while (s != 0) {
3494 mchunkptr q = align_as_chunk(s->base);
3495 while (segment_holds(s, q) &&
3496 q != m->top && q->head != FENCEPOST_HEAD) {
3497 size_t sz = chunksize(q);
3498 sum += sz;
3499 if (!is_inuse(q)) {
3500 mfree += sz;
3501 ++nfree;
3502 }
3503 q = next_chunk(q);
3504 }
3505 s = s->next;
3506 }
3507
3508 nm.arena = sum;
3509 nm.ordblks = nfree;
3510 nm.hblkhd = m->footprint - sum;
3511 nm.usmblks = m->max_footprint;
3512 nm.uordblks = m->footprint - mfree;
3513 nm.fordblks = mfree;
3514 nm.keepcost = m->topsize;
3515 }
3516
3517 POSTACTION(m);
3518 }
3519 return nm;
3520 }
3521 #endif /* !NO_MALLINFO */
3522
3523 #if !NO_MALLOC_STATS
internal_malloc_stats(mstate m)3524 static void internal_malloc_stats(mstate m) {
3525 ensure_initialization();
3526 if (!PREACTION(m)) {
3527 size_t maxfp = 0;
3528 size_t fp = 0;
3529 size_t used = 0;
3530 check_malloc_state(m);
3531 if (is_initialized(m)) {
3532 msegmentptr s = &m->seg;
3533 maxfp = m->max_footprint;
3534 fp = m->footprint;
3535 used = fp - (m->topsize + TOP_FOOT_SIZE);
3536
3537 while (s != 0) {
3538 mchunkptr q = align_as_chunk(s->base);
3539 while (segment_holds(s, q) &&
3540 q != m->top && q->head != FENCEPOST_HEAD) {
3541 if (!is_inuse(q))
3542 used -= chunksize(q);
3543 q = next_chunk(q);
3544 }
3545 s = s->next;
3546 }
3547 }
3548 POSTACTION(m); /* drop lock */
3549 fprintf(stderr, "max system bytes = %10lu\n", (unsigned long)(maxfp));
3550 fprintf(stderr, "system bytes = %10lu\n", (unsigned long)(fp));
3551 fprintf(stderr, "in use bytes = %10lu\n", (unsigned long)(used));
3552 }
3553 }
3554 #endif /* NO_MALLOC_STATS */
3555
3556 /* ----------------------- Operations on smallbins ----------------------- */
3557
3558 /*
3559 Various forms of linking and unlinking are defined as macros. Even
3560 the ones for trees, which are very long but have very short typical
3561 paths. This is ugly but reduces reliance on inlining support of
3562 compilers.
3563 */
3564
3565 /* Link a free chunk into a smallbin */
3566 #define insert_small_chunk(M, P, S) {\
3567 bindex_t I = small_index(S);\
3568 mchunkptr B = smallbin_at(M, I);\
3569 mchunkptr F = B;\
3570 assert(S >= MIN_CHUNK_SIZE);\
3571 if (!smallmap_is_marked(M, I))\
3572 mark_smallmap(M, I);\
3573 else if (RTCHECK(ok_address(M, B->fd)))\
3574 F = B->fd;\
3575 else {\
3576 CORRUPTION_ERROR_ACTION(M);\
3577 }\
3578 B->fd = P;\
3579 F->bk = P;\
3580 P->fd = F;\
3581 P->bk = B;\
3582 }
3583
3584 /* Unlink a chunk from a smallbin */
3585 #define unlink_small_chunk(M, P, S) {\
3586 mchunkptr F = P->fd;\
3587 mchunkptr B = P->bk;\
3588 bindex_t I = small_index(S);\
3589 assert(P != B);\
3590 assert(P != F);\
3591 assert(chunksize(P) == small_index2size(I));\
3592 if (RTCHECK(F == smallbin_at(M,I) || (ok_address(M, F) && F->bk == P))) { \
3593 if (B == F) {\
3594 clear_smallmap(M, I);\
3595 }\
3596 else if (RTCHECK(B == smallbin_at(M,I) ||\
3597 (ok_address(M, B) && B->fd == P))) {\
3598 F->bk = B;\
3599 B->fd = F;\
3600 }\
3601 else {\
3602 CORRUPTION_ERROR_ACTION(M);\
3603 }\
3604 }\
3605 else {\
3606 CORRUPTION_ERROR_ACTION(M);\
3607 }\
3608 }
3609
3610 /* Unlink the first chunk from a smallbin */
3611 #define unlink_first_small_chunk(M, B, P, I) {\
3612 mchunkptr F = P->fd;\
3613 assert(P != B);\
3614 assert(P != F);\
3615 assert(chunksize(P) == small_index2size(I));\
3616 if (B == F) {\
3617 clear_smallmap(M, I);\
3618 }\
3619 else if (RTCHECK(ok_address(M, F) && F->bk == P)) {\
3620 F->bk = B;\
3621 B->fd = F;\
3622 }\
3623 else {\
3624 CORRUPTION_ERROR_ACTION(M);\
3625 }\
3626 }
3627
3628 /* Replace dv node, binning the old one */
3629 /* Used only when dvsize known to be small */
3630 #define replace_dv(M, P, S) {\
3631 size_t DVS = M->dvsize;\
3632 assert(is_small(DVS));\
3633 if (DVS != 0) {\
3634 mchunkptr DV = M->dv;\
3635 insert_small_chunk(M, DV, DVS);\
3636 }\
3637 M->dvsize = S;\
3638 M->dv = P;\
3639 }
3640
3641 /* ------------------------- Operations on trees ------------------------- */
3642
3643 /* Insert chunk into tree */
3644 #define insert_large_chunk(M, X, S) {\
3645 tbinptr* H;\
3646 bindex_t I;\
3647 compute_tree_index(S, I);\
3648 H = treebin_at(M, I);\
3649 X->index = I;\
3650 X->child[0] = X->child[1] = 0;\
3651 if (!treemap_is_marked(M, I)) {\
3652 mark_treemap(M, I);\
3653 *H = X;\
3654 X->parent = (tchunkptr)H;\
3655 X->fd = X->bk = X;\
3656 }\
3657 else {\
3658 tchunkptr T = *H;\
3659 size_t K = S << leftshift_for_tree_index(I);\
3660 for (;;) {\
3661 if (chunksize(T) != S) {\
3662 tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
3663 K <<= 1;\
3664 if (*C != 0)\
3665 T = *C;\
3666 else if (RTCHECK(ok_address(M, C))) {\
3667 *C = X;\
3668 X->parent = T;\
3669 X->fd = X->bk = X;\
3670 break;\
3671 }\
3672 else {\
3673 CORRUPTION_ERROR_ACTION(M);\
3674 break;\
3675 }\
3676 }\
3677 else {\
3678 tchunkptr F = T->fd;\
3679 if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
3680 T->fd = F->bk = X;\
3681 X->fd = F;\
3682 X->bk = T;\
3683 X->parent = 0;\
3684 break;\
3685 }\
3686 else {\
3687 CORRUPTION_ERROR_ACTION(M);\
3688 break;\
3689 }\
3690 }\
3691 }\
3692 }\
3693 }
3694
3695 /*
3696 Unlink steps:
3697
3698 1. If x is a chained node, unlink it from its same-sized fd/bk links
3699 and choose its bk node as its replacement.
3700 2. If x was the last node of its size, but not a leaf node, it must
3701 be replaced with a leaf node (not merely one with an open left or
3702 right), to make sure that lefts and rights of descendents
3703 correspond properly to bit masks. We use the rightmost descendent
3704 of x. We could use any other leaf, but this is easy to locate and
3705 tends to counteract removal of leftmosts elsewhere, and so keeps
3706 paths shorter than minimally guaranteed. This doesn't loop much
3707 because on average a node in a tree is near the bottom.
3708 3. If x is the base of a chain (i.e., has parent links) relink
3709 x's parent and children to x's replacement (or null if none).
3710 */
3711
3712 #define unlink_large_chunk(M, X) {\
3713 tchunkptr XP = X->parent;\
3714 tchunkptr R;\
3715 if (X->bk != X) {\
3716 tchunkptr F = X->fd;\
3717 R = X->bk;\
3718 if (RTCHECK(ok_address(M, F) && F->bk == X && R->fd == X)) {\
3719 F->bk = R;\
3720 R->fd = F;\
3721 }\
3722 else {\
3723 CORRUPTION_ERROR_ACTION(M);\
3724 }\
3725 }\
3726 else {\
3727 tchunkptr* RP;\
3728 if (((R = *(RP = &(X->child[1]))) != 0) ||\
3729 ((R = *(RP = &(X->child[0]))) != 0)) {\
3730 tchunkptr* CP;\
3731 while ((*(CP = &(R->child[1])) != 0) ||\
3732 (*(CP = &(R->child[0])) != 0)) {\
3733 R = *(RP = CP);\
3734 }\
3735 if (RTCHECK(ok_address(M, RP)))\
3736 *RP = 0;\
3737 else {\
3738 CORRUPTION_ERROR_ACTION(M);\
3739 }\
3740 }\
3741 }\
3742 if (XP != 0) {\
3743 tbinptr* H = treebin_at(M, X->index);\
3744 if (X == *H) {\
3745 if ((*H = R) == 0) \
3746 clear_treemap(M, X->index);\
3747 }\
3748 else if (RTCHECK(ok_address(M, XP))) {\
3749 if (XP->child[0] == X) \
3750 XP->child[0] = R;\
3751 else \
3752 XP->child[1] = R;\
3753 }\
3754 else\
3755 CORRUPTION_ERROR_ACTION(M);\
3756 if (R != 0) {\
3757 if (RTCHECK(ok_address(M, R))) {\
3758 tchunkptr C0, C1;\
3759 R->parent = XP;\
3760 if ((C0 = X->child[0]) != 0) {\
3761 if (RTCHECK(ok_address(M, C0))) {\
3762 R->child[0] = C0;\
3763 C0->parent = R;\
3764 }\
3765 else\
3766 CORRUPTION_ERROR_ACTION(M);\
3767 }\
3768 if ((C1 = X->child[1]) != 0) {\
3769 if (RTCHECK(ok_address(M, C1))) {\
3770 R->child[1] = C1;\
3771 C1->parent = R;\
3772 }\
3773 else\
3774 CORRUPTION_ERROR_ACTION(M);\
3775 }\
3776 }\
3777 else\
3778 CORRUPTION_ERROR_ACTION(M);\
3779 }\
3780 }\
3781 }
3782
3783 /* Relays to large vs small bin operations */
3784
3785 #define insert_chunk(M, P, S)\
3786 if (is_small(S)) insert_small_chunk(M, P, S)\
3787 else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
3788
3789 #define unlink_chunk(M, P, S)\
3790 if (is_small(S)) unlink_small_chunk(M, P, S)\
3791 else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
3792
3793
3794 /* Relays to internal calls to malloc/free from realloc, memalign etc */
3795
3796 #if ONLY_MSPACES
3797 #define internal_malloc(m, b) mspace_malloc(m, b)
3798 #define internal_free(m, mem) mspace_free(m,mem);
3799 #else /* ONLY_MSPACES */
3800 #if MSPACES
3801 #define internal_malloc(m, b)\
3802 ((m == gm)? dlmalloc(b) : mspace_malloc(m, b))
3803 #define internal_free(m, mem)\
3804 if (m == gm) dlfree(mem); else mspace_free(m,mem);
3805 #else /* MSPACES */
3806 #define internal_malloc(m, b) dlmalloc(b)
3807 #define internal_free(m, mem) dlfree(mem)
3808 #endif /* MSPACES */
3809 #endif /* ONLY_MSPACES */
3810
3811 /* ----------------------- Direct-mmapping chunks ----------------------- */
3812
3813 /*
3814 Directly mmapped chunks are set up with an offset to the start of
3815 the mmapped region stored in the prev_foot field of the chunk. This
3816 allows reconstruction of the required argument to MUNMAP when freed,
3817 and also allows adjustment of the returned chunk to meet alignment
3818 requirements (especially in memalign).
3819 */
3820
3821 /* Malloc using mmap */
mmap_alloc(mstate m,size_t nb)3822 static void* mmap_alloc(mstate m, size_t nb) {
3823 size_t mmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
3824 if (m->footprint_limit != 0) {
3825 size_t fp = m->footprint + mmsize;
3826 if (fp <= m->footprint || fp > m->footprint_limit)
3827 return 0;
3828 }
3829 if (mmsize > nb) { /* Check for wrap around 0 */
3830 char* mm = (char*)(CALL_DIRECT_MMAP(mmsize));
3831 if (mm != CMFAIL) {
3832 size_t offset = align_offset(chunk2mem(mm));
3833 size_t psize = mmsize - offset - MMAP_FOOT_PAD;
3834 mchunkptr p = (mchunkptr)(mm + offset);
3835 p->prev_foot = offset;
3836 p->head = psize;
3837 mark_inuse_foot(m, p, psize);
3838 chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
3839 chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
3840
3841 if (m->least_addr == 0 || mm < m->least_addr)
3842 m->least_addr = mm;
3843 if ((m->footprint += mmsize) > m->max_footprint)
3844 m->max_footprint = m->footprint;
3845 assert(is_aligned(chunk2mem(p)));
3846 check_mmapped_chunk(m, p);
3847 return chunk2mem(p);
3848 }
3849 }
3850 return 0;
3851 }
3852
3853 /* Realloc using mmap */
mmap_resize(mstate m,mchunkptr oldp,size_t nb,int flags)3854 static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb, int flags) {
3855 size_t oldsize = chunksize(oldp);
3856 (void)flags; /* placate people compiling -Wunused */
3857 if (is_small(nb)) /* Can't shrink mmap regions below small size */
3858 return 0;
3859 /* Keep old chunk if big enough but not too big */
3860 if (oldsize >= nb + SIZE_T_SIZE &&
3861 (oldsize - nb) <= (mparams.granularity << 1))
3862 return oldp;
3863 else {
3864 size_t offset = oldp->prev_foot;
3865 size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
3866 size_t newmmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
3867 char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
3868 oldmmsize, newmmsize, flags);
3869 if (cp != CMFAIL) {
3870 mchunkptr newp = (mchunkptr)(cp + offset);
3871 size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
3872 newp->head = psize;
3873 mark_inuse_foot(m, newp, psize);
3874 chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
3875 chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
3876
3877 if (cp < m->least_addr)
3878 m->least_addr = cp;
3879 if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
3880 m->max_footprint = m->footprint;
3881 check_mmapped_chunk(m, newp);
3882 return newp;
3883 }
3884 }
3885 return 0;
3886 }
3887
3888
3889 /* -------------------------- mspace management -------------------------- */
3890
3891 /* Initialize top chunk and its size */
init_top(mstate m,mchunkptr p,size_t psize)3892 static void init_top(mstate m, mchunkptr p, size_t psize) {
3893 /* Ensure alignment */
3894 size_t offset = align_offset(chunk2mem(p));
3895 p = (mchunkptr)((char*)p + offset);
3896 psize -= offset;
3897
3898 m->top = p;
3899 m->topsize = psize;
3900 p->head = psize | PINUSE_BIT;
3901 /* set size of fake trailing chunk holding overhead space only once */
3902 chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
3903 m->trim_check = mparams.trim_threshold; /* reset on each update */
3904 }
3905
3906 /* Initialize bins for a new mstate that is otherwise zeroed out */
init_bins(mstate m)3907 static void init_bins(mstate m) {
3908 /* Establish circular links for smallbins */
3909 bindex_t i;
3910 for (i = 0; i < NSMALLBINS; ++i) {
3911 sbinptr bin = smallbin_at(m,i);
3912 bin->fd = bin->bk = bin;
3913 }
3914 }
3915
3916 #if PROCEED_ON_ERROR
3917
3918 /* default corruption action */
reset_on_error(mstate m)3919 static void reset_on_error(mstate m) {
3920 int i;
3921 ++malloc_corruption_error_count;
3922 /* Reinitialize fields to forget about all memory */
3923 m->smallmap = m->treemap = 0;
3924 m->dvsize = m->topsize = 0;
3925 m->seg.base = 0;
3926 m->seg.size = 0;
3927 m->seg.next = 0;
3928 m->top = m->dv = 0;
3929 for (i = 0; i < NTREEBINS; ++i)
3930 *treebin_at(m, i) = 0;
3931 init_bins(m);
3932 }
3933 #endif /* PROCEED_ON_ERROR */
3934
3935 /* Allocate chunk and prepend remainder with chunk in successor base. */
prepend_alloc(mstate m,char * newbase,char * oldbase,size_t nb)3936 static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
3937 size_t nb) {
3938 mchunkptr p = align_as_chunk(newbase);
3939 mchunkptr oldfirst = align_as_chunk(oldbase);
3940 size_t psize = (char*)oldfirst - (char*)p;
3941 mchunkptr q = chunk_plus_offset(p, nb);
3942 size_t qsize = psize - nb;
3943 set_size_and_pinuse_of_inuse_chunk(m, p, nb);
3944
3945 assert((char*)oldfirst > (char*)q);
3946 assert(pinuse(oldfirst));
3947 assert(qsize >= MIN_CHUNK_SIZE);
3948
3949 /* consolidate remainder with first chunk of old base */
3950 if (oldfirst == m->top) {
3951 size_t tsize = m->topsize += qsize;
3952 m->top = q;
3953 q->head = tsize | PINUSE_BIT;
3954 check_top_chunk(m, q);
3955 }
3956 else if (oldfirst == m->dv) {
3957 size_t dsize = m->dvsize += qsize;
3958 m->dv = q;
3959 set_size_and_pinuse_of_free_chunk(q, dsize);
3960 }
3961 else {
3962 if (!is_inuse(oldfirst)) {
3963 size_t nsize = chunksize(oldfirst);
3964 unlink_chunk(m, oldfirst, nsize);
3965 oldfirst = chunk_plus_offset(oldfirst, nsize);
3966 qsize += nsize;
3967 }
3968 set_free_with_pinuse(q, qsize, oldfirst);
3969 insert_chunk(m, q, qsize);
3970 check_free_chunk(m, q);
3971 }
3972
3973 check_malloced_chunk(m, chunk2mem(p), nb);
3974 return chunk2mem(p);
3975 }
3976
3977 /* Add a segment to hold a new noncontiguous region */
add_segment(mstate m,char * tbase,size_t tsize,flag_t mmapped)3978 static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
3979 /* Determine locations and sizes of segment, fenceposts, old top */
3980 char* old_top = (char*)m->top;
3981 msegmentptr oldsp = segment_holding(m, old_top);
3982 char* old_end = oldsp->base + oldsp->size;
3983 size_t ssize = pad_request(sizeof(struct malloc_segment));
3984 char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
3985 size_t offset = align_offset(chunk2mem(rawsp));
3986 char* asp = rawsp + offset;
3987 char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
3988 mchunkptr sp = (mchunkptr)csp;
3989 msegmentptr ss = (msegmentptr)(chunk2mem(sp));
3990 mchunkptr tnext = chunk_plus_offset(sp, ssize);
3991 mchunkptr p = tnext;
3992 int nfences = 0;
3993
3994 /* reset top to new space */
3995 init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
3996
3997 /* Set up segment record */
3998 assert(is_aligned(ss));
3999 set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
4000 *ss = m->seg; /* Push current record */
4001 m->seg.base = tbase;
4002 m->seg.size = tsize;
4003 m->seg.sflags = mmapped;
4004 m->seg.next = ss;
4005
4006 /* Insert trailing fenceposts */
4007 for (;;) {
4008 mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
4009 p->head = FENCEPOST_HEAD;
4010 ++nfences;
4011 if ((char*)(&(nextp->head)) < old_end)
4012 p = nextp;
4013 else
4014 break;
4015 }
4016 assert(nfences >= 2);
4017
4018 /* Insert the rest of old top into a bin as an ordinary free chunk */
4019 if (csp != old_top) {
4020 mchunkptr q = (mchunkptr)old_top;
4021 size_t psize = csp - old_top;
4022 mchunkptr tn = chunk_plus_offset(q, psize);
4023 set_free_with_pinuse(q, psize, tn);
4024 insert_chunk(m, q, psize);
4025 }
4026
4027 check_top_chunk(m, m->top);
4028 }
4029
4030 /* -------------------------- System allocation -------------------------- */
4031
4032 /* Get memory from system using MORECORE or MMAP */
sys_alloc(mstate m,size_t nb)4033 static void* sys_alloc(mstate m, size_t nb) {
4034 char* tbase = CMFAIL;
4035 size_t tsize = 0;
4036 flag_t mmap_flag = 0;
4037 size_t asize; /* allocation size */
4038
4039 ensure_initialization();
4040
4041 /* Directly map large chunks, but only if already initialized */
4042 if (use_mmap(m) && nb >= mparams.mmap_threshold && m->topsize != 0) {
4043 void* mem = mmap_alloc(m, nb);
4044 if (mem != 0)
4045 return mem;
4046 }
4047
4048 asize = granularity_align(nb + SYS_ALLOC_PADDING);
4049 if (asize <= nb)
4050 return 0; /* wraparound */
4051 if (m->footprint_limit != 0) {
4052 size_t fp = m->footprint + asize;
4053 if (fp <= m->footprint || fp > m->footprint_limit)
4054 return 0;
4055 }
4056
4057 /*
4058 Try getting memory in any of three ways (in most-preferred to
4059 least-preferred order):
4060 1. A call to MORECORE that can normally contiguously extend memory.
4061 (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
4062 or main space is mmapped or a previous contiguous call failed)
4063 2. A call to MMAP new space (disabled if not HAVE_MMAP).
4064 Note that under the default settings, if MORECORE is unable to
4065 fulfill a request, and HAVE_MMAP is true, then mmap is
4066 used as a noncontiguous system allocator. This is a useful backup
4067 strategy for systems with holes in address spaces -- in this case
4068 sbrk cannot contiguously expand the heap, but mmap may be able to
4069 find space.
4070 3. A call to MORECORE that cannot usually contiguously extend memory.
4071 (disabled if not HAVE_MORECORE)
4072
4073 In all cases, we need to request enough bytes from system to ensure
4074 we can malloc nb bytes upon success, so pad with enough space for
4075 top_foot, plus alignment-pad to make sure we don't lose bytes if
4076 not on boundary, and round this up to a granularity unit.
4077 */
4078
4079 if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
4080 char* br = CMFAIL;
4081 size_t ssize = asize; /* sbrk call size */
4082 msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
4083 ACQUIRE_MALLOC_GLOBAL_LOCK();
4084
4085 if (ss == 0) { /* First time through or recovery */
4086 char* base = (char*)CALL_MORECORE(0);
4087 if (base != CMFAIL) {
4088 size_t fp;
4089 /* Adjust to end on a page boundary */
4090 if (!is_page_aligned(base))
4091 ssize += (page_align((size_t)base) - (size_t)base);
4092 fp = m->footprint + ssize; /* recheck limits */
4093 if (ssize > nb && ssize < HALF_MAX_SIZE_T &&
4094 (m->footprint_limit == 0 ||
4095 (fp > m->footprint && fp <= m->footprint_limit)) &&
4096 (br = (char*)(CALL_MORECORE(ssize))) == base) {
4097 tbase = base;
4098 tsize = ssize;
4099 }
4100 }
4101 }
4102 else {
4103 /* Subtract out existing available top space from MORECORE request. */
4104 ssize = granularity_align(nb - m->topsize + SYS_ALLOC_PADDING);
4105 /* Use mem here only if it did continuously extend old space */
4106 if (ssize < HALF_MAX_SIZE_T &&
4107 (br = (char*)(CALL_MORECORE(ssize))) == ss->base+ss->size) {
4108 tbase = br;
4109 tsize = ssize;
4110 }
4111 }
4112
4113 if (tbase == CMFAIL) { /* Cope with partial failure */
4114 if (br != CMFAIL) { /* Try to use/extend the space we did get */
4115 if (ssize < HALF_MAX_SIZE_T &&
4116 ssize < nb + SYS_ALLOC_PADDING) {
4117 size_t esize = granularity_align(nb + SYS_ALLOC_PADDING - ssize);
4118 if (esize < HALF_MAX_SIZE_T) {
4119 char* end = (char*)CALL_MORECORE(esize);
4120 if (end != CMFAIL)
4121 ssize += esize;
4122 else { /* Can't use; try to release */
4123 (void) CALL_MORECORE(-ssize);
4124 br = CMFAIL;
4125 }
4126 }
4127 }
4128 }
4129 if (br != CMFAIL) { /* Use the space we did get */
4130 tbase = br;
4131 tsize = ssize;
4132 }
4133 else
4134 disable_contiguous(m); /* Don't try contiguous path in the future */
4135 }
4136
4137 RELEASE_MALLOC_GLOBAL_LOCK();
4138 }
4139
4140 if (HAVE_MMAP && tbase == CMFAIL) { /* Try MMAP */
4141 char* mp = (char*)(CALL_MMAP(asize));
4142 if (mp != CMFAIL) {
4143 tbase = mp;
4144 tsize = asize;
4145 mmap_flag = USE_MMAP_BIT;
4146 }
4147 }
4148
4149 if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
4150 if (asize < HALF_MAX_SIZE_T) {
4151 char* br = CMFAIL;
4152 char* end = CMFAIL;
4153 ACQUIRE_MALLOC_GLOBAL_LOCK();
4154 br = (char*)(CALL_MORECORE(asize));
4155 end = (char*)(CALL_MORECORE(0));
4156 RELEASE_MALLOC_GLOBAL_LOCK();
4157 if (br != CMFAIL && end != CMFAIL && br < end) {
4158 size_t ssize = end - br;
4159 if (ssize > nb + TOP_FOOT_SIZE) {
4160 tbase = br;
4161 tsize = ssize;
4162 }
4163 }
4164 }
4165 }
4166
4167 if (tbase != CMFAIL) {
4168
4169 if ((m->footprint += tsize) > m->max_footprint)
4170 m->max_footprint = m->footprint;
4171
4172 if (!is_initialized(m)) { /* first-time initialization */
4173 if (m->least_addr == 0 || tbase < m->least_addr)
4174 m->least_addr = tbase;
4175 m->seg.base = tbase;
4176 m->seg.size = tsize;
4177 m->seg.sflags = mmap_flag;
4178 m->magic = mparams.magic;
4179 m->release_checks = MAX_RELEASE_CHECK_RATE;
4180 init_bins(m);
4181 #if !ONLY_MSPACES
4182 if (is_global(m))
4183 init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
4184 else
4185 #endif
4186 {
4187 /* Offset top by embedded malloc_state */
4188 mchunkptr mn = next_chunk(mem2chunk(m));
4189 init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
4190 }
4191 }
4192
4193 else {
4194 /* Try to merge with an existing segment */
4195 msegmentptr sp = &m->seg;
4196 /* Only consider most recent segment if traversal suppressed */
4197 while (sp != 0 && tbase != sp->base + sp->size)
4198 sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
4199 if (sp != 0 &&
4200 !is_extern_segment(sp) &&
4201 (sp->sflags & USE_MMAP_BIT) == mmap_flag &&
4202 segment_holds(sp, m->top)) { /* append */
4203 sp->size += tsize;
4204 init_top(m, m->top, m->topsize + tsize);
4205 }
4206 else {
4207 if (tbase < m->least_addr)
4208 m->least_addr = tbase;
4209 sp = &m->seg;
4210 while (sp != 0 && sp->base != tbase + tsize)
4211 sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
4212 if (sp != 0 &&
4213 !is_extern_segment(sp) &&
4214 (sp->sflags & USE_MMAP_BIT) == mmap_flag) {
4215 char* oldbase = sp->base;
4216 sp->base = tbase;
4217 sp->size += tsize;
4218 return prepend_alloc(m, tbase, oldbase, nb);
4219 }
4220 else
4221 add_segment(m, tbase, tsize, mmap_flag);
4222 }
4223 }
4224
4225 if (nb < m->topsize) { /* Allocate from new or extended top space */
4226 size_t rsize = m->topsize -= nb;
4227 mchunkptr p = m->top;
4228 mchunkptr r = m->top = chunk_plus_offset(p, nb);
4229 r->head = rsize | PINUSE_BIT;
4230 set_size_and_pinuse_of_inuse_chunk(m, p, nb);
4231 check_top_chunk(m, m->top);
4232 check_malloced_chunk(m, chunk2mem(p), nb);
4233 return chunk2mem(p);
4234 }
4235 }
4236
4237 MALLOC_FAILURE_ACTION;
4238 return 0;
4239 }
4240
4241 /* ----------------------- system deallocation -------------------------- */
4242
4243 /* Unmap and unlink any mmapped segments that don't contain used chunks */
release_unused_segments(mstate m)4244 static size_t release_unused_segments(mstate m) {
4245 size_t released = 0;
4246 int nsegs = 0;
4247 msegmentptr pred = &m->seg;
4248 msegmentptr sp = pred->next;
4249 while (sp != 0) {
4250 char* base = sp->base;
4251 size_t size = sp->size;
4252 msegmentptr next = sp->next;
4253 ++nsegs;
4254 if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
4255 mchunkptr p = align_as_chunk(base);
4256 size_t psize = chunksize(p);
4257 /* Can unmap if first chunk holds entire segment and not pinned */
4258 if (!is_inuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
4259 tchunkptr tp = (tchunkptr)p;
4260 assert(segment_holds(sp, (char*)sp));
4261 if (p == m->dv) {
4262 m->dv = 0;
4263 m->dvsize = 0;
4264 }
4265 else {
4266 unlink_large_chunk(m, tp);
4267 }
4268 if (CALL_MUNMAP(base, size) == 0) {
4269 released += size;
4270 m->footprint -= size;
4271 /* unlink obsoleted record */
4272 sp = pred;
4273 sp->next = next;
4274 }
4275 else { /* back out if cannot unmap */
4276 insert_large_chunk(m, tp, psize);
4277 }
4278 }
4279 }
4280 if (NO_SEGMENT_TRAVERSAL) /* scan only first segment */
4281 break;
4282 pred = sp;
4283 sp = next;
4284 }
4285 /* Reset check counter */
4286 m->release_checks = (((size_t) nsegs > (size_t) MAX_RELEASE_CHECK_RATE)?
4287 (size_t) nsegs : (size_t) MAX_RELEASE_CHECK_RATE);
4288 return released;
4289 }
4290
sys_trim(mstate m,size_t pad)4291 static int sys_trim(mstate m, size_t pad) {
4292 size_t released = 0;
4293 ensure_initialization();
4294 if (pad < MAX_REQUEST && is_initialized(m)) {
4295 pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */
4296
4297 if (m->topsize > pad) {
4298 /* Shrink top space in granularity-size units, keeping at least one */
4299 size_t unit = mparams.granularity;
4300 size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
4301 SIZE_T_ONE) * unit;
4302 msegmentptr sp = segment_holding(m, (char*)m->top);
4303
4304 if (!is_extern_segment(sp)) {
4305 if (is_mmapped_segment(sp)) {
4306 if (HAVE_MMAP &&
4307 sp->size >= extra &&
4308 !has_segment_link(m, sp)) { /* can't shrink if pinned */
4309 size_t newsize = sp->size - extra;
4310 (void)newsize; /* placate people compiling -Wunused-variable */
4311 /* Prefer mremap, fall back to munmap */
4312 if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
4313 (CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
4314 released = extra;
4315 }
4316 }
4317 }
4318 else if (HAVE_MORECORE) {
4319 if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
4320 extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
4321 ACQUIRE_MALLOC_GLOBAL_LOCK();
4322 {
4323 /* Make sure end of memory is where we last set it. */
4324 char* old_br = (char*)(CALL_MORECORE(0));
4325 if (old_br == sp->base + sp->size) {
4326 char* rel_br = (char*)(CALL_MORECORE(-extra));
4327 char* new_br = (char*)(CALL_MORECORE(0));
4328 if (rel_br != CMFAIL && new_br < old_br)
4329 released = old_br - new_br;
4330 }
4331 }
4332 RELEASE_MALLOC_GLOBAL_LOCK();
4333 }
4334 }
4335
4336 if (released != 0) {
4337 sp->size -= released;
4338 m->footprint -= released;
4339 init_top(m, m->top, m->topsize - released);
4340 check_top_chunk(m, m->top);
4341 }
4342 }
4343
4344 /* Unmap any unused mmapped segments */
4345 if (HAVE_MMAP)
4346 released += release_unused_segments(m);
4347
4348 /* On failure, disable autotrim to avoid repeated failed future calls */
4349 if (released == 0 && m->topsize > m->trim_check)
4350 m->trim_check = MAX_SIZE_T;
4351 }
4352
4353 return (released != 0)? 1 : 0;
4354 }
4355
4356 /* Consolidate and bin a chunk. Differs from exported versions
4357 of free mainly in that the chunk need not be marked as inuse.
4358 */
dispose_chunk(mstate m,mchunkptr p,size_t psize)4359 static void dispose_chunk(mstate m, mchunkptr p, size_t psize) {
4360 mchunkptr next = chunk_plus_offset(p, psize);
4361 if (!pinuse(p)) {
4362 mchunkptr prev;
4363 size_t prevsize = p->prev_foot;
4364 if (is_mmapped(p)) {
4365 psize += prevsize + MMAP_FOOT_PAD;
4366 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
4367 m->footprint -= psize;
4368 return;
4369 }
4370 prev = chunk_minus_offset(p, prevsize);
4371 psize += prevsize;
4372 p = prev;
4373 if (RTCHECK(ok_address(m, prev))) { /* consolidate backward */
4374 if (p != m->dv) {
4375 unlink_chunk(m, p, prevsize);
4376 }
4377 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
4378 m->dvsize = psize;
4379 set_free_with_pinuse(p, psize, next);
4380 return;
4381 }
4382 }
4383 else {
4384 CORRUPTION_ERROR_ACTION(m);
4385 return;
4386 }
4387 }
4388 if (RTCHECK(ok_address(m, next))) {
4389 if (!cinuse(next)) { /* consolidate forward */
4390 if (next == m->top) {
4391 size_t tsize = m->topsize += psize;
4392 m->top = p;
4393 p->head = tsize | PINUSE_BIT;
4394 if (p == m->dv) {
4395 m->dv = 0;
4396 m->dvsize = 0;
4397 }
4398 return;
4399 }
4400 else if (next == m->dv) {
4401 size_t dsize = m->dvsize += psize;
4402 m->dv = p;
4403 set_size_and_pinuse_of_free_chunk(p, dsize);
4404 return;
4405 }
4406 else {
4407 size_t nsize = chunksize(next);
4408 psize += nsize;
4409 unlink_chunk(m, next, nsize);
4410 set_size_and_pinuse_of_free_chunk(p, psize);
4411 if (p == m->dv) {
4412 m->dvsize = psize;
4413 return;
4414 }
4415 }
4416 }
4417 else {
4418 set_free_with_pinuse(p, psize, next);
4419 }
4420 insert_chunk(m, p, psize);
4421 }
4422 else {
4423 CORRUPTION_ERROR_ACTION(m);
4424 }
4425 }
4426
4427 /* ---------------------------- malloc --------------------------- */
4428
4429 /* allocate a large request from the best fitting chunk in a treebin */
tmalloc_large(mstate m,size_t nb)4430 static void* tmalloc_large(mstate m, size_t nb) {
4431 tchunkptr v = 0;
4432 size_t rsize = -nb; /* Unsigned negation */
4433 tchunkptr t;
4434 bindex_t idx;
4435 compute_tree_index(nb, idx);
4436 if ((t = *treebin_at(m, idx)) != 0) {
4437 /* Traverse tree for this bin looking for node with size == nb */
4438 size_t sizebits = nb << leftshift_for_tree_index(idx);
4439 tchunkptr rst = 0; /* The deepest untaken right subtree */
4440 for (;;) {
4441 tchunkptr rt;
4442 size_t trem = chunksize(t) - nb;
4443 if (trem < rsize) {
4444 v = t;
4445 if ((rsize = trem) == 0)
4446 break;
4447 }
4448 rt = t->child[1];
4449 t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
4450 if (rt != 0 && rt != t)
4451 rst = rt;
4452 if (t == 0) {
4453 t = rst; /* set t to least subtree holding sizes > nb */
4454 break;
4455 }
4456 sizebits <<= 1;
4457 }
4458 }
4459 if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
4460 binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
4461 if (leftbits != 0) {
4462 bindex_t i;
4463 binmap_t leastbit = least_bit(leftbits);
4464 compute_bit2idx(leastbit, i);
4465 t = *treebin_at(m, i);
4466 }
4467 }
4468
4469 while (t != 0) { /* find smallest of tree or subtree */
4470 size_t trem = chunksize(t) - nb;
4471 if (trem < rsize) {
4472 rsize = trem;
4473 v = t;
4474 }
4475 t = leftmost_child(t);
4476 }
4477
4478 /* If dv is a better fit, return 0 so malloc will use it */
4479 if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
4480 if (RTCHECK(ok_address(m, v))) { /* split */
4481 mchunkptr r = chunk_plus_offset(v, nb);
4482 assert(chunksize(v) == rsize + nb);
4483 if (RTCHECK(ok_next(v, r))) {
4484 unlink_large_chunk(m, v);
4485 if (rsize < MIN_CHUNK_SIZE)
4486 set_inuse_and_pinuse(m, v, (rsize + nb));
4487 else {
4488 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
4489 set_size_and_pinuse_of_free_chunk(r, rsize);
4490 insert_chunk(m, r, rsize);
4491 }
4492 return chunk2mem(v);
4493 }
4494 }
4495 CORRUPTION_ERROR_ACTION(m);
4496 }
4497 return 0;
4498 }
4499
4500 /* allocate a small request from the best fitting chunk in a treebin */
tmalloc_small(mstate m,size_t nb)4501 static void* tmalloc_small(mstate m, size_t nb) {
4502 tchunkptr t, v;
4503 size_t rsize;
4504 bindex_t i;
4505 binmap_t leastbit = least_bit(m->treemap);
4506 compute_bit2idx(leastbit, i);
4507 v = t = *treebin_at(m, i);
4508 rsize = chunksize(t) - nb;
4509
4510 while ((t = leftmost_child(t)) != 0) {
4511 size_t trem = chunksize(t) - nb;
4512 if (trem < rsize) {
4513 rsize = trem;
4514 v = t;
4515 }
4516 }
4517
4518 if (RTCHECK(ok_address(m, v))) {
4519 mchunkptr r = chunk_plus_offset(v, nb);
4520 assert(chunksize(v) == rsize + nb);
4521 if (RTCHECK(ok_next(v, r))) {
4522 unlink_large_chunk(m, v);
4523 if (rsize < MIN_CHUNK_SIZE)
4524 set_inuse_and_pinuse(m, v, (rsize + nb));
4525 else {
4526 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
4527 set_size_and_pinuse_of_free_chunk(r, rsize);
4528 replace_dv(m, r, rsize);
4529 }
4530 return chunk2mem(v);
4531 }
4532 }
4533
4534 CORRUPTION_ERROR_ACTION(m);
4535 return 0;
4536 }
4537
4538 #if !ONLY_MSPACES
4539
dlmalloc(size_t bytes)4540 void* dlmalloc(size_t bytes) {
4541 /*
4542 Basic algorithm:
4543 If a small request (< 256 bytes minus per-chunk overhead):
4544 1. If one exists, use a remainderless chunk in associated smallbin.
4545 (Remainderless means that there are too few excess bytes to
4546 represent as a chunk.)
4547 2. If it is big enough, use the dv chunk, which is normally the
4548 chunk adjacent to the one used for the most recent small request.
4549 3. If one exists, split the smallest available chunk in a bin,
4550 saving remainder in dv.
4551 4. If it is big enough, use the top chunk.
4552 5. If available, get memory from system and use it
4553 Otherwise, for a large request:
4554 1. Find the smallest available binned chunk that fits, and use it
4555 if it is better fitting than dv chunk, splitting if necessary.
4556 2. If better fitting than any binned chunk, use the dv chunk.
4557 3. If it is big enough, use the top chunk.
4558 4. If request size >= mmap threshold, try to directly mmap this chunk.
4559 5. If available, get memory from system and use it
4560
4561 The ugly goto's here ensure that postaction occurs along all paths.
4562 */
4563
4564 #if USE_LOCKS
4565 ensure_initialization(); /* initialize in sys_alloc if not using locks */
4566 #endif
4567
4568 if (!PREACTION(gm)) {
4569 void* mem;
4570 size_t nb;
4571 if (bytes <= MAX_SMALL_REQUEST) {
4572 bindex_t idx;
4573 binmap_t smallbits;
4574 nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
4575 idx = small_index(nb);
4576 smallbits = gm->smallmap >> idx;
4577
4578 if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
4579 mchunkptr b, p;
4580 idx += ~smallbits & 1; /* Uses next bin if idx empty */
4581 b = smallbin_at(gm, idx);
4582 p = b->fd;
4583 assert(chunksize(p) == small_index2size(idx));
4584 unlink_first_small_chunk(gm, b, p, idx);
4585 set_inuse_and_pinuse(gm, p, small_index2size(idx));
4586 mem = chunk2mem(p);
4587 check_malloced_chunk(gm, mem, nb);
4588 goto postaction;
4589 }
4590
4591 else if (nb > gm->dvsize) {
4592 if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
4593 mchunkptr b, p, r;
4594 size_t rsize;
4595 bindex_t i;
4596 binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
4597 binmap_t leastbit = least_bit(leftbits);
4598 compute_bit2idx(leastbit, i);
4599 b = smallbin_at(gm, i);
4600 p = b->fd;
4601 assert(chunksize(p) == small_index2size(i));
4602 unlink_first_small_chunk(gm, b, p, i);
4603 rsize = small_index2size(i) - nb;
4604 /* Fit here cannot be remainderless if 4byte sizes */
4605 if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
4606 set_inuse_and_pinuse(gm, p, small_index2size(i));
4607 else {
4608 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
4609 r = chunk_plus_offset(p, nb);
4610 set_size_and_pinuse_of_free_chunk(r, rsize);
4611 replace_dv(gm, r, rsize);
4612 }
4613 mem = chunk2mem(p);
4614 check_malloced_chunk(gm, mem, nb);
4615 goto postaction;
4616 }
4617
4618 else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
4619 check_malloced_chunk(gm, mem, nb);
4620 goto postaction;
4621 }
4622 }
4623 }
4624 else if (bytes >= MAX_REQUEST)
4625 nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
4626 else {
4627 nb = pad_request(bytes);
4628 if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
4629 check_malloced_chunk(gm, mem, nb);
4630 goto postaction;
4631 }
4632 }
4633
4634 if (nb <= gm->dvsize) {
4635 size_t rsize = gm->dvsize - nb;
4636 mchunkptr p = gm->dv;
4637 if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
4638 mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
4639 gm->dvsize = rsize;
4640 set_size_and_pinuse_of_free_chunk(r, rsize);
4641 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
4642 }
4643 else { /* exhaust dv */
4644 size_t dvs = gm->dvsize;
4645 gm->dvsize = 0;
4646 gm->dv = 0;
4647 set_inuse_and_pinuse(gm, p, dvs);
4648 }
4649 mem = chunk2mem(p);
4650 check_malloced_chunk(gm, mem, nb);
4651 goto postaction;
4652 }
4653
4654 else if (nb < gm->topsize) { /* Split top */
4655 size_t rsize = gm->topsize -= nb;
4656 mchunkptr p = gm->top;
4657 mchunkptr r = gm->top = chunk_plus_offset(p, nb);
4658 r->head = rsize | PINUSE_BIT;
4659 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
4660 mem = chunk2mem(p);
4661 check_top_chunk(gm, gm->top);
4662 check_malloced_chunk(gm, mem, nb);
4663 goto postaction;
4664 }
4665
4666 mem = sys_alloc(gm, nb);
4667
4668 postaction:
4669 POSTACTION(gm);
4670 return mem;
4671 }
4672
4673 return 0;
4674 }
4675
4676 /* ---------------------------- free --------------------------- */
4677
dlfree(void * mem)4678 void dlfree(void* mem) {
4679 /*
4680 Consolidate freed chunks with preceeding or succeeding bordering
4681 free chunks, if they exist, and then place in a bin. Intermixed
4682 with special cases for top, dv, mmapped chunks, and usage errors.
4683 */
4684
4685 if (mem != 0) {
4686 mchunkptr p = mem2chunk(mem);
4687 #if FOOTERS
4688 mstate fm = get_mstate_for(p);
4689 if (!ok_magic(fm)) {
4690 USAGE_ERROR_ACTION(fm, p);
4691 return;
4692 }
4693 #else /* FOOTERS */
4694 #define fm gm
4695 #endif /* FOOTERS */
4696 if (!PREACTION(fm)) {
4697 check_inuse_chunk(fm, p);
4698 if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
4699 size_t psize = chunksize(p);
4700 mchunkptr next = chunk_plus_offset(p, psize);
4701 if (!pinuse(p)) {
4702 size_t prevsize = p->prev_foot;
4703 if (is_mmapped(p)) {
4704 psize += prevsize + MMAP_FOOT_PAD;
4705 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
4706 fm->footprint -= psize;
4707 goto postaction;
4708 }
4709 else {
4710 mchunkptr prev = chunk_minus_offset(p, prevsize);
4711 psize += prevsize;
4712 p = prev;
4713 if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
4714 if (p != fm->dv) {
4715 unlink_chunk(fm, p, prevsize);
4716 }
4717 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
4718 fm->dvsize = psize;
4719 set_free_with_pinuse(p, psize, next);
4720 goto postaction;
4721 }
4722 }
4723 else
4724 goto erroraction;
4725 }
4726 }
4727
4728 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
4729 if (!cinuse(next)) { /* consolidate forward */
4730 if (next == fm->top) {
4731 size_t tsize = fm->topsize += psize;
4732 fm->top = p;
4733 p->head = tsize | PINUSE_BIT;
4734 if (p == fm->dv) {
4735 fm->dv = 0;
4736 fm->dvsize = 0;
4737 }
4738 if (should_trim(fm, tsize))
4739 sys_trim(fm, 0);
4740 goto postaction;
4741 }
4742 else if (next == fm->dv) {
4743 size_t dsize = fm->dvsize += psize;
4744 fm->dv = p;
4745 set_size_and_pinuse_of_free_chunk(p, dsize);
4746 goto postaction;
4747 }
4748 else {
4749 size_t nsize = chunksize(next);
4750 psize += nsize;
4751 unlink_chunk(fm, next, nsize);
4752 set_size_and_pinuse_of_free_chunk(p, psize);
4753 if (p == fm->dv) {
4754 fm->dvsize = psize;
4755 goto postaction;
4756 }
4757 }
4758 }
4759 else
4760 set_free_with_pinuse(p, psize, next);
4761
4762 if (is_small(psize)) {
4763 insert_small_chunk(fm, p, psize);
4764 check_free_chunk(fm, p);
4765 }
4766 else {
4767 tchunkptr tp = (tchunkptr)p;
4768 insert_large_chunk(fm, tp, psize);
4769 check_free_chunk(fm, p);
4770 if (--fm->release_checks == 0)
4771 release_unused_segments(fm);
4772 }
4773 goto postaction;
4774 }
4775 }
4776 erroraction:
4777 USAGE_ERROR_ACTION(fm, p);
4778 postaction:
4779 POSTACTION(fm);
4780 }
4781 }
4782 #if !FOOTERS
4783 #undef fm
4784 #endif /* FOOTERS */
4785 }
4786
dlcalloc(size_t n_elements,size_t elem_size)4787 void* dlcalloc(size_t n_elements, size_t elem_size) {
4788 void* mem;
4789 size_t req = 0;
4790 if (n_elements != 0) {
4791 req = n_elements * elem_size;
4792 if (((n_elements | elem_size) & ~(size_t)0xffff) &&
4793 (req / n_elements != elem_size))
4794 req = MAX_SIZE_T; /* force downstream failure on overflow */
4795 }
4796 mem = dlmalloc(req);
4797 if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
4798 memset(mem, 0, req);
4799 return mem;
4800 }
4801
4802 #endif /* !ONLY_MSPACES */
4803
4804 /* ------------ Internal support for realloc, memalign, etc -------------- */
4805
4806 /* Try to realloc; only in-place unless can_move true */
try_realloc_chunk(mstate m,mchunkptr p,size_t nb,int can_move)4807 static mchunkptr try_realloc_chunk(mstate m, mchunkptr p, size_t nb,
4808 int can_move) {
4809 mchunkptr newp = 0;
4810 size_t oldsize = chunksize(p);
4811 mchunkptr next = chunk_plus_offset(p, oldsize);
4812 if (RTCHECK(ok_address(m, p) && ok_inuse(p) &&
4813 ok_next(p, next) && ok_pinuse(next))) {
4814 if (is_mmapped(p)) {
4815 newp = mmap_resize(m, p, nb, can_move);
4816 }
4817 else if (oldsize >= nb) { /* already big enough */
4818 size_t rsize = oldsize - nb;
4819 if (rsize >= MIN_CHUNK_SIZE) { /* split off remainder */
4820 mchunkptr r = chunk_plus_offset(p, nb);
4821 set_inuse(m, p, nb);
4822 set_inuse(m, r, rsize);
4823 dispose_chunk(m, r, rsize);
4824 }
4825 newp = p;
4826 }
4827 else if (next == m->top) { /* extend into top */
4828 if (oldsize + m->topsize > nb) {
4829 size_t newsize = oldsize + m->topsize;
4830 size_t newtopsize = newsize - nb;
4831 mchunkptr newtop = chunk_plus_offset(p, nb);
4832 set_inuse(m, p, nb);
4833 newtop->head = newtopsize |PINUSE_BIT;
4834 m->top = newtop;
4835 m->topsize = newtopsize;
4836 newp = p;
4837 }
4838 }
4839 else if (next == m->dv) { /* extend into dv */
4840 size_t dvs = m->dvsize;
4841 if (oldsize + dvs >= nb) {
4842 size_t dsize = oldsize + dvs - nb;
4843 if (dsize >= MIN_CHUNK_SIZE) {
4844 mchunkptr r = chunk_plus_offset(p, nb);
4845 mchunkptr n = chunk_plus_offset(r, dsize);
4846 set_inuse(m, p, nb);
4847 set_size_and_pinuse_of_free_chunk(r, dsize);
4848 clear_pinuse(n);
4849 m->dvsize = dsize;
4850 m->dv = r;
4851 }
4852 else { /* exhaust dv */
4853 size_t newsize = oldsize + dvs;
4854 set_inuse(m, p, newsize);
4855 m->dvsize = 0;
4856 m->dv = 0;
4857 }
4858 newp = p;
4859 }
4860 }
4861 else if (!cinuse(next)) { /* extend into next free chunk */
4862 size_t nextsize = chunksize(next);
4863 if (oldsize + nextsize >= nb) {
4864 size_t rsize = oldsize + nextsize - nb;
4865 unlink_chunk(m, next, nextsize);
4866 if (rsize < MIN_CHUNK_SIZE) {
4867 size_t newsize = oldsize + nextsize;
4868 set_inuse(m, p, newsize);
4869 }
4870 else {
4871 mchunkptr r = chunk_plus_offset(p, nb);
4872 set_inuse(m, p, nb);
4873 set_inuse(m, r, rsize);
4874 dispose_chunk(m, r, rsize);
4875 }
4876 newp = p;
4877 }
4878 }
4879 }
4880 else {
4881 USAGE_ERROR_ACTION(m, chunk2mem(p));
4882 }
4883 return newp;
4884 }
4885
internal_memalign(mstate m,size_t alignment,size_t bytes)4886 static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
4887 void* mem = 0;
4888 if (alignment < MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
4889 alignment = MIN_CHUNK_SIZE;
4890 if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
4891 size_t a = MALLOC_ALIGNMENT << 1;
4892 while (a < alignment) a <<= 1;
4893 alignment = a;
4894 }
4895 if (bytes >= MAX_REQUEST - alignment) {
4896 if (m != 0) { /* Test isn't needed but avoids compiler warning */
4897 MALLOC_FAILURE_ACTION;
4898 }
4899 }
4900 else {
4901 size_t nb = request2size(bytes);
4902 size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
4903 mem = internal_malloc(m, req);
4904 if (mem != 0) {
4905 mchunkptr p = mem2chunk(mem);
4906 if (PREACTION(m))
4907 return 0;
4908 if ((((size_t)(mem)) & (alignment - 1)) != 0) { /* misaligned */
4909 /*
4910 Find an aligned spot inside chunk. Since we need to give
4911 back leading space in a chunk of at least MIN_CHUNK_SIZE, if
4912 the first calculation places us at a spot with less than
4913 MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
4914 We've allocated enough total room so that this is always
4915 possible.
4916 */
4917 char* br = (char*)mem2chunk((size_t)(((size_t)((char*)mem + alignment -
4918 SIZE_T_ONE)) &
4919 -alignment));
4920 char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
4921 br : br+alignment;
4922 mchunkptr newp = (mchunkptr)pos;
4923 size_t leadsize = pos - (char*)(p);
4924 size_t newsize = chunksize(p) - leadsize;
4925
4926 if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
4927 newp->prev_foot = p->prev_foot + leadsize;
4928 newp->head = newsize;
4929 }
4930 else { /* Otherwise, give back leader, use the rest */
4931 set_inuse(m, newp, newsize);
4932 set_inuse(m, p, leadsize);
4933 dispose_chunk(m, p, leadsize);
4934 }
4935 p = newp;
4936 }
4937
4938 /* Give back spare room at the end */
4939 if (!is_mmapped(p)) {
4940 size_t size = chunksize(p);
4941 if (size > nb + MIN_CHUNK_SIZE) {
4942 size_t remainder_size = size - nb;
4943 mchunkptr remainder = chunk_plus_offset(p, nb);
4944 set_inuse(m, p, nb);
4945 set_inuse(m, remainder, remainder_size);
4946 dispose_chunk(m, remainder, remainder_size);
4947 }
4948 }
4949
4950 mem = chunk2mem(p);
4951 assert (chunksize(p) >= nb);
4952 assert(((size_t)mem & (alignment - 1)) == 0);
4953 check_inuse_chunk(m, p);
4954 POSTACTION(m);
4955 }
4956 }
4957 return mem;
4958 }
4959
4960 /*
4961 Common support for independent_X routines, handling
4962 all of the combinations that can result.
4963 The opts arg has:
4964 bit 0 set if all elements are same size (using sizes[0])
4965 bit 1 set if elements should be zeroed
4966 */
ialloc(mstate m,size_t n_elements,size_t * sizes,int opts,void * chunks[])4967 static void** ialloc(mstate m,
4968 size_t n_elements,
4969 size_t* sizes,
4970 int opts,
4971 void* chunks[]) {
4972
4973 size_t element_size; /* chunksize of each element, if all same */
4974 size_t contents_size; /* total size of elements */
4975 size_t array_size; /* request size of pointer array */
4976 void* mem; /* malloced aggregate space */
4977 mchunkptr p; /* corresponding chunk */
4978 size_t remainder_size; /* remaining bytes while splitting */
4979 void** marray; /* either "chunks" or malloced ptr array */
4980 mchunkptr array_chunk; /* chunk for malloced ptr array */
4981 flag_t was_enabled; /* to disable mmap */
4982 size_t size;
4983 size_t i;
4984
4985 ensure_initialization();
4986 /* compute array length, if needed */
4987 if (chunks != 0) {
4988 if (n_elements == 0)
4989 return chunks; /* nothing to do */
4990 marray = chunks;
4991 array_size = 0;
4992 }
4993 else {
4994 /* if empty req, must still return chunk representing empty array */
4995 if (n_elements == 0)
4996 return (void**)internal_malloc(m, 0);
4997 marray = 0;
4998 array_size = request2size(n_elements * (sizeof(void*)));
4999 }
5000
5001 /* compute total element size */
5002 if (opts & 0x1) { /* all-same-size */
5003 element_size = request2size(*sizes);
5004 contents_size = n_elements * element_size;
5005 }
5006 else { /* add up all the sizes */
5007 element_size = 0;
5008 contents_size = 0;
5009 for (i = 0; i != n_elements; ++i)
5010 contents_size += request2size(sizes[i]);
5011 }
5012
5013 size = contents_size + array_size;
5014
5015 /*
5016 Allocate the aggregate chunk. First disable direct-mmapping so
5017 malloc won't use it, since we would not be able to later
5018 free/realloc space internal to a segregated mmap region.
5019 */
5020 was_enabled = use_mmap(m);
5021 disable_mmap(m);
5022 mem = internal_malloc(m, size - CHUNK_OVERHEAD);
5023 if (was_enabled)
5024 enable_mmap(m);
5025 if (mem == 0)
5026 return 0;
5027
5028 if (PREACTION(m)) return 0;
5029 p = mem2chunk(mem);
5030 remainder_size = chunksize(p);
5031
5032 assert(!is_mmapped(p));
5033
5034 if (opts & 0x2) { /* optionally clear the elements */
5035 memset((size_t*)mem, 0, remainder_size - SIZE_T_SIZE - array_size);
5036 }
5037
5038 /* If not provided, allocate the pointer array as final part of chunk */
5039 if (marray == 0) {
5040 size_t array_chunk_size;
5041 array_chunk = chunk_plus_offset(p, contents_size);
5042 array_chunk_size = remainder_size - contents_size;
5043 marray = (void**) (chunk2mem(array_chunk));
5044 set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
5045 remainder_size = contents_size;
5046 }
5047
5048 /* split out elements */
5049 for (i = 0; ; ++i) {
5050 marray[i] = chunk2mem(p);
5051 if (i != n_elements-1) {
5052 if (element_size != 0)
5053 size = element_size;
5054 else
5055 size = request2size(sizes[i]);
5056 remainder_size -= size;
5057 set_size_and_pinuse_of_inuse_chunk(m, p, size);
5058 p = chunk_plus_offset(p, size);
5059 }
5060 else { /* the final element absorbs any overallocation slop */
5061 set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
5062 break;
5063 }
5064 }
5065
5066 #if DEBUG
5067 if (marray != chunks) {
5068 /* final element must have exactly exhausted chunk */
5069 if (element_size != 0) {
5070 assert(remainder_size == element_size);
5071 }
5072 else {
5073 assert(remainder_size == request2size(sizes[i]));
5074 }
5075 check_inuse_chunk(m, mem2chunk(marray));
5076 }
5077 for (i = 0; i != n_elements; ++i)
5078 check_inuse_chunk(m, mem2chunk(marray[i]));
5079
5080 #endif /* DEBUG */
5081
5082 POSTACTION(m);
5083 return marray;
5084 }
5085
5086 /* Try to free all pointers in the given array.
5087 Note: this could be made faster, by delaying consolidation,
5088 at the price of disabling some user integrity checks, We
5089 still optimize some consolidations by combining adjacent
5090 chunks before freeing, which will occur often if allocated
5091 with ialloc or the array is sorted.
5092 */
internal_bulk_free(mstate m,void * array[],size_t nelem)5093 static size_t internal_bulk_free(mstate m, void* array[], size_t nelem) {
5094 size_t unfreed = 0;
5095 if (!PREACTION(m)) {
5096 void** a;
5097 void** fence = &(array[nelem]);
5098 for (a = array; a != fence; ++a) {
5099 void* mem = *a;
5100 if (mem != 0) {
5101 mchunkptr p = mem2chunk(mem);
5102 size_t psize = chunksize(p);
5103 #if FOOTERS
5104 if (get_mstate_for(p) != m) {
5105 ++unfreed;
5106 continue;
5107 }
5108 #endif
5109 check_inuse_chunk(m, p);
5110 *a = 0;
5111 if (RTCHECK(ok_address(m, p) && ok_inuse(p))) {
5112 void ** b = a + 1; /* try to merge with next chunk */
5113 mchunkptr next = next_chunk(p);
5114 if (b != fence && *b == chunk2mem(next)) {
5115 size_t newsize = chunksize(next) + psize;
5116 set_inuse(m, p, newsize);
5117 *b = chunk2mem(p);
5118 }
5119 else
5120 dispose_chunk(m, p, psize);
5121 }
5122 else {
5123 CORRUPTION_ERROR_ACTION(m);
5124 break;
5125 }
5126 }
5127 }
5128 if (should_trim(m, m->topsize))
5129 sys_trim(m, 0);
5130 POSTACTION(m);
5131 }
5132 return unfreed;
5133 }
5134
5135 /* Traversal */
5136 #if MALLOC_INSPECT_ALL
internal_inspect_all(mstate m,void (* handler)(void * start,void * end,size_t used_bytes,void * callback_arg),void * arg)5137 static void internal_inspect_all(mstate m,
5138 void(*handler)(void *start,
5139 void *end,
5140 size_t used_bytes,
5141 void* callback_arg),
5142 void* arg) {
5143 if (is_initialized(m)) {
5144 mchunkptr top = m->top;
5145 msegmentptr s;
5146 for (s = &m->seg; s != 0; s = s->next) {
5147 mchunkptr q = align_as_chunk(s->base);
5148 while (segment_holds(s, q) && q->head != FENCEPOST_HEAD) {
5149 mchunkptr next = next_chunk(q);
5150 size_t sz = chunksize(q);
5151 size_t used;
5152 void* start;
5153 if (is_inuse(q)) {
5154 used = sz - CHUNK_OVERHEAD; /* must not be mmapped */
5155 start = chunk2mem(q);
5156 }
5157 else {
5158 used = 0;
5159 if (is_small(sz)) { /* offset by possible bookkeeping */
5160 start = (void*)((char*)q + sizeof(struct malloc_chunk));
5161 }
5162 else {
5163 start = (void*)((char*)q + sizeof(struct malloc_tree_chunk));
5164 }
5165 }
5166 if (start < (void*)next) /* skip if all space is bookkeeping */
5167 handler(start, next, used, arg);
5168 if (q == top)
5169 break;
5170 q = next;
5171 }
5172 }
5173 }
5174 }
5175 #endif /* MALLOC_INSPECT_ALL */
5176
5177 /* ------------------ Exported realloc, memalign, etc -------------------- */
5178
5179 #if !ONLY_MSPACES
5180
dlrealloc(void * oldmem,size_t bytes)5181 void* dlrealloc(void* oldmem, size_t bytes) {
5182 void* mem = 0;
5183 if (oldmem == 0) {
5184 mem = dlmalloc(bytes);
5185 }
5186 else if (bytes >= MAX_REQUEST) {
5187 MALLOC_FAILURE_ACTION;
5188 }
5189 #ifdef REALLOC_ZERO_BYTES_FREES
5190 else if (bytes == 0) {
5191 dlfree(oldmem);
5192 }
5193 #endif /* REALLOC_ZERO_BYTES_FREES */
5194 else {
5195 size_t nb = request2size(bytes);
5196 mchunkptr oldp = mem2chunk(oldmem);
5197 #if ! FOOTERS
5198 mstate m = gm;
5199 #else /* FOOTERS */
5200 mstate m = get_mstate_for(oldp);
5201 if (!ok_magic(m)) {
5202 USAGE_ERROR_ACTION(m, oldmem);
5203 return 0;
5204 }
5205 #endif /* FOOTERS */
5206 if (!PREACTION(m)) {
5207 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
5208 POSTACTION(m);
5209 if (newp != 0) {
5210 check_inuse_chunk(m, newp);
5211 mem = chunk2mem(newp);
5212 }
5213 else {
5214 mem = internal_malloc(m, bytes);
5215 if (mem != 0) {
5216 size_t oc = chunksize(oldp) - overhead_for(oldp);
5217 memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
5218 internal_free(m, oldmem);
5219 }
5220 }
5221 }
5222 }
5223 return mem;
5224 }
5225
dlrealloc_in_place(void * oldmem,size_t bytes)5226 void* dlrealloc_in_place(void* oldmem, size_t bytes) {
5227 void* mem = 0;
5228 if (oldmem != 0) {
5229 if (bytes >= MAX_REQUEST) {
5230 MALLOC_FAILURE_ACTION;
5231 }
5232 else {
5233 size_t nb = request2size(bytes);
5234 mchunkptr oldp = mem2chunk(oldmem);
5235 #if ! FOOTERS
5236 mstate m = gm;
5237 #else /* FOOTERS */
5238 mstate m = get_mstate_for(oldp);
5239 if (!ok_magic(m)) {
5240 USAGE_ERROR_ACTION(m, oldmem);
5241 return 0;
5242 }
5243 #endif /* FOOTERS */
5244 if (!PREACTION(m)) {
5245 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
5246 POSTACTION(m);
5247 if (newp == oldp) {
5248 check_inuse_chunk(m, newp);
5249 mem = oldmem;
5250 }
5251 }
5252 }
5253 }
5254 return mem;
5255 }
5256
dlmemalign(size_t alignment,size_t bytes)5257 void* dlmemalign(size_t alignment, size_t bytes) {
5258 if (alignment <= MALLOC_ALIGNMENT) {
5259 return dlmalloc(bytes);
5260 }
5261 return internal_memalign(gm, alignment, bytes);
5262 }
5263
dlposix_memalign(void ** pp,size_t alignment,size_t bytes)5264 int dlposix_memalign(void** pp, size_t alignment, size_t bytes) {
5265 void* mem = 0;
5266 if (alignment == MALLOC_ALIGNMENT)
5267 mem = dlmalloc(bytes);
5268 else {
5269 size_t d = alignment / sizeof(void*);
5270 size_t r = alignment % sizeof(void*);
5271 if (r != 0 || d == 0 || (d & (d-SIZE_T_ONE)) != 0)
5272 return EINVAL;
5273 else if (bytes <= MAX_REQUEST - alignment) {
5274 if (alignment < MIN_CHUNK_SIZE)
5275 alignment = MIN_CHUNK_SIZE;
5276 mem = internal_memalign(gm, alignment, bytes);
5277 }
5278 }
5279 if (mem == 0)
5280 return ENOMEM;
5281 else {
5282 *pp = mem;
5283 return 0;
5284 }
5285 }
5286
dlvalloc(size_t bytes)5287 void* dlvalloc(size_t bytes) {
5288 size_t pagesz;
5289 ensure_initialization();
5290 pagesz = mparams.page_size;
5291 return dlmemalign(pagesz, bytes);
5292 }
5293
dlpvalloc(size_t bytes)5294 void* dlpvalloc(size_t bytes) {
5295 size_t pagesz;
5296 ensure_initialization();
5297 pagesz = mparams.page_size;
5298 return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
5299 }
5300
dlindependent_calloc(size_t n_elements,size_t elem_size,void * chunks[])5301 void** dlindependent_calloc(size_t n_elements, size_t elem_size,
5302 void* chunks[]) {
5303 size_t sz = elem_size; /* serves as 1-element array */
5304 return ialloc(gm, n_elements, &sz, 3, chunks);
5305 }
5306
dlindependent_comalloc(size_t n_elements,size_t sizes[],void * chunks[])5307 void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
5308 void* chunks[]) {
5309 return ialloc(gm, n_elements, sizes, 0, chunks);
5310 }
5311
dlbulk_free(void * array[],size_t nelem)5312 size_t dlbulk_free(void* array[], size_t nelem) {
5313 return internal_bulk_free(gm, array, nelem);
5314 }
5315
5316 #if MALLOC_INSPECT_ALL
dlmalloc_inspect_all(void (* handler)(void * start,void * end,size_t used_bytes,void * callback_arg),void * arg)5317 void dlmalloc_inspect_all(void(*handler)(void *start,
5318 void *end,
5319 size_t used_bytes,
5320 void* callback_arg),
5321 void* arg) {
5322 ensure_initialization();
5323 if (!PREACTION(gm)) {
5324 internal_inspect_all(gm, handler, arg);
5325 POSTACTION(gm);
5326 }
5327 }
5328 #endif /* MALLOC_INSPECT_ALL */
5329
dlmalloc_trim(size_t pad)5330 int dlmalloc_trim(size_t pad) {
5331 int result = 0;
5332 ensure_initialization();
5333 if (!PREACTION(gm)) {
5334 result = sys_trim(gm, pad);
5335 POSTACTION(gm);
5336 }
5337 return result;
5338 }
5339
dlmalloc_footprint(void)5340 size_t dlmalloc_footprint(void) {
5341 return gm->footprint;
5342 }
5343
dlmalloc_max_footprint(void)5344 size_t dlmalloc_max_footprint(void) {
5345 return gm->max_footprint;
5346 }
5347
dlmalloc_footprint_limit(void)5348 size_t dlmalloc_footprint_limit(void) {
5349 size_t maf = gm->footprint_limit;
5350 return maf == 0 ? MAX_SIZE_T : maf;
5351 }
5352
dlmalloc_set_footprint_limit(size_t bytes)5353 size_t dlmalloc_set_footprint_limit(size_t bytes) {
5354 size_t result; /* invert sense of 0 */
5355 if (bytes == 0)
5356 result = granularity_align(1); /* Use minimal size */
5357 if (bytes == MAX_SIZE_T)
5358 result = 0; /* disable */
5359 else
5360 result = granularity_align(bytes);
5361 return gm->footprint_limit = result;
5362 }
5363
5364 #if !NO_MALLINFO
dlmallinfo(void)5365 struct mallinfo dlmallinfo(void) {
5366 return internal_mallinfo(gm);
5367 }
5368 #endif /* NO_MALLINFO */
5369
5370 #if !NO_MALLOC_STATS
dlmalloc_stats()5371 void dlmalloc_stats() {
5372 internal_malloc_stats(gm);
5373 }
5374 #endif /* NO_MALLOC_STATS */
5375
dlmallopt(int param_number,int value)5376 int dlmallopt(int param_number, int value) {
5377 return change_mparam(param_number, value);
5378 }
5379
dlmalloc_usable_size(void * mem)5380 size_t dlmalloc_usable_size(void* mem) {
5381 if (mem != 0) {
5382 mchunkptr p = mem2chunk(mem);
5383 if (is_inuse(p))
5384 return chunksize(p) - overhead_for(p);
5385 }
5386 return 0;
5387 }
5388
5389 #endif /* !ONLY_MSPACES */
5390
5391 /* ----------------------------- user mspaces ---------------------------- */
5392
5393 #if MSPACES
5394
init_user_mstate(char * tbase,size_t tsize)5395 static mstate init_user_mstate(char* tbase, size_t tsize) {
5396 size_t msize = pad_request(sizeof(struct malloc_state));
5397 mchunkptr mn;
5398 mchunkptr msp = align_as_chunk(tbase);
5399 mstate m = (mstate)(chunk2mem(msp));
5400 memset(m, 0, msize);
5401 (void)INITIAL_LOCK(&m->mutex);
5402 msp->head = (msize|INUSE_BITS);
5403 m->seg.base = m->least_addr = tbase;
5404 m->seg.size = m->footprint = m->max_footprint = tsize;
5405 m->magic = mparams.magic;
5406 m->release_checks = MAX_RELEASE_CHECK_RATE;
5407 m->mflags = mparams.default_mflags;
5408 m->extp = 0;
5409 m->exts = 0;
5410 disable_contiguous(m);
5411 init_bins(m);
5412 mn = next_chunk(mem2chunk(m));
5413 init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) - TOP_FOOT_SIZE);
5414 check_top_chunk(m, m->top);
5415 return m;
5416 }
5417
create_mspace(size_t capacity,int locked)5418 mspace create_mspace(size_t capacity, int locked) {
5419 mstate m = 0;
5420 size_t msize;
5421 ensure_initialization();
5422 msize = pad_request(sizeof(struct malloc_state));
5423 if (capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
5424 size_t rs = ((capacity == 0)? mparams.granularity :
5425 (capacity + TOP_FOOT_SIZE + msize));
5426 size_t tsize = granularity_align(rs);
5427 char* tbase = (char*)(CALL_MMAP(tsize));
5428 if (tbase != CMFAIL) {
5429 m = init_user_mstate(tbase, tsize);
5430 m->seg.sflags = USE_MMAP_BIT;
5431 set_lock(m, locked);
5432 }
5433 }
5434 return (mspace)m;
5435 }
5436
create_mspace_with_base(void * base,size_t capacity,int locked)5437 mspace create_mspace_with_base(void* base, size_t capacity, int locked) {
5438 mstate m = 0;
5439 size_t msize;
5440 ensure_initialization();
5441 msize = pad_request(sizeof(struct malloc_state));
5442 if (capacity > msize + TOP_FOOT_SIZE &&
5443 capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
5444 m = init_user_mstate((char*)base, capacity);
5445 m->seg.sflags = EXTERN_BIT;
5446 set_lock(m, locked);
5447 }
5448 return (mspace)m;
5449 }
5450
mspace_track_large_chunks(mspace msp,int enable)5451 int mspace_track_large_chunks(mspace msp, int enable) {
5452 int ret = 0;
5453 mstate ms = (mstate)msp;
5454 if (!PREACTION(ms)) {
5455 if (!use_mmap(ms)) {
5456 ret = 1;
5457 }
5458 if (!enable) {
5459 enable_mmap(ms);
5460 } else {
5461 disable_mmap(ms);
5462 }
5463 POSTACTION(ms);
5464 }
5465 return ret;
5466 }
5467
destroy_mspace(mspace msp)5468 size_t destroy_mspace(mspace msp) {
5469 size_t freed = 0;
5470 mstate ms = (mstate)msp;
5471 if (ok_magic(ms)) {
5472 msegmentptr sp = &ms->seg;
5473 (void)DESTROY_LOCK(&ms->mutex); /* destroy before unmapped */
5474 while (sp != 0) {
5475 char* base = sp->base;
5476 size_t size = sp->size;
5477 flag_t flag = sp->sflags;
5478 (void)base; /* placate people compiling -Wunused-variable */
5479 sp = sp->next;
5480 if ((flag & USE_MMAP_BIT) && !(flag & EXTERN_BIT) &&
5481 CALL_MUNMAP(base, size) == 0)
5482 freed += size;
5483 }
5484 }
5485 else {
5486 USAGE_ERROR_ACTION(ms,ms);
5487 }
5488 return freed;
5489 }
5490
5491 /*
5492 mspace versions of routines are near-clones of the global
5493 versions. This is not so nice but better than the alternatives.
5494 */
5495
mspace_malloc(mspace msp,size_t bytes)5496 void* mspace_malloc(mspace msp, size_t bytes) {
5497 mstate ms = (mstate)msp;
5498 if (!ok_magic(ms)) {
5499 USAGE_ERROR_ACTION(ms,ms);
5500 return 0;
5501 }
5502 if (!PREACTION(ms)) {
5503 void* mem;
5504 size_t nb;
5505 if (bytes <= MAX_SMALL_REQUEST) {
5506 bindex_t idx;
5507 binmap_t smallbits;
5508 nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
5509 idx = small_index(nb);
5510 smallbits = ms->smallmap >> idx;
5511
5512 if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
5513 mchunkptr b, p;
5514 idx += ~smallbits & 1; /* Uses next bin if idx empty */
5515 b = smallbin_at(ms, idx);
5516 p = b->fd;
5517 assert(chunksize(p) == small_index2size(idx));
5518 unlink_first_small_chunk(ms, b, p, idx);
5519 set_inuse_and_pinuse(ms, p, small_index2size(idx));
5520 mem = chunk2mem(p);
5521 check_malloced_chunk(ms, mem, nb);
5522 goto postaction;
5523 }
5524
5525 else if (nb > ms->dvsize) {
5526 if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
5527 mchunkptr b, p, r;
5528 size_t rsize;
5529 bindex_t i;
5530 binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
5531 binmap_t leastbit = least_bit(leftbits);
5532 compute_bit2idx(leastbit, i);
5533 b = smallbin_at(ms, i);
5534 p = b->fd;
5535 assert(chunksize(p) == small_index2size(i));
5536 unlink_first_small_chunk(ms, b, p, i);
5537 rsize = small_index2size(i) - nb;
5538 /* Fit here cannot be remainderless if 4byte sizes */
5539 if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
5540 set_inuse_and_pinuse(ms, p, small_index2size(i));
5541 else {
5542 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
5543 r = chunk_plus_offset(p, nb);
5544 set_size_and_pinuse_of_free_chunk(r, rsize);
5545 replace_dv(ms, r, rsize);
5546 }
5547 mem = chunk2mem(p);
5548 check_malloced_chunk(ms, mem, nb);
5549 goto postaction;
5550 }
5551
5552 else if (ms->treemap != 0 && (mem = tmalloc_small(ms, nb)) != 0) {
5553 check_malloced_chunk(ms, mem, nb);
5554 goto postaction;
5555 }
5556 }
5557 }
5558 else if (bytes >= MAX_REQUEST)
5559 nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
5560 else {
5561 nb = pad_request(bytes);
5562 if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
5563 check_malloced_chunk(ms, mem, nb);
5564 goto postaction;
5565 }
5566 }
5567
5568 if (nb <= ms->dvsize) {
5569 size_t rsize = ms->dvsize - nb;
5570 mchunkptr p = ms->dv;
5571 if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
5572 mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
5573 ms->dvsize = rsize;
5574 set_size_and_pinuse_of_free_chunk(r, rsize);
5575 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
5576 }
5577 else { /* exhaust dv */
5578 size_t dvs = ms->dvsize;
5579 ms->dvsize = 0;
5580 ms->dv = 0;
5581 set_inuse_and_pinuse(ms, p, dvs);
5582 }
5583 mem = chunk2mem(p);
5584 check_malloced_chunk(ms, mem, nb);
5585 goto postaction;
5586 }
5587
5588 else if (nb < ms->topsize) { /* Split top */
5589 size_t rsize = ms->topsize -= nb;
5590 mchunkptr p = ms->top;
5591 mchunkptr r = ms->top = chunk_plus_offset(p, nb);
5592 r->head = rsize | PINUSE_BIT;
5593 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
5594 mem = chunk2mem(p);
5595 check_top_chunk(ms, ms->top);
5596 check_malloced_chunk(ms, mem, nb);
5597 goto postaction;
5598 }
5599
5600 mem = sys_alloc(ms, nb);
5601
5602 postaction:
5603 POSTACTION(ms);
5604 return mem;
5605 }
5606
5607 return 0;
5608 }
5609
mspace_free(mspace msp,void * mem)5610 void mspace_free(mspace msp, void* mem) {
5611 if (mem != 0) {
5612 mchunkptr p = mem2chunk(mem);
5613 #if FOOTERS
5614 mstate fm = get_mstate_for(p);
5615 (void)msp; /* placate people compiling -Wunused */
5616 #else /* FOOTERS */
5617 mstate fm = (mstate)msp;
5618 #endif /* FOOTERS */
5619 if (!ok_magic(fm)) {
5620 USAGE_ERROR_ACTION(fm, p);
5621 return;
5622 }
5623 if (!PREACTION(fm)) {
5624 check_inuse_chunk(fm, p);
5625 if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
5626 size_t psize = chunksize(p);
5627 mchunkptr next = chunk_plus_offset(p, psize);
5628 if (!pinuse(p)) {
5629 size_t prevsize = p->prev_foot;
5630 if (is_mmapped(p)) {
5631 psize += prevsize + MMAP_FOOT_PAD;
5632 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
5633 fm->footprint -= psize;
5634 goto postaction;
5635 }
5636 else {
5637 mchunkptr prev = chunk_minus_offset(p, prevsize);
5638 psize += prevsize;
5639 p = prev;
5640 if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
5641 if (p != fm->dv) {
5642 unlink_chunk(fm, p, prevsize);
5643 }
5644 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
5645 fm->dvsize = psize;
5646 set_free_with_pinuse(p, psize, next);
5647 goto postaction;
5648 }
5649 }
5650 else
5651 goto erroraction;
5652 }
5653 }
5654
5655 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
5656 if (!cinuse(next)) { /* consolidate forward */
5657 if (next == fm->top) {
5658 size_t tsize = fm->topsize += psize;
5659 fm->top = p;
5660 p->head = tsize | PINUSE_BIT;
5661 if (p == fm->dv) {
5662 fm->dv = 0;
5663 fm->dvsize = 0;
5664 }
5665 if (should_trim(fm, tsize))
5666 sys_trim(fm, 0);
5667 goto postaction;
5668 }
5669 else if (next == fm->dv) {
5670 size_t dsize = fm->dvsize += psize;
5671 fm->dv = p;
5672 set_size_and_pinuse_of_free_chunk(p, dsize);
5673 goto postaction;
5674 }
5675 else {
5676 size_t nsize = chunksize(next);
5677 psize += nsize;
5678 unlink_chunk(fm, next, nsize);
5679 set_size_and_pinuse_of_free_chunk(p, psize);
5680 if (p == fm->dv) {
5681 fm->dvsize = psize;
5682 goto postaction;
5683 }
5684 }
5685 }
5686 else
5687 set_free_with_pinuse(p, psize, next);
5688
5689 if (is_small(psize)) {
5690 insert_small_chunk(fm, p, psize);
5691 check_free_chunk(fm, p);
5692 }
5693 else {
5694 tchunkptr tp = (tchunkptr)p;
5695 insert_large_chunk(fm, tp, psize);
5696 check_free_chunk(fm, p);
5697 if (--fm->release_checks == 0)
5698 release_unused_segments(fm);
5699 }
5700 goto postaction;
5701 }
5702 }
5703 erroraction:
5704 USAGE_ERROR_ACTION(fm, p);
5705 postaction:
5706 POSTACTION(fm);
5707 }
5708 }
5709 }
5710
mspace_calloc(mspace msp,size_t n_elements,size_t elem_size)5711 void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size) {
5712 void* mem;
5713 size_t req = 0;
5714 mstate ms = (mstate)msp;
5715 if (!ok_magic(ms)) {
5716 USAGE_ERROR_ACTION(ms,ms);
5717 return 0;
5718 }
5719 if (n_elements != 0) {
5720 req = n_elements * elem_size;
5721 if (((n_elements | elem_size) & ~(size_t)0xffff) &&
5722 (req / n_elements != elem_size))
5723 req = MAX_SIZE_T; /* force downstream failure on overflow */
5724 }
5725 mem = internal_malloc(ms, req);
5726 if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
5727 memset(mem, 0, req);
5728 return mem;
5729 }
5730
mspace_realloc(mspace msp,void * oldmem,size_t bytes)5731 void* mspace_realloc(mspace msp, void* oldmem, size_t bytes) {
5732 void* mem = 0;
5733 if (oldmem == 0) {
5734 mem = mspace_malloc(msp, bytes);
5735 }
5736 else if (bytes >= MAX_REQUEST) {
5737 MALLOC_FAILURE_ACTION;
5738 }
5739 #ifdef REALLOC_ZERO_BYTES_FREES
5740 else if (bytes == 0) {
5741 mspace_free(msp, oldmem);
5742 }
5743 #endif /* REALLOC_ZERO_BYTES_FREES */
5744 else {
5745 size_t nb = request2size(bytes);
5746 mchunkptr oldp = mem2chunk(oldmem);
5747 #if ! FOOTERS
5748 mstate m = (mstate)msp;
5749 #else /* FOOTERS */
5750 mstate m = get_mstate_for(oldp);
5751 if (!ok_magic(m)) {
5752 USAGE_ERROR_ACTION(m, oldmem);
5753 return 0;
5754 }
5755 #endif /* FOOTERS */
5756 if (!PREACTION(m)) {
5757 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
5758 POSTACTION(m);
5759 if (newp != 0) {
5760 check_inuse_chunk(m, newp);
5761 mem = chunk2mem(newp);
5762 }
5763 else {
5764 mem = mspace_malloc(m, bytes);
5765 if (mem != 0) {
5766 size_t oc = chunksize(oldp) - overhead_for(oldp);
5767 memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
5768 mspace_free(m, oldmem);
5769 }
5770 }
5771 }
5772 }
5773 return mem;
5774 }
5775
mspace_realloc_in_place(mspace msp,void * oldmem,size_t bytes)5776 void* mspace_realloc_in_place(mspace msp, void* oldmem, size_t bytes) {
5777 void* mem = 0;
5778 if (oldmem != 0) {
5779 if (bytes >= MAX_REQUEST) {
5780 MALLOC_FAILURE_ACTION;
5781 }
5782 else {
5783 size_t nb = request2size(bytes);
5784 mchunkptr oldp = mem2chunk(oldmem);
5785 #if ! FOOTERS
5786 mstate m = (mstate)msp;
5787 #else /* FOOTERS */
5788 mstate m = get_mstate_for(oldp);
5789 (void)msp; /* placate people compiling -Wunused */
5790 if (!ok_magic(m)) {
5791 USAGE_ERROR_ACTION(m, oldmem);
5792 return 0;
5793 }
5794 #endif /* FOOTERS */
5795 if (!PREACTION(m)) {
5796 mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
5797 POSTACTION(m);
5798 if (newp == oldp) {
5799 check_inuse_chunk(m, newp);
5800 mem = oldmem;
5801 }
5802 }
5803 }
5804 }
5805 return mem;
5806 }
5807
mspace_memalign(mspace msp,size_t alignment,size_t bytes)5808 void* mspace_memalign(mspace msp, size_t alignment, size_t bytes) {
5809 mstate ms = (mstate)msp;
5810 if (!ok_magic(ms)) {
5811 USAGE_ERROR_ACTION(ms,ms);
5812 return 0;
5813 }
5814 if (alignment <= MALLOC_ALIGNMENT)
5815 return mspace_malloc(msp, bytes);
5816 return internal_memalign(ms, alignment, bytes);
5817 }
5818
mspace_independent_calloc(mspace msp,size_t n_elements,size_t elem_size,void * chunks[])5819 void** mspace_independent_calloc(mspace msp, size_t n_elements,
5820 size_t elem_size, void* chunks[]) {
5821 size_t sz = elem_size; /* serves as 1-element array */
5822 mstate ms = (mstate)msp;
5823 if (!ok_magic(ms)) {
5824 USAGE_ERROR_ACTION(ms,ms);
5825 return 0;
5826 }
5827 return ialloc(ms, n_elements, &sz, 3, chunks);
5828 }
5829
mspace_independent_comalloc(mspace msp,size_t n_elements,size_t sizes[],void * chunks[])5830 void** mspace_independent_comalloc(mspace msp, size_t n_elements,
5831 size_t sizes[], void* chunks[]) {
5832 mstate ms = (mstate)msp;
5833 if (!ok_magic(ms)) {
5834 USAGE_ERROR_ACTION(ms,ms);
5835 return 0;
5836 }
5837 return ialloc(ms, n_elements, sizes, 0, chunks);
5838 }
5839
mspace_bulk_free(mspace msp,void * array[],size_t nelem)5840 size_t mspace_bulk_free(mspace msp, void* array[], size_t nelem) {
5841 return internal_bulk_free((mstate)msp, array, nelem);
5842 }
5843
5844 #if MALLOC_INSPECT_ALL
mspace_inspect_all(mspace msp,void (* handler)(void * start,void * end,size_t used_bytes,void * callback_arg),void * arg)5845 void mspace_inspect_all(mspace msp,
5846 void(*handler)(void *start,
5847 void *end,
5848 size_t used_bytes,
5849 void* callback_arg),
5850 void* arg) {
5851 mstate ms = (mstate)msp;
5852 if (ok_magic(ms)) {
5853 if (!PREACTION(ms)) {
5854 internal_inspect_all(ms, handler, arg);
5855 POSTACTION(ms);
5856 }
5857 }
5858 else {
5859 USAGE_ERROR_ACTION(ms,ms);
5860 }
5861 }
5862 #endif /* MALLOC_INSPECT_ALL */
5863
mspace_trim(mspace msp,size_t pad)5864 int mspace_trim(mspace msp, size_t pad) {
5865 int result = 0;
5866 mstate ms = (mstate)msp;
5867 if (ok_magic(ms)) {
5868 if (!PREACTION(ms)) {
5869 result = sys_trim(ms, pad);
5870 POSTACTION(ms);
5871 }
5872 }
5873 else {
5874 USAGE_ERROR_ACTION(ms,ms);
5875 }
5876 return result;
5877 }
5878
5879 #if !NO_MALLOC_STATS
mspace_malloc_stats(mspace msp)5880 void mspace_malloc_stats(mspace msp) {
5881 mstate ms = (mstate)msp;
5882 if (ok_magic(ms)) {
5883 internal_malloc_stats(ms);
5884 }
5885 else {
5886 USAGE_ERROR_ACTION(ms,ms);
5887 }
5888 }
5889 #endif /* NO_MALLOC_STATS */
5890
mspace_footprint(mspace msp)5891 size_t mspace_footprint(mspace msp) {
5892 size_t result = 0;
5893 mstate ms = (mstate)msp;
5894 if (ok_magic(ms)) {
5895 result = ms->footprint;
5896 }
5897 else {
5898 USAGE_ERROR_ACTION(ms,ms);
5899 }
5900 return result;
5901 }
5902
mspace_max_footprint(mspace msp)5903 size_t mspace_max_footprint(mspace msp) {
5904 size_t result = 0;
5905 mstate ms = (mstate)msp;
5906 if (ok_magic(ms)) {
5907 result = ms->max_footprint;
5908 }
5909 else {
5910 USAGE_ERROR_ACTION(ms,ms);
5911 }
5912 return result;
5913 }
5914
mspace_footprint_limit(mspace msp)5915 size_t mspace_footprint_limit(mspace msp) {
5916 size_t result = 0;
5917 mstate ms = (mstate)msp;
5918 if (ok_magic(ms)) {
5919 size_t maf = ms->footprint_limit;
5920 result = (maf == 0) ? MAX_SIZE_T : maf;
5921 }
5922 else {
5923 USAGE_ERROR_ACTION(ms,ms);
5924 }
5925 return result;
5926 }
5927
mspace_set_footprint_limit(mspace msp,size_t bytes)5928 size_t mspace_set_footprint_limit(mspace msp, size_t bytes) {
5929 size_t result = 0;
5930 mstate ms = (mstate)msp;
5931 if (ok_magic(ms)) {
5932 if (bytes == 0)
5933 result = granularity_align(1); /* Use minimal size */
5934 if (bytes == MAX_SIZE_T)
5935 result = 0; /* disable */
5936 else
5937 result = granularity_align(bytes);
5938 ms->footprint_limit = result;
5939 }
5940 else {
5941 USAGE_ERROR_ACTION(ms,ms);
5942 }
5943 return result;
5944 }
5945
5946 #if !NO_MALLINFO
mspace_mallinfo(mspace msp)5947 struct mallinfo mspace_mallinfo(mspace msp) {
5948 mstate ms = (mstate)msp;
5949 if (!ok_magic(ms)) {
5950 USAGE_ERROR_ACTION(ms,ms);
5951 }
5952 return internal_mallinfo(ms);
5953 }
5954 #endif /* NO_MALLINFO */
5955
mspace_usable_size(const void * mem)5956 size_t mspace_usable_size(const void* mem) {
5957 if (mem != 0) {
5958 mchunkptr p = mem2chunk(mem);
5959 if (is_inuse(p))
5960 return chunksize(p) - overhead_for(p);
5961 }
5962 return 0;
5963 }
5964
mspace_mallopt(int param_number,int value)5965 int mspace_mallopt(int param_number, int value) {
5966 return change_mparam(param_number, value);
5967 }
5968
5969 #endif /* MSPACES */
5970
5971
5972 /* -------------------- Alternative MORECORE functions ------------------- */
5973
5974 /*
5975 Guidelines for creating a custom version of MORECORE:
5976
5977 * For best performance, MORECORE should allocate in multiples of pagesize.
5978 * MORECORE may allocate more memory than requested. (Or even less,
5979 but this will usually result in a malloc failure.)
5980 * MORECORE must not allocate memory when given argument zero, but
5981 instead return one past the end address of memory from previous
5982 nonzero call.
5983 * For best performance, consecutive calls to MORECORE with positive
5984 arguments should return increasing addresses, indicating that
5985 space has been contiguously extended.
5986 * Even though consecutive calls to MORECORE need not return contiguous
5987 addresses, it must be OK for malloc'ed chunks to span multiple
5988 regions in those cases where they do happen to be contiguous.
5989 * MORECORE need not handle negative arguments -- it may instead
5990 just return MFAIL when given negative arguments.
5991 Negative arguments are always multiples of pagesize. MORECORE
5992 must not misinterpret negative args as large positive unsigned
5993 args. You can suppress all such calls from even occurring by defining
5994 MORECORE_CANNOT_TRIM,
5995
5996 As an example alternative MORECORE, here is a custom allocator
5997 kindly contributed for pre-OSX macOS. It uses virtually but not
5998 necessarily physically contiguous non-paged memory (locked in,
5999 present and won't get swapped out). You can use it by uncommenting
6000 this section, adding some #includes, and setting up the appropriate
6001 defines above:
6002
6003 #define MORECORE osMoreCore
6004
6005 There is also a shutdown routine that should somehow be called for
6006 cleanup upon program exit.
6007
6008 #define MAX_POOL_ENTRIES 100
6009 #define MINIMUM_MORECORE_SIZE (64 * 1024U)
6010 static int next_os_pool;
6011 void *our_os_pools[MAX_POOL_ENTRIES];
6012
6013 void *osMoreCore(int size)
6014 {
6015 void *ptr = 0;
6016 static void *sbrk_top = 0;
6017
6018 if (size > 0)
6019 {
6020 if (size < MINIMUM_MORECORE_SIZE)
6021 size = MINIMUM_MORECORE_SIZE;
6022 if (CurrentExecutionLevel() == kTaskLevel)
6023 ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
6024 if (ptr == 0)
6025 {
6026 return (void *) MFAIL;
6027 }
6028 // save ptrs so they can be freed during cleanup
6029 our_os_pools[next_os_pool] = ptr;
6030 next_os_pool++;
6031 ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
6032 sbrk_top = (char *) ptr + size;
6033 return ptr;
6034 }
6035 else if (size < 0)
6036 {
6037 // we don't currently support shrink behavior
6038 return (void *) MFAIL;
6039 }
6040 else
6041 {
6042 return sbrk_top;
6043 }
6044 }
6045
6046 // cleanup any allocated memory pools
6047 // called as last thing before shutting down driver
6048
6049 void osCleanupMem(void)
6050 {
6051 void **ptr;
6052
6053 for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
6054 if (*ptr)
6055 {
6056 PoolDeallocate(*ptr);
6057 *ptr = 0;
6058 }
6059 }
6060
6061 */
6062
6063
6064 /* -----------------------------------------------------------------------
6065 History:
6066 v2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea
6067 * fix bad comparison in dlposix_memalign
6068 * don't reuse adjusted asize in sys_alloc
6069 * add LOCK_AT_FORK -- thanks to Kirill Artamonov for the suggestion
6070 * reduce compiler warnings -- thanks to all who reported/suggested these
6071
6072 v2.8.5 Sun May 22 10:26:02 2011 Doug Lea (dl at gee)
6073 * Always perform unlink checks unless INSECURE
6074 * Add posix_memalign.
6075 * Improve realloc to expand in more cases; expose realloc_in_place.
6076 Thanks to Peter Buhr for the suggestion.
6077 * Add footprint_limit, inspect_all, bulk_free. Thanks
6078 to Barry Hayes and others for the suggestions.
6079 * Internal refactorings to avoid calls while holding locks
6080 * Use non-reentrant locks by default. Thanks to Roland McGrath
6081 for the suggestion.
6082 * Small fixes to mspace_destroy, reset_on_error.
6083 * Various configuration extensions/changes. Thanks
6084 to all who contributed these.
6085
6086 V2.8.4a Thu Apr 28 14:39:43 2011 (dl at gee.cs.oswego.edu)
6087 * Update Creative Commons URL
6088
6089 V2.8.4 Wed May 27 09:56:23 2009 Doug Lea (dl at gee)
6090 * Use zeros instead of prev foot for is_mmapped
6091 * Add mspace_track_large_chunks; thanks to Jean Brouwers
6092 * Fix set_inuse in internal_realloc; thanks to Jean Brouwers
6093 * Fix insufficient sys_alloc padding when using 16byte alignment
6094 * Fix bad error check in mspace_footprint
6095 * Adaptations for ptmalloc; thanks to Wolfram Gloger.
6096 * Reentrant spin locks; thanks to Earl Chew and others
6097 * Win32 improvements; thanks to Niall Douglas and Earl Chew
6098 * Add NO_SEGMENT_TRAVERSAL and MAX_RELEASE_CHECK_RATE options
6099 * Extension hook in malloc_state
6100 * Various small adjustments to reduce warnings on some compilers
6101 * Various configuration extensions/changes for more platforms. Thanks
6102 to all who contributed these.
6103
6104 V2.8.3 Thu Sep 22 11:16:32 2005 Doug Lea (dl at gee)
6105 * Add max_footprint functions
6106 * Ensure all appropriate literals are size_t
6107 * Fix conditional compilation problem for some #define settings
6108 * Avoid concatenating segments with the one provided
6109 in create_mspace_with_base
6110 * Rename some variables to avoid compiler shadowing warnings
6111 * Use explicit lock initialization.
6112 * Better handling of sbrk interference.
6113 * Simplify and fix segment insertion, trimming and mspace_destroy
6114 * Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
6115 * Thanks especially to Dennis Flanagan for help on these.
6116
6117 V2.8.2 Sun Jun 12 16:01:10 2005 Doug Lea (dl at gee)
6118 * Fix memalign brace error.
6119
6120 V2.8.1 Wed Jun 8 16:11:46 2005 Doug Lea (dl at gee)
6121 * Fix improper #endif nesting in C++
6122 * Add explicit casts needed for C++
6123
6124 V2.8.0 Mon May 30 14:09:02 2005 Doug Lea (dl at gee)
6125 * Use trees for large bins
6126 * Support mspaces
6127 * Use segments to unify sbrk-based and mmap-based system allocation,
6128 removing need for emulation on most platforms without sbrk.
6129 * Default safety checks
6130 * Optional footer checks. Thanks to William Robertson for the idea.
6131 * Internal code refactoring
6132 * Incorporate suggestions and platform-specific changes.
6133 Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
6134 Aaron Bachmann, Emery Berger, and others.
6135 * Speed up non-fastbin processing enough to remove fastbins.
6136 * Remove useless cfree() to avoid conflicts with other apps.
6137 * Remove internal memcpy, memset. Compilers handle builtins better.
6138 * Remove some options that no one ever used and rename others.
6139
6140 V2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
6141 * Fix malloc_state bitmap array misdeclaration
6142
6143 V2.7.1 Thu Jul 25 10:58:03 2002 Doug Lea (dl at gee)
6144 * Allow tuning of FIRST_SORTED_BIN_SIZE
6145 * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
6146 * Better detection and support for non-contiguousness of MORECORE.
6147 Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
6148 * Bypass most of malloc if no frees. Thanks To Emery Berger.
6149 * Fix freeing of old top non-contiguous chunk im sysmalloc.
6150 * Raised default trim and map thresholds to 256K.
6151 * Fix mmap-related #defines. Thanks to Lubos Lunak.
6152 * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
6153 * Branch-free bin calculation
6154 * Default trim and mmap thresholds now 256K.
6155
6156 V2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
6157 * Introduce independent_comalloc and independent_calloc.
6158 Thanks to Michael Pachos for motivation and help.
6159 * Make optional .h file available
6160 * Allow > 2GB requests on 32bit systems.
6161 * new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
6162 Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
6163 and Anonymous.
6164 * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
6165 helping test this.)
6166 * memalign: check alignment arg
6167 * realloc: don't try to shift chunks backwards, since this
6168 leads to more fragmentation in some programs and doesn't
6169 seem to help in any others.
6170 * Collect all cases in malloc requiring system memory into sysmalloc
6171 * Use mmap as backup to sbrk
6172 * Place all internal state in malloc_state
6173 * Introduce fastbins (although similar to 2.5.1)
6174 * Many minor tunings and cosmetic improvements
6175 * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
6176 * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
6177 Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
6178 * Include errno.h to support default failure action.
6179
6180 V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
6181 * return null for negative arguments
6182 * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
6183 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
6184 (e.g. WIN32 platforms)
6185 * Cleanup header file inclusion for WIN32 platforms
6186 * Cleanup code to avoid Microsoft Visual C++ compiler complaints
6187 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
6188 memory allocation routines
6189 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
6190 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
6191 usage of 'assert' in non-WIN32 code
6192 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
6193 avoid infinite loop
6194 * Always call 'fREe()' rather than 'free()'
6195
6196 V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
6197 * Fixed ordering problem with boundary-stamping
6198
6199 V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
6200 * Added pvalloc, as recommended by H.J. Liu
6201 * Added 64bit pointer support mainly from Wolfram Gloger
6202 * Added anonymously donated WIN32 sbrk emulation
6203 * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
6204 * malloc_extend_top: fix mask error that caused wastage after
6205 foreign sbrks
6206 * Add linux mremap support code from HJ Liu
6207
6208 V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
6209 * Integrated most documentation with the code.
6210 * Add support for mmap, with help from
6211 Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
6212 * Use last_remainder in more cases.
6213 * Pack bins using idea from colin@nyx10.cs.du.edu
6214 * Use ordered bins instead of best-fit threshhold
6215 * Eliminate block-local decls to simplify tracing and debugging.
6216 * Support another case of realloc via move into top
6217 * Fix error occuring when initial sbrk_base not word-aligned.
6218 * Rely on page size for units instead of SBRK_UNIT to
6219 avoid surprises about sbrk alignment conventions.
6220 * Add mallinfo, mallopt. Thanks to Raymond Nijssen
6221 (raymond@es.ele.tue.nl) for the suggestion.
6222 * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
6223 * More precautions for cases where other routines call sbrk,
6224 courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
6225 * Added macros etc., allowing use in linux libc from
6226 H.J. Lu (hjl@gnu.ai.mit.edu)
6227 * Inverted this history list
6228
6229 V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
6230 * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
6231 * Removed all preallocation code since under current scheme
6232 the work required to undo bad preallocations exceeds
6233 the work saved in good cases for most test programs.
6234 * No longer use return list or unconsolidated bins since
6235 no scheme using them consistently outperforms those that don't
6236 given above changes.
6237 * Use best fit for very large chunks to prevent some worst-cases.
6238 * Added some support for debugging
6239
6240 V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
6241 * Removed footers when chunks are in use. Thanks to
6242 Paul Wilson (wilson@cs.texas.edu) for the suggestion.
6243
6244 V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
6245 * Added malloc_trim, with help from Wolfram Gloger
6246 (wmglo@Dent.MED.Uni-Muenchen.DE).
6247
6248 V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
6249
6250 V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
6251 * realloc: try to expand in both directions
6252 * malloc: swap order of clean-bin strategy;
6253 * realloc: only conditionally expand backwards
6254 * Try not to scavenge used bins
6255 * Use bin counts as a guide to preallocation
6256 * Occasionally bin return list chunks in first scan
6257 * Add a few optimizations from colin@nyx10.cs.du.edu
6258
6259 V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
6260 * faster bin computation & slightly different binning
6261 * merged all consolidations to one part of malloc proper
6262 (eliminating old malloc_find_space & malloc_clean_bin)
6263 * Scan 2 returns chunks (not just 1)
6264 * Propagate failure in realloc if malloc returns 0
6265 * Add stuff to allow compilation on non-ANSI compilers
6266 from kpv@research.att.com
6267
6268 V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
6269 * removed potential for odd address access in prev_chunk
6270 * removed dependency on getpagesize.h
6271 * misc cosmetics and a bit more internal documentation
6272 * anticosmetics: mangled names in macros to evade debugger strangeness
6273 * tested on sparc, hp-700, dec-mips, rs6000
6274 with gcc & native cc (hp, dec only) allowing
6275 Detlefs & Zorn comparison study (in SIGPLAN Notices.)
6276
6277 Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
6278 * Based loosely on libg++-1.2X malloc. (It retains some of the overall
6279 structure of old version, but most details differ.)
6280
6281 */
6282