1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* Copyright (c) The Exim maintainers 2019 - 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
8
9 /* Exim gets and frees all its store through these functions. In the original
10 implementation there was a lot of mallocing and freeing of small bits of store.
11 The philosophy has now changed to a scheme which includes the concept of
12 "stacking pools" of store. For the short-lived processes, there isn't any real
13 need to do any garbage collection, but the stack concept allows quick resetting
14 in places where this seems sensible.
15
16 Obviously the long-running processes (the daemon, the queue runner, and eximon)
17 must take care not to eat store.
18
19 The following different types of store are recognized:
20
21 . Long-lived, large blocks: This is implemented by retaining the original
22 malloc/free functions, and it used for permanent working buffers and for
23 getting blocks to cut up for the other types.
24
25 . Long-lived, small blocks: This is used for blocks that have to survive until
26 the process exits. It is implemented as a stacking pool (POOL_PERM). This is
27 functionally the same as store_malloc(), except that the store can't be
28 freed, but I expect it to be more efficient for handling small blocks.
29
30 . Short-lived, short blocks: Most of the dynamic store falls into this
31 category. It is implemented as a stacking pool (POOL_MAIN) which is reset
32 after accepting a message when multiple messages are received by a single
33 process. Resetting happens at some other times as well, usually fairly
34 locally after some specific processing that needs working store.
35
36 . There is a separate pool (POOL_SEARCH) that is used only for lookup storage.
37 This means it can be freed when search_tidyup() is called to close down all
38 the lookup caching.
39
40 - There is another pool (POOL_MESSAGE) used for medium-lifetime objects; within
41 a single message transaction but needed for longer than the use of the main
42 pool permits. Currently this means only receive-time DKIM information.
43
44 - There is a dedicated pool for configuration data read from the config file(s).
45 Once complete, it is made readonly.
46
47 . Orthogonal to the three pool types, there are two classes of memory: untainted
48 and tainted. The latter is used for values derived from untrusted input, and
49 the string-expansion mechanism refuses to operate on such values (obviously,
50 it can expand an untainted value to return a tainted result). The classes
51 are implemented by duplicating the four pool types. Pool resets are requested
52 against the nontainted sibling and apply to both siblings.
53
54 Only memory blocks requested for tainted use are regarded as tainted; anything
55 else (including stack auto variables) is untainted. Care is needed when coding
56 to not copy untrusted data into untainted memory, as downstream taint-checks
57 would be avoided.
58
59 Intermediate layers (eg. the string functions) can test for taint, and use this
60 for ensurinng that results have proper state. For example the
61 string_vformat_trc() routing supporting the string_sprintf() interface will
62 recopy a string being built into a tainted allocation if it meets a %s for a
63 tainted argument. Any intermediate-layer function that (can) return a new
64 allocation should behave this way; returning a tainted result if any tainted
65 content is used. Intermediate-layer functions (eg. Ustrncpy) that modify
66 existing allocations fail if tainted data is written into an untainted area.
67 Users of functions that modify existing allocations should check if a tainted
68 source and an untainted destination is used, and fail instead (sprintf() being
69 the classic case).
70 */
71
72
73 #include "exim.h"
74 /* keep config.h before memcheck.h, for NVALGRIND */
75 #include "config.h"
76
77 #include <sys/mman.h>
78 #include "memcheck.h"
79
80
81 /* We need to know how to align blocks of data for general use. I'm not sure
82 how to get an alignment factor in general. In the current world, a value of 8
83 is probably right, and this is sizeof(double) on some systems and sizeof(void
84 *) on others, so take the larger of those. Since everything in this expression
85 is a constant, the compiler should optimize it to a simple constant wherever it
86 appears (I checked that gcc does do this). */
87
88 #define alignment \
89 (sizeof(void *) > sizeof(double) ? sizeof(void *) : sizeof(double))
90
91 /* store_reset() will not free the following block if the last used block has
92 less than this much left in it. */
93
94 #define STOREPOOL_MIN_SIZE 256
95
96 /* Structure describing the beginning of each big block. */
97
98 typedef struct storeblock {
99 struct storeblock *next;
100 size_t length;
101 } storeblock;
102
103 /* Just in case we find ourselves on a system where the structure above has a
104 length that is not a multiple of the alignment, set up a macro for the padded
105 length. */
106
107 #define ALIGNED_SIZEOF_STOREBLOCK \
108 (((sizeof(storeblock) + alignment - 1) / alignment) * alignment)
109
110 /* Size of block to get from malloc to carve up into smaller ones. This
111 must be a multiple of the alignment. We assume that 4096 is going to be
112 suitably aligned. Double the size per-pool for every malloc, to mitigate
113 certain denial-of-service attacks. Don't bother to decrease on block frees.
114 We waste average half the current alloc size per pool. This could be several
115 hundred kB now, vs. 4kB with a constant-size block size. But the search time
116 for is_tainted(), linear in the number of blocks for the pool, is O(n log n)
117 rather than O(n^2).
118 A test of 2000 RCPTs and just accept ACL had 370kB in 21 blocks before,
119 504kB in 6 blocks now, for the untainted-main (largest) pool.
120 Builds for restricted-memory system can disable the expansion by
121 defining RESTRICTED_MEMORY */
122 /*XXX should we allow any for malloc's own overhead? But how much? */
123
124 /* #define RESTRICTED_MEMORY */
125 #define STORE_BLOCK_SIZE(order) ((1U << (order)) - ALIGNED_SIZEOF_STOREBLOCK)
126
127 /* Variables holding data for the local pools of store. The current pool number
128 is held in store_pool, which is global so that it can be changed from outside.
129 Setting the initial length values to -1 forces a malloc for the first call,
130 even if the length is zero (which is used for getting a point to reset to). */
131
132 int store_pool = POOL_MAIN;
133
134 static storeblock *chainbase[NPOOLS];
135 static storeblock *current_block[NPOOLS];
136 static void *next_yield[NPOOLS];
137 static int yield_length[NPOOLS];
138 static unsigned store_block_order[NPOOLS];
139
140 /* pool_malloc holds the amount of memory used by the store pools; this goes up
141 and down as store is reset or released. nonpool_malloc is the total got by
142 malloc from other calls; this doesn't go down because it is just freed by
143 pointer. */
144
145 static int pool_malloc;
146 static int nonpool_malloc;
147
148 /* This variable is set by store_get() to its yield, and by store_reset() to
149 NULL. This enables string_cat() to optimize its store handling for very long
150 strings. That's why the variable is global. */
151
152 void *store_last_get[NPOOLS];
153
154 /* These are purely for stats-gathering */
155
156 static int nbytes[NPOOLS]; /* current bytes allocated */
157 static int maxbytes[NPOOLS]; /* max number reached */
158 static int nblocks[NPOOLS]; /* current number of blocks allocated */
159 static int maxblocks[NPOOLS];
160 static unsigned maxorder[NPOOLS];
161 static int n_nonpool_blocks; /* current number of direct store_malloc() blocks */
162 static int max_nonpool_blocks;
163 static int max_pool_malloc; /* max value for pool_malloc */
164 static int max_nonpool_malloc; /* max value for nonpool_malloc */
165
166
167 #ifndef COMPILE_UTILITY
168 static const uschar * pooluse[NPOOLS] = {
169 [POOL_MAIN] = US"main",
170 [POOL_PERM] = US"perm",
171 [POOL_CONFIG] = US"config",
172 [POOL_SEARCH] = US"search",
173 [POOL_MESSAGE] = US"message",
174 [POOL_TAINT_MAIN] = US"main",
175 [POOL_TAINT_PERM] = US"perm",
176 [POOL_TAINT_CONFIG] = US"config",
177 [POOL_TAINT_SEARCH] = US"search",
178 [POOL_TAINT_MESSAGE] = US"message",
179 };
180 static const uschar * poolclass[NPOOLS] = {
181 [POOL_MAIN] = US"untainted",
182 [POOL_PERM] = US"untainted",
183 [POOL_CONFIG] = US"untainted",
184 [POOL_SEARCH] = US"untainted",
185 [POOL_MESSAGE] = US"untainted",
186 [POOL_TAINT_MAIN] = US"tainted",
187 [POOL_TAINT_PERM] = US"tainted",
188 [POOL_TAINT_CONFIG] = US"tainted",
189 [POOL_TAINT_SEARCH] = US"tainted",
190 [POOL_TAINT_MESSAGE] = US"tainted",
191 };
192 #endif
193
194
195 static void * internal_store_malloc(size_t, const char *, int);
196 static void internal_store_free(void *, const char *, int linenumber);
197
198 /******************************************************************************/
199 /* Initialisation, for things fragile with parameter channges when using
200 static initialisers. */
201
202 void
store_init(void)203 store_init(void)
204 {
205 for (int i = 0; i < NPOOLS; i++)
206 {
207 yield_length[i] = -1;
208 store_block_order[i] = 12; /* log2(allocation_size) ie. 4kB */
209 }
210 }
211
212 /******************************************************************************/
213
214 /* Test if a pointer refers to tainted memory.
215
216 Slower version check, for use when platform intermixes malloc and mmap area
217 addresses. Test against the current-block of all tainted pools first, then all
218 blocks of all tainted pools.
219
220 Return: TRUE iff tainted
221 */
222
223 BOOL
is_tainted_fn(const void * p)224 is_tainted_fn(const void * p)
225 {
226 storeblock * b;
227
228 for (int pool = POOL_TAINT_BASE; pool < nelem(chainbase); pool++)
229 if ((b = current_block[pool]))
230 {
231 uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
232 if (US p >= bc && US p < bc + b->length) return TRUE;
233 }
234
235 for (int pool = POOL_TAINT_BASE; pool < nelem(chainbase); pool++)
236 for (b = chainbase[pool]; b; b = b->next)
237 {
238 uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
239 if (US p >= bc && US p < bc + b->length) return TRUE;
240 }
241 return FALSE;
242 }
243
244
245 void
die_tainted(const uschar * msg,const uschar * func,int line)246 die_tainted(const uschar * msg, const uschar * func, int line)
247 {
248 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Taint mismatch, %s: %s %d\n",
249 msg, func, line);
250 }
251
252
253
254 /******************************************************************************/
255 void
store_writeprotect(int pool)256 store_writeprotect(int pool)
257 {
258 #if !defined(COMPILE_UTILITY) && !defined(MISSING_POSIX_MEMALIGN)
259 for (storeblock * b = chainbase[pool]; b; b = b->next)
260 if (mprotect(b, ALIGNED_SIZEOF_STOREBLOCK + b->length, PROT_READ) != 0)
261 DEBUG(D_any) debug_printf("config block mprotect: (%d) %s\n", errno, strerror(errno));
262 #endif
263 }
264
265 /******************************************************************************/
266
267 /*************************************************
268 * Get a block from the current pool *
269 *************************************************/
270
271 /* Running out of store is a total disaster. This function is called via the
272 macro store_get(). It passes back a block of store within the current big
273 block, getting a new one if necessary. The address is saved in
274 store_last_was_get.
275
276 Arguments:
277 size amount wanted, bytes
278 tainted class: set to true for untrusted data (eg. from smtp input)
279 func function from which called
280 linenumber line number in source file
281
282 Returns: pointer to store (panic on malloc failure)
283 */
284
285 void *
store_get_3(int size,BOOL tainted,const char * func,int linenumber)286 store_get_3(int size, BOOL tainted, const char *func, int linenumber)
287 {
288 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
289
290 /* Ensure we've been asked to allocate memory.
291 A negative size is a sign of a security problem.
292 A zero size might be also suspect, but our internal usage deliberately
293 does this to return a current watermark value for a later release of
294 allocated store. */
295
296 if (size < 0 || size >= INT_MAX/2)
297 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
298 "bad memory allocation requested (%d bytes) at %s %d",
299 size, func, linenumber);
300
301 /* Round up the size to a multiple of the alignment. Although this looks a
302 messy statement, because "alignment" is a constant expression, the compiler can
303 do a reasonable job of optimizing, especially if the value of "alignment" is a
304 power of two. I checked this with -O2, and gcc did very well, compiling it to 4
305 instructions on a Sparc (alignment = 8). */
306
307 if (size % alignment != 0) size += alignment - (size % alignment);
308
309 /* If there isn't room in the current block, get a new one. The minimum
310 size is STORE_BLOCK_SIZE, and we would expect this to be the norm, since
311 these functions are mostly called for small amounts of store. */
312
313 if (size > yield_length[pool])
314 {
315 int length = MAX(
316 STORE_BLOCK_SIZE(store_block_order[pool]) - ALIGNED_SIZEOF_STOREBLOCK,
317 size);
318 int mlength = length + ALIGNED_SIZEOF_STOREBLOCK;
319 storeblock * newblock;
320
321 /* Sometimes store_reset() may leave a block for us; check if we can use it */
322
323 if ( (newblock = current_block[pool])
324 && (newblock = newblock->next)
325 && newblock->length < length
326 )
327 {
328 /* Give up on this block, because it's too small */
329 nblocks[pool]--;
330 internal_store_free(newblock, func, linenumber);
331 newblock = NULL;
332 }
333
334 /* If there was no free block, get a new one */
335
336 if (!newblock)
337 {
338 if ((nbytes[pool] += mlength) > maxbytes[pool])
339 maxbytes[pool] = nbytes[pool];
340 if ((pool_malloc += mlength) > max_pool_malloc) /* Used in pools */
341 max_pool_malloc = pool_malloc;
342 nonpool_malloc -= mlength; /* Exclude from overall total */
343 if (++nblocks[pool] > maxblocks[pool])
344 maxblocks[pool] = nblocks[pool];
345
346 #ifndef MISSING_POSIX_MEMALIGN
347 if (pool == POOL_CONFIG)
348 {
349 long pgsize = sysconf(_SC_PAGESIZE);
350 posix_memalign((void **)&newblock, pgsize, (mlength + pgsize - 1) & ~(pgsize - 1));
351 }
352 else
353 #endif
354 newblock = internal_store_malloc(mlength, func, linenumber);
355 newblock->next = NULL;
356 newblock->length = length;
357 #ifndef RESTRICTED_MEMORY
358 if (store_block_order[pool]++ > maxorder[pool])
359 maxorder[pool] = store_block_order[pool];
360 #endif
361
362 if (!chainbase[pool])
363 chainbase[pool] = newblock;
364 else
365 current_block[pool]->next = newblock;
366 }
367
368 current_block[pool] = newblock;
369 yield_length[pool] = newblock->length;
370 next_yield[pool] =
371 (void *)(CS current_block[pool] + ALIGNED_SIZEOF_STOREBLOCK);
372 (void) VALGRIND_MAKE_MEM_NOACCESS(next_yield[pool], yield_length[pool]);
373 }
374
375 /* There's (now) enough room in the current block; the yield is the next
376 pointer. */
377
378 store_last_get[pool] = next_yield[pool];
379
380 /* Cut out the debugging stuff for utilities, but stop picky compilers from
381 giving warnings. */
382
383 #ifndef COMPILE_UTILITY
384 DEBUG(D_memory)
385 debug_printf("---%d Get %6p %5d %-14s %4d\n", pool,
386 store_last_get[pool], size, func, linenumber);
387 #endif /* COMPILE_UTILITY */
388
389 (void) VALGRIND_MAKE_MEM_UNDEFINED(store_last_get[pool], size);
390 /* Update next pointer and number of bytes left in the current block. */
391
392 next_yield[pool] = (void *)(CS next_yield[pool] + size);
393 yield_length[pool] -= size;
394 return store_last_get[pool];
395 }
396
397
398
399 /*************************************************
400 * Get a block from the PERM pool *
401 *************************************************/
402
403 /* This is just a convenience function, useful when just a single block is to
404 be obtained.
405
406 Arguments:
407 size amount wanted
408 func function from which called
409 linenumber line number in source file
410
411 Returns: pointer to store (panic on malloc failure)
412 */
413
414 void *
store_get_perm_3(int size,BOOL tainted,const char * func,int linenumber)415 store_get_perm_3(int size, BOOL tainted, const char *func, int linenumber)
416 {
417 void *yield;
418 int old_pool = store_pool;
419 store_pool = POOL_PERM;
420 yield = store_get_3(size, tainted, func, linenumber);
421 store_pool = old_pool;
422 return yield;
423 }
424
425
426
427 /*************************************************
428 * Extend a block if it is at the top *
429 *************************************************/
430
431 /* While reading strings of unknown length, it is often the case that the
432 string is being read into the block at the top of the stack. If it needs to be
433 extended, it is more efficient just to extend within the top block rather than
434 allocate a new block and then have to copy the data. This function is provided
435 for the use of string_cat(), but of course can be used elsewhere too.
436 The block itself is not expanded; only the top allocation from it.
437
438 Arguments:
439 ptr pointer to store block
440 oldsize current size of the block, as requested by user
441 newsize new size required
442 func function from which called
443 linenumber line number in source file
444
445 Returns: TRUE if the block is at the top of the stack and has been
446 extended; FALSE if it isn't at the top of the stack, or cannot
447 be extended
448 */
449
450 BOOL
store_extend_3(void * ptr,BOOL tainted,int oldsize,int newsize,const char * func,int linenumber)451 store_extend_3(void *ptr, BOOL tainted, int oldsize, int newsize,
452 const char *func, int linenumber)
453 {
454 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
455 int inc = newsize - oldsize;
456 int rounded_oldsize = oldsize;
457
458 if (oldsize < 0 || newsize < oldsize || newsize >= INT_MAX/2)
459 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
460 "bad memory extension requested (%d -> %d bytes) at %s %d",
461 oldsize, newsize, func, linenumber);
462
463 /* Check that the block being extended was already of the required taint status;
464 refuse to extend if not. */
465
466 if (is_tainted(ptr) != tainted)
467 return FALSE;
468
469 if (rounded_oldsize % alignment != 0)
470 rounded_oldsize += alignment - (rounded_oldsize % alignment);
471
472 if (CS ptr + rounded_oldsize != CS (next_yield[pool]) ||
473 inc > yield_length[pool] + rounded_oldsize - oldsize)
474 return FALSE;
475
476 /* Cut out the debugging stuff for utilities, but stop picky compilers from
477 giving warnings. */
478
479 #ifndef COMPILE_UTILITY
480 DEBUG(D_memory)
481 debug_printf("---%d Ext %6p %5d %-14s %4d\n", pool, ptr, newsize,
482 func, linenumber);
483 #endif /* COMPILE_UTILITY */
484
485 if (newsize % alignment != 0) newsize += alignment - (newsize % alignment);
486 next_yield[pool] = CS ptr + newsize;
487 yield_length[pool] -= newsize - rounded_oldsize;
488 (void) VALGRIND_MAKE_MEM_UNDEFINED(ptr + oldsize, inc);
489 return TRUE;
490 }
491
492
493
494
495 static BOOL
is_pwr2_size(int len)496 is_pwr2_size(int len)
497 {
498 unsigned x = len;
499 return (x & (x - 1)) == 0;
500 }
501
502
503 /*************************************************
504 * Back up to a previous point on the stack *
505 *************************************************/
506
507 /* This function resets the next pointer, freeing any subsequent whole blocks
508 that are now unused. Call with a cookie obtained from store_mark() only; do
509 not call with a pointer returned by store_get(). Both the untainted and tainted
510 pools corresposding to store_pool are reset.
511
512 Arguments:
513 ptr place to back up to
514 pool pool holding the pointer
515 func function from which called
516 linenumber line number in source file
517
518 Returns: nothing
519 */
520
521 static void
internal_store_reset(void * ptr,int pool,const char * func,int linenumber)522 internal_store_reset(void * ptr, int pool, const char *func, int linenumber)
523 {
524 storeblock * bb;
525 storeblock * b = current_block[pool];
526 char * bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
527 int newlength, count;
528 #ifndef COMPILE_UTILITY
529 int oldmalloc = pool_malloc;
530 #endif
531
532 /* Last store operation was not a get */
533
534 store_last_get[pool] = NULL;
535
536 /* See if the place is in the current block - as it often will be. Otherwise,
537 search for the block in which it lies. */
538
539 if (CS ptr < bc || CS ptr > bc + b->length)
540 {
541 for (b = chainbase[pool]; b; b = b->next)
542 {
543 bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
544 if (CS ptr >= bc && CS ptr <= bc + b->length) break;
545 }
546 if (!b)
547 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "internal error: store_reset(%p) "
548 "failed: pool=%d %-14s %4d", ptr, pool, func, linenumber);
549 }
550
551 /* Back up, rounding to the alignment if necessary. When testing, flatten
552 the released memory. */
553
554 newlength = bc + b->length - CS ptr;
555 #ifndef COMPILE_UTILITY
556 if (debug_store)
557 {
558 assert_no_variables(ptr, newlength, func, linenumber);
559 if (f.running_in_test_harness)
560 {
561 (void) VALGRIND_MAKE_MEM_DEFINED(ptr, newlength);
562 memset(ptr, 0xF0, newlength);
563 }
564 }
565 #endif
566 (void) VALGRIND_MAKE_MEM_NOACCESS(ptr, newlength);
567 next_yield[pool] = CS ptr + (newlength % alignment);
568 count = yield_length[pool];
569 count = (yield_length[pool] = newlength - (newlength % alignment)) - count;
570 current_block[pool] = b;
571
572 /* Free any subsequent block. Do NOT free the first
573 successor, if our current block has less than 256 bytes left. This should
574 prevent us from flapping memory. However, keep this block only when it has
575 a power-of-two size so probably is not a custom inflated one. */
576
577 if ( yield_length[pool] < STOREPOOL_MIN_SIZE
578 && b->next
579 && is_pwr2_size(b->next->length + ALIGNED_SIZEOF_STOREBLOCK))
580 {
581 b = b->next;
582 #ifndef COMPILE_UTILITY
583 if (debug_store)
584 assert_no_variables(b, b->length + ALIGNED_SIZEOF_STOREBLOCK,
585 func, linenumber);
586 #endif
587 (void) VALGRIND_MAKE_MEM_NOACCESS(CS b + ALIGNED_SIZEOF_STOREBLOCK,
588 b->length - ALIGNED_SIZEOF_STOREBLOCK);
589 }
590
591 bb = b->next;
592 if (pool != POOL_CONFIG)
593 b->next = NULL;
594
595 while ((b = bb))
596 {
597 int siz = b->length + ALIGNED_SIZEOF_STOREBLOCK;
598
599 #ifndef COMPILE_UTILITY
600 if (debug_store)
601 assert_no_variables(b, b->length + ALIGNED_SIZEOF_STOREBLOCK,
602 func, linenumber);
603 #endif
604 bb = bb->next;
605 nbytes[pool] -= siz;
606 pool_malloc -= siz;
607 nblocks[pool]--;
608 if (pool != POOL_CONFIG)
609 internal_store_free(b, func, linenumber);
610
611 #ifndef RESTRICTED_MEMORY
612 if (store_block_order[pool] > 13) store_block_order[pool]--;
613 #endif
614 }
615
616 /* Cut out the debugging stuff for utilities, but stop picky compilers from
617 giving warnings. */
618
619 #ifndef COMPILE_UTILITY
620 DEBUG(D_memory)
621 debug_printf("---%d Rst %6p %5d %-14s %4d\tpool %d\n", pool, ptr,
622 count + oldmalloc - pool_malloc,
623 func, linenumber, pool_malloc);
624 #endif /* COMPILE_UTILITY */
625 }
626
627
628 rmark
store_reset_3(rmark r,const char * func,int linenumber)629 store_reset_3(rmark r, const char *func, int linenumber)
630 {
631 void ** ptr = r;
632
633 if (store_pool >= POOL_TAINT_BASE)
634 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
635 "store_reset called for pool %d: %s %d\n", store_pool, func, linenumber);
636 if (!r)
637 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
638 "store_reset called with bad mark: %s %d\n", func, linenumber);
639
640 internal_store_reset(*ptr, store_pool + POOL_TAINT_BASE, func, linenumber);
641 internal_store_reset(ptr, store_pool, func, linenumber);
642 return NULL;
643 }
644
645
646
647 /* Free tail-end unused allocation. This lets us allocate a big chunk
648 early, for cases when we only discover later how much was really needed.
649
650 Can be called with a value from store_get(), or an offset after such. Only
651 the tainted or untainted pool that serviced the store_get() will be affected.
652
653 This is mostly a cut-down version of internal_store_reset().
654 XXX needs rationalising
655 */
656
657 void
store_release_above_3(void * ptr,const char * func,int linenumber)658 store_release_above_3(void *ptr, const char *func, int linenumber)
659 {
660 /* Search all pools' "current" blocks. If it isn't one of those,
661 ignore it (it usually will be). */
662
663 for (int pool = 0; pool < nelem(current_block); pool++)
664 {
665 storeblock * b = current_block[pool];
666 char * bc;
667 int count, newlength;
668
669 if (!b)
670 continue;
671
672 bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
673 if (CS ptr < bc || CS ptr > bc + b->length)
674 continue;
675
676 /* Last store operation was not a get */
677
678 store_last_get[pool] = NULL;
679
680 /* Back up, rounding to the alignment if necessary. When testing, flatten
681 the released memory. */
682
683 newlength = bc + b->length - CS ptr;
684 #ifndef COMPILE_UTILITY
685 if (debug_store)
686 {
687 assert_no_variables(ptr, newlength, func, linenumber);
688 if (f.running_in_test_harness)
689 {
690 (void) VALGRIND_MAKE_MEM_DEFINED(ptr, newlength);
691 memset(ptr, 0xF0, newlength);
692 }
693 }
694 #endif
695 (void) VALGRIND_MAKE_MEM_NOACCESS(ptr, newlength);
696 next_yield[pool] = CS ptr + (newlength % alignment);
697 count = yield_length[pool];
698 count = (yield_length[pool] = newlength - (newlength % alignment)) - count;
699
700 /* Cut out the debugging stuff for utilities, but stop picky compilers from
701 giving warnings. */
702
703 #ifndef COMPILE_UTILITY
704 DEBUG(D_memory)
705 debug_printf("---%d Rel %6p %5d %-14s %4d\tpool %d\n", pool, ptr, count,
706 func, linenumber, pool_malloc);
707 #endif
708 return;
709 }
710 #ifndef COMPILE_UTILITY
711 DEBUG(D_memory)
712 debug_printf("non-last memory release try: %s %d\n", func, linenumber);
713 #endif
714 }
715
716
717
718 rmark
store_mark_3(const char * func,int linenumber)719 store_mark_3(const char *func, int linenumber)
720 {
721 void ** p;
722
723 #ifndef COMPILE_UTILITY
724 DEBUG(D_memory)
725 debug_printf("---%d Mrk %-14s %4d\tpool %d\n",
726 store_pool, func, linenumber, pool_malloc);
727 #endif /* COMPILE_UTILITY */
728
729 if (store_pool >= POOL_TAINT_BASE)
730 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
731 "store_mark called for pool %d: %s %d\n", store_pool, func, linenumber);
732
733 /* Stash a mark for the tainted-twin release, in the untainted twin. Return
734 a cookie (actually the address in the untainted pool) to the caller.
735 Reset uses the cookie to recover the t-mark, winds back the tainted pool with it
736 and winds back the untainted pool with the cookie. */
737
738 p = store_get_3(sizeof(void *), FALSE, func, linenumber);
739 *p = store_get_3(0, TRUE, func, linenumber);
740 return p;
741 }
742
743
744
745
746 /************************************************
747 * Release store *
748 ************************************************/
749
750 /* This function checks that the pointer it is given is the first thing in a
751 block, and if so, releases that block.
752
753 Arguments:
754 block block of store to consider
755 func function from which called
756 linenumber line number in source file
757
758 Returns: nothing
759 */
760
761 static void
store_release_3(void * block,int pool,const char * func,int linenumber)762 store_release_3(void * block, int pool, const char * func, int linenumber)
763 {
764 /* It will never be the first block, so no need to check that. */
765
766 for (storeblock * b = chainbase[pool]; b; b = b->next)
767 {
768 storeblock * bb = b->next;
769 if (bb && CS block == CS bb + ALIGNED_SIZEOF_STOREBLOCK)
770 {
771 int siz = bb->length + ALIGNED_SIZEOF_STOREBLOCK;
772 b->next = bb->next;
773 nbytes[pool] -= siz;
774 pool_malloc -= siz;
775 nblocks[pool]--;
776
777 /* Cut out the debugging stuff for utilities, but stop picky compilers
778 from giving warnings. */
779
780 #ifndef COMPILE_UTILITY
781 DEBUG(D_memory)
782 debug_printf("-Release %6p %-20s %4d %d\n", (void *)bb, func,
783 linenumber, pool_malloc);
784
785 if (f.running_in_test_harness)
786 memset(bb, 0xF0, bb->length+ALIGNED_SIZEOF_STOREBLOCK);
787 #endif /* COMPILE_UTILITY */
788
789 internal_store_free(bb, func, linenumber);
790 return;
791 }
792 }
793 }
794
795
796 /************************************************
797 * Move store *
798 ************************************************/
799
800 /* Allocate a new block big enough to expend to the given size and
801 copy the current data into it. Free the old one if possible.
802
803 This function is specifically provided for use when reading very
804 long strings, e.g. header lines. When the string gets longer than a
805 complete block, it gets copied to a new block. It is helpful to free
806 the old block iff the previous copy of the string is at its start,
807 and therefore the only thing in it. Otherwise, for very long strings,
808 dead store can pile up somewhat disastrously. This function checks that
809 the pointer it is given is the first thing in a block, and that nothing
810 has been allocated since. If so, releases that block.
811
812 Arguments:
813 block
814 newsize
815 len
816
817 Returns: new location of data
818 */
819
820 void *
store_newblock_3(void * block,BOOL tainted,int newsize,int len,const char * func,int linenumber)821 store_newblock_3(void * block, BOOL tainted, int newsize, int len,
822 const char * func, int linenumber)
823 {
824 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
825 BOOL release_ok = !tainted && store_last_get[pool] == block;
826 uschar * newtext;
827
828 #if !defined(MACRO_PREDEF) && !defined(COMPILE_UTILITY)
829 if (is_tainted(block) != tainted)
830 die_tainted(US"store_newblock", CUS func, linenumber);
831 #endif
832
833 if (len < 0 || len > newsize)
834 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
835 "bad memory extension requested (%d -> %d bytes) at %s %d",
836 len, newsize, func, linenumber);
837
838 newtext = store_get(newsize, tainted);
839 memcpy(newtext, block, len);
840 if (release_ok) store_release_3(block, pool, func, linenumber);
841 return (void *)newtext;
842 }
843
844
845
846
847 /*************************************************
848 * Malloc store *
849 *************************************************/
850
851 /* Running out of store is a total disaster for exim. Some malloc functions
852 do not run happily on very small sizes, nor do they document this fact. This
853 function is called via the macro store_malloc().
854
855 Arguments:
856 size amount of store wanted
857 func function from which called
858 line line number in source file
859
860 Returns: pointer to gotten store (panic on failure)
861 */
862
863 static void *
internal_store_malloc(size_t size,const char * func,int line)864 internal_store_malloc(size_t size, const char *func, int line)
865 {
866 void * yield;
867
868 /* Check specifically for a possibly result of conversion from
869 a negative int, to the (unsigned, wider) size_t */
870
871 if (size >= INT_MAX/2)
872 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
873 "bad memory allocation requested (%lld bytes) at %s %d",
874 (unsigned long long)size, func, line);
875
876 size += sizeof(size_t); /* space to store the size, used under debug */
877 if (size < 16) size = 16;
878
879 if (!(yield = malloc(size)))
880 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to malloc %d bytes of memory: "
881 "called from line %d in %s", size, line, func);
882
883 #ifndef COMPILE_UTILITY
884 DEBUG(D_any) *(size_t *)yield = size;
885 #endif
886 yield = US yield + sizeof(size_t);
887
888 if ((nonpool_malloc += size) > max_nonpool_malloc)
889 max_nonpool_malloc = nonpool_malloc;
890
891 /* Cut out the debugging stuff for utilities, but stop picky compilers from
892 giving warnings. */
893
894 #ifndef COMPILE_UTILITY
895 /* If running in test harness, spend time making sure all the new store
896 is not filled with zeros so as to catch problems. */
897
898 if (f.running_in_test_harness)
899 memset(yield, 0xF0, size - sizeof(size_t));
900 DEBUG(D_memory) debug_printf("--Malloc %6p %5lld bytes\t%-20s %4d\tpool %5d nonpool %5d\n",
901 yield, size, func, line, pool_malloc, nonpool_malloc);
902 #endif /* COMPILE_UTILITY */
903
904 return yield;
905 }
906
907 void *
store_malloc_3(size_t size,const char * func,int linenumber)908 store_malloc_3(size_t size, const char *func, int linenumber)
909 {
910 if (n_nonpool_blocks++ > max_nonpool_blocks)
911 max_nonpool_blocks = n_nonpool_blocks;
912 return internal_store_malloc(size, func, linenumber);
913 }
914
915
916 /************************************************
917 * Free store *
918 ************************************************/
919
920 /* This function is called by the macro store_free().
921
922 Arguments:
923 block block of store to free
924 func function from which called
925 linenumber line number in source file
926
927 Returns: nothing
928 */
929
930 static void
internal_store_free(void * block,const char * func,int linenumber)931 internal_store_free(void * block, const char * func, int linenumber)
932 {
933 uschar * p = US block - sizeof(size_t);
934 #ifndef COMPILE_UTILITY
935 DEBUG(D_any) nonpool_malloc -= *(size_t *)p;
936 DEBUG(D_memory) debug_printf("----Free %6p %5lld bytes\t%-20s %4d\n",
937 block, (unsigned long long) *(size_t *)p, func, linenumber);
938 #endif
939 free(p);
940 }
941
942 void
store_free_3(void * block,const char * func,int linenumber)943 store_free_3(void * block, const char * func, int linenumber)
944 {
945 n_nonpool_blocks--;
946 internal_store_free(block, func, linenumber);
947 }
948
949 /******************************************************************************/
950 /* Stats output on process exit */
951 void
store_exit(void)952 store_exit(void)
953 {
954 #ifndef COMPILE_UTILITY
955 DEBUG(D_memory)
956 {
957 debug_printf("----Exit nonpool max: %3d kB in %d blocks\n",
958 (max_nonpool_malloc+1023)/1024, max_nonpool_blocks);
959 debug_printf("----Exit npools max: %3d kB\n", max_pool_malloc/1024);
960 for (int i = 0; i < NPOOLS; i++)
961 debug_printf("----Exit pool %d max: %3d kB in %d blocks at order %u\t%s %s\n",
962 i, (maxbytes[i]+1023)/1024, maxblocks[i], maxorder[i],
963 poolclass[i], pooluse[i]);
964 }
965 #endif
966 }
967
968
969 /******************************************************************************/
970 /* Per-message pool management */
971
972 static rmark message_reset_point = NULL;
973
974 void
message_start(void)975 message_start(void)
976 {
977 int oldpool = store_pool;
978 store_pool = POOL_MESSAGE;
979 if (!message_reset_point) message_reset_point = store_mark();
980 store_pool = oldpool;
981 }
982
message_tidyup(void)983 void message_tidyup(void)
984 {
985 int oldpool;
986 if (!message_reset_point) return;
987 oldpool = store_pool;
988 store_pool = POOL_MESSAGE;
989 message_reset_point = store_reset(message_reset_point);
990 store_pool = oldpool;
991 }
992
993 /* End of store.c */
994