1 /* Implementation header for mudflap runtime library.
2 Mudflap: narrow-pointer bounds-checking by tree rewriting.
3 Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
4 Contributed by Frank Ch. Eigler <fche@redhat.com>
5 and Graydon Hoare <graydon@redhat.com>
6
7 This file is part of GCC.
8
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 2, or (at your option) any later
12 version.
13
14 In addition to the permissions in the GNU General Public License, the
15 Free Software Foundation gives you unlimited permission to link the
16 compiled version of this file into combinations with other programs,
17 and to distribute those combinations without any restriction coming
18 from the use of this file. (The General Public License restrictions
19 do apply in other respects; for example, they cover modification of
20 the file, and distribution when not linked into a combine
21 executable.)
22
23 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
24 WARRANTY; without even the implied warranty of MERCHANTABILITY or
25 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
26 for more details.
27
28 You should have received a copy of the GNU General Public License
29 along with GCC; see the file COPYING. If not, write to the Free
30 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
31 02110-1301, USA. */
32
33 #ifndef __MF_IMPL_H
34 #define __MF_IMPL_H
35
36 #ifdef _MUDFLAP
37 #error "Do not compile this file with -fmudflap!"
38 #endif
39
40 #if HAVE_PTHREAD_H
41 #include <pthread.h>
42 #elif LIBMUDFLAPTH
43 #error "Cannot build libmudflapth without pthread.h."
44 #endif
45
46 #if HAVE_STDINT_H
47 #include <stdint.h>
48 #else
49 typedef __mf_uintptr_t uintptr_t;
50 #endif
51
52 /* Private definitions related to mf-runtime.h */
53
54 #define __MF_TYPE_MAX_CEM __MF_TYPE_STACK /* largest type# for the cemetary */
55 #define __MF_TYPE_MAX __MF_TYPE_GUESS
56
57
58 #ifndef max
59 #define max(a,b) ((a) > (b) ? (a) : (b))
60 #endif
61
62 #ifndef min
63 #define min(a,b) ((a) < (b) ? (a) : (b))
64 #endif
65
66 /* Address calculation macros. */
67
68 #define MINPTR ((uintptr_t) 0)
69 #define MAXPTR (~ (uintptr_t) 0)
70
71 /* Clamp the addition/subtraction of uintptr_t's to [MINPTR,MAXPTR] */
72 #define CLAMPSUB(ptr,offset) (((uintptr_t) ptr) >= (offset) ? ((uintptr_t) ptr)-((uintptr_t) offset) : MINPTR)
73 #define CLAMPADD(ptr,offset) (((uintptr_t) ptr) <= MAXPTR-(offset) ? ((uintptr_t) ptr)+((uintptr_t) offset) : MAXPTR)
74 #define CLAMPSZ(ptr,size) ((size) ? (((uintptr_t) ptr) <= MAXPTR-(size)+1 ? ((uintptr_t) ptr)+((uintptr_t) size) - 1 : MAXPTR) : ((uintptr_t) ptr))
75
76 #define __MF_CACHE_INDEX(ptr) ((((uintptr_t) (ptr)) >> __mf_lc_shift) & __mf_lc_mask)
77 #define __MF_CACHE_MISS_P(ptr,sz) ({ \
78 struct __mf_cache *elem = & __mf_lookup_cache[__MF_CACHE_INDEX((ptr))]; \
79 ((elem->low > (uintptr_t) (ptr)) || \
80 (elem->high < (CLAMPADD((uintptr_t) (ptr), (uintptr_t) CLAMPSUB(sz,1) )))); })
81 /* XXX: the above should use CLAMPSZ () */
82
83
84
85 /* Private functions. */
86
87 extern void __mf_violation (void *ptr, size_t sz,
88 uintptr_t pc, const char *location,
89 int type);
90 extern size_t __mf_backtrace (char ***, void *, unsigned);
91 extern int __mf_heuristic_check (uintptr_t, uintptr_t);
92
93 /* ------------------------------------------------------------------------ */
94 /* Type definitions. */
95 /* ------------------------------------------------------------------------ */
96
97 /* The mf_state type codes describe recursion and initialization order.
98
99 reentrant means we are inside a mf-runtime support routine, such as
100 __mf_register, and thus there should be no calls to any wrapped functions,
101 such as the wrapped malloc. This indicates a bug if it occurs.
102 in_malloc means we are inside a real malloc call inside a wrapped malloc
103 call, and thus there should be no calls to any wrapped functions like the
104 wrapped mmap. This happens on some systems due to how the system libraries
105 are constructed. */
106
107 enum __mf_state_enum { active, reentrant, in_malloc };
108
109 /* The __mf_options structure records optional or tunable aspects of the
110 mudflap library's behavior. There is a single global instance of this
111 structure which is populated from user input (in an environment variable)
112 when the library initializes. */
113
114 struct __mf_options
115 {
116 /* Emit a trace message for each call. */
117 unsigned trace_mf_calls;
118
119 /* Collect and emit statistics. */
120 unsigned collect_stats;
121
122 /* Set up a SIGUSR1 -> __mf_report handler. */
123 unsigned sigusr1_report;
124
125 /* Execute internal checking code. */
126 unsigned internal_checking;
127
128 /* Age object liveness periodically. */
129 unsigned tree_aging;
130
131 /* Adapt the lookup cache to working set. */
132 unsigned adapt_cache;
133
134 /* Print list of leaked heap objects on shutdown. */
135 unsigned print_leaks;
136
137 /* Detect reads of uninitialized objects. */
138 unsigned check_initialization;
139
140 /* Print verbose description of violations. */
141 unsigned verbose_violations;
142
143 /* Abbreviate duplicate object descriptions. */
144 unsigned abbreviate;
145
146 /* Emit internal tracing message. */
147 unsigned verbose_trace;
148
149 /* Wipe stack/heap objects upon unwind. */
150 unsigned wipe_stack;
151 unsigned wipe_heap;
152
153 /* Maintain a queue of this many deferred free()s,
154 to trap use of freed memory. */
155 unsigned free_queue_length;
156
157 /* Maintain a history of this many past unregistered objects. */
158 unsigned persistent_count;
159
160 /* Pad allocated extents by this many bytes on either side. */
161 unsigned crumple_zone;
162
163 /* Maintain this many stack frames for contexts. */
164 unsigned backtrace;
165
166 /* Ignore read operations even if mode_check is in effect. */
167 unsigned ignore_reads;
168
169 /* Collect register/unregister timestamps. */
170 unsigned timestamps;
171
172 #ifdef LIBMUDFLAPTH
173 /* Thread stack size. */
174 unsigned thread_stack;
175 #endif
176
177 /* Major operation mode */
178 #define mode_nop 0 /* Do nothing. */
179 #define mode_populate 1 /* Populate tree but do not check for violations. */
180 #define mode_check 2 /* Populate and check for violations (normal). */
181 #define mode_violate 3 /* Trigger a violation on every call (diagnostic). */
182 unsigned mudflap_mode;
183
184 /* How to handle a violation. */
185 #define viol_nop 0 /* Return control to application. */
186 #define viol_segv 1 /* Signal self with segv. */
187 #define viol_abort 2 /* Call abort (). */
188 #define viol_gdb 3 /* Fork a debugger on self */
189 unsigned violation_mode;
190
191 /* Violation heuristics selection. */
192 unsigned heur_stack_bound; /* allow current stack region */
193 unsigned heur_proc_map; /* allow & cache /proc/self/map regions. */
194 unsigned heur_start_end; /* allow _start .. _end */
195 unsigned heur_std_data; /* allow & cache stdlib data */
196 };
197
198
199 #ifdef PIC
200
201 /* This is a table of dynamically resolved function pointers. */
202
203 struct __mf_dynamic_entry
204 {
205 void *pointer;
206 char *name;
207 char *version;
208 };
209
210 /* The definition of the array (mf-runtime.c) must match the enums! */
211 extern struct __mf_dynamic_entry __mf_dynamic[];
212 enum __mf_dynamic_index
213 {
214 dyn_calloc, dyn_free, dyn_malloc, dyn_mmap,
215 dyn_munmap, dyn_realloc,
216 dyn_INITRESOLVE, /* Marker for last init-time resolution. */
217 #ifdef LIBMUDFLAPTH
218 dyn_pthread_create
219 #endif
220 };
221
222 #endif /* PIC */
223
224 /* ------------------------------------------------------------------------ */
225 /* Private global variables. */
226 /* ------------------------------------------------------------------------ */
227
228 #ifdef LIBMUDFLAPTH
229 extern pthread_mutex_t __mf_biglock;
230 #define LOCKTH() do { extern unsigned long __mf_lock_contention; \
231 int rc = pthread_mutex_trylock (& __mf_biglock); \
232 if (rc) { __mf_lock_contention ++; \
233 rc = pthread_mutex_lock (& __mf_biglock); } \
234 assert (rc==0); } while (0)
235 #define UNLOCKTH() do { int rc = pthread_mutex_unlock (& __mf_biglock); \
236 assert (rc==0); } while (0)
237 #else
238 #define LOCKTH() do {} while (0)
239 #define UNLOCKTH() do {} while (0)
240 #endif
241
242 #if defined(LIBMUDFLAPTH) && !defined(HAVE_TLS)
243 extern enum __mf_state_enum __mf_get_state (void);
244 extern void __mf_set_state (enum __mf_state_enum);
245 #else
246 # ifdef LIBMUDFLAPTH
247 extern __thread enum __mf_state_enum __mf_state_1;
248 # else
249 extern enum __mf_state_enum __mf_state_1;
250 # endif
__mf_get_state(void)251 static inline enum __mf_state_enum __mf_get_state (void)
252 {
253 return __mf_state_1;
254 }
__mf_set_state(enum __mf_state_enum s)255 static inline void __mf_set_state (enum __mf_state_enum s)
256 {
257 __mf_state_1 = s;
258 }
259 #endif
260
261 extern int __mf_starting_p;
262 extern struct __mf_options __mf_opts;
263
264 /* ------------------------------------------------------------------------ */
265 /* Utility macros. */
266 /* ------------------------------------------------------------------------ */
267
268 #define UNLIKELY(e) (__builtin_expect (!!(e), 0))
269 #define LIKELY(e) (__builtin_expect (!!(e), 1))
270 #define STRINGIFY2(e) #e
271 #define STRINGIFY(e) STRINGIFY2(e)
272
273 #ifdef LIBMUDFLAPTH
274 #define VERBOSE_TRACE(...) \
275 do { if (UNLIKELY (__mf_opts.verbose_trace)) { \
276 fprintf (stderr, "mf(%u): ", (unsigned) pthread_self ()); \
277 fprintf (stderr, __VA_ARGS__); \
278 } } while (0)
279 #define TRACE(...) \
280 do { if (UNLIKELY (__mf_opts.trace_mf_calls)) { \
281 fprintf (stderr, "mf(%u): ", (unsigned) pthread_self ()); \
282 fprintf (stderr, __VA_ARGS__); \
283 } } while (0)
284 #else
285 #define VERBOSE_TRACE(...) \
286 do { if (UNLIKELY (__mf_opts.verbose_trace)) { \
287 fprintf (stderr, "mf: "); \
288 fprintf (stderr, __VA_ARGS__); \
289 } } while (0)
290 #define TRACE(...) \
291 do { if (UNLIKELY (__mf_opts.trace_mf_calls)) { \
292 fprintf (stderr, "mf: "); \
293 fprintf (stderr, __VA_ARGS__); \
294 } } while (0)
295 #endif
296
297
298 #define __MF_PERSIST_MAX 256
299 #define __MF_FREEQ_MAX 256
300
301 /*
302 Wrapping and redirection:
303
304 Mudflap redirects a number of libc functions into itself, for "cheap"
305 verification (eg. strcpy, bzero, memcpy) and also to register /
306 unregister regions of memory as they are manipulated by the program
307 (eg. malloc/free, mmap/munmap).
308
309 There are two methods of wrapping.
310
311 (1) The static method involves a list of -wrap=foo flags being passed to
312 the linker, which then links references to "foo" to the symbol
313 "__wrap_foo", and links references to "__real_foo" to the symbol "foo".
314 When compiled without -DPIC, libmudflap.a contains such __wrap_foo
315 functions which delegate to __real_foo functions in libc to get their
316 work done.
317
318 (2) The dynamic method involves providing a definition of symbol foo in
319 libmudflap.so and linking it earlier in the compiler command line,
320 before libc.so. The function "foo" in libmudflap must then call
321 dlsym(RTLD_NEXT, "foo") to acquire a pointer to the "real" libc foo, or
322 at least the "next" foo in the dynamic link resolution order.
323
324 We switch between these two techniques by the presence of the -DPIC
325 #define passed in by libtool when building libmudflap.
326 */
327
328
329 #ifdef PIC
330
331 extern void __mf_resolve_single_dynamic (struct __mf_dynamic_entry *);
332
333 #define _GNU_SOURCE
334 #include <dlfcn.h>
335
336 #define WRAPPER(ret, fname, ...) \
337 ret __wrap_ ## fname (__VA_ARGS__) \
338 __attribute__ (( alias (#fname) )); \
339 ret __real_ ## fname (__VA_ARGS__) \
340 __attribute__ (( alias (#fname) )); \
341 ret fname (__VA_ARGS__)
342 #define DECLARE(ty, fname, ...) \
343 typedef ty (*__mf_fn_ ## fname) (__VA_ARGS__); \
344 extern ty __mf_0fn_ ## fname (__VA_ARGS__);
345 #define CALL_REAL(fname, ...) \
346 ({__mf_starting_p \
347 ? __mf_0fn_ ## fname (__VA_ARGS__) \
348 : (__mf_resolve_single_dynamic (& __mf_dynamic[dyn_ ## fname]), \
349 (((__mf_fn_ ## fname)(__mf_dynamic[dyn_ ## fname].pointer)) (__VA_ARGS__)));})
350 #define CALL_BACKUP(fname, ...) \
351 __mf_0fn_ ## fname(__VA_ARGS__)
352
353 #else /* not PIC --> static library */
354
355 #define WRAPPER(ret, fname, ...) \
356 ret __wrap_ ## fname (__VA_ARGS__)
357 #define DECLARE(ty, fname, ...) \
358 extern ty __real_ ## fname (__VA_ARGS__)
359 #define CALL_REAL(fname, ...) \
360 __real_ ## fname (__VA_ARGS__)
361 #define CALL_BACKUP(fname, ...) \
362 __real_ ## fname(__VA_ARGS__)
363
364 #endif /* PIC */
365
366 /* WRAPPER2 is for functions intercepted via macros at compile time. */
367 #define WRAPPER2(ret, fname, ...) \
368 ret __mfwrap_ ## fname (__VA_ARGS__)
369
370
371 /* Utility macros for mf-hooks*.c */
372
373 #define MF_VALIDATE_EXTENT(value,size,acc,context) \
374 do { \
375 if (UNLIKELY (size > 0 && __MF_CACHE_MISS_P (value, size))) \
376 if (acc == __MF_CHECK_WRITE || ! __mf_opts.ignore_reads) \
377 __mf_check ((void *) (value), (size), acc, "(" context ")"); \
378 } while (0)
379 #define BEGIN_PROTECT(fname, ...) \
380 if (UNLIKELY (__mf_starting_p)) \
381 { \
382 return CALL_BACKUP(fname, __VA_ARGS__); \
383 } \
384 else if (UNLIKELY (__mf_get_state () == reentrant)) \
385 { \
386 extern unsigned long __mf_reentrancy; \
387 __mf_reentrancy ++; \
388 return CALL_REAL(fname, __VA_ARGS__); \
389 } \
390 else if (UNLIKELY (__mf_get_state () == in_malloc)) \
391 { \
392 return CALL_REAL(fname, __VA_ARGS__); \
393 } \
394 else \
395 { \
396 TRACE ("%s\n", __PRETTY_FUNCTION__); \
397 }
398
399 /* There is an assumption here that these will only be called in routines
400 that call BEGIN_PROTECT at the start, and hence the state must always
401 be active when BEGIN_MALLOC_PROTECT is called. */
402 #define BEGIN_MALLOC_PROTECT() \
403 __mf_set_state (in_malloc)
404
405 #define END_MALLOC_PROTECT() \
406 __mf_set_state (active)
407
408 /* Unlocked variants of main entry points from mf-runtime.h. */
409 extern void __mfu_check (void *ptr, size_t sz, int type, const char *location);
410 extern void __mfu_register (void *ptr, size_t sz, int type, const char *name);
411 extern void __mfu_unregister (void *ptr, size_t sz, int type);
412 extern void __mfu_report ();
413 extern int __mfu_set_options (const char *opts);
414
415
416 #endif /* __MF_IMPL_H */
417