libmudflap/mf-impl.h

   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
 251 static inline enum __mf_state_enum __mf_get_state (void)
 252 {
 253   return __mf_state_1;
 254 }
 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 */