libmudflap/mf-hooks1.c

   1 /* Mudflap: narrow-pointer bounds-checking by tree rewriting.
   2    Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
   3    Contributed by Frank Ch. Eigler <fche@redhat.com>
   4    and Graydon Hoare <graydon@redhat.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 In addition to the permissions in the GNU General Public License, the
  14 Free Software Foundation gives you unlimited permission to link the
  15 compiled version of this file into combinations with other programs,
  16 and to distribute those combinations without any restriction coming
  17 from the use of this file.  (The General Public License restrictions
  18 do apply in other respects; for example, they cover modification of
  19 the file, and distribution when not linked into a combine
  20 executable.)
  21
  22 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  23 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  24 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  25 for more details.
  26
  27 You should have received a copy of the GNU General Public License
  28 along with GCC; see the file COPYING.  If not, write to the Free
  29 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  30 02111-1307, USA.  */
  31
  32
  33 #include "config.h"
  34
  35 #ifndef HAVE_SOCKLEN_T
  36 #define socklen_t int
  37 #endif
  38
  39
  40 /* These attempt to coax various unix flavours to declare all our
  41    needed tidbits in the system headers.  */
  42 #if !defined(__FreeBSD__)  && !defined(__APPLE__)
  43 #define _POSIX_SOURCE
  44 #endif /* Some BSDs break <sys/socket.h> if this is defined. */
  45 #define _GNU_SOURCE
  46 #define _XOPEN_SOURCE
  47 #define _BSD_TYPES
  48 #define __EXTENSIONS__
  49 #define _ALL_SOURCE
  50 #define _LARGE_FILE_API
  51 #define _XOPEN_SOURCE_EXTENDED 1
  52
  53 #include <string.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <sys/time.h>
  57 #include <sys/types.h>
  58 #include <unistd.h>
  59 #include <assert.h>
  60 #include <errno.h>
  61 #include <limits.h>
  62 #include <time.h>
  63
  64 #include "mf-runtime.h"
  65 #include "mf-impl.h"
  66
  67 #ifdef _MUDFLAP
  68 #error "Do not compile this file with -fmudflap!"
  69 #endif
  70
  71
  72 /* Memory allocation related hook functions.  Some of these are
  73    intercepted via linker wrapping or symbol interposition.  Others
  74    use plain macros in mf-runtime.h.  */
  75
  76
  77 #if PIC
  78 /* A special bootstrap variant. */
  79 void *
  80 __mf_0fn_malloc (size_t c)
  81 {
  82   /* fprintf (stderr, "0fn malloc c=%lu\n", c); */
  83   return NULL;
  84 }
  85 #endif
  86
  87
  88 #undef malloc
  89 WRAPPER(void *, malloc, size_t c)
  90 {
  91   size_t size_with_crumple_zones;
  92   DECLARE(void *, malloc, size_t c);
  93   void *result;
  94   BEGIN_PROTECT (malloc, c);
  95
  96   size_with_crumple_zones =
  97     CLAMPADD(c,CLAMPADD(__mf_opts.crumple_zone,
  98                         __mf_opts.crumple_zone));
  99   result = (char *) CALL_REAL (malloc, size_with_crumple_zones);
 100
 101   if (LIKELY(result))
 102     {
 103       result += __mf_opts.crumple_zone;
 104       __mf_register (result, c, __MF_TYPE_HEAP, "malloc region");
 105       /* XXX: register __MF_TYPE_NOACCESS for crumple zones.  */
 106     }
 107
 108   return result;
 109 }
 110
 111
 112 #ifdef PIC
 113 /* A special bootstrap variant. */
 114 void *
 115 __mf_0fn_calloc (size_t c, size_t n)
 116 {
 117   enum foo { BS = 4096, NB=10 };
 118   static char bufs[NB][BS];
 119   static unsigned bufs_used[NB];
 120   unsigned i;
 121
 122   /* fprintf (stderr, "0fn calloc c=%lu n=%lu\n", c, n); */
 123   for (i=0; i<NB; i++)
 124     {
 125       if (! bufs_used[i] && (c*n) < BS)
 126         {
 127           bufs_used[i] = 1;
 128           return & bufs[i][0];
 129         }
 130     }
 131   return NULL;
 132 }
 133 #endif
 134
 135
 136 #undef calloc
 137 WRAPPER(void *, calloc, size_t c, size_t n)
 138 {
 139   size_t size_with_crumple_zones;
 140   DECLARE(void *, calloc, size_t, size_t);
 141   DECLARE(void *, malloc, size_t);
 142   DECLARE(void *, memset, void *, int, size_t);
 143   char *result;
 144   BEGIN_PROTECT (calloc, c, n);
 145
 146   size_with_crumple_zones =
 147     CLAMPADD((c * n), /* XXX: CLAMPMUL */
 148              CLAMPADD(__mf_opts.crumple_zone,
 149                       __mf_opts.crumple_zone));
 150   result = (char *) CALL_REAL (malloc, size_with_crumple_zones);
 151
 152   if (LIKELY(result))
 153     memset (result, 0, size_with_crumple_zones);
 154
 155   if (LIKELY(result))
 156     {
 157       result += __mf_opts.crumple_zone;
 158       __mf_register (result, c*n /* XXX: clamp */, __MF_TYPE_HEAP_I, "calloc region");
 159       /* XXX: register __MF_TYPE_NOACCESS for crumple zones.  */
 160     }
 161
 162   return result;
 163 }
 164
 165
 166 #if PIC
 167 /* A special bootstrap variant. */
 168 void *
 169 __mf_0fn_realloc (void *buf, size_t c)
 170 {
 171   return NULL;
 172 }
 173 #endif
 174
 175
 176 #undef realloc
 177 WRAPPER(void *, realloc, void *buf, size_t c)
 178 {
 179   DECLARE(void * , realloc, void *, size_t);
 180   size_t size_with_crumple_zones;
 181   char *base = buf;
 182   unsigned saved_wipe_heap;
 183   char *result;
 184   BEGIN_PROTECT (realloc, buf, c);
 185
 186   if (LIKELY(buf))
 187     base -= __mf_opts.crumple_zone;
 188
 189   size_with_crumple_zones =
 190     CLAMPADD(c, CLAMPADD(__mf_opts.crumple_zone,
 191                          __mf_opts.crumple_zone));
 192   result = (char *) CALL_REAL (realloc, base, size_with_crumple_zones);
 193
 194   /* Ensure heap wiping doesn't occur during this peculiar
 195      unregister/reregister pair.  */
 196   LOCKTH ();
 197   __mf_state = reentrant;
 198   saved_wipe_heap = __mf_opts.wipe_heap;
 199   __mf_opts.wipe_heap = 0;
 200
 201   if (LIKELY(buf))
 202     __mfu_unregister (buf, 0, __MF_TYPE_HEAP_I);
 203   /* NB: underlying region may have been __MF_TYPE_HEAP. */
 204
 205   if (LIKELY(result))
 206     {
 207       result += __mf_opts.crumple_zone;
 208       __mfu_register (result, c, __MF_TYPE_HEAP_I, "realloc region");
 209       /* XXX: register __MF_TYPE_NOACCESS for crumple zones.  */
 210     }
 211
 212   /* Restore previous setting.  */
 213   __mf_opts.wipe_heap = saved_wipe_heap;
 214
 215   __mf_state = active;
 216   UNLOCKTH ();
 217
 218   return result;
 219 }
 220
 221
 222 #if PIC
 223 /* A special bootstrap variant. */
 224 void
 225 __mf_0fn_free (void *buf)
 226 {
 227   return;
 228 }
 229 #endif
 230
 231 #undef free
 232 WRAPPER(void, free, void *buf)
 233 {
 234   /* Use a circular queue to delay some number (__mf_opts.free_queue_length) of free()s.  */
 235   static void *free_queue [__MF_FREEQ_MAX];
 236   static unsigned free_ptr = 0;
 237   static int freeq_initialized = 0;
 238   DECLARE(void, free, void *);
 239
 240   BEGIN_PROTECT (free, buf);
 241
 242   if (UNLIKELY(buf == NULL))
 243     return;
 244
 245   LOCKTH ();
 246   if (UNLIKELY(!freeq_initialized))
 247     {
 248       memset (free_queue, 0,
 249                      __MF_FREEQ_MAX * sizeof (void *));
 250       freeq_initialized = 1;
 251     }
 252   UNLOCKTH ();
 253
 254   __mf_unregister (buf, 0, __MF_TYPE_HEAP_I);
 255   /* NB: underlying region may have been __MF_TYPE_HEAP. */
 256
 257   if (UNLIKELY(__mf_opts.free_queue_length > 0))
 258     {
 259       char *freeme = NULL;
 260       LOCKTH ();
 261       if (free_queue [free_ptr] != NULL)
 262         {
 263           freeme = free_queue [free_ptr];
 264           freeme -= __mf_opts.crumple_zone;
 265         }
 266       free_queue [free_ptr] = buf;
 267       free_ptr = (free_ptr == (__mf_opts.free_queue_length-1) ? 0 : free_ptr + 1);
 268       UNLOCKTH ();
 269       if (freeme)
 270         {
 271           if (__mf_opts.trace_mf_calls)
 272             {
 273               VERBOSE_TRACE ("freeing deferred pointer %p (crumple %u)\n",
 274                              (void *) freeme,
 275                              __mf_opts.crumple_zone);
 276             }
 277           CALL_REAL (free, freeme);
 278         }
 279     }
 280   else
 281     {
 282       /* back pointer up a bit to the beginning of crumple zone */
 283       char *base = (char *)buf;
 284       base -= __mf_opts.crumple_zone;
 285       if (__mf_opts.trace_mf_calls)
 286         {
 287           VERBOSE_TRACE ("freeing pointer %p = %p - %u\n",
 288                          (void *) base,
 289                          (void *) buf,
 290                          __mf_opts.crumple_zone);
 291         }
 292       CALL_REAL (free, base);
 293     }
 294 }
 295
 296
 297 #if PIC
 298 /* A special bootstrap variant. */
 299 void *
 300 __mf_0fn_mmap (void *start, size_t l, int prot, int f, int fd, off_t off)
 301 {
 302   return (void *) -1;
 303 }
 304 #endif
 305
 306
 307 #undef mmap
 308 WRAPPER(void *, mmap,
 309         void  *start,  size_t length, int prot,
 310         int flags, int fd, off_t offset)
 311 {
 312   DECLARE(void *, mmap, void *, size_t, int,
 313                             int, int, off_t);
 314   void *result;
 315   BEGIN_PROTECT (mmap, start, length, prot, flags, fd, offset);
 316
 317   result = CALL_REAL (mmap, start, length, prot,
 318                         flags, fd, offset);
 319
 320   /*
 321   VERBOSE_TRACE ("mmap (%08lx, %08lx, ...) => %08lx\n",
 322                  (uintptr_t) start, (uintptr_t) length,
 323                  (uintptr_t) result);
 324   */
 325
 326   if (result != (void *)-1)
 327     {
 328       /* Register each page as a heap object.  Why not register it all
 329          as a single segment?  That's so that a later munmap() call
 330          can unmap individual pages.  XXX: would __MF_TYPE_GUESS make
 331          this more automatic?  */
 332       size_t ps = getpagesize ();
 333       uintptr_t base = (uintptr_t) result;
 334       uintptr_t offset;
 335
 336       for (offset=0; offset<length; offset+=ps)
 337         {
 338           /* XXX: We could map PROT_NONE to __MF_TYPE_NOACCESS. */
 339           /* XXX: Unaccessed HEAP pages are reported as leaks.  Is this
 340              appropriate for unaccessed mmap pages? */
 341           __mf_register ((void *) CLAMPADD (base, offset), ps,
 342                          __MF_TYPE_HEAP_I, "mmap page");
 343         }
 344     }
 345
 346   return result;
 347 }
 348
 349
 350 #if PIC
 351 /* A special bootstrap variant. */
 352 int
 353 __mf_0fn_munmap (void *start, size_t length)
 354 {
 355   return -1;
 356 }
 357 #endif
 358
 359
 360 #undef munmap
 361 WRAPPER(int , munmap, void *start, size_t length)
 362 {
 363   DECLARE(int, munmap, void *, size_t);
 364   int result;
 365   BEGIN_PROTECT (munmap, start, length);
 366
 367   result = CALL_REAL (munmap, start, length);
 368
 369   /*
 370   VERBOSE_TRACE ("munmap (%08lx, %08lx, ...) => %08lx\n",
 371                  (uintptr_t) start, (uintptr_t) length,
 372                  (uintptr_t) result);
 373   */
 374
 375   if (result == 0)
 376     {
 377       /* Unregister each page as a heap object.  */
 378       size_t ps = getpagesize ();
 379       uintptr_t base = (uintptr_t) start & (~ (ps - 1)); /* page align */
 380       uintptr_t offset;
 381
 382       for (offset=0; offset<length; offset+=ps)
 383         __mf_unregister ((void *) CLAMPADD (base, offset), ps, __MF_TYPE_HEAP_I);
 384     }
 385   return result;
 386 }
 387
 388
 389 /* This wrapper is a little different, as it's called indirectly from
 390    __mf_fini also to clean up pending allocations.  */
 391 void *
 392 __mf_wrap_alloca_indirect (size_t c)
 393 {
 394   DECLARE (void *, malloc, size_t);
 395   DECLARE (void, free, void *);
 396
 397   /* This struct, a linked list, tracks alloca'd objects.  The newest
 398      object is at the head of the list.  If we detect that we've
 399      popped a few levels of stack, then the listed objects are freed
 400      as needed.  NB: The tracking struct is allocated with
 401      real_malloc; the user data with wrap_malloc.
 402   */
 403   struct alloca_tracking { void *ptr; void *stack; struct alloca_tracking* next; };
 404   static struct alloca_tracking *alloca_history = NULL;
 405
 406   void *stack = __builtin_frame_address (0);
 407   void *result;
 408   struct alloca_tracking *track;
 409
 410   TRACE ("%s\n", __PRETTY_FUNCTION__);
 411   VERBOSE_TRACE ("alloca stack level %p\n", (void *) stack);
 412
 413   /* XXX: thread locking! */
 414
 415   /* Free any previously alloca'd blocks that belong to deeper-nested functions,
 416      which must therefore have exited by now.  */
 417
 418 #define DEEPER_THAN < /* XXX: for x86; steal find_stack_direction() from libiberty/alloca.c */
 419
 420   while (alloca_history &&
 421          ((uintptr_t) alloca_history->stack DEEPER_THAN (uintptr_t) stack))
 422     {
 423       struct alloca_tracking *next = alloca_history->next;
 424       __mf_unregister (alloca_history->ptr, 0, __MF_TYPE_HEAP);
 425       CALL_REAL (free, alloca_history->ptr);
 426       CALL_REAL (free, alloca_history);
 427       alloca_history = next;
 428     }
 429
 430   /* Allocate new block.  */
 431   result = NULL;
 432   if (LIKELY (c > 0)) /* alloca(0) causes no allocation.  */
 433     {
 434       track = (struct alloca_tracking *) CALL_REAL (malloc,
 435                                                     sizeof (struct alloca_tracking));
 436       if (LIKELY (track != NULL))
 437         {
 438           result = CALL_REAL (malloc, c);
 439           if (UNLIKELY (result == NULL))
 440             {
 441               CALL_REAL (free, track);
 442               /* Too bad.  XXX: What about errno?  */
 443             }
 444           else
 445             {
 446               __mf_register (result, c, __MF_TYPE_HEAP, "alloca region");
 447               track->ptr = result;
 448               track->stack = stack;
 449               track->next = alloca_history;
 450               alloca_history = track;
 451             }
 452         }
 453     }
 454
 455   return result;
 456 }
 457
 458
 459 #undef alloca
 460 WRAPPER(void *, alloca, size_t c)
 461 {
 462   return __mf_wrap_alloca_indirect (c);
 463 }
 464