lib/bcheck.c

   1 /*
   2  *  Tiny C Memory and bounds checker
   3  *
   4  *  Copyright (c) 2002 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <stdarg.h>
  23 #include <string.h>
  24 #if !defined(__FreeBSD__) && !defined(__FreeBSD_kernel__) \
  25     && !defined(__DragonFly__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
  26 #include <malloc.h>
  27 #endif
  28 #if !defined(_WIN32)
  29 #include <unistd.h>
  30 #endif
  31
  32 /* #define BOUND_DEBUG */
  33
  34 /* define so that bound array is static (faster, but use memory if
  35    bound checking not used) */
  36 /* #define BOUND_STATIC */
  37
  38 /* use malloc hooks. Currently the code cannot be reliable if no hooks */
  39 #define CONFIG_TCC_MALLOC_HOOKS
  40 #define HAVE_MEMALIGN
  41
  42 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) \
  43     || defined(__DragonFly__) || defined(__dietlibc__) \
  44     || defined(__UCLIBC__) || defined(__OpenBSD__) || defined(__NetBSD__) \
  45     || defined(_WIN32) || defined(TCC_UCLIBC)
  46 #warning Bound checking does not support malloc (etc.) in this environment.
  47 #undef CONFIG_TCC_MALLOC_HOOKS
  48 #undef HAVE_MEMALIGN
  49 #endif
  50
  51 #define BOUND_T1_BITS 13
  52 #define BOUND_T2_BITS 11
  53 #define BOUND_T3_BITS (32 - BOUND_T1_BITS - BOUND_T2_BITS)
  54
  55 #define BOUND_T1_SIZE (1 << BOUND_T1_BITS)
  56 #define BOUND_T2_SIZE (1 << BOUND_T2_BITS)
  57 #define BOUND_T3_SIZE (1 << BOUND_T3_BITS)
  58 #define BOUND_E_BITS  4
  59
  60 #define BOUND_T23_BITS (BOUND_T2_BITS + BOUND_T3_BITS)
  61 #define BOUND_T23_SIZE (1 << BOUND_T23_BITS)
  62
  63
  64 /* this pointer is generated when bound check is incorrect */
  65 #define INVALID_POINTER ((void *)(-2))
  66 /* size of an empty region */
  67 #define EMPTY_SIZE        0xffffffff
  68 /* size of an invalid region */
  69 #define INVALID_SIZE      0
  70
  71 typedef struct BoundEntry {
  72     unsigned long start;
  73     unsigned long size;
  74     struct BoundEntry *next;
  75     unsigned long is_invalid; /* true if pointers outside region are invalid */
  76 } BoundEntry;
  77
  78 /* external interface */
  79 void __bound_init(void);
  80 void __bound_new_region(void *p, unsigned long size);
  81 int __bound_delete_region(void *p);
  82
  83 #define FASTCALL __attribute__((regparm(3)))
  84
  85 void *__bound_malloc(size_t size, const void *caller);
  86 void *__bound_memalign(size_t size, size_t align, const void *caller);
  87 void __bound_free(void *ptr, const void *caller);
  88 void *__bound_realloc(void *ptr, size_t size, const void *caller);
  89 static void *libc_malloc(size_t size);
  90 static void libc_free(void *ptr);
  91 static void install_malloc_hooks(void);
  92 static void restore_malloc_hooks(void);
  93
  94 #ifdef CONFIG_TCC_MALLOC_HOOKS
  95 static void *saved_malloc_hook;
  96 static void *saved_free_hook;
  97 static void *saved_realloc_hook;
  98 static void *saved_memalign_hook;
  99 #endif
 100
 101 /* TCC definitions */
 102 extern char __bounds_start; /* start of static bounds table */
 103 /* error message, just for TCC */
 104 const char *__bound_error_msg;
 105
 106 /* runtime error output */
 107 extern void rt_error(unsigned long pc, const char *fmt, ...);
 108
 109 #ifdef BOUND_STATIC
 110 static BoundEntry *__bound_t1[BOUND_T1_SIZE]; /* page table */
 111 #else
 112 static BoundEntry **__bound_t1; /* page table */
 113 #endif
 114 static BoundEntry *__bound_empty_t2;   /* empty page, for unused pages */
 115 static BoundEntry *__bound_invalid_t2; /* invalid page, for invalid pointers */
 116
 117 static BoundEntry *__bound_find_region(BoundEntry *e1, void *p)
 118 {
 119     unsigned long addr, tmp;
 120     BoundEntry *e;
 121
 122     e = e1;
 123     while (e != NULL) {
 124         addr = (unsigned long)p;
 125         addr -= e->start;
 126         if (addr <= e->size) {
 127             /* put region at the head */
 128             tmp = e1->start;
 129             e1->start = e->start;
 130             e->start = tmp;
 131             tmp = e1->size;
 132             e1->size = e->size;
 133             e->size = tmp;
 134             return e1;
 135         }
 136         e = e->next;
 137     }
 138     /* no entry found: return empty entry or invalid entry */
 139     if (e1->is_invalid)
 140         return __bound_invalid_t2;
 141     else
 142         return __bound_empty_t2;
 143 }
 144
 145 /* print a bound error message */
 146 static void bound_error(const char *fmt, ...)
 147 {
 148     __bound_error_msg = fmt;
 149     *(int *)0 = 0; /* force a runtime error */
 150 }
 151
 152 static void bound_alloc_error(void)
 153 {
 154     bound_error("not enough memory for bound checking code");
 155 }
 156
 157 /* return '(p + offset)' for pointer arithmetic (a pointer can reach
 158    the end of a region in this case */
 159 void * FASTCALL __bound_ptr_add(void *p, int offset)
 160 {
 161     unsigned long addr = (unsigned long)p;
 162     BoundEntry *e;
 163 #if defined(BOUND_DEBUG)
 164     printf("add: 0x%x %d\n", (int)p, offset);
 165 #endif
 166
 167     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];
 168     e = (BoundEntry *)((char *)e +
 169                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 170                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));
 171     addr -= e->start;
 172     if (addr > e->size) {
 173         e = __bound_find_region(e, p);
 174         addr = (unsigned long)p - e->start;
 175     }
 176     addr += offset;
 177     if (addr > e->size)
 178         return INVALID_POINTER; /* return an invalid pointer */
 179     return p + offset;
 180 }
 181
 182 /* return '(p + offset)' for pointer indirection (the resulting must
 183    be strictly inside the region */
 184 #define BOUND_PTR_INDIR(dsize)                                          \
 185 void * FASTCALL __bound_ptr_indir ## dsize (void *p, int offset)        \
 186 {                                                                       \
 187     unsigned long addr = (unsigned long)p;                              \
 188     BoundEntry *e;                                                      \
 189                                                                         \
 190     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];            \
 191     e = (BoundEntry *)((char *)e +                                      \
 192                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &      \
 193                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));        \
 194     addr -= e->start;                                                   \
 195     if (addr > e->size) {                                               \
 196         e = __bound_find_region(e, p);                                  \
 197         addr = (unsigned long)p - e->start;                             \
 198     }                                                                   \
 199     addr += offset + dsize;                                             \
 200     if (addr > e->size)                                                 \
 201         return INVALID_POINTER; /* return an invalid pointer */         \
 202     return p + offset;                                                  \
 203 }
 204
 205 BOUND_PTR_INDIR(1)
 206 BOUND_PTR_INDIR(2)
 207 BOUND_PTR_INDIR(4)
 208 BOUND_PTR_INDIR(8)
 209 BOUND_PTR_INDIR(12)
 210 BOUND_PTR_INDIR(16)
 211
 212 /* return the frame pointer of the caller */
 213 #define GET_CALLER_FP(fp)\
 214 {\
 215     fp = (unsigned long)__builtin_frame_address(1);\
 216 }
 217
 218 /* called when entering a function to add all the local regions */
 219 void FASTCALL __bound_local_new(void *p1)
 220 {
 221     unsigned long addr, size, fp, *p = p1;
 222     GET_CALLER_FP(fp);
 223     for(;;) {
 224         addr = p[0];
 225         if (addr == 0)
 226             break;
 227         addr += fp;
 228         size = p[1];
 229         p += 2;
 230         __bound_new_region((void *)addr, size);
 231     }
 232 }
 233
 234 /* called when leaving a function to delete all the local regions */
 235 void FASTCALL __bound_local_delete(void *p1)
 236 {
 237     unsigned long addr, fp, *p = p1;
 238     GET_CALLER_FP(fp);
 239     for(;;) {
 240         addr = p[0];
 241         if (addr == 0)
 242             break;
 243         addr += fp;
 244         p += 2;
 245         __bound_delete_region((void *)addr);
 246     }
 247 }
 248
 249 static BoundEntry *__bound_new_page(void)
 250 {
 251     BoundEntry *page;
 252     int i;
 253
 254     page = libc_malloc(sizeof(BoundEntry) * BOUND_T2_SIZE);
 255     if (!page)
 256         bound_alloc_error();
 257     for(i=0;i<BOUND_T2_SIZE;i++) {
 258         /* put empty entries */
 259         page[i].start = 0;
 260         page[i].size = EMPTY_SIZE;
 261         page[i].next = NULL;
 262         page[i].is_invalid = 0;
 263     }
 264     return page;
 265 }
 266
 267 /* currently we use malloc(). Should use bound_new_page() */
 268 static BoundEntry *bound_new_entry(void)
 269 {
 270     BoundEntry *e;
 271     e = libc_malloc(sizeof(BoundEntry));
 272     return e;
 273 }
 274
 275 static void bound_free_entry(BoundEntry *e)
 276 {
 277     libc_free(e);
 278 }
 279
 280 static inline BoundEntry *get_page(int index)
 281 {
 282     BoundEntry *page;
 283     page = __bound_t1[index];
 284     if (page == __bound_empty_t2 || page == __bound_invalid_t2) {
 285         /* create a new page if necessary */
 286         page = __bound_new_page();
 287         __bound_t1[index] = page;
 288     }
 289     return page;
 290 }
 291
 292 /* mark a region as being invalid (can only be used during init) */
 293 static void mark_invalid(unsigned long addr, unsigned long size)
 294 {
 295     unsigned long start, end;
 296     BoundEntry *page;
 297     int t1_start, t1_end, i, j, t2_start, t2_end;
 298
 299     start = addr;
 300     end = addr + size;
 301
 302     t2_start = (start + BOUND_T3_SIZE - 1) >> BOUND_T3_BITS;
 303     if (end != 0)
 304         t2_end = end >> BOUND_T3_BITS;
 305     else
 306         t2_end = 1 << (BOUND_T1_BITS + BOUND_T2_BITS);
 307
 308 #if 0
 309     printf("mark_invalid: start = %x %x\n", t2_start, t2_end);
 310 #endif
 311
 312     /* first we handle full pages */
 313     t1_start = (t2_start + BOUND_T2_SIZE - 1) >> BOUND_T2_BITS;
 314     t1_end = t2_end >> BOUND_T2_BITS;
 315
 316     i = t2_start & (BOUND_T2_SIZE - 1);
 317     j = t2_end & (BOUND_T2_SIZE - 1);
 318
 319     if (t1_start == t1_end) {
 320         page = get_page(t2_start >> BOUND_T2_BITS);
 321         for(; i < j; i++) {
 322             page[i].size = INVALID_SIZE;
 323             page[i].is_invalid = 1;
 324         }
 325     } else {
 326         if (i > 0) {
 327             page = get_page(t2_start >> BOUND_T2_BITS);
 328             for(; i < BOUND_T2_SIZE; i++) {
 329                 page[i].size = INVALID_SIZE;
 330                 page[i].is_invalid = 1;
 331             }
 332         }
 333         for(i = t1_start; i < t1_end; i++) {
 334             __bound_t1[i] = __bound_invalid_t2;
 335         }
 336         if (j != 0) {
 337             page = get_page(t1_end);
 338             for(i = 0; i < j; i++) {
 339                 page[i].size = INVALID_SIZE;
 340                 page[i].is_invalid = 1;
 341             }
 342         }
 343     }
 344 }
 345
 346 void __bound_init(void)
 347 {
 348     int i;
 349     BoundEntry *page;
 350     unsigned long start, size;
 351     int *p;
 352
 353     /* save malloc hooks and install bound check hooks */
 354     install_malloc_hooks();
 355
 356 #ifndef BOUND_STATIC
 357     __bound_t1 = libc_malloc(BOUND_T1_SIZE * sizeof(BoundEntry *));
 358     if (!__bound_t1)
 359         bound_alloc_error();
 360 #endif
 361     __bound_empty_t2 = __bound_new_page();
 362     for(i=0;i<BOUND_T1_SIZE;i++) {
 363         __bound_t1[i] = __bound_empty_t2;
 364     }
 365
 366     page = __bound_new_page();
 367     for(i=0;i<BOUND_T2_SIZE;i++) {
 368         /* put invalid entries */
 369         page[i].start = 0;
 370         page[i].size = INVALID_SIZE;
 371         page[i].next = NULL;
 372         page[i].is_invalid = 1;
 373     }
 374     __bound_invalid_t2 = page;
 375
 376     /* invalid pointer zone */
 377     start = (unsigned long)INVALID_POINTER & ~(BOUND_T23_SIZE - 1);
 378     size = BOUND_T23_SIZE;
 379     mark_invalid(start, size);
 380
 381 #if defined(CONFIG_TCC_MALLOC_HOOKS)
 382     /* malloc zone is also marked invalid. can only use that with
 383      * hooks because all libs should use the same malloc. The solution
 384      * would be to build a new malloc for tcc.
 385      *
 386      * usually heap (= malloc zone) comes right after bss, i.e. after _end, but
 387      * not always - either if we are running from under `tcc -b -run`, or if
 388      * address space randomization is turned on(a), heap start will be separated
 389      * from bss end.
 390      *
 391      * So sbrk(0) will be a good approximation for start_brk:
 392      *
 393      *   - if we are a separately compiled program, __bound_init() runs early,
 394      *     and sbrk(0) should be equal or very near to start_brk(b) (in case other
 395      *     constructors malloc something), or
 396      *
 397      *   - if we are running from under `tcc -b -run`, sbrk(0) will return
 398      *     start of heap portion which is under this program control, and not
 399      *     mark as invalid earlier allocated memory.
 400      *
 401      *
 402      * (a) /proc/sys/kernel/randomize_va_space = 2, on Linux;
 403      *     usually turned on by default.
 404      *
 405      * (b) on Linux >= v3.3, the alternative is to read
 406      *     start_brk from /proc/self/stat
 407      */
 408     start = (unsigned long)sbrk(0);
 409     size = 128 * 0x100000;
 410     mark_invalid(start, size);
 411 #endif
 412
 413     /* add all static bound check values */
 414     p = (int *)&__bounds_start;
 415     while (p[0] != 0) {
 416         __bound_new_region((void *)p[0], p[1]);
 417         p += 2;
 418     }
 419 }
 420
 421 void __bound_main_arg(void **p)
 422 {
 423     void *start = p;
 424     while (*p++);
 425     __bound_new_region(start, (void *) p - start);
 426 }
 427
 428 void __bound_exit(void)
 429 {
 430     restore_malloc_hooks();
 431 }
 432
 433 static inline void add_region(BoundEntry *e,
 434                               unsigned long start, unsigned long size)
 435 {
 436     BoundEntry *e1;
 437     if (e->start == 0) {
 438         /* no region : add it */
 439         e->start = start;
 440         e->size = size;
 441     } else {
 442         /* already regions in the list: add it at the head */
 443         e1 = bound_new_entry();
 444         e1->start = e->start;
 445         e1->size = e->size;
 446         e1->next = e->next;
 447         e->start = start;
 448         e->size = size;
 449         e->next = e1;
 450     }
 451 }
 452
 453 /* create a new region. It should not already exist in the region list */
 454 void __bound_new_region(void *p, unsigned long size)
 455 {
 456     unsigned long start, end;
 457     BoundEntry *page, *e, *e2;
 458     int t1_start, t1_end, i, t2_start, t2_end;
 459
 460     start = (unsigned long)p;
 461     end = start + size;
 462     t1_start = start >> (BOUND_T2_BITS + BOUND_T3_BITS);
 463     t1_end = end >> (BOUND_T2_BITS + BOUND_T3_BITS);
 464
 465     /* start */
 466     page = get_page(t1_start);
 467     t2_start = (start >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 468         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 469     t2_end = (end >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 470         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 471 #ifdef BOUND_DEBUG
 472     printf("new %lx %lx %x %x %x %x\n",
 473            start, end, t1_start, t1_end, t2_start, t2_end);
 474 #endif
 475
 476     e = (BoundEntry *)((char *)page + t2_start);
 477     add_region(e, start, size);
 478
 479     if (t1_end == t1_start) {
 480         /* same ending page */
 481         e2 = (BoundEntry *)((char *)page + t2_end);
 482         if (e2 > e) {
 483             e++;
 484             for(;e<e2;e++) {
 485                 e->start = start;
 486                 e->size = size;
 487             }
 488             add_region(e, start, size);
 489         }
 490     } else {
 491         /* mark until end of page */
 492         e2 = page + BOUND_T2_SIZE;
 493         e++;
 494         for(;e<e2;e++) {
 495             e->start = start;
 496             e->size = size;
 497         }
 498         /* mark intermediate pages, if any */
 499         for(i=t1_start+1;i<t1_end;i++) {
 500             page = get_page(i);
 501             e2 = page + BOUND_T2_SIZE;
 502             for(e=page;e<e2;e++) {
 503                 e->start = start;
 504                 e->size = size;
 505             }
 506         }
 507         /* last page */
 508         page = get_page(t1_end);
 509         e2 = (BoundEntry *)((char *)page + t2_end);
 510         for(e=page;e<e2;e++) {
 511             e->start = start;
 512             e->size = size;
 513         }
 514         add_region(e, start, size);
 515     }
 516 }
 517
 518 /* delete a region */
 519 static inline void delete_region(BoundEntry *e,
 520                                  void *p, unsigned long empty_size)
 521 {
 522     unsigned long addr;
 523     BoundEntry *e1;
 524
 525     addr = (unsigned long)p;
 526     addr -= e->start;
 527     if (addr <= e->size) {
 528         /* region found is first one */
 529         e1 = e->next;
 530         if (e1 == NULL) {
 531             /* no more region: mark it empty */
 532             e->start = 0;
 533             e->size = empty_size;
 534         } else {
 535             /* copy next region in head */
 536             e->start = e1->start;
 537             e->size = e1->size;
 538             e->next = e1->next;
 539             bound_free_entry(e1);
 540         }
 541     } else {
 542         /* find the matching region */
 543         for(;;) {
 544             e1 = e;
 545             e = e->next;
 546             /* region not found: do nothing */
 547             if (e == NULL)
 548                 break;
 549             addr = (unsigned long)p - e->start;
 550             if (addr <= e->size) {
 551                 /* found: remove entry */
 552                 e1->next = e->next;
 553                 bound_free_entry(e);
 554                 break;
 555             }
 556         }
 557     }
 558 }
 559
 560 /* WARNING: 'p' must be the starting point of the region. */
 561 /* return non zero if error */
 562 int __bound_delete_region(void *p)
 563 {
 564     unsigned long start, end, addr, size, empty_size;
 565     BoundEntry *page, *e, *e2;
 566     int t1_start, t1_end, t2_start, t2_end, i;
 567
 568     start = (unsigned long)p;
 569     t1_start = start >> (BOUND_T2_BITS + BOUND_T3_BITS);
 570     t2_start = (start >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 571         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 572
 573     /* find region size */
 574     page = __bound_t1[t1_start];
 575     e = (BoundEntry *)((char *)page + t2_start);
 576     addr = start - e->start;
 577     if (addr > e->size)
 578         e = __bound_find_region(e, p);
 579     /* test if invalid region */
 580     if (e->size == EMPTY_SIZE || (unsigned long)p != e->start)
 581         return -1;
 582     /* compute the size we put in invalid regions */
 583     if (e->is_invalid)
 584         empty_size = INVALID_SIZE;
 585     else
 586         empty_size = EMPTY_SIZE;
 587     size = e->size;
 588     end = start + size;
 589
 590     /* now we can free each entry */
 591     t1_end = end >> (BOUND_T2_BITS + BOUND_T3_BITS);
 592     t2_end = (end >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 593         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 594
 595     delete_region(e, p, empty_size);
 596     if (t1_end == t1_start) {
 597         /* same ending page */
 598         e2 = (BoundEntry *)((char *)page + t2_end);
 599         if (e2 > e) {
 600             e++;
 601             for(;e<e2;e++) {
 602                 e->start = 0;
 603                 e->size = empty_size;
 604             }
 605             delete_region(e, p, empty_size);
 606         }
 607     } else {
 608         /* mark until end of page */
 609         e2 = page + BOUND_T2_SIZE;
 610         e++;
 611         for(;e<e2;e++) {
 612             e->start = 0;
 613             e->size = empty_size;
 614         }
 615         /* mark intermediate pages, if any */
 616         /* XXX: should free them */
 617         for(i=t1_start+1;i<t1_end;i++) {
 618             page = get_page(i);
 619             e2 = page + BOUND_T2_SIZE;
 620             for(e=page;e<e2;e++) {
 621                 e->start = 0;
 622                 e->size = empty_size;
 623             }
 624         }
 625         /* last page */
 626         page = get_page(t1_end);
 627         e2 = (BoundEntry *)((char *)page + t2_end);
 628         for(e=page;e<e2;e++) {
 629             e->start = 0;
 630             e->size = empty_size;
 631         }
 632         delete_region(e, p, empty_size);
 633     }
 634     return 0;
 635 }
 636
 637 /* return the size of the region starting at p, or EMPTY_SIZE if non
 638    existent region. */
 639 static unsigned long get_region_size(void *p)
 640 {
 641     unsigned long addr = (unsigned long)p;
 642     BoundEntry *e;
 643
 644     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];
 645     e = (BoundEntry *)((char *)e +
 646                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 647                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));
 648     addr -= e->start;
 649     if (addr > e->size)
 650         e = __bound_find_region(e, p);
 651     if (e->start != (unsigned long)p)
 652         return EMPTY_SIZE;
 653     return e->size;
 654 }
 655
 656 /* patched memory functions */
 657
 658 /* force compiler to perform stores coded up to this point */
 659 #define barrier()   __asm__ __volatile__ ("": : : "memory")
 660
 661 static void install_malloc_hooks(void)
 662 {
 663 #ifdef CONFIG_TCC_MALLOC_HOOKS
 664     saved_malloc_hook = __malloc_hook;
 665     saved_free_hook = __free_hook;
 666     saved_realloc_hook = __realloc_hook;
 667     saved_memalign_hook = __memalign_hook;
 668     __malloc_hook = __bound_malloc;
 669     __free_hook = __bound_free;
 670     __realloc_hook = __bound_realloc;
 671     __memalign_hook = __bound_memalign;
 672
 673     barrier();
 674 #endif
 675 }
 676
 677 static void restore_malloc_hooks(void)
 678 {
 679 #ifdef CONFIG_TCC_MALLOC_HOOKS
 680     __malloc_hook = saved_malloc_hook;
 681     __free_hook = saved_free_hook;
 682     __realloc_hook = saved_realloc_hook;
 683     __memalign_hook = saved_memalign_hook;
 684
 685     barrier();
 686 #endif
 687 }
 688
 689 static void *libc_malloc(size_t size)
 690 {
 691     void *ptr;
 692     restore_malloc_hooks();
 693     ptr = malloc(size);
 694     install_malloc_hooks();
 695     return ptr;
 696 }
 697
 698 static void libc_free(void *ptr)
 699 {
 700     restore_malloc_hooks();
 701     free(ptr);
 702     install_malloc_hooks();
 703 }
 704
 705 /* XXX: we should use a malloc which ensure that it is unlikely that
 706    two malloc'ed data have the same address if 'free' are made in
 707    between. */
 708 void *__bound_malloc(size_t size, const void *caller)
 709 {
 710     void *ptr;
 711
 712     /* we allocate one more byte to ensure the regions will be
 713        separated by at least one byte. With the glibc malloc, it may
 714        be in fact not necessary */
 715     ptr = libc_malloc(size + 1);
 716
 717     if (!ptr)
 718         return NULL;
 719     __bound_new_region(ptr, size);
 720     return ptr;
 721 }
 722
 723 void *__bound_memalign(size_t size, size_t align, const void *caller)
 724 {
 725     void *ptr;
 726
 727     restore_malloc_hooks();
 728
 729 #ifndef HAVE_MEMALIGN
 730     if (align > 4) {
 731         /* XXX: handle it ? */
 732         ptr = NULL;
 733     } else {
 734         /* we suppose that malloc aligns to at least four bytes */
 735         ptr = malloc(size + 1);
 736     }
 737 #else
 738     /* we allocate one more byte to ensure the regions will be
 739        separated by at least one byte. With the glibc malloc, it may
 740        be in fact not necessary */
 741     ptr = memalign(size + 1, align);
 742 #endif
 743
 744     install_malloc_hooks();
 745
 746     if (!ptr)
 747         return NULL;
 748     __bound_new_region(ptr, size);
 749     return ptr;
 750 }
 751
 752 void __bound_free(void *ptr, const void *caller)
 753 {
 754     if (ptr == NULL)
 755         return;
 756     if (__bound_delete_region(ptr) != 0)
 757         bound_error("freeing invalid region");
 758
 759     libc_free(ptr);
 760 }
 761
 762 void *__bound_realloc(void *ptr, size_t size, const void *caller)
 763 {
 764     void *ptr1;
 765     int old_size;
 766
 767     if (size == 0) {
 768         __bound_free(ptr, caller);
 769         return NULL;
 770     } else {
 771         ptr1 = __bound_malloc(size, caller);
 772         if (ptr == NULL || ptr1 == NULL)
 773             return ptr1;
 774         old_size = get_region_size(ptr);
 775         if (old_size == EMPTY_SIZE)
 776             bound_error("realloc'ing invalid pointer");
 777         memcpy(ptr1, ptr, old_size);
 778         __bound_free(ptr, caller);
 779         return ptr1;
 780     }
 781 }
 782
 783 #ifndef CONFIG_TCC_MALLOC_HOOKS
 784 void *__bound_calloc(size_t nmemb, size_t size)
 785 {
 786     void *ptr;
 787     size = size * nmemb;
 788     ptr = __bound_malloc(size, NULL);
 789     if (!ptr)
 790         return NULL;
 791     memset(ptr, 0, size);
 792     return ptr;
 793 }
 794 #endif
 795
 796 #if 0
 797 static void bound_dump(void)
 798 {
 799     BoundEntry *page, *e;
 800     int i, j;
 801
 802     printf("region dump:\n");
 803     for(i=0;i<BOUND_T1_SIZE;i++) {
 804         page = __bound_t1[i];
 805         for(j=0;j<BOUND_T2_SIZE;j++) {
 806             e = page + j;
 807             /* do not print invalid or empty entries */
 808             if (e->size != EMPTY_SIZE && e->start != 0) {
 809                 printf("%08x:",
 810                        (i << (BOUND_T2_BITS + BOUND_T3_BITS)) +
 811                        (j << BOUND_T3_BITS));
 812                 do {
 813                     printf(" %08lx:%08lx", e->start, e->start + e->size);
 814                     e = e->next;
 815                 } while (e != NULL);
 816                 printf("\n");
 817             }
 818         }
 819     }
 820 }
 821 #endif
 822
 823 /* some useful checked functions */
 824
 825 /* check that (p ... p + size - 1) lies inside 'p' region, if any */
 826 static void __bound_check(const void *p, size_t size)
 827 {
 828     if (size == 0)
 829         return;
 830     p = __bound_ptr_add((void *)p, size);
 831     if (p == INVALID_POINTER)
 832         bound_error("invalid pointer");
 833 }
 834
 835 void *__bound_memcpy(void *dst, const void *src, size_t size)
 836 {
 837     __bound_check(dst, size);
 838     __bound_check(src, size);
 839     /* check also region overlap */
 840     if (src >= dst && src < dst + size)
 841         bound_error("overlapping regions in memcpy()");
 842     return memcpy(dst, src, size);
 843 }
 844
 845 void *__bound_memmove(void *dst, const void *src, size_t size)
 846 {
 847     __bound_check(dst, size);
 848     __bound_check(src, size);
 849     return memmove(dst, src, size);
 850 }
 851
 852 void *__bound_memset(void *dst, int c, size_t size)
 853 {
 854     __bound_check(dst, size);
 855     return memset(dst, c, size);
 856 }
 857
 858 /* XXX: could be optimized */
 859 int __bound_strlen(const char *s)
 860 {
 861     const char *p;
 862     int len;
 863
 864     len = 0;
 865     for(;;) {
 866         p = __bound_ptr_indir1((char *)s, len);
 867         if (p == INVALID_POINTER)
 868             bound_error("bad pointer in strlen()");
 869         if (*p == '\0')
 870             break;
 871         len++;
 872     }
 873     return len;
 874 }
 875
 876 char *__bound_strcpy(char *dst, const char *src)
 877 {
 878     int len;
 879     len = __bound_strlen(src);
 880     return __bound_memcpy(dst, src, len + 1);
 881 }
 882