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(__DragonFly__) && !defined(__OpenBSD__)
  25 #include <malloc.h>
  26 #endif
  27
  28 //#define BOUND_DEBUG
  29
  30 /* define so that bound array is static (faster, but use memory if
  31    bound checking not used) */
  32 //#define BOUND_STATIC
  33
  34 /* use malloc hooks. Currently the code cannot be reliable if no hooks */
  35 #define CONFIG_TCC_MALLOC_HOOKS
  36
  37 #define HAVE_MEMALIGN
  38
  39 #if defined(__FreeBSD__) || defined(__DragonFly__) || defined(__dietlibc__) \
  40     || defined(__UCLIBC__) || defined(__OpenBSD__) || defined(__CYGWIN__) \
  41     || defined(_WIN32)
  42 #warning Bound checking not fully supported in this environment.
  43 #undef CONFIG_TCC_MALLOC_HOOKS
  44 #undef HAVE_MEMALIGN
  45 #endif
  46
  47 #define BOUND_T1_BITS 13
  48 #define BOUND_T2_BITS 11
  49 #define BOUND_T3_BITS (32 - BOUND_T1_BITS - BOUND_T2_BITS)
  50
  51 #define BOUND_T1_SIZE (1 << BOUND_T1_BITS)
  52 #define BOUND_T2_SIZE (1 << BOUND_T2_BITS)
  53 #define BOUND_T3_SIZE (1 << BOUND_T3_BITS)
  54 #define BOUND_E_BITS  4
  55
  56 #define BOUND_T23_BITS (BOUND_T2_BITS + BOUND_T3_BITS)
  57 #define BOUND_T23_SIZE (1 << BOUND_T23_BITS)
  58
  59
  60 /* this pointer is generated when bound check is incorrect */
  61 #define INVALID_POINTER ((void *)(-2))
  62 /* size of an empty region */
  63 #define EMPTY_SIZE        0xffffffff
  64 /* size of an invalid region */
  65 #define INVALID_SIZE      0
  66
  67 typedef struct BoundEntry {
  68     unsigned long start;
  69     unsigned long size;
  70     struct BoundEntry *next;
  71     unsigned long is_invalid; /* true if pointers outside region are invalid */
  72 } BoundEntry;
  73
  74 /* external interface */
  75 void __bound_init(void);
  76 void __bound_new_region(void *p, unsigned long size);
  77 int __bound_delete_region(void *p);
  78
  79 #define FASTCALL __attribute__((regparm(3)))
  80
  81 void *__bound_malloc(size_t size, const void *caller);
  82 void *__bound_memalign(size_t size, size_t align, const void *caller);
  83 void __bound_free(void *ptr, const void *caller);
  84 void *__bound_realloc(void *ptr, size_t size, const void *caller);
  85 static void *libc_malloc(size_t size);
  86 static void libc_free(void *ptr);
  87 static void install_malloc_hooks(void);
  88 static void restore_malloc_hooks(void);
  89
  90 #ifdef CONFIG_TCC_MALLOC_HOOKS
  91 static void *saved_malloc_hook;
  92 static void *saved_free_hook;
  93 static void *saved_realloc_hook;
  94 static void *saved_memalign_hook;
  95 #endif
  96
  97 /* linker definitions */
  98 extern char _end;
  99
 100 /* TCC definitions */
 101 extern char __bounds_start; /* start of static bounds table */
 102 /* error message, just for TCC */
 103 const char *__bound_error_msg;
 104
 105 /* runtime error output */
 106 extern void rt_error(unsigned long pc, const char *fmt, ...);
 107
 108 #ifdef BOUND_STATIC
 109 static BoundEntry *__bound_t1[BOUND_T1_SIZE]; /* page table */
 110 #else
 111 static BoundEntry **__bound_t1; /* page table */
 112 #endif
 113 static BoundEntry *__bound_empty_t2;   /* empty page, for unused pages */
 114 static BoundEntry *__bound_invalid_t2; /* invalid page, for invalid pointers */
 115
 116 static BoundEntry *__bound_find_region(BoundEntry *e1, void *p)
 117 {
 118     unsigned long addr, tmp;
 119     BoundEntry *e;
 120
 121     e = e1;
 122     while (e != NULL) {
 123         addr = (unsigned long)p;
 124         addr -= e->start;
 125         if (addr <= e->size) {
 126             /* put region at the head */
 127             tmp = e1->start;
 128             e1->start = e->start;
 129             e->start = tmp;
 130             tmp = e1->size;
 131             e1->size = e->size;
 132             e->size = tmp;
 133             return e1;
 134         }
 135         e = e->next;
 136     }
 137     /* no entry found: return empty entry or invalid entry */
 138     if (e1->is_invalid)
 139         return __bound_invalid_t2;
 140     else
 141         return __bound_empty_t2;
 142 }
 143
 144 /* print a bound error message */
 145 static void bound_error(const char *fmt, ...)
 146 {
 147     __bound_error_msg = fmt;
 148     *(int *)0 = 0; /* force a runtime error */
 149 }
 150
 151 static void bound_alloc_error(void)
 152 {
 153     bound_error("not enough memory for bound checking code");
 154 }
 155
 156 /* currently, tcc cannot compile that because we use GNUC extensions */
 157 #if !defined(__TINYC__)
 158
 159 /* return '(p + offset)' for pointer arithmetic (a pointer can reach
 160    the end of a region in this case */
 161 void * FASTCALL __bound_ptr_add(void *p, int offset)
 162 {
 163     unsigned long addr = (unsigned long)p;
 164     BoundEntry *e;
 165 #if defined(BOUND_DEBUG)
 166     printf("add: 0x%x %d\n", (int)p, offset);
 167 #endif
 168
 169     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];
 170     e = (BoundEntry *)((char *)e +
 171                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 172                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));
 173     addr -= e->start;
 174     if (addr > e->size) {
 175         e = __bound_find_region(e, p);
 176         addr = (unsigned long)p - e->start;
 177     }
 178     addr += offset;
 179     if (addr > e->size)
 180         return INVALID_POINTER; /* return an invalid pointer */
 181     return p + offset;
 182 }
 183
 184 /* return '(p + offset)' for pointer indirection (the resulting must
 185    be strictly inside the region */
 186 #define BOUND_PTR_INDIR(dsize)                                          \
 187 void * FASTCALL __bound_ptr_indir ## dsize (void *p, int offset)        \
 188 {                                                                       \
 189     unsigned long addr = (unsigned long)p;                              \
 190     BoundEntry *e;                                                      \
 191                                                                         \
 192     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];            \
 193     e = (BoundEntry *)((char *)e +                                      \
 194                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &      \
 195                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));        \
 196     addr -= e->start;                                                   \
 197     if (addr > e->size) {                                               \
 198         e = __bound_find_region(e, p);                                  \
 199         addr = (unsigned long)p - e->start;                             \
 200     }                                                                   \
 201     addr += offset + dsize;                                             \
 202     if (addr > e->size)                                                 \
 203         return INVALID_POINTER; /* return an invalid pointer */         \
 204     return p + offset;                                                  \
 205 }
 206
 207 #ifdef __i386__
 208 /* return the frame pointer of the caller */
 209 #define GET_CALLER_FP(fp)\
 210 {\
 211     unsigned long *fp1;\
 212     __asm__ __volatile__ ("movl %%ebp,%0" :"=g" (fp1));\
 213     fp = fp1[0];\
 214 }
 215 #else
 216 #error put code to extract the calling frame pointer
 217 #endif
 218
 219 /* called when entering a function to add all the local regions */
 220 void FASTCALL __bound_local_new(void *p1)
 221 {
 222     unsigned long addr, size, fp, *p = p1;
 223     GET_CALLER_FP(fp);
 224     for(;;) {
 225         addr = p[0];
 226         if (addr == 0)
 227             break;
 228         addr += fp;
 229         size = p[1];
 230         p += 2;
 231         __bound_new_region((void *)addr, size);
 232     }
 233 }
 234
 235 /* called when leaving a function to delete all the local regions */
 236 void FASTCALL __bound_local_delete(void *p1)
 237 {
 238     unsigned long addr, fp, *p = p1;
 239     GET_CALLER_FP(fp);
 240     for(;;) {
 241         addr = p[0];
 242         if (addr == 0)
 243             break;
 244         addr += fp;
 245         p += 2;
 246         __bound_delete_region((void *)addr);
 247     }
 248 }
 249
 250 #else
 251
 252 void __bound_local_new(void *p)
 253 {
 254 }
 255 void __bound_local_delete(void *p)
 256 {
 257 }
 258
 259 void *__bound_ptr_add(void *p, int offset)
 260 {
 261     return p + offset;
 262 }
 263
 264 #define BOUND_PTR_INDIR(dsize)                               \
 265 void *__bound_ptr_indir ## dsize (void *p, int offset)       \
 266 {                                                            \
 267     return p + offset;                                       \
 268 }
 269 #endif
 270
 271 BOUND_PTR_INDIR(1)
 272 BOUND_PTR_INDIR(2)
 273 BOUND_PTR_INDIR(4)
 274 BOUND_PTR_INDIR(8)
 275 BOUND_PTR_INDIR(12)
 276 BOUND_PTR_INDIR(16)
 277
 278 static BoundEntry *__bound_new_page(void)
 279 {
 280     BoundEntry *page;
 281     int i;
 282
 283     page = libc_malloc(sizeof(BoundEntry) * BOUND_T2_SIZE);
 284     if (!page)
 285         bound_alloc_error();
 286     for(i=0;i<BOUND_T2_SIZE;i++) {
 287         /* put empty entries */
 288         page[i].start = 0;
 289         page[i].size = EMPTY_SIZE;
 290         page[i].next = NULL;
 291         page[i].is_invalid = 0;
 292     }
 293     return page;
 294 }
 295
 296 /* currently we use malloc(). Should use bound_new_page() */
 297 static BoundEntry *bound_new_entry(void)
 298 {
 299     BoundEntry *e;
 300     e = libc_malloc(sizeof(BoundEntry));
 301     return e;
 302 }
 303
 304 static void bound_free_entry(BoundEntry *e)
 305 {
 306     libc_free(e);
 307 }
 308
 309 static inline BoundEntry *get_page(int index)
 310 {
 311     BoundEntry *page;
 312     page = __bound_t1[index];
 313     if (page == __bound_empty_t2 || page == __bound_invalid_t2) {
 314         /* create a new page if necessary */
 315         page = __bound_new_page();
 316         __bound_t1[index] = page;
 317     }
 318     return page;
 319 }
 320
 321 /* mark a region as being invalid (can only be used during init) */
 322 static void mark_invalid(unsigned long addr, unsigned long size)
 323 {
 324     unsigned long start, end;
 325     BoundEntry *page;
 326     int t1_start, t1_end, i, j, t2_start, t2_end;
 327
 328     start = addr;
 329     end = addr + size;
 330
 331     t2_start = (start + BOUND_T3_SIZE - 1) >> BOUND_T3_BITS;
 332     if (end != 0)
 333         t2_end = end >> BOUND_T3_BITS;
 334     else
 335         t2_end = 1 << (BOUND_T1_BITS + BOUND_T2_BITS);
 336
 337 #if 0
 338     printf("mark_invalid: start = %x %x\n", t2_start, t2_end);
 339 #endif
 340
 341     /* first we handle full pages */
 342     t1_start = (t2_start + BOUND_T2_SIZE - 1) >> BOUND_T2_BITS;
 343     t1_end = t2_end >> BOUND_T2_BITS;
 344
 345     i = t2_start & (BOUND_T2_SIZE - 1);
 346     j = t2_end & (BOUND_T2_SIZE - 1);
 347
 348     if (t1_start == t1_end) {
 349         page = get_page(t2_start >> BOUND_T2_BITS);
 350         for(; i < j; i++) {
 351             page[i].size = INVALID_SIZE;
 352             page[i].is_invalid = 1;
 353         }
 354     } else {
 355         if (i > 0) {
 356             page = get_page(t2_start >> BOUND_T2_BITS);
 357             for(; i < BOUND_T2_SIZE; i++) {
 358                 page[i].size = INVALID_SIZE;
 359                 page[i].is_invalid = 1;
 360             }
 361         }
 362         for(i = t1_start; i < t1_end; i++) {
 363             __bound_t1[i] = __bound_invalid_t2;
 364         }
 365         if (j != 0) {
 366             page = get_page(t1_end);
 367             for(i = 0; i < j; i++) {
 368                 page[i].size = INVALID_SIZE;
 369                 page[i].is_invalid = 1;
 370             }
 371         }
 372     }
 373 }
 374
 375 void __bound_init(void)
 376 {
 377     int i;
 378     BoundEntry *page;
 379     unsigned long start, size;
 380     int *p;
 381
 382     /* save malloc hooks and install bound check hooks */
 383     install_malloc_hooks();
 384
 385 #ifndef BOUND_STATIC
 386     __bound_t1 = libc_malloc(BOUND_T1_SIZE * sizeof(BoundEntry *));
 387     if (!__bound_t1)
 388         bound_alloc_error();
 389 #endif
 390     __bound_empty_t2 = __bound_new_page();
 391     for(i=0;i<BOUND_T1_SIZE;i++) {
 392         __bound_t1[i] = __bound_empty_t2;
 393     }
 394
 395     page = __bound_new_page();
 396     for(i=0;i<BOUND_T2_SIZE;i++) {
 397         /* put invalid entries */
 398         page[i].start = 0;
 399         page[i].size = INVALID_SIZE;
 400         page[i].next = NULL;
 401         page[i].is_invalid = 1;
 402     }
 403     __bound_invalid_t2 = page;
 404
 405     /* invalid pointer zone */
 406     start = (unsigned long)INVALID_POINTER & ~(BOUND_T23_SIZE - 1);
 407     size = BOUND_T23_SIZE;
 408     mark_invalid(start, size);
 409
 410 #if !defined(__TINYC__) && defined(CONFIG_TCC_MALLOC_HOOKS)
 411     /* malloc zone is also marked invalid. can only use that with
 412        hooks because all libs should use the same malloc. The solution
 413        would be to build a new malloc for tcc. */
 414     start = (unsigned long)&_end;
 415     size = 128 * 0x100000;
 416     mark_invalid(start, size);
 417 #endif
 418
 419     /* add all static bound check values */
 420     p = (int *)&__bounds_start;
 421     while (p[0] != 0) {
 422         __bound_new_region((void *)p[0], p[1]);
 423         p += 2;
 424     }
 425 }
 426
 427 void __bound_exit(void)
 428 {
 429     restore_malloc_hooks();
 430 }
 431
 432 static inline void add_region(BoundEntry *e,
 433                               unsigned long start, unsigned long size)
 434 {
 435     BoundEntry *e1;
 436     if (e->start == 0) {
 437         /* no region : add it */
 438         e->start = start;
 439         e->size = size;
 440     } else {
 441         /* already regions in the list: add it at the head */
 442         e1 = bound_new_entry();
 443         e1->start = e->start;
 444         e1->size = e->size;
 445         e1->next = e->next;
 446         e->start = start;
 447         e->size = size;
 448         e->next = e1;
 449     }
 450 }
 451
 452 /* create a new region. It should not already exist in the region list */
 453 void __bound_new_region(void *p, unsigned long size)
 454 {
 455     unsigned long start, end;
 456     BoundEntry *page, *e, *e2;
 457     int t1_start, t1_end, i, t2_start, t2_end;
 458
 459     start = (unsigned long)p;
 460     end = start + size;
 461     t1_start = start >> (BOUND_T2_BITS + BOUND_T3_BITS);
 462     t1_end = end >> (BOUND_T2_BITS + BOUND_T3_BITS);
 463
 464     /* start */
 465     page = get_page(t1_start);
 466     t2_start = (start >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 467         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 468     t2_end = (end >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 469         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 470 #ifdef BOUND_DEBUG
 471     printf("new %lx %lx %x %x %x %x\n",
 472            start, end, t1_start, t1_end, t2_start, t2_end);
 473 #endif
 474
 475     e = (BoundEntry *)((char *)page + t2_start);
 476     add_region(e, start, size);
 477
 478     if (t1_end == t1_start) {
 479         /* same ending page */
 480         e2 = (BoundEntry *)((char *)page + t2_end);
 481         if (e2 > e) {
 482             e++;
 483             for(;e<e2;e++) {
 484                 e->start = start;
 485                 e->size = size;
 486             }
 487             add_region(e, start, size);
 488         }
 489     } else {
 490         /* mark until end of page */
 491         e2 = page + BOUND_T2_SIZE;
 492         e++;
 493         for(;e<e2;e++) {
 494             e->start = start;
 495             e->size = size;
 496         }
 497         /* mark intermediate pages, if any */
 498         for(i=t1_start+1;i<t1_end;i++) {
 499             page = get_page(i);
 500             e2 = page + BOUND_T2_SIZE;
 501             for(e=page;e<e2;e++) {
 502                 e->start = start;
 503                 e->size = size;
 504             }
 505         }
 506         /* last page */
 507         page = get_page(t1_end);
 508         e2 = (BoundEntry *)((char *)page + t2_end);
 509         for(e=page;e<e2;e++) {
 510             e->start = start;
 511             e->size = size;
 512         }
 513         add_region(e, start, size);
 514     }
 515 }
 516
 517 /* delete a region */
 518 static inline void delete_region(BoundEntry *e,
 519                                  void *p, unsigned long empty_size)
 520 {
 521     unsigned long addr;
 522     BoundEntry *e1;
 523
 524     addr = (unsigned long)p;
 525     addr -= e->start;
 526     if (addr <= e->size) {
 527         /* region found is first one */
 528         e1 = e->next;
 529         if (e1 == NULL) {
 530             /* no more region: mark it empty */
 531             e->start = 0;
 532             e->size = empty_size;
 533         } else {
 534             /* copy next region in head */
 535             e->start = e1->start;
 536             e->size = e1->size;
 537             e->next = e1->next;
 538             bound_free_entry(e1);
 539         }
 540     } else {
 541         /* find the matching region */
 542         for(;;) {
 543             e1 = e;
 544             e = e->next;
 545             /* region not found: do nothing */
 546             if (e == NULL)
 547                 break;
 548             addr = (unsigned long)p - e->start;
 549             if (addr <= e->size) {
 550                 /* found: remove entry */
 551                 e1->next = e->next;
 552                 bound_free_entry(e);
 553                 break;
 554             }
 555         }
 556     }
 557 }
 558
 559 /* WARNING: 'p' must be the starting point of the region. */
 560 /* return non zero if error */
 561 int __bound_delete_region(void *p)
 562 {
 563     unsigned long start, end, addr, size, empty_size;
 564     BoundEntry *page, *e, *e2;
 565     int t1_start, t1_end, t2_start, t2_end, i;
 566
 567     start = (unsigned long)p;
 568     t1_start = start >> (BOUND_T2_BITS + BOUND_T3_BITS);
 569     t2_start = (start >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 570         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 571
 572     /* find region size */
 573     page = __bound_t1[t1_start];
 574     e = (BoundEntry *)((char *)page + t2_start);
 575     addr = start - e->start;
 576     if (addr > e->size)
 577         e = __bound_find_region(e, p);
 578     /* test if invalid region */
 579     if (e->size == EMPTY_SIZE || (unsigned long)p != e->start)
 580         return -1;
 581     /* compute the size we put in invalid regions */
 582     if (e->is_invalid)
 583         empty_size = INVALID_SIZE;
 584     else
 585         empty_size = EMPTY_SIZE;
 586     size = e->size;
 587     end = start + size;
 588
 589     /* now we can free each entry */
 590     t1_end = end >> (BOUND_T2_BITS + BOUND_T3_BITS);
 591     t2_end = (end >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 592         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 593
 594     delete_region(e, p, empty_size);
 595     if (t1_end == t1_start) {
 596         /* same ending page */
 597         e2 = (BoundEntry *)((char *)page + t2_end);
 598         if (e2 > e) {
 599             e++;
 600             for(;e<e2;e++) {
 601                 e->start = 0;
 602                 e->size = empty_size;
 603             }
 604             delete_region(e, p, empty_size);
 605         }
 606     } else {
 607         /* mark until end of page */
 608         e2 = page + BOUND_T2_SIZE;
 609         e++;
 610         for(;e<e2;e++) {
 611             e->start = 0;
 612             e->size = empty_size;
 613         }
 614         /* mark intermediate pages, if any */
 615         /* XXX: should free them */
 616         for(i=t1_start+1;i<t1_end;i++) {
 617             page = get_page(i);
 618             e2 = page + BOUND_T2_SIZE;
 619             for(e=page;e<e2;e++) {
 620                 e->start = 0;
 621                 e->size = empty_size;
 622             }
 623         }
 624         /* last page */
 625         page = get_page(t2_end);
 626         e2 = (BoundEntry *)((char *)page + t2_end);
 627         for(e=page;e<e2;e++) {
 628             e->start = 0;
 629             e->size = empty_size;
 630         }
 631         delete_region(e, p, empty_size);
 632     }
 633     return 0;
 634 }
 635
 636 /* return the size of the region starting at p, or EMPTY_SIZE if non
 637    existant region. */
 638 static unsigned long get_region_size(void *p)
 639 {
 640     unsigned long addr = (unsigned long)p;
 641     BoundEntry *e;
 642
 643     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];
 644     e = (BoundEntry *)((char *)e +
 645                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 646                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));
 647     addr -= e->start;
 648     if (addr > e->size)
 649         e = __bound_find_region(e, p);
 650     if (e->start != (unsigned long)p)
 651         return EMPTY_SIZE;
 652     return e->size;
 653 }
 654
 655 /* patched memory functions */
 656
 657 static void install_malloc_hooks(void)
 658 {
 659 #ifdef CONFIG_TCC_MALLOC_HOOKS
 660     saved_malloc_hook = __malloc_hook;
 661     saved_free_hook = __free_hook;
 662     saved_realloc_hook = __realloc_hook;
 663     saved_memalign_hook = __memalign_hook;
 664     __malloc_hook = __bound_malloc;
 665     __free_hook = __bound_free;
 666     __realloc_hook = __bound_realloc;
 667     __memalign_hook = __bound_memalign;
 668 #endif
 669 }
 670
 671 static void restore_malloc_hooks(void)
 672 {
 673 #ifdef CONFIG_TCC_MALLOC_HOOKS
 674     __malloc_hook = saved_malloc_hook;
 675     __free_hook = saved_free_hook;
 676     __realloc_hook = saved_realloc_hook;
 677     __memalign_hook = saved_memalign_hook;
 678 #endif
 679 }
 680
 681 static void *libc_malloc(size_t size)
 682 {
 683     void *ptr;
 684     restore_malloc_hooks();
 685     ptr = malloc(size);
 686     install_malloc_hooks();
 687     return ptr;
 688 }
 689
 690 static void libc_free(void *ptr)
 691 {
 692     restore_malloc_hooks();
 693     free(ptr);
 694     install_malloc_hooks();
 695 }
 696
 697 /* XXX: we should use a malloc which ensure that it is unlikely that
 698    two malloc'ed data have the same address if 'free' are made in
 699    between. */
 700 void *__bound_malloc(size_t size, const void *caller)
 701 {
 702     void *ptr;
 703
 704     /* we allocate one more byte to ensure the regions will be
 705        separated by at least one byte. With the glibc malloc, it may
 706        be in fact not necessary */
 707     ptr = libc_malloc(size + 1);
 708
 709     if (!ptr)
 710         return NULL;
 711     __bound_new_region(ptr, size);
 712     return ptr;
 713 }
 714
 715 void *__bound_memalign(size_t size, size_t align, const void *caller)
 716 {
 717     void *ptr;
 718
 719     restore_malloc_hooks();
 720
 721 #ifndef HAVE_MEMALIGN
 722     if (align > 4) {
 723         /* XXX: handle it ? */
 724         ptr = NULL;
 725     } else {
 726         /* we suppose that malloc aligns to at least four bytes */
 727         ptr = malloc(size + 1);
 728     }
 729 #else
 730     /* we allocate one more byte to ensure the regions will be
 731        separated by at least one byte. With the glibc malloc, it may
 732        be in fact not necessary */
 733     ptr = memalign(size + 1, align);
 734 #endif
 735
 736     install_malloc_hooks();
 737
 738     if (!ptr)
 739         return NULL;
 740     __bound_new_region(ptr, size);
 741     return ptr;
 742 }
 743
 744 void __bound_free(void *ptr, const void *caller)
 745 {
 746     if (ptr == NULL)
 747         return;
 748     if (__bound_delete_region(ptr) != 0)
 749         bound_error("freeing invalid region");
 750
 751     libc_free(ptr);
 752 }
 753
 754 void *__bound_realloc(void *ptr, size_t size, const void *caller)
 755 {
 756     void *ptr1;
 757     int old_size;
 758
 759     if (size == 0) {
 760         __bound_free(ptr, caller);
 761         return NULL;
 762     } else {
 763         ptr1 = __bound_malloc(size, caller);
 764         if (ptr == NULL || ptr1 == NULL)
 765             return ptr1;
 766         old_size = get_region_size(ptr);
 767         if (old_size == EMPTY_SIZE)
 768             bound_error("realloc'ing invalid pointer");
 769         memcpy(ptr1, ptr, old_size);
 770         __bound_free(ptr, caller);
 771         return ptr1;
 772     }
 773 }
 774
 775 #ifndef CONFIG_TCC_MALLOC_HOOKS
 776 void *__bound_calloc(size_t nmemb, size_t size)
 777 {
 778     void *ptr;
 779     size = size * nmemb;
 780     ptr = __bound_malloc(size, NULL);
 781     if (!ptr)
 782         return NULL;
 783     memset(ptr, 0, size);
 784     return ptr;
 785 }
 786 #endif
 787
 788 #if 0
 789 static void bound_dump(void)
 790 {
 791     BoundEntry *page, *e;
 792     int i, j;
 793
 794     printf("region dump:\n");
 795     for(i=0;i<BOUND_T1_SIZE;i++) {
 796         page = __bound_t1[i];
 797         for(j=0;j<BOUND_T2_SIZE;j++) {
 798             e = page + j;
 799             /* do not print invalid or empty entries */
 800             if (e->size != EMPTY_SIZE && e->start != 0) {
 801                 printf("%08x:",
 802                        (i << (BOUND_T2_BITS + BOUND_T3_BITS)) +
 803                        (j << BOUND_T3_BITS));
 804                 do {
 805                     printf(" %08lx:%08lx", e->start, e->start + e->size);
 806                     e = e->next;
 807                 } while (e != NULL);
 808                 printf("\n");
 809             }
 810         }
 811     }
 812 }
 813 #endif
 814
 815 /* some useful checked functions */
 816
 817 /* check that (p ... p + size - 1) lies inside 'p' region, if any */
 818 static void __bound_check(const void *p, size_t size)
 819 {
 820     if (size == 0)
 821         return;
 822     p = __bound_ptr_add((void *)p, size);
 823     if (p == INVALID_POINTER)
 824         bound_error("invalid pointer");
 825 }
 826
 827 void *__bound_memcpy(void *dst, const void *src, size_t size)
 828 {
 829     __bound_check(dst, size);
 830     __bound_check(src, size);
 831     /* check also region overlap */
 832     if (src >= dst && src < dst + size)
 833         bound_error("overlapping regions in memcpy()");
 834     return memcpy(dst, src, size);
 835 }
 836
 837 void *__bound_memmove(void *dst, const void *src, size_t size)
 838 {
 839     __bound_check(dst, size);
 840     __bound_check(src, size);
 841     return memmove(dst, src, size);
 842 }
 843
 844 void *__bound_memset(void *dst, int c, size_t size)
 845 {
 846     __bound_check(dst, size);
 847     return memset(dst, c, size);
 848 }
 849
 850 /* XXX: could be optimized */
 851 int __bound_strlen(const char *s)
 852 {
 853     const char *p;
 854     int len;
 855
 856     len = 0;
 857     for(;;) {
 858         p = __bound_ptr_indir1((char *)s, len);
 859         if (p == INVALID_POINTER)
 860             bound_error("bad pointer in strlen()");
 861         if (*p == '\0')
 862             break;
 863         len++;
 864     }
 865     return len;
 866 }
 867
 868 char *__bound_strcpy(char *dst, const char *src)
 869 {
 870     int len;
 871     len = __bound_strlen(src);
 872     return __bound_memcpy(dst, src, len + 1);
 873 }
 874