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__)
  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(_WIN32)
  45 #warning Bound checking does not support malloc (etc.) in this environment.
  46 #undef CONFIG_TCC_MALLOC_HOOKS
  47 #undef HAVE_MEMALIGN
  48 #endif
  49
  50 #define BOUND_T1_BITS 13
  51 #define BOUND_T2_BITS 11
  52 #define BOUND_T3_BITS (32 - BOUND_T1_BITS - BOUND_T2_BITS)
  53
  54 #define BOUND_T1_SIZE (1 << BOUND_T1_BITS)
  55 #define BOUND_T2_SIZE (1 << BOUND_T2_BITS)
  56 #define BOUND_T3_SIZE (1 << BOUND_T3_BITS)
  57 #define BOUND_E_BITS  4
  58
  59 #define BOUND_T23_BITS (BOUND_T2_BITS + BOUND_T3_BITS)
  60 #define BOUND_T23_SIZE (1 << BOUND_T23_BITS)
  61
  62
  63 /* this pointer is generated when bound check is incorrect */
  64 #define INVALID_POINTER ((void *)(-2))
  65 /* size of an empty region */
  66 #define EMPTY_SIZE        0xffffffff
  67 /* size of an invalid region */
  68 #define INVALID_SIZE      0
  69
  70 typedef struct BoundEntry {
  71     unsigned long start;
  72     unsigned long size;
  73     struct BoundEntry *next;
  74     unsigned long is_invalid; /* true if pointers outside region are invalid */
  75 } BoundEntry;
  76
  77 /* external interface */
  78 void __bound_init(void);
  79 void __bound_new_region(void *p, unsigned long size);
  80 int __bound_delete_region(void *p);
  81
  82 #define FASTCALL __attribute__((regparm(3)))
  83
  84 void *__bound_malloc(size_t size, const void *caller);
  85 void *__bound_memalign(size_t size, size_t align, const void *caller);
  86 void __bound_free(void *ptr, const void *caller);
  87 void *__bound_realloc(void *ptr, size_t size, const void *caller);
  88 static void *libc_malloc(size_t size);
  89 static void libc_free(void *ptr);
  90 static void install_malloc_hooks(void);
  91 static void restore_malloc_hooks(void);
  92
  93 #ifdef CONFIG_TCC_MALLOC_HOOKS
  94 static void *saved_malloc_hook;
  95 static void *saved_free_hook;
  96 static void *saved_realloc_hook;
  97 static void *saved_memalign_hook;
  98 #endif
  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 /* return '(p + offset)' for pointer arithmetic (a pointer can reach
 157    the end of a region in this case */
 158 void * FASTCALL __bound_ptr_add(void *p, int offset)
 159 {
 160     unsigned long addr = (unsigned long)p;
 161     BoundEntry *e;
 162 #if defined(BOUND_DEBUG)
 163     printf("add: 0x%x %d\n", (int)p, offset);
 164 #endif
 165
 166     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];
 167     e = (BoundEntry *)((char *)e +
 168                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 169                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));
 170     addr -= e->start;
 171     if (addr > e->size) {
 172         e = __bound_find_region(e, p);
 173         addr = (unsigned long)p - e->start;
 174     }
 175     addr += offset;
 176     if (addr > e->size)
 177         return INVALID_POINTER; /* return an invalid pointer */
 178     return p + offset;
 179 }
 180
 181 /* return '(p + offset)' for pointer indirection (the resulting must
 182    be strictly inside the region */
 183 #define BOUND_PTR_INDIR(dsize)                                          \
 184 void * FASTCALL __bound_ptr_indir ## dsize (void *p, int offset)        \
 185 {                                                                       \
 186     unsigned long addr = (unsigned long)p;                              \
 187     BoundEntry *e;                                                      \
 188                                                                         \
 189     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];            \
 190     e = (BoundEntry *)((char *)e +                                      \
 191                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &      \
 192                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));        \
 193     addr -= e->start;                                                   \
 194     if (addr > e->size) {                                               \
 195         e = __bound_find_region(e, p);                                  \
 196         addr = (unsigned long)p - e->start;                             \
 197     }                                                                   \
 198     addr += offset + dsize;                                             \
 199     if (addr > e->size)                                                 \
 200         return INVALID_POINTER; /* return an invalid pointer */         \
 201     return p + offset;                                                  \
 202 }
 203
 204 BOUND_PTR_INDIR(1)
 205 BOUND_PTR_INDIR(2)
 206 BOUND_PTR_INDIR(4)
 207 BOUND_PTR_INDIR(8)
 208 BOUND_PTR_INDIR(12)
 209 BOUND_PTR_INDIR(16)
 210
 211 /* return the frame pointer of the caller */
 212 #define GET_CALLER_FP(fp)\
 213 {\
 214     fp = (unsigned long)__builtin_frame_address(1);\
 215 }
 216
 217 /* called when entering a function to add all the local regions */
 218 void FASTCALL __bound_local_new(void *p1)
 219 {
 220     unsigned long addr, size, fp, *p = p1;
 221     GET_CALLER_FP(fp);
 222     for(;;) {
 223         addr = p[0];
 224         if (addr == 0)
 225             break;
 226         addr += fp;
 227         size = p[1];
 228         p += 2;
 229         __bound_new_region((void *)addr, size);
 230     }
 231 }
 232
 233 /* called when leaving a function to delete all the local regions */
 234 void FASTCALL __bound_local_delete(void *p1)
 235 {
 236     unsigned long addr, fp, *p = p1;
 237     GET_CALLER_FP(fp);
 238     for(;;) {
 239         addr = p[0];
 240         if (addr == 0)
 241             break;
 242         addr += fp;
 243         p += 2;
 244         __bound_delete_region((void *)addr);
 245     }
 246 }
 247
 248 static BoundEntry *__bound_new_page(void)
 249 {
 250     BoundEntry *page;
 251     int i;
 252
 253     page = libc_malloc(sizeof(BoundEntry) * BOUND_T2_SIZE);
 254     if (!page)
 255         bound_alloc_error();
 256     for(i=0;i<BOUND_T2_SIZE;i++) {
 257         /* put empty entries */
 258         page[i].start = 0;
 259         page[i].size = EMPTY_SIZE;
 260         page[i].next = NULL;
 261         page[i].is_invalid = 0;
 262     }
 263     return page;
 264 }
 265
 266 /* currently we use malloc(). Should use bound_new_page() */
 267 static BoundEntry *bound_new_entry(void)
 268 {
 269     BoundEntry *e;
 270     e = libc_malloc(sizeof(BoundEntry));
 271     return e;
 272 }
 273
 274 static void bound_free_entry(BoundEntry *e)
 275 {
 276     libc_free(e);
 277 }
 278
 279 static inline BoundEntry *get_page(int index)
 280 {
 281     BoundEntry *page;
 282     page = __bound_t1[index];
 283     if (page == __bound_empty_t2 || page == __bound_invalid_t2) {
 284         /* create a new page if necessary */
 285         page = __bound_new_page();
 286         __bound_t1[index] = page;
 287     }
 288     return page;
 289 }
 290
 291 /* mark a region as being invalid (can only be used during init) */
 292 static void mark_invalid(unsigned long addr, unsigned long size)
 293 {
 294     unsigned long start, end;
 295     BoundEntry *page;
 296     int t1_start, t1_end, i, j, t2_start, t2_end;
 297
 298     start = addr;
 299     end = addr + size;
 300
 301     t2_start = (start + BOUND_T3_SIZE - 1) >> BOUND_T3_BITS;
 302     if (end != 0)
 303         t2_end = end >> BOUND_T3_BITS;
 304     else
 305         t2_end = 1 << (BOUND_T1_BITS + BOUND_T2_BITS);
 306
 307 #if 0
 308     printf("mark_invalid: start = %x %x\n", t2_start, t2_end);
 309 #endif
 310
 311     /* first we handle full pages */
 312     t1_start = (t2_start + BOUND_T2_SIZE - 1) >> BOUND_T2_BITS;
 313     t1_end = t2_end >> BOUND_T2_BITS;
 314
 315     i = t2_start & (BOUND_T2_SIZE - 1);
 316     j = t2_end & (BOUND_T2_SIZE - 1);
 317
 318     if (t1_start == t1_end) {
 319         page = get_page(t2_start >> BOUND_T2_BITS);
 320         for(; i < j; i++) {
 321             page[i].size = INVALID_SIZE;
 322             page[i].is_invalid = 1;
 323         }
 324     } else {
 325         if (i > 0) {
 326             page = get_page(t2_start >> BOUND_T2_BITS);
 327             for(; i < BOUND_T2_SIZE; i++) {
 328                 page[i].size = INVALID_SIZE;
 329                 page[i].is_invalid = 1;
 330             }
 331         }
 332         for(i = t1_start; i < t1_end; i++) {
 333             __bound_t1[i] = __bound_invalid_t2;
 334         }
 335         if (j != 0) {
 336             page = get_page(t1_end);
 337             for(i = 0; i < j; i++) {
 338                 page[i].size = INVALID_SIZE;
 339                 page[i].is_invalid = 1;
 340             }
 341         }
 342     }
 343 }
 344
 345 void __bound_init(void)
 346 {
 347     int i;
 348     BoundEntry *page;
 349     unsigned long start, size;
 350     int *p;
 351
 352     /* save malloc hooks and install bound check hooks */
 353     install_malloc_hooks();
 354
 355 #ifndef BOUND_STATIC
 356     __bound_t1 = libc_malloc(BOUND_T1_SIZE * sizeof(BoundEntry *));
 357     if (!__bound_t1)
 358         bound_alloc_error();
 359 #endif
 360     __bound_empty_t2 = __bound_new_page();
 361     for(i=0;i<BOUND_T1_SIZE;i++) {
 362         __bound_t1[i] = __bound_empty_t2;
 363     }
 364
 365     page = __bound_new_page();
 366     for(i=0;i<BOUND_T2_SIZE;i++) {
 367         /* put invalid entries */
 368         page[i].start = 0;
 369         page[i].size = INVALID_SIZE;
 370         page[i].next = NULL;
 371         page[i].is_invalid = 1;
 372     }
 373     __bound_invalid_t2 = page;
 374
 375     /* invalid pointer zone */
 376     start = (unsigned long)INVALID_POINTER & ~(BOUND_T23_SIZE - 1);
 377     size = BOUND_T23_SIZE;
 378     mark_invalid(start, size);
 379
 380 #if !defined(__TINYC__) && defined(CONFIG_TCC_MALLOC_HOOKS)
 381     /* malloc zone is also marked invalid. can only use that with
 382      * hooks because all libs should use the same malloc. The solution
 383      * would be to build a new malloc for tcc.
 384      *
 385      * usually heap (= malloc zone) comes right after bss, i.e. after _end, but
 386      * not always - either if we are running from under `tcc -b -run`, or if
 387      * address space randomization is turned on(a), heap start will be separated
 388      * from bss end.
 389      *
 390      * So sbrk(0) will be a good approximation for start_brk:
 391      *
 392      *   - if we are a separately compiled program, __bound_init() runs early,
 393      *     and sbrk(0) should be equal or very near to start_brk(b) (in case other
 394      *     constructors malloc something), or
 395      *
 396      *   - if we are running from under `tcc -b -run`, sbrk(0) will return
 397      *     start of heap portion which is under this program control, and not
 398      *     mark as invalid earlier allocated memory.
 399      *
 400      *
 401      * (a) /proc/sys/kernel/randomize_va_space = 2, on Linux;
 402      *     usually turned on by default.
 403      *
 404      * (b) on Linux >= v3.3, the alternative is to read
 405      *     start_brk from /proc/self/stat
 406      */
 407     start = (unsigned long)sbrk(0);
 408     size = 128 * 0x100000;
 409     mark_invalid(start, size);
 410 #endif
 411
 412     /* add all static bound check values */
 413     p = (int *)&__bounds_start;
 414     while (p[0] != 0) {
 415         __bound_new_region((void *)p[0], p[1]);
 416         p += 2;
 417     }
 418 }
 419
 420 void __bound_exit(void)
 421 {
 422     restore_malloc_hooks();
 423 }
 424
 425 static inline void add_region(BoundEntry *e,
 426                               unsigned long start, unsigned long size)
 427 {
 428     BoundEntry *e1;
 429     if (e->start == 0) {
 430         /* no region : add it */
 431         e->start = start;
 432         e->size = size;
 433     } else {
 434         /* already regions in the list: add it at the head */
 435         e1 = bound_new_entry();
 436         e1->start = e->start;
 437         e1->size = e->size;
 438         e1->next = e->next;
 439         e->start = start;
 440         e->size = size;
 441         e->next = e1;
 442     }
 443 }
 444
 445 /* create a new region. It should not already exist in the region list */
 446 void __bound_new_region(void *p, unsigned long size)
 447 {
 448     unsigned long start, end;
 449     BoundEntry *page, *e, *e2;
 450     int t1_start, t1_end, i, t2_start, t2_end;
 451
 452     start = (unsigned long)p;
 453     end = start + size;
 454     t1_start = start >> (BOUND_T2_BITS + BOUND_T3_BITS);
 455     t1_end = end >> (BOUND_T2_BITS + BOUND_T3_BITS);
 456
 457     /* start */
 458     page = get_page(t1_start);
 459     t2_start = (start >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 460         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 461     t2_end = (end >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 462         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 463 #ifdef BOUND_DEBUG
 464     printf("new %lx %lx %x %x %x %x\n",
 465            start, end, t1_start, t1_end, t2_start, t2_end);
 466 #endif
 467
 468     e = (BoundEntry *)((char *)page + t2_start);
 469     add_region(e, start, size);
 470
 471     if (t1_end == t1_start) {
 472         /* same ending page */
 473         e2 = (BoundEntry *)((char *)page + t2_end);
 474         if (e2 > e) {
 475             e++;
 476             for(;e<e2;e++) {
 477                 e->start = start;
 478                 e->size = size;
 479             }
 480             add_region(e, start, size);
 481         }
 482     } else {
 483         /* mark until end of page */
 484         e2 = page + BOUND_T2_SIZE;
 485         e++;
 486         for(;e<e2;e++) {
 487             e->start = start;
 488             e->size = size;
 489         }
 490         /* mark intermediate pages, if any */
 491         for(i=t1_start+1;i<t1_end;i++) {
 492             page = get_page(i);
 493             e2 = page + BOUND_T2_SIZE;
 494             for(e=page;e<e2;e++) {
 495                 e->start = start;
 496                 e->size = size;
 497             }
 498         }
 499         /* last page */
 500         page = get_page(t1_end);
 501         e2 = (BoundEntry *)((char *)page + t2_end);
 502         for(e=page;e<e2;e++) {
 503             e->start = start;
 504             e->size = size;
 505         }
 506         add_region(e, start, size);
 507     }
 508 }
 509
 510 /* delete a region */
 511 static inline void delete_region(BoundEntry *e,
 512                                  void *p, unsigned long empty_size)
 513 {
 514     unsigned long addr;
 515     BoundEntry *e1;
 516
 517     addr = (unsigned long)p;
 518     addr -= e->start;
 519     if (addr <= e->size) {
 520         /* region found is first one */
 521         e1 = e->next;
 522         if (e1 == NULL) {
 523             /* no more region: mark it empty */
 524             e->start = 0;
 525             e->size = empty_size;
 526         } else {
 527             /* copy next region in head */
 528             e->start = e1->start;
 529             e->size = e1->size;
 530             e->next = e1->next;
 531             bound_free_entry(e1);
 532         }
 533     } else {
 534         /* find the matching region */
 535         for(;;) {
 536             e1 = e;
 537             e = e->next;
 538             /* region not found: do nothing */
 539             if (e == NULL)
 540                 break;
 541             addr = (unsigned long)p - e->start;
 542             if (addr <= e->size) {
 543                 /* found: remove entry */
 544                 e1->next = e->next;
 545                 bound_free_entry(e);
 546                 break;
 547             }
 548         }
 549     }
 550 }
 551
 552 /* WARNING: 'p' must be the starting point of the region. */
 553 /* return non zero if error */
 554 int __bound_delete_region(void *p)
 555 {
 556     unsigned long start, end, addr, size, empty_size;
 557     BoundEntry *page, *e, *e2;
 558     int t1_start, t1_end, t2_start, t2_end, i;
 559
 560     start = (unsigned long)p;
 561     t1_start = start >> (BOUND_T2_BITS + BOUND_T3_BITS);
 562     t2_start = (start >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 563         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 564
 565     /* find region size */
 566     page = __bound_t1[t1_start];
 567     e = (BoundEntry *)((char *)page + t2_start);
 568     addr = start - e->start;
 569     if (addr > e->size)
 570         e = __bound_find_region(e, p);
 571     /* test if invalid region */
 572     if (e->size == EMPTY_SIZE || (unsigned long)p != e->start)
 573         return -1;
 574     /* compute the size we put in invalid regions */
 575     if (e->is_invalid)
 576         empty_size = INVALID_SIZE;
 577     else
 578         empty_size = EMPTY_SIZE;
 579     size = e->size;
 580     end = start + size;
 581
 582     /* now we can free each entry */
 583     t1_end = end >> (BOUND_T2_BITS + BOUND_T3_BITS);
 584     t2_end = (end >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 585         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS);
 586
 587     delete_region(e, p, empty_size);
 588     if (t1_end == t1_start) {
 589         /* same ending page */
 590         e2 = (BoundEntry *)((char *)page + t2_end);
 591         if (e2 > e) {
 592             e++;
 593             for(;e<e2;e++) {
 594                 e->start = 0;
 595                 e->size = empty_size;
 596             }
 597             delete_region(e, p, empty_size);
 598         }
 599     } else {
 600         /* mark until end of page */
 601         e2 = page + BOUND_T2_SIZE;
 602         e++;
 603         for(;e<e2;e++) {
 604             e->start = 0;
 605             e->size = empty_size;
 606         }
 607         /* mark intermediate pages, if any */
 608         /* XXX: should free them */
 609         for(i=t1_start+1;i<t1_end;i++) {
 610             page = get_page(i);
 611             e2 = page + BOUND_T2_SIZE;
 612             for(e=page;e<e2;e++) {
 613                 e->start = 0;
 614                 e->size = empty_size;
 615             }
 616         }
 617         /* last page */
 618         page = get_page(t1_end);
 619         e2 = (BoundEntry *)((char *)page + t2_end);
 620         for(e=page;e<e2;e++) {
 621             e->start = 0;
 622             e->size = empty_size;
 623         }
 624         delete_region(e, p, empty_size);
 625     }
 626     return 0;
 627 }
 628
 629 /* return the size of the region starting at p, or EMPTY_SIZE if non
 630    existant region. */
 631 static unsigned long get_region_size(void *p)
 632 {
 633     unsigned long addr = (unsigned long)p;
 634     BoundEntry *e;
 635
 636     e = __bound_t1[addr >> (BOUND_T2_BITS + BOUND_T3_BITS)];
 637     e = (BoundEntry *)((char *)e +
 638                        ((addr >> (BOUND_T3_BITS - BOUND_E_BITS)) &
 639                         ((BOUND_T2_SIZE - 1) << BOUND_E_BITS)));
 640     addr -= e->start;
 641     if (addr > e->size)
 642         e = __bound_find_region(e, p);
 643     if (e->start != (unsigned long)p)
 644         return EMPTY_SIZE;
 645     return e->size;
 646 }
 647
 648 /* patched memory functions */
 649
 650 /* force compiler to perform stores coded up to this point */
 651 #define barrier()   __asm__ __volatile__ ("": : : "memory")
 652
 653 static void install_malloc_hooks(void)
 654 {
 655 #ifdef CONFIG_TCC_MALLOC_HOOKS
 656     saved_malloc_hook = __malloc_hook;
 657     saved_free_hook = __free_hook;
 658     saved_realloc_hook = __realloc_hook;
 659     saved_memalign_hook = __memalign_hook;
 660     __malloc_hook = __bound_malloc;
 661     __free_hook = __bound_free;
 662     __realloc_hook = __bound_realloc;
 663     __memalign_hook = __bound_memalign;
 664
 665     barrier();
 666 #endif
 667 }
 668
 669 static void restore_malloc_hooks(void)
 670 {
 671 #ifdef CONFIG_TCC_MALLOC_HOOKS
 672     __malloc_hook = saved_malloc_hook;
 673     __free_hook = saved_free_hook;
 674     __realloc_hook = saved_realloc_hook;
 675     __memalign_hook = saved_memalign_hook;
 676
 677     barrier();
 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