src/util/ralloc.c

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include <assert.h>
  25 #include <stdlib.h>
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <stdint.h>
  30
  31 /* Android defines SIZE_MAX in limits.h, instead of the standard stdint.h */
  32 #ifdef ANDROID
  33 #include <limits.h>
  34 #endif
  35
  36 /* Some versions of MinGW are missing _vscprintf's declaration, although they
  37  * still provide the symbol in the import library. */
  38 #ifdef __MINGW32__
  39 _CRTIMP int _vscprintf(const char *format, va_list argptr);
  40 #endif
  41
  42 #include "ralloc.h"
  43
  44 #ifndef va_copy
  45 #ifdef __va_copy
  46 #define va_copy(dest, src) __va_copy((dest), (src))
  47 #else
  48 #define va_copy(dest, src) (dest) = (src)
  49 #endif
  50 #endif
  51
  52 #define CANARY 0x5A1106
  53
  54 struct ralloc_header
  55 {
  56 #ifdef DEBUG
  57    /* A canary value used to determine whether a pointer is ralloc'd. */
  58    unsigned canary;
  59 #endif
  60
  61    struct ralloc_header *parent;
  62
  63    /* The first child (head of a linked list) */
  64    struct ralloc_header *child;
  65
  66    /* Linked list of siblings */
  67    struct ralloc_header *prev;
  68    struct ralloc_header *next;
  69
  70    void (*destructor)(void *);
  71 };
  72
  73 typedef struct ralloc_header ralloc_header;
  74
  75 static void unlink_block(ralloc_header *info);
  76 static void unsafe_free(ralloc_header *info);
  77
  78 static ralloc_header *
  79 get_header(const void *ptr)
  80 {
  81    ralloc_header *info = (ralloc_header *) (((char *) ptr) -
  82                                             sizeof(ralloc_header));
  83 #ifdef DEBUG
  84    assert(info->canary == CANARY);
  85 #endif
  86    return info;
  87 }
  88
  89 #define PTR_FROM_HEADER(info) (((char *) info) + sizeof(ralloc_header))
  90
  91 static void
  92 add_child(ralloc_header *parent, ralloc_header *info)
  93 {
  94    if (parent != NULL) {
  95       info->parent = parent;
  96       info->next = parent->child;
  97       parent->child = info;
  98
  99       if (info->next != NULL)
 100          info->next->prev = info;
 101    }
 102 }
 103
 104 void *
 105 ralloc_context(const void *ctx)
 106 {
 107    return ralloc_size(ctx, 0);
 108 }
 109
 110 void *
 111 ralloc_size(const void *ctx, size_t size)
 112 {
 113    /* ralloc_size was originally implemented using calloc, which meant some
 114     * code accidentally relied on its zero filling behavior.
 115     *
 116     * TODO: Make ralloc_size not zero fill memory, and cleanup any code that
 117     * should instead be using rzalloc.
 118     */
 119    return rzalloc_size(ctx, size);
 120 }
 121
 122 void *
 123 rzalloc_size(const void *ctx, size_t size)
 124 {
 125    void *block = malloc(size + sizeof(ralloc_header));
 126    ralloc_header *info;
 127    ralloc_header *parent;
 128
 129    if (unlikely(block == NULL))
 130       return NULL;
 131
 132    info = (ralloc_header *) block;
 133    /* measurements have shown that calloc is slower (because of
 134     * the multiplication overflow checking?), so clear things
 135     * manually
 136     */
 137    info->parent = NULL;
 138    info->child = NULL;
 139    info->prev = NULL;
 140    info->next = NULL;
 141    info->destructor = NULL;
 142
 143    /* memset the allocation except for ralloc_header */
 144    memset(&info[1], 0, size);
 145
 146    parent = ctx != NULL ? get_header(ctx) : NULL;
 147
 148    add_child(parent, info);
 149
 150 #ifdef DEBUG
 151    info->canary = CANARY;
 152 #endif
 153
 154    return PTR_FROM_HEADER(info);
 155 }
 156
 157 /* helper function - assumes ptr != NULL */
 158 static void *
 159 resize(void *ptr, size_t size)
 160 {
 161    ralloc_header *child, *old, *info;
 162
 163    old = get_header(ptr);
 164    info = realloc(old, size + sizeof(ralloc_header));
 165
 166    if (info == NULL)
 167       return NULL;
 168
 169    /* Update parent and sibling's links to the reallocated node. */
 170    if (info != old && info->parent != NULL) {
 171       if (info->parent->child == old)
 172          info->parent->child = info;
 173
 174       if (info->prev != NULL)
 175          info->prev->next = info;
 176
 177       if (info->next != NULL)
 178          info->next->prev = info;
 179    }
 180
 181    /* Update child->parent links for all children */
 182    for (child = info->child; child != NULL; child = child->next)
 183       child->parent = info;
 184
 185    return PTR_FROM_HEADER(info);
 186 }
 187
 188 void *
 189 reralloc_size(const void *ctx, void *ptr, size_t size)
 190 {
 191    if (unlikely(ptr == NULL))
 192       return ralloc_size(ctx, size);
 193
 194    assert(ralloc_parent(ptr) == ctx);
 195    return resize(ptr, size);
 196 }
 197
 198 void *
 199 ralloc_array_size(const void *ctx, size_t size, unsigned count)
 200 {
 201    if (count > SIZE_MAX/size)
 202       return NULL;
 203
 204    return ralloc_size(ctx, size * count);
 205 }
 206
 207 void *
 208 rzalloc_array_size(const void *ctx, size_t size, unsigned count)
 209 {
 210    if (count > SIZE_MAX/size)
 211       return NULL;
 212
 213    return rzalloc_size(ctx, size * count);
 214 }
 215
 216 void *
 217 reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count)
 218 {
 219    if (count > SIZE_MAX/size)
 220       return NULL;
 221
 222    return reralloc_size(ctx, ptr, size * count);
 223 }
 224
 225 void
 226 ralloc_free(void *ptr)
 227 {
 228    ralloc_header *info;
 229
 230    if (ptr == NULL)
 231       return;
 232
 233    info = get_header(ptr);
 234    unlink_block(info);
 235    unsafe_free(info);
 236 }
 237
 238 static void
 239 unlink_block(ralloc_header *info)
 240 {
 241    /* Unlink from parent & siblings */
 242    if (info->parent != NULL) {
 243       if (info->parent->child == info)
 244          info->parent->child = info->next;
 245
 246       if (info->prev != NULL)
 247          info->prev->next = info->next;
 248
 249       if (info->next != NULL)
 250          info->next->prev = info->prev;
 251    }
 252    info->parent = NULL;
 253    info->prev = NULL;
 254    info->next = NULL;
 255 }
 256
 257 static void
 258 unsafe_free(ralloc_header *info)
 259 {
 260    /* Recursively free any children...don't waste time unlinking them. */
 261    ralloc_header *temp;
 262    while (info->child != NULL) {
 263       temp = info->child;
 264       info->child = temp->next;
 265       unsafe_free(temp);
 266    }
 267
 268    /* Free the block itself.  Call the destructor first, if any. */
 269    if (info->destructor != NULL)
 270       info->destructor(PTR_FROM_HEADER(info));
 271
 272    free(info);
 273 }
 274
 275 void
 276 ralloc_steal(const void *new_ctx, void *ptr)
 277 {
 278    ralloc_header *info, *parent;
 279
 280    if (unlikely(ptr == NULL))
 281       return;
 282
 283    info = get_header(ptr);
 284    parent = get_header(new_ctx);
 285
 286    unlink_block(info);
 287
 288    add_child(parent, info);
 289 }
 290
 291 void
 292 ralloc_adopt(const void *new_ctx, void *old_ctx)
 293 {
 294    ralloc_header *new_info, *old_info, *child;
 295
 296    if (unlikely(old_ctx == NULL))
 297       return;
 298
 299    old_info = get_header(old_ctx);
 300    new_info = get_header(new_ctx);
 301
 302    /* If there are no children, bail. */
 303    if (unlikely(old_info->child == NULL))
 304       return;
 305
 306    /* Set all the children's parent to new_ctx; get a pointer to the last child. */
 307    for (child = old_info->child; child->next != NULL; child = child->next) {
 308       child->parent = new_info;
 309    }
 310
 311    /* Connect the two lists together; parent them to new_ctx; make old_ctx empty. */
 312    child->next = new_info->child;
 313    child->parent = new_info;
 314    new_info->child = old_info->child;
 315    old_info->child = NULL;
 316 }
 317
 318 void *
 319 ralloc_parent(const void *ptr)
 320 {
 321    ralloc_header *info;
 322
 323    if (unlikely(ptr == NULL))
 324       return NULL;
 325
 326    info = get_header(ptr);
 327    return info->parent ? PTR_FROM_HEADER(info->parent) : NULL;
 328 }
 329
 330 static void *autofree_context = NULL;
 331
 332 static void
 333 autofree(void)
 334 {
 335    ralloc_free(autofree_context);
 336 }
 337
 338 void *
 339 ralloc_autofree_context(void)
 340 {
 341    if (unlikely(autofree_context == NULL)) {
 342       autofree_context = ralloc_context(NULL);
 343       atexit(autofree);
 344    }
 345    return autofree_context;
 346 }
 347
 348 void
 349 ralloc_set_destructor(const void *ptr, void(*destructor)(void *))
 350 {
 351    ralloc_header *info = get_header(ptr);
 352    info->destructor = destructor;
 353 }
 354
 355 char *
 356 ralloc_strdup(const void *ctx, const char *str)
 357 {
 358    size_t n;
 359    char *ptr;
 360
 361    if (unlikely(str == NULL))
 362       return NULL;
 363
 364    n = strlen(str);
 365    ptr = ralloc_array(ctx, char, n + 1);
 366    memcpy(ptr, str, n);
 367    ptr[n] = '\0';
 368    return ptr;
 369 }
 370
 371 char *
 372 ralloc_strndup(const void *ctx, const char *str, size_t max)
 373 {
 374    size_t n;
 375    char *ptr;
 376
 377    if (unlikely(str == NULL))
 378       return NULL;
 379
 380    n = strnlen(str, max);
 381    ptr = ralloc_array(ctx, char, n + 1);
 382    memcpy(ptr, str, n);
 383    ptr[n] = '\0';
 384    return ptr;
 385 }
 386
 387 /* helper routine for strcat/strncat - n is the exact amount to copy */
 388 static bool
 389 cat(char **dest, const char *str, size_t n)
 390 {
 391    char *both;
 392    size_t existing_length;
 393    assert(dest != NULL && *dest != NULL);
 394
 395    existing_length = strlen(*dest);
 396    both = resize(*dest, existing_length + n + 1);
 397    if (unlikely(both == NULL))
 398       return false;
 399
 400    memcpy(both + existing_length, str, n);
 401    both[existing_length + n] = '\0';
 402
 403    *dest = both;
 404    return true;
 405 }
 406
 407
 408 bool
 409 ralloc_strcat(char **dest, const char *str)
 410 {
 411    return cat(dest, str, strlen(str));
 412 }
 413
 414 bool
 415 ralloc_strncat(char **dest, const char *str, size_t n)
 416 {
 417    /* Clamp n to the string length */
 418    size_t str_length = strlen(str);
 419    if (str_length < n)
 420       n = str_length;
 421
 422    return cat(dest, str, n);
 423 }
 424
 425 char *
 426 ralloc_asprintf(const void *ctx, const char *fmt, ...)
 427 {
 428    char *ptr;
 429    va_list args;
 430    va_start(args, fmt);
 431    ptr = ralloc_vasprintf(ctx, fmt, args);
 432    va_end(args);
 433    return ptr;
 434 }
 435
 436 /* Return the length of the string that would be generated by a printf-style
 437  * format and argument list, not including the \0 byte.
 438  */
 439 static size_t
 440 printf_length(const char *fmt, va_list untouched_args)
 441 {
 442    int size;
 443    char junk;
 444
 445    /* Make a copy of the va_list so the original caller can still use it */
 446    va_list args;
 447    va_copy(args, untouched_args);
 448
 449 #ifdef _WIN32
 450    /* We need to use _vcsprintf to calculate the size as vsnprintf returns -1
 451     * if the number of characters to write is greater than count.
 452     */
 453    size = _vscprintf(fmt, args);
 454    (void)junk;
 455 #else
 456    size = vsnprintf(&junk, 1, fmt, args);
 457 #endif
 458    assert(size >= 0);
 459
 460    va_end(args);
 461
 462    return size;
 463 }
 464
 465 char *
 466 ralloc_vasprintf(const void *ctx, const char *fmt, va_list args)
 467 {
 468    size_t size = printf_length(fmt, args) + 1;
 469
 470    char *ptr = ralloc_size(ctx, size);
 471    if (ptr != NULL)
 472       vsnprintf(ptr, size, fmt, args);
 473
 474    return ptr;
 475 }
 476
 477 bool
 478 ralloc_asprintf_append(char **str, const char *fmt, ...)
 479 {
 480    bool success;
 481    va_list args;
 482    va_start(args, fmt);
 483    success = ralloc_vasprintf_append(str, fmt, args);
 484    va_end(args);
 485    return success;
 486 }
 487
 488 bool
 489 ralloc_vasprintf_append(char **str, const char *fmt, va_list args)
 490 {
 491    size_t existing_length;
 492    assert(str != NULL);
 493    existing_length = *str ? strlen(*str) : 0;
 494    return ralloc_vasprintf_rewrite_tail(str, &existing_length, fmt, args);
 495 }
 496
 497 bool
 498 ralloc_asprintf_rewrite_tail(char **str, size_t *start, const char *fmt, ...)
 499 {
 500    bool success;
 501    va_list args;
 502    va_start(args, fmt);
 503    success = ralloc_vasprintf_rewrite_tail(str, start, fmt, args);
 504    va_end(args);
 505    return success;
 506 }
 507
 508 bool
 509 ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
 510                               va_list args)
 511 {
 512    size_t new_length;
 513    char *ptr;
 514
 515    assert(str != NULL);
 516
 517    if (unlikely(*str == NULL)) {
 518       // Assuming a NULL context is probably bad, but it's expected behavior.
 519       *str = ralloc_vasprintf(NULL, fmt, args);
 520       *start = strlen(*str);
 521       return true;
 522    }
 523
 524    new_length = printf_length(fmt, args);
 525
 526    ptr = resize(*str, *start + new_length + 1);
 527    if (unlikely(ptr == NULL))
 528       return false;
 529
 530    vsnprintf(ptr + *start, new_length + 1, fmt, args);
 531    *str = ptr;
 532    *start += new_length;
 533    return true;
 534 }