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 = calloc(1, size + sizeof(ralloc_header));
 126    ralloc_header *info;
 127    ralloc_header *parent;
 128
 129    if (unlikely(block == NULL))
 130       return NULL;
 131    info = (ralloc_header *) block;
 132    parent = ctx != NULL ? get_header(ctx) : NULL;
 133
 134    add_child(parent, info);
 135
 136 #ifdef DEBUG
 137    info->canary = CANARY;
 138 #endif
 139
 140    return PTR_FROM_HEADER(info);
 141 }
 142
 143 /* helper function - assumes ptr != NULL */
 144 static void *
 145 resize(void *ptr, size_t size)
 146 {
 147    ralloc_header *child, *old, *info;
 148
 149    old = get_header(ptr);
 150    info = realloc(old, size + sizeof(ralloc_header));
 151
 152    if (info == NULL)
 153       return NULL;
 154
 155    /* Update parent and sibling's links to the reallocated node. */
 156    if (info != old && info->parent != NULL) {
 157       if (info->parent->child == old)
 158          info->parent->child = info;
 159
 160       if (info->prev != NULL)
 161          info->prev->next = info;
 162
 163       if (info->next != NULL)
 164          info->next->prev = info;
 165    }
 166
 167    /* Update child->parent links for all children */
 168    for (child = info->child; child != NULL; child = child->next)
 169       child->parent = info;
 170
 171    return PTR_FROM_HEADER(info);
 172 }
 173
 174 void *
 175 reralloc_size(const void *ctx, void *ptr, size_t size)
 176 {
 177    if (unlikely(ptr == NULL))
 178       return ralloc_size(ctx, size);
 179
 180    assert(ralloc_parent(ptr) == ctx);
 181    return resize(ptr, size);
 182 }
 183
 184 void *
 185 ralloc_array_size(const void *ctx, size_t size, unsigned count)
 186 {
 187    if (count > SIZE_MAX/size)
 188       return NULL;
 189
 190    return ralloc_size(ctx, size * count);
 191 }
 192
 193 void *
 194 rzalloc_array_size(const void *ctx, size_t size, unsigned count)
 195 {
 196    if (count > SIZE_MAX/size)
 197       return NULL;
 198
 199    return rzalloc_size(ctx, size * count);
 200 }
 201
 202 void *
 203 reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count)
 204 {
 205    if (count > SIZE_MAX/size)
 206       return NULL;
 207
 208    return reralloc_size(ctx, ptr, size * count);
 209 }
 210
 211 void
 212 ralloc_free(void *ptr)
 213 {
 214    ralloc_header *info;
 215
 216    if (ptr == NULL)
 217       return;
 218
 219    info = get_header(ptr);
 220    unlink_block(info);
 221    unsafe_free(info);
 222 }
 223
 224 static void
 225 unlink_block(ralloc_header *info)
 226 {
 227    /* Unlink from parent & siblings */
 228    if (info->parent != NULL) {
 229       if (info->parent->child == info)
 230          info->parent->child = info->next;
 231
 232       if (info->prev != NULL)
 233          info->prev->next = info->next;
 234
 235       if (info->next != NULL)
 236          info->next->prev = info->prev;
 237    }
 238    info->parent = NULL;
 239    info->prev = NULL;
 240    info->next = NULL;
 241 }
 242
 243 static void
 244 unsafe_free(ralloc_header *info)
 245 {
 246    /* Recursively free any children...don't waste time unlinking them. */
 247    ralloc_header *temp;
 248    while (info->child != NULL) {
 249       temp = info->child;
 250       info->child = temp->next;
 251       unsafe_free(temp);
 252    }
 253
 254    /* Free the block itself.  Call the destructor first, if any. */
 255    if (info->destructor != NULL)
 256       info->destructor(PTR_FROM_HEADER(info));
 257
 258    free(info);
 259 }
 260
 261 void
 262 ralloc_steal(const void *new_ctx, void *ptr)
 263 {
 264    ralloc_header *info, *parent;
 265
 266    if (unlikely(ptr == NULL))
 267       return;
 268
 269    info = get_header(ptr);
 270    parent = get_header(new_ctx);
 271
 272    unlink_block(info);
 273
 274    add_child(parent, info);
 275 }
 276
 277 void
 278 ralloc_adopt(const void *new_ctx, void *old_ctx)
 279 {
 280    ralloc_header *new_info, *old_info, *child;
 281
 282    if (unlikely(old_ctx == NULL))
 283       return;
 284
 285    old_info = get_header(old_ctx);
 286    new_info = get_header(new_ctx);
 287
 288    /* If there are no children, bail. */
 289    if (unlikely(old_info->child == NULL))
 290       return;
 291
 292    /* Set all the children's parent to new_ctx; get a pointer to the last child. */
 293    for (child = old_info->child; child->next != NULL; child = child->next) {
 294       child->parent = new_info;
 295    }
 296
 297    /* Connect the two lists together; parent them to new_ctx; make old_ctx empty. */
 298    child->next = new_info->child;
 299    child->parent = new_info;
 300    new_info->child = old_info->child;
 301    old_info->child = NULL;
 302 }
 303
 304 void *
 305 ralloc_parent(const void *ptr)
 306 {
 307    ralloc_header *info;
 308
 309    if (unlikely(ptr == NULL))
 310       return NULL;
 311
 312    info = get_header(ptr);
 313    return info->parent ? PTR_FROM_HEADER(info->parent) : NULL;
 314 }
 315
 316 static void *autofree_context = NULL;
 317
 318 static void
 319 autofree(void)
 320 {
 321    ralloc_free(autofree_context);
 322 }
 323
 324 void *
 325 ralloc_autofree_context(void)
 326 {
 327    if (unlikely(autofree_context == NULL)) {
 328       autofree_context = ralloc_context(NULL);
 329       atexit(autofree);
 330    }
 331    return autofree_context;
 332 }
 333
 334 void
 335 ralloc_set_destructor(const void *ptr, void(*destructor)(void *))
 336 {
 337    ralloc_header *info = get_header(ptr);
 338    info->destructor = destructor;
 339 }
 340
 341 char *
 342 ralloc_strdup(const void *ctx, const char *str)
 343 {
 344    size_t n;
 345    char *ptr;
 346
 347    if (unlikely(str == NULL))
 348       return NULL;
 349
 350    n = strlen(str);
 351    ptr = ralloc_array(ctx, char, n + 1);
 352    memcpy(ptr, str, n);
 353    ptr[n] = '\0';
 354    return ptr;
 355 }
 356
 357 char *
 358 ralloc_strndup(const void *ctx, const char *str, size_t max)
 359 {
 360    size_t n;
 361    char *ptr;
 362
 363    if (unlikely(str == NULL))
 364       return NULL;
 365
 366    n = strnlen(str, max);
 367    ptr = ralloc_array(ctx, char, n + 1);
 368    memcpy(ptr, str, n);
 369    ptr[n] = '\0';
 370    return ptr;
 371 }
 372
 373 /* helper routine for strcat/strncat - n is the exact amount to copy */
 374 static bool
 375 cat(char **dest, const char *str, size_t n)
 376 {
 377    char *both;
 378    size_t existing_length;
 379    assert(dest != NULL && *dest != NULL);
 380
 381    existing_length = strlen(*dest);
 382    both = resize(*dest, existing_length + n + 1);
 383    if (unlikely(both == NULL))
 384       return false;
 385
 386    memcpy(both + existing_length, str, n);
 387    both[existing_length + n] = '\0';
 388
 389    *dest = both;
 390    return true;
 391 }
 392
 393
 394 bool
 395 ralloc_strcat(char **dest, const char *str)
 396 {
 397    return cat(dest, str, strlen(str));
 398 }
 399
 400 bool
 401 ralloc_strncat(char **dest, const char *str, size_t n)
 402 {
 403    /* Clamp n to the string length */
 404    size_t str_length = strlen(str);
 405    if (str_length < n)
 406       n = str_length;
 407
 408    return cat(dest, str, n);
 409 }
 410
 411 char *
 412 ralloc_asprintf(const void *ctx, const char *fmt, ...)
 413 {
 414    char *ptr;
 415    va_list args;
 416    va_start(args, fmt);
 417    ptr = ralloc_vasprintf(ctx, fmt, args);
 418    va_end(args);
 419    return ptr;
 420 }
 421
 422 /* Return the length of the string that would be generated by a printf-style
 423  * format and argument list, not including the \0 byte.
 424  */
 425 static size_t
 426 printf_length(const char *fmt, va_list untouched_args)
 427 {
 428    int size;
 429    char junk;
 430
 431    /* Make a copy of the va_list so the original caller can still use it */
 432    va_list args;
 433    va_copy(args, untouched_args);
 434
 435 #ifdef _WIN32
 436    /* We need to use _vcsprintf to calculate the size as vsnprintf returns -1
 437     * if the number of characters to write is greater than count.
 438     */
 439    size = _vscprintf(fmt, args);
 440    (void)junk;
 441 #else
 442    size = vsnprintf(&junk, 1, fmt, args);
 443 #endif
 444    assert(size >= 0);
 445
 446    va_end(args);
 447
 448    return size;
 449 }
 450
 451 char *
 452 ralloc_vasprintf(const void *ctx, const char *fmt, va_list args)
 453 {
 454    size_t size = printf_length(fmt, args) + 1;
 455
 456    char *ptr = ralloc_size(ctx, size);
 457    if (ptr != NULL)
 458       vsnprintf(ptr, size, fmt, args);
 459
 460    return ptr;
 461 }
 462
 463 bool
 464 ralloc_asprintf_append(char **str, const char *fmt, ...)
 465 {
 466    bool success;
 467    va_list args;
 468    va_start(args, fmt);
 469    success = ralloc_vasprintf_append(str, fmt, args);
 470    va_end(args);
 471    return success;
 472 }
 473
 474 bool
 475 ralloc_vasprintf_append(char **str, const char *fmt, va_list args)
 476 {
 477    size_t existing_length;
 478    assert(str != NULL);
 479    existing_length = *str ? strlen(*str) : 0;
 480    return ralloc_vasprintf_rewrite_tail(str, &existing_length, fmt, args);
 481 }
 482
 483 bool
 484 ralloc_asprintf_rewrite_tail(char **str, size_t *start, const char *fmt, ...)
 485 {
 486    bool success;
 487    va_list args;
 488    va_start(args, fmt);
 489    success = ralloc_vasprintf_rewrite_tail(str, start, fmt, args);
 490    va_end(args);
 491    return success;
 492 }
 493
 494 bool
 495 ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
 496                               va_list args)
 497 {
 498    size_t new_length;
 499    char *ptr;
 500
 501    assert(str != NULL);
 502
 503    if (unlikely(*str == NULL)) {
 504       // Assuming a NULL context is probably bad, but it's expected behavior.
 505       *str = ralloc_vasprintf(NULL, fmt, args);
 506       *start = strlen(*str);
 507       return true;
 508    }
 509
 510    new_length = printf_length(fmt, args);
 511
 512    ptr = resize(*str, *start + new_length + 1);
 513    if (unlikely(ptr == NULL))
 514       return false;
 515
 516    vsnprintf(ptr + *start, new_length + 1, fmt, args);
 517    *str = ptr;
 518    *start += new_length;
 519    return true;
 520 }