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 /* Some versions of MinGW are missing _vscprintf's declaration, although they 32 * still provide the symbol in the import library. */ 33 #ifdef __MINGW32__ 34 _CRTIMP int _vscprintf(const char *format, va_list argptr); 35 #endif 36 37 #include "ralloc.h" 38 39 #ifndef va_copy 40 #ifdef __va_copy 41 #define va_copy(dest, src) __va_copy((dest), (src)) 42 #else 43 #define va_copy(dest, src) (dest) = (src) 44 #endif 45 #endif 46 47 #define CANARY 0x5A1106 48 49 /* Align the header's size so that ralloc() allocations will return with the 50 * same alignment as a libc malloc would have (8 on 32-bit GLIBC, 16 on 51 * 64-bit), avoiding performance penalities on x86 and alignment faults on 52 * ARM. 53 */ 54 struct 55 #ifdef _MSC_VER 56 __declspec(align(8)) 57 #elif defined(__LP64__) 58 __attribute__((aligned(16))) 59 #else 60 __attribute__((aligned(8))) 61 #endif 62 ralloc_header 63 { 64 #ifdef DEBUG 65 /* A canary value used to determine whether a pointer is ralloc'd. */ 66 unsigned canary; 67 #endif 68 69 struct ralloc_header *parent; 70 71 /* The first child (head of a linked list) */ 72 struct ralloc_header *child; 73 74 /* Linked list of siblings */ 75 struct ralloc_header *prev; 76 struct ralloc_header *next; 77 78 void (*destructor)(void *); 79 }; 80 81 typedef struct ralloc_header ralloc_header; 82 83 static void unlink_block(ralloc_header *info); 84 static void unsafe_free(ralloc_header *info); 85 86 static ralloc_header * 87 get_header(const void *ptr) 88 { 89 ralloc_header *info = (ralloc_header *) (((char *) ptr) - 90 sizeof(ralloc_header)); 91 #ifdef DEBUG 92 assert(info->canary == CANARY); 93 #endif 94 return info; 95 } 96 97 #define PTR_FROM_HEADER(info) (((char *) info) + sizeof(ralloc_header)) 98 99 static void 100 add_child(ralloc_header *parent, ralloc_header *info) 101 { 102 if (parent != NULL) { 103 info->parent = parent; 104 info->next = parent->child; 105 parent->child = info; 106 107 if (info->next != NULL) 108 info->next->prev = info; 109 } 110 } 111 112 void * 113 ralloc_context(const void *ctx) 114 { 115 return ralloc_size(ctx, 0); 116 } 117 118 void * 119 ralloc_size(const void *ctx, size_t size) 120 { 121 void *block = malloc(size + sizeof(ralloc_header)); 122 ralloc_header *info; 123 ralloc_header *parent; 124 125 if (unlikely(block == NULL)) 126 return NULL; 127 128 info = (ralloc_header *) block; 129 /* measurements have shown that calloc is slower (because of 130 * the multiplication overflow checking?), so clear things 131 * manually 132 */ 133 info->parent = NULL; 134 info->child = NULL; 135 info->prev = NULL; 136 info->next = NULL; 137 info->destructor = NULL; 138 139 parent = ctx != NULL ? get_header(ctx) : NULL; 140 141 add_child(parent, info); 142 143 #ifdef DEBUG 144 info->canary = CANARY; 145 #endif 146 147 return PTR_FROM_HEADER(info); 148 } 149 150 void * 151 rzalloc_size(const void *ctx, size_t size) 152 { 153 void *ptr = ralloc_size(ctx, size); 154 155 if (likely(ptr)) 156 memset(ptr, 0, size); 157 158 return ptr; 159 } 160 161 /* helper function - assumes ptr != NULL */ 162 static void * 163 resize(void *ptr, size_t size) 164 { 165 ralloc_header *child, *old, *info; 166 167 old = get_header(ptr); 168 info = realloc(old, size + sizeof(ralloc_header)); 169 170 if (info == NULL) 171 return NULL; 172 173 /* Update parent and sibling's links to the reallocated node. */ 174 if (info != old && info->parent != NULL) { 175 if (info->parent->child == old) 176 info->parent->child = info; 177 178 if (info->prev != NULL) 179 info->prev->next = info; 180 181 if (info->next != NULL) 182 info->next->prev = info; 183 } 184 185 /* Update child->parent links for all children */ 186 for (child = info->child; child != NULL; child = child->next) 187 child->parent = info; 188 189 return PTR_FROM_HEADER(info); 190 } 191 192 void * 193 reralloc_size(const void *ctx, void *ptr, size_t size) 194 { 195 if (unlikely(ptr == NULL)) 196 return ralloc_size(ctx, size); 197 198 assert(ralloc_parent(ptr) == ctx); 199 return resize(ptr, size); 200 } 201 202 void * 203 ralloc_array_size(const void *ctx, size_t size, unsigned count) 204 { 205 if (count > SIZE_MAX/size) 206 return NULL; 207 208 return ralloc_size(ctx, size * count); 209 } 210 211 void * 212 rzalloc_array_size(const void *ctx, size_t size, unsigned count) 213 { 214 if (count > SIZE_MAX/size) 215 return NULL; 216 217 return rzalloc_size(ctx, size * count); 218 } 219 220 void * 221 reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count) 222 { 223 if (count > SIZE_MAX/size) 224 return NULL; 225 226 return reralloc_size(ctx, ptr, size * count); 227 } 228 229 void 230 ralloc_free(void *ptr) 231 { 232 ralloc_header *info; 233 234 if (ptr == NULL) 235 return; 236 237 info = get_header(ptr); 238 unlink_block(info); 239 unsafe_free(info); 240 } 241 242 static void 243 unlink_block(ralloc_header *info) 244 { 245 /* Unlink from parent & siblings */ 246 if (info->parent != NULL) { 247 if (info->parent->child == info) 248 info->parent->child = info->next; 249 250 if (info->prev != NULL) 251 info->prev->next = info->next; 252 253 if (info->next != NULL) 254 info->next->prev = info->prev; 255 } 256 info->parent = NULL; 257 info->prev = NULL; 258 info->next = NULL; 259 } 260 261 static void 262 unsafe_free(ralloc_header *info) 263 { 264 /* Recursively free any children...don't waste time unlinking them. */ 265 ralloc_header *temp; 266 while (info->child != NULL) { 267 temp = info->child; 268 info->child = temp->next; 269 unsafe_free(temp); 270 } 271 272 /* Free the block itself. Call the destructor first, if any. */ 273 if (info->destructor != NULL) 274 info->destructor(PTR_FROM_HEADER(info)); 275 276 free(info); 277 } 278 279 void 280 ralloc_steal(const void *new_ctx, void *ptr) 281 { 282 ralloc_header *info, *parent; 283 284 if (unlikely(ptr == NULL)) 285 return; 286 287 info = get_header(ptr); 288 parent = new_ctx ? get_header(new_ctx) : NULL; 289 290 unlink_block(info); 291 292 add_child(parent, info); 293 } 294 295 void 296 ralloc_adopt(const void *new_ctx, void *old_ctx) 297 { 298 ralloc_header *new_info, *old_info, *child; 299 300 if (unlikely(old_ctx == NULL)) 301 return; 302 303 old_info = get_header(old_ctx); 304 new_info = get_header(new_ctx); 305 306 /* If there are no children, bail. */ 307 if (unlikely(old_info->child == NULL)) 308 return; 309 310 /* Set all the children's parent to new_ctx; get a pointer to the last child. */ 311 for (child = old_info->child; child->next != NULL; child = child->next) { 312 child->parent = new_info; 313 } 314 child->parent = new_info; 315 316 /* Connect the two lists together; parent them to new_ctx; make old_ctx empty. */ 317 child->next = new_info->child; 318 if (child->next) 319 child->next->prev = child; 320 new_info->child = old_info->child; 321 old_info->child = NULL; 322 } 323 324 void * 325 ralloc_parent(const void *ptr) 326 { 327 ralloc_header *info; 328 329 if (unlikely(ptr == NULL)) 330 return NULL; 331 332 info = get_header(ptr); 333 return info->parent ? PTR_FROM_HEADER(info->parent) : NULL; 334 } 335 336 void 337 ralloc_set_destructor(const void *ptr, void(*destructor)(void *)) 338 { 339 ralloc_header *info = get_header(ptr); 340 info->destructor = destructor; 341 } 342 343 char * 344 ralloc_strdup(const void *ctx, const char *str) 345 { 346 size_t n; 347 char *ptr; 348 349 if (unlikely(str == NULL)) 350 return NULL; 351 352 n = strlen(str); 353 ptr = ralloc_array(ctx, char, n + 1); 354 memcpy(ptr, str, n); 355 ptr[n] = '\0'; 356 return ptr; 357 } 358 359 char * 360 ralloc_strndup(const void *ctx, const char *str, size_t max) 361 { 362 size_t n; 363 char *ptr; 364 365 if (unlikely(str == NULL)) 366 return NULL; 367 368 n = strnlen(str, max); 369 ptr = ralloc_array(ctx, char, n + 1); 370 memcpy(ptr, str, n); 371 ptr[n] = '\0'; 372 return ptr; 373 } 374 375 /* helper routine for strcat/strncat - n is the exact amount to copy */ 376 static bool 377 cat(char **dest, const char *str, size_t n) 378 { 379 char *both; 380 size_t existing_length; 381 assert(dest != NULL && *dest != NULL); 382 383 existing_length = strlen(*dest); 384 both = resize(*dest, existing_length + n + 1); 385 if (unlikely(both == NULL)) 386 return false; 387 388 memcpy(both + existing_length, str, n); 389 both[existing_length + n] = '\0'; 390 391 *dest = both; 392 return true; 393 } 394 395 396 bool 397 ralloc_strcat(char **dest, const char *str) 398 { 399 return cat(dest, str, strlen(str)); 400 } 401 402 bool 403 ralloc_strncat(char **dest, const char *str, size_t n) 404 { 405 return cat(dest, str, strnlen(str, n)); 406 } 407 408 bool 409 ralloc_str_append(char **dest, const char *str, 410 size_t existing_length, size_t str_size) 411 { 412 char *both; 413 assert(dest != NULL && *dest != NULL); 414 415 both = resize(*dest, existing_length + str_size + 1); 416 if (unlikely(both == NULL)) 417 return false; 418 419 memcpy(both + existing_length, str, str_size); 420 both[existing_length + str_size] = '\0'; 421 422 *dest = both; 423 424 return true; 425 } 426 427 char * 428 ralloc_asprintf(const void *ctx, const char *fmt, ...) 429 { 430 char *ptr; 431 va_list args; 432 va_start(args, fmt); 433 ptr = ralloc_vasprintf(ctx, fmt, args); 434 va_end(args); 435 return ptr; 436 } 437 438 /* Return the length of the string that would be generated by a printf-style 439 * format and argument list, not including the \0 byte. 440 */ 441 static size_t 442 printf_length(const char *fmt, va_list untouched_args) 443 { 444 int size; 445 char junk; 446 447 /* Make a copy of the va_list so the original caller can still use it */ 448 va_list args; 449 va_copy(args, untouched_args); 450 451 #ifdef _WIN32 452 /* We need to use _vcsprintf to calculate the size as vsnprintf returns -1 453 * if the number of characters to write is greater than count. 454 */ 455 size = _vscprintf(fmt, args); 456 (void)junk; 457 #else 458 size = vsnprintf(&junk, 1, fmt, args); 459 #endif 460 assert(size >= 0); 461 462 va_end(args); 463 464 return size; 465 } 466 467 char * 468 ralloc_vasprintf(const void *ctx, const char *fmt, va_list args) 469 { 470 size_t size = printf_length(fmt, args) + 1; 471 472 char *ptr = ralloc_size(ctx, size); 473 if (ptr != NULL) 474 vsnprintf(ptr, size, fmt, args); 475 476 return ptr; 477 } 478 479 bool 480 ralloc_asprintf_append(char **str, const char *fmt, ...) 481 { 482 bool success; 483 va_list args; 484 va_start(args, fmt); 485 success = ralloc_vasprintf_append(str, fmt, args); 486 va_end(args); 487 return success; 488 } 489 490 bool 491 ralloc_vasprintf_append(char **str, const char *fmt, va_list args) 492 { 493 size_t existing_length; 494 assert(str != NULL); 495 existing_length = *str ? strlen(*str) : 0; 496 return ralloc_vasprintf_rewrite_tail(str, &existing_length, fmt, args); 497 } 498 499 bool 500 ralloc_asprintf_rewrite_tail(char **str, size_t *start, const char *fmt, ...) 501 { 502 bool success; 503 va_list args; 504 va_start(args, fmt); 505 success = ralloc_vasprintf_rewrite_tail(str, start, fmt, args); 506 va_end(args); 507 return success; 508 } 509 510 bool 511 ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt, 512 va_list args) 513 { 514 size_t new_length; 515 char *ptr; 516 517 assert(str != NULL); 518 519 if (unlikely(*str == NULL)) { 520 // Assuming a NULL context is probably bad, but it's expected behavior. 521 *str = ralloc_vasprintf(NULL, fmt, args); 522 *start = strlen(*str); 523 return true; 524 } 525 526 new_length = printf_length(fmt, args); 527 528 ptr = resize(*str, *start + new_length + 1); 529 if (unlikely(ptr == NULL)) 530 return false; 531 532 vsnprintf(ptr + *start, new_length + 1, fmt, args); 533 *str = ptr; 534 *start += new_length; 535 return true; 536 } 537 538 /*************************************************************************** 539 * Linear allocator for short-lived allocations. 540 *************************************************************************** 541 * 542 * The allocator consists of a parent node (2K buffer), which requires 543 * a ralloc parent, and child nodes (allocations). Child nodes can't be freed 544 * directly, because the parent doesn't track them. You have to release 545 * the parent node in order to release all its children. 546 * 547 * The allocator uses a fixed-sized buffer with a monotonically increasing 548 * offset after each allocation. If the buffer is all used, another buffer 549 * is allocated, sharing the same ralloc parent, so all buffers are at 550 * the same level in the ralloc hierarchy. 551 * 552 * The linear parent node is always the first buffer and keeps track of all 553 * other buffers. 554 */ 555 556 #define ALIGN_POT(x, y) (((x) + (y) - 1) & ~((y) - 1)) 557 558 #define MIN_LINEAR_BUFSIZE 2048 559 #define SUBALLOC_ALIGNMENT sizeof(uintptr_t) 560 #define LMAGIC 0x87b9c7d3 561 562 struct linear_header { 563 #ifdef DEBUG 564 unsigned magic; /* for debugging */ 565 #endif 566 unsigned offset; /* points to the first unused byte in the buffer */ 567 unsigned size; /* size of the buffer */ 568 void *ralloc_parent; /* new buffers will use this */ 569 struct linear_header *next; /* next buffer if we have more */ 570 struct linear_header *latest; /* the only buffer that has free space */ 571 572 /* After this structure, the buffer begins. 573 * Each suballocation consists of linear_size_chunk as its header followed 574 * by the suballocation, so it goes: 575 * 576 * - linear_size_chunk 577 * - allocated space 578 * - linear_size_chunk 579 * - allocated space 580 * etc. 581 * 582 * linear_size_chunk is only needed by linear_realloc. 583 */ 584 }; 585 586 struct linear_size_chunk { 587 unsigned size; /* for realloc */ 588 unsigned _padding; 589 }; 590 591 typedef struct linear_header linear_header; 592 typedef struct linear_size_chunk linear_size_chunk; 593 594 #define LINEAR_PARENT_TO_HEADER(parent) \ 595 (linear_header*) \ 596 ((char*)(parent) - sizeof(linear_size_chunk) - sizeof(linear_header)) 597 598 /* Allocate the linear buffer with its header. */ 599 static linear_header * 600 create_linear_node(void *ralloc_ctx, unsigned min_size) 601 { 602 linear_header *node; 603 604 min_size += sizeof(linear_size_chunk); 605 606 if (likely(min_size < MIN_LINEAR_BUFSIZE)) 607 min_size = MIN_LINEAR_BUFSIZE; 608 609 node = ralloc_size(ralloc_ctx, sizeof(linear_header) + min_size); 610 if (unlikely(!node)) 611 return NULL; 612 613 #ifdef DEBUG 614 node->magic = LMAGIC; 615 #endif 616 node->offset = 0; 617 node->size = min_size; 618 node->ralloc_parent = ralloc_ctx; 619 node->next = NULL; 620 node->latest = node; 621 return node; 622 } 623 624 void * 625 linear_alloc_child(void *parent, unsigned size) 626 { 627 linear_header *first = LINEAR_PARENT_TO_HEADER(parent); 628 linear_header *latest = first->latest; 629 linear_header *new_node; 630 linear_size_chunk *ptr; 631 unsigned full_size; 632 633 #ifdef DEBUG 634 assert(first->magic == LMAGIC); 635 #endif 636 assert(!latest->next); 637 638 size = ALIGN_POT(size, SUBALLOC_ALIGNMENT); 639 full_size = sizeof(linear_size_chunk) + size; 640 641 if (unlikely(latest->offset + full_size > latest->size)) { 642 /* allocate a new node */ 643 new_node = create_linear_node(latest->ralloc_parent, size); 644 if (unlikely(!new_node)) 645 return NULL; 646 647 first->latest = new_node; 648 latest->latest = new_node; 649 latest->next = new_node; 650 latest = new_node; 651 } 652 653 ptr = (linear_size_chunk *)((char*)&latest[1] + latest->offset); 654 ptr->size = size; 655 latest->offset += full_size; 656 return &ptr[1]; 657 } 658 659 void * 660 linear_alloc_parent(void *ralloc_ctx, unsigned size) 661 { 662 linear_header *node; 663 664 if (unlikely(!ralloc_ctx)) 665 return NULL; 666 667 size = ALIGN_POT(size, SUBALLOC_ALIGNMENT); 668 669 node = create_linear_node(ralloc_ctx, size); 670 if (unlikely(!node)) 671 return NULL; 672 673 return linear_alloc_child((char*)node + 674 sizeof(linear_header) + 675 sizeof(linear_size_chunk), size); 676 } 677 678 void * 679 linear_zalloc_child(void *parent, unsigned size) 680 { 681 void *ptr = linear_alloc_child(parent, size); 682 683 if (likely(ptr)) 684 memset(ptr, 0, size); 685 return ptr; 686 } 687 688 void * 689 linear_zalloc_parent(void *parent, unsigned size) 690 { 691 void *ptr = linear_alloc_parent(parent, size); 692 693 if (likely(ptr)) 694 memset(ptr, 0, size); 695 return ptr; 696 } 697 698 void 699 linear_free_parent(void *ptr) 700 { 701 linear_header *node; 702 703 if (unlikely(!ptr)) 704 return; 705 706 node = LINEAR_PARENT_TO_HEADER(ptr); 707 #ifdef DEBUG 708 assert(node->magic == LMAGIC); 709 #endif 710 711 while (node) { 712 void *ptr = node; 713 714 node = node->next; 715 ralloc_free(ptr); 716 } 717 } 718 719 void 720 ralloc_steal_linear_parent(void *new_ralloc_ctx, void *ptr) 721 { 722 linear_header *node; 723 724 if (unlikely(!ptr)) 725 return; 726 727 node = LINEAR_PARENT_TO_HEADER(ptr); 728 #ifdef DEBUG 729 assert(node->magic == LMAGIC); 730 #endif 731 732 while (node) { 733 ralloc_steal(new_ralloc_ctx, node); 734 node->ralloc_parent = new_ralloc_ctx; 735 node = node->next; 736 } 737 } 738 739 void * 740 ralloc_parent_of_linear_parent(void *ptr) 741 { 742 linear_header *node = LINEAR_PARENT_TO_HEADER(ptr); 743 #ifdef DEBUG 744 assert(node->magic == LMAGIC); 745 #endif 746 return node->ralloc_parent; 747 } 748 749 void * 750 linear_realloc(void *parent, void *old, unsigned new_size) 751 { 752 unsigned old_size = 0; 753 ralloc_header *new_ptr; 754 755 new_ptr = linear_alloc_child(parent, new_size); 756 757 if (unlikely(!old)) 758 return new_ptr; 759 760 old_size = ((linear_size_chunk*)old)[-1].size; 761 762 if (likely(new_ptr && old_size)) 763 memcpy(new_ptr, old, MIN2(old_size, new_size)); 764 765 return new_ptr; 766 } 767 768 /* All code below is pretty much copied from ralloc and only the alloc 769 * calls are different. 770 */ 771 772 char * 773 linear_strdup(void *parent, const char *str) 774 { 775 unsigned n; 776 char *ptr; 777 778 if (unlikely(!str)) 779 return NULL; 780 781 n = strlen(str); 782 ptr = linear_alloc_child(parent, n + 1); 783 if (unlikely(!ptr)) 784 return NULL; 785 786 memcpy(ptr, str, n); 787 ptr[n] = '\0'; 788 return ptr; 789 } 790 791 char * 792 linear_asprintf(void *parent, const char *fmt, ...) 793 { 794 char *ptr; 795 va_list args; 796 va_start(args, fmt); 797 ptr = linear_vasprintf(parent, fmt, args); 798 va_end(args); 799 return ptr; 800 } 801 802 char * 803 linear_vasprintf(void *parent, const char *fmt, va_list args) 804 { 805 unsigned size = printf_length(fmt, args) + 1; 806 807 char *ptr = linear_alloc_child(parent, size); 808 if (ptr != NULL) 809 vsnprintf(ptr, size, fmt, args); 810 811 return ptr; 812 } 813 814 bool 815 linear_asprintf_append(void *parent, char **str, const char *fmt, ...) 816 { 817 bool success; 818 va_list args; 819 va_start(args, fmt); 820 success = linear_vasprintf_append(parent, str, fmt, args); 821 va_end(args); 822 return success; 823 } 824 825 bool 826 linear_vasprintf_append(void *parent, char **str, const char *fmt, va_list args) 827 { 828 size_t existing_length; 829 assert(str != NULL); 830 existing_length = *str ? strlen(*str) : 0; 831 return linear_vasprintf_rewrite_tail(parent, str, &existing_length, fmt, args); 832 } 833 834 bool 835 linear_asprintf_rewrite_tail(void *parent, char **str, size_t *start, 836 const char *fmt, ...) 837 { 838 bool success; 839 va_list args; 840 va_start(args, fmt); 841 success = linear_vasprintf_rewrite_tail(parent, str, start, fmt, args); 842 va_end(args); 843 return success; 844 } 845 846 bool 847 linear_vasprintf_rewrite_tail(void *parent, char **str, size_t *start, 848 const char *fmt, va_list args) 849 { 850 size_t new_length; 851 char *ptr; 852 853 assert(str != NULL); 854 855 if (unlikely(*str == NULL)) { 856 *str = linear_vasprintf(parent, fmt, args); 857 *start = strlen(*str); 858 return true; 859 } 860 861 new_length = printf_length(fmt, args); 862 863 ptr = linear_realloc(parent, *str, *start + new_length + 1); 864 if (unlikely(ptr == NULL)) 865 return false; 866 867 vsnprintf(ptr + *start, new_length + 1, fmt, args); 868 *str = ptr; 869 *start += new_length; 870 return true; 871 } 872 873 /* helper routine for strcat/strncat - n is the exact amount to copy */ 874 static bool 875 linear_cat(void *parent, char **dest, const char *str, unsigned n) 876 { 877 char *both; 878 unsigned existing_length; 879 assert(dest != NULL && *dest != NULL); 880 881 existing_length = strlen(*dest); 882 both = linear_realloc(parent, *dest, existing_length + n + 1); 883 if (unlikely(both == NULL)) 884 return false; 885 886 memcpy(both + existing_length, str, n); 887 both[existing_length + n] = '\0'; 888 889 *dest = both; 890 return true; 891 } 892 893 bool 894 linear_strcat(void *parent, char **dest, const char *str) 895 { 896 return linear_cat(parent, dest, str, strlen(str)); 897 } 898
