1 // Copyright 2012 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // Misc. common utility functions 11 // 12 // Author: Skal (pascal.massimino (at) gmail.com) 13 14 #include <stdlib.h> 15 #include "./utils.h" 16 17 // If PRINT_MEM_INFO is defined, extra info (like total memory used, number of 18 // alloc/free etc) is printed. For debugging/tuning purpose only (it's slow, 19 // and not multi-thread safe!). 20 // An interesting alternative is valgrind's 'massif' tool: 21 // http://valgrind.org/docs/manual/ms-manual.html 22 // Here is an example command line: 23 /* valgrind --tool=massif --massif-out-file=massif.out \ 24 --stacks=yes --alloc-fn=WebPSafeAlloc --alloc-fn=WebPSafeCalloc 25 ms_print massif.out 26 */ 27 // In addition: 28 // * if PRINT_MEM_TRAFFIC is defined, all the details of the malloc/free cycles 29 // are printed. 30 // * if MALLOC_FAIL_AT is defined, the global environment variable 31 // $MALLOC_FAIL_AT is used to simulate a memory error when calloc or malloc 32 // is called for the nth time. Example usage: 33 // export MALLOC_FAIL_AT=50 && ./examples/cwebp input.png 34 // * if MALLOC_LIMIT is defined, the global environment variable $MALLOC_LIMIT 35 // sets the maximum amount of memory (in bytes) made available to libwebp. 36 // This can be used to emulate environment with very limited memory. 37 // Example: export MALLOC_LIMIT=64000000 && ./examples/dwebp picture.webp 38 39 // #define PRINT_MEM_INFO 40 // #define PRINT_MEM_TRAFFIC 41 // #define MALLOC_FAIL_AT 42 // #define MALLOC_LIMIT 43 44 //------------------------------------------------------------------------------ 45 // Checked memory allocation 46 47 #if defined(PRINT_MEM_INFO) 48 49 #include <stdio.h> 50 #include <stdlib.h> // for abort() 51 52 static int num_malloc_calls = 0; 53 static int num_calloc_calls = 0; 54 static int num_free_calls = 0; 55 static int countdown_to_fail = 0; // 0 = off 56 57 typedef struct MemBlock MemBlock; 58 struct MemBlock { 59 void* ptr_; 60 size_t size_; 61 MemBlock* next_; 62 }; 63 64 static MemBlock* all_blocks = NULL; 65 static size_t total_mem = 0; 66 static size_t total_mem_allocated = 0; 67 static size_t high_water_mark = 0; 68 static size_t mem_limit = 0; 69 70 static int exit_registered = 0; 71 72 static void PrintMemInfo(void) { 73 fprintf(stderr, "\nMEMORY INFO:\n"); 74 fprintf(stderr, "num calls to: malloc = %4d\n", num_malloc_calls); 75 fprintf(stderr, " calloc = %4d\n", num_calloc_calls); 76 fprintf(stderr, " free = %4d\n", num_free_calls); 77 fprintf(stderr, "total_mem: %u\n", (uint32_t)total_mem); 78 fprintf(stderr, "total_mem allocated: %u\n", (uint32_t)total_mem_allocated); 79 fprintf(stderr, "high-water mark: %u\n", (uint32_t)high_water_mark); 80 while (all_blocks != NULL) { 81 MemBlock* b = all_blocks; 82 all_blocks = b->next_; 83 free(b); 84 } 85 } 86 87 static void Increment(int* const v) { 88 if (!exit_registered) { 89 #if defined(MALLOC_FAIL_AT) 90 { 91 const char* const malloc_fail_at_str = getenv("MALLOC_FAIL_AT"); 92 if (malloc_fail_at_str != NULL) { 93 countdown_to_fail = atoi(malloc_fail_at_str); 94 } 95 } 96 #endif 97 #if defined(MALLOC_LIMIT) 98 { 99 const char* const malloc_limit_str = getenv("MALLOC_LIMIT"); 100 if (malloc_limit_str != NULL) { 101 mem_limit = atoi(malloc_limit_str); 102 } 103 } 104 #endif 105 (void)countdown_to_fail; 106 (void)mem_limit; 107 atexit(PrintMemInfo); 108 exit_registered = 1; 109 } 110 ++*v; 111 } 112 113 static void AddMem(void* ptr, size_t size) { 114 if (ptr != NULL) { 115 MemBlock* const b = (MemBlock*)malloc(sizeof(*b)); 116 if (b == NULL) abort(); 117 b->next_ = all_blocks; 118 all_blocks = b; 119 b->ptr_ = ptr; 120 b->size_ = size; 121 total_mem += size; 122 total_mem_allocated += size; 123 #if defined(PRINT_MEM_TRAFFIC) 124 #if defined(MALLOC_FAIL_AT) 125 fprintf(stderr, "fail-count: %5d [mem=%u]\n", 126 num_malloc_calls + num_calloc_calls, (uint32_t)total_mem); 127 #else 128 fprintf(stderr, "Mem: %u (+%u)\n", (uint32_t)total_mem, (uint32_t)size); 129 #endif 130 #endif 131 if (total_mem > high_water_mark) high_water_mark = total_mem; 132 } 133 } 134 135 static void SubMem(void* ptr) { 136 if (ptr != NULL) { 137 MemBlock** b = &all_blocks; 138 // Inefficient search, but that's just for debugging. 139 while (*b != NULL && (*b)->ptr_ != ptr) b = &(*b)->next_; 140 if (*b == NULL) { 141 fprintf(stderr, "Invalid pointer free! (%p)\n", ptr); 142 abort(); 143 } 144 { 145 MemBlock* const block = *b; 146 *b = block->next_; 147 total_mem -= block->size_; 148 #if defined(PRINT_MEM_TRAFFIC) 149 fprintf(stderr, "Mem: %u (-%u)\n", 150 (uint32_t)total_mem, (uint32_t)block->size_); 151 #endif 152 free(block); 153 } 154 } 155 } 156 157 #else 158 #define Increment(v) do {} while(0) 159 #define AddMem(p, s) do {} while(0) 160 #define SubMem(p) do {} while(0) 161 #endif 162 163 // Returns 0 in case of overflow of nmemb * size. 164 static int CheckSizeArgumentsOverflow(uint64_t nmemb, size_t size) { 165 const uint64_t total_size = nmemb * size; 166 if (nmemb == 0) return 1; 167 if ((uint64_t)size > WEBP_MAX_ALLOCABLE_MEMORY / nmemb) return 0; 168 if (total_size != (size_t)total_size) return 0; 169 #if defined(PRINT_MEM_INFO) && defined(MALLOC_FAIL_AT) 170 if (countdown_to_fail > 0 && --countdown_to_fail == 0) { 171 return 0; // fake fail! 172 } 173 #endif 174 #if defined(MALLOC_LIMIT) 175 if (mem_limit > 0 && total_mem + total_size >= mem_limit) { 176 return 0; // fake fail! 177 } 178 #endif 179 180 return 1; 181 } 182 183 void* WebPSafeMalloc(uint64_t nmemb, size_t size) { 184 void* ptr; 185 Increment(&num_malloc_calls); 186 if (!CheckSizeArgumentsOverflow(nmemb, size)) return NULL; 187 assert(nmemb * size > 0); 188 ptr = malloc((size_t)(nmemb * size)); 189 AddMem(ptr, (size_t)(nmemb * size)); 190 return ptr; 191 } 192 193 void* WebPSafeCalloc(uint64_t nmemb, size_t size) { 194 void* ptr; 195 Increment(&num_calloc_calls); 196 if (!CheckSizeArgumentsOverflow(nmemb, size)) return NULL; 197 assert(nmemb * size > 0); 198 ptr = calloc((size_t)nmemb, size); 199 AddMem(ptr, (size_t)(nmemb * size)); 200 return ptr; 201 } 202 203 void WebPSafeFree(void* const ptr) { 204 if (ptr != NULL) { 205 Increment(&num_free_calls); 206 SubMem(ptr); 207 } 208 free(ptr); 209 } 210 211 //------------------------------------------------------------------------------ 212