git.m6w6.name Git - awesomized/libmemcached/blob - memcached/cache.c

   1 /* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
   2 #include "memcached.h"
   3
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <inttypes.h>
   7 #include <string.h>
   8
   9 #ifndef NDEBUG
  10 #include <signal.h>
  11 #endif
  12
  13 #include "cache.h"
  14
  15 #ifndef NDEBUG
  16 const uint64_t redzone_pattern = 0xdeadbeefcafebabe;
  17 int cache_error = 0;
  18 #endif
  19
  20 const int initial_pool_size = 64;
  21
  22 cache_t* cache_create(const char *name, size_t bufsize, size_t align,
  23                       cache_constructor_t* constructor,
  24                       cache_destructor_t* destructor) {
  25     cache_t* ret = calloc(1, sizeof(cache_t));
  26     char* nm = strdup(name);
  27     void** ptr = calloc(initial_pool_size, sizeof(void*));
  28     if (ret == NULL || nm == NULL || ptr == NULL ||
  29         pthread_mutex_init(&ret->mutex, NULL) == -1) {
  30         free(ret);
  31         free(nm);
  32         free(ptr);
  33         return NULL;
  34     }
  35
  36     ret->name = nm;
  37     ret->ptr = ptr;
  38     ret->freetotal = initial_pool_size;
  39     ret->constructor = constructor;
  40     ret->destructor = destructor;
  41
  42 #ifndef NDEBUG
  43     ret->bufsize = bufsize + 2 * sizeof(redzone_pattern);
  44 #else
  45     ret->bufsize = bufsize;
  46 #endif
  47
  48     return ret;
  49 }
  50
  51 static inline void* get_object(void *ptr) {
  52 #ifndef NDEBUG
  53     uint64_t *pre = ptr;
  54     return pre + 1;
  55 #else
  56     return ptr;
  57 #endif
  58 }
  59
  60 void cache_destroy(cache_t *cache) {
  61     while (cache->freecurr > 0) {
  62         void *ptr = cache->ptr[--cache->freecurr];
  63         if (cache->destructor) {
  64             cache->destructor(get_object(ptr), NULL);
  65         }
  66         free(ptr);
  67     }
  68     free(cache->name);
  69     free(cache->ptr);
  70     pthread_mutex_destroy(&cache->mutex);
  71 }
  72
  73 void* cache_alloc(cache_t *cache) {
  74     void *ret;
  75     void *object;
  76     pthread_mutex_lock(&cache->mutex);
  77     if (cache->freecurr > 0) {
  78         ret = cache->ptr[--cache->freecurr];
  79         object = get_object(ret);
  80     } else {
  81         object = ret = malloc(cache->bufsize);
  82         if (ret != NULL) {
  83             object = get_object(ret);
  84
  85             if (cache->constructor != NULL &&
  86                 cache->constructor(object, NULL, 0) != 0) {
  87                 free(ret);
  88                 object = NULL;
  89             }
  90         }
  91     }
  92     pthread_mutex_unlock(&cache->mutex);
  93
  94 #ifndef NDEBUG
  95     if (object != NULL) {
  96         /* add a simple form of buffer-check */
  97         uint64_t *pre = ret;
  98         *pre = redzone_pattern;
  99         ret = pre+1;
 100         memcpy(((char*)ret) + cache->bufsize - (2 * sizeof(redzone_pattern)),
 101                &redzone_pattern, sizeof(redzone_pattern));
 102     }
 103 #endif
 104
 105     return object;
 106 }
 107
 108 void cache_free(cache_t *cache, void *ptr) {
 109     pthread_mutex_lock(&cache->mutex);
 110
 111 #ifndef NDEBUG
 112     /* validate redzone... */
 113     if (memcmp(((char*)ptr) + cache->bufsize - (2 * sizeof(redzone_pattern)),
 114                &redzone_pattern, sizeof(redzone_pattern)) != 0) {
 115         raise(SIGABRT);
 116         cache_error = 1;
 117         pthread_mutex_unlock(&cache->mutex);
 118         return;
 119     }
 120     uint64_t *pre = ptr;
 121     --pre;
 122     if (*pre != redzone_pattern) {
 123         raise(SIGABRT);
 124         cache_error = -1;
 125         pthread_mutex_unlock(&cache->mutex);
 126         return;
 127     }
 128     ptr = pre;
 129 #endif
 130     if (cache->freecurr < cache->freetotal) {
 131         cache->ptr[cache->freecurr++] = ptr;
 132     } else {
 133         /* try to enlarge free connections array */
 134         size_t newtotal = cache->freetotal * 2;
 135         void **new_free = realloc(cache->ptr, sizeof(char *) * newtotal);
 136         if (new_free) {
 137             cache->freetotal = newtotal;
 138             cache->ptr = new_free;
 139             cache->ptr[cache->freecurr++] = ptr;
 140         } else {
 141             if (cache->destructor) {
 142                 cache->destructor(ptr, NULL);
 143             }
 144             free(ptr);
 145
 146         }
 147     }
 148     pthread_mutex_unlock(&cache->mutex);
 149 }
 150