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

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