buckets/apr_buckets_alloc.c

   1 /* Licensed to the Apache Software Foundation (ASF) under one or more
   2  * contributor license agreements.  See the NOTICE file distributed with
   3  * this work for additional information regarding copyright ownership.
   4  * The ASF licenses this file to You under the Apache License, Version 2.0
   5  * (the "License"); you may not use this file except in compliance with
   6  * the License.  You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <stdlib.h>
  18
  19 #include "apr_buckets.h"
  20 #include "apr_allocator.h"
  21
  22 #define ALLOC_AMT (8192 - APR_MEMNODE_T_SIZE)
  23
  24 typedef struct node_header_t {
  25     apr_size_t size;
  26     apr_bucket_alloc_t *alloc;
  27     apr_memnode_t *memnode;
  28     struct node_header_t *next;
  29 } node_header_t;
  30
  31 #define SIZEOF_NODE_HEADER_T  APR_ALIGN_DEFAULT(sizeof(node_header_t))
  32 #define SMALL_NODE_SIZE       (APR_BUCKET_ALLOC_SIZE + SIZEOF_NODE_HEADER_T)
  33
  34 /** A list of free memory from which new buckets or private bucket
  35  *  structures can be allocated.
  36  */
  37 struct apr_bucket_alloc_t {
  38     apr_pool_t *pool;
  39     apr_allocator_t *allocator;
  40     node_header_t *freelist;
  41     apr_memnode_t *blocks;
  42 };
  43
  44 static apr_status_t alloc_cleanup(void *data)
  45 {
  46     apr_bucket_alloc_t *list = data;
  47
  48     apr_allocator_free(list->allocator, list->blocks);
  49
  50 #if APR_POOL_DEBUG
  51     if (list->pool && list->allocator != apr_pool_allocator_get(list->pool)) {
  52         apr_allocator_destroy(list->allocator);
  53     }
  54 #endif
  55
  56     return APR_SUCCESS;
  57 }
  58
  59 APU_DECLARE_NONSTD(apr_bucket_alloc_t *) apr_bucket_alloc_create(apr_pool_t *p)
  60 {
  61     apr_allocator_t *allocator = apr_pool_allocator_get(p);
  62     apr_bucket_alloc_t *list;
  63
  64 #if APR_POOL_DEBUG
  65     /* may be NULL for debug mode. */
  66     if (allocator == NULL) {
  67         if (apr_allocator_create(&allocator) != APR_SUCCESS) {
  68             abort();
  69         }
  70     }
  71 #endif
  72
  73     list = apr_bucket_alloc_create_ex(allocator);
  74     list->pool = p;
  75     apr_pool_cleanup_register(list->pool, list, alloc_cleanup,
  76                               apr_pool_cleanup_null);
  77
  78     return list;
  79 }
  80
  81 APU_DECLARE_NONSTD(apr_bucket_alloc_t *) apr_bucket_alloc_create_ex(
  82                                              apr_allocator_t *allocator)
  83 {
  84     apr_bucket_alloc_t *list;
  85     apr_memnode_t *block;
  86
  87     block = apr_allocator_alloc(allocator, ALLOC_AMT);
  88     list = (apr_bucket_alloc_t *)block->first_avail;
  89     list->pool = NULL;
  90     list->allocator = allocator;
  91     list->freelist = NULL;
  92     list->blocks = block;
  93     block->first_avail += APR_ALIGN_DEFAULT(sizeof(*list));
  94
  95     return list;
  96 }
  97
  98 APU_DECLARE_NONSTD(void) apr_bucket_alloc_destroy(apr_bucket_alloc_t *list)
  99 {
 100     if (list->pool) {
 101         apr_pool_cleanup_kill(list->pool, list, alloc_cleanup);
 102     }
 103
 104     apr_allocator_free(list->allocator, list->blocks);
 105
 106 #if APR_POOL_DEBUG
 107     if (list->pool && list->allocator != apr_pool_allocator_get(list->pool)) {
 108         apr_allocator_destroy(list->allocator);
 109     }
 110 #endif
 111 }
 112
 113 APU_DECLARE_NONSTD(void *) apr_bucket_alloc(apr_size_t size,
 114                                             apr_bucket_alloc_t *list)
 115 {
 116     node_header_t *node;
 117     apr_memnode_t *active = list->blocks;
 118     char *endp;
 119
 120     size += SIZEOF_NODE_HEADER_T;
 121     if (size <= SMALL_NODE_SIZE) {
 122         if (list->freelist) {
 123             node = list->freelist;
 124             list->freelist = node->next;
 125         }
 126         else {
 127             endp = active->first_avail + SMALL_NODE_SIZE;
 128             if (endp >= active->endp) {
 129                 list->blocks = apr_allocator_alloc(list->allocator, ALLOC_AMT);
 130                 list->blocks->next = active;
 131                 active = list->blocks;
 132                 endp = active->first_avail + SMALL_NODE_SIZE;
 133             }
 134             node = (node_header_t *)active->first_avail;
 135             node->alloc = list;
 136             node->memnode = active;
 137             node->size = SMALL_NODE_SIZE;
 138             active->first_avail = endp;
 139         }
 140     }
 141     else {
 142         apr_memnode_t *memnode = apr_allocator_alloc(list->allocator, size);
 143         node = (node_header_t *)memnode->first_avail;
 144         node->alloc = list;
 145         node->memnode = memnode;
 146         node->size = size;
 147     }
 148     return ((char *)node) + SIZEOF_NODE_HEADER_T;
 149 }
 150
 151 #ifdef APR_BUCKET_DEBUG
 152 #if APR_HAVE_STDLIB_H
 153 #include <stdlib.h>
 154 #endif
 155 static void check_not_already_free(node_header_t *node)
 156 {
 157     apr_bucket_alloc_t *list = node->alloc;
 158     node_header_t *curr = list->freelist;
 159
 160     while (curr) {
 161         if (node == curr) {
 162             abort();
 163         }
 164         curr = curr->next;
 165     }
 166 }
 167 #else
 168 #define check_not_already_free(node)
 169 #endif
 170
 171 APU_DECLARE_NONSTD(void) apr_bucket_free(void *mem)
 172 {
 173     node_header_t *node = (node_header_t *)((char *)mem - SIZEOF_NODE_HEADER_T);
 174     apr_bucket_alloc_t *list = node->alloc;
 175
 176     if (node->size == SMALL_NODE_SIZE) {
 177         check_not_already_free(node);
 178         node->next = list->freelist;
 179         list->freelist = node;
 180     }
 181     else {
 182         apr_allocator_free(list->allocator, node->memnode);
 183     }
 184 }