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
24typedef 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 */
37struct 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
44static 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
59APU_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
81APU_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    if (!block) {
89        return NULL;
90    }
91    list = (apr_bucket_alloc_t *)block->first_avail;
92    list->pool = NULL;
93    list->allocator = allocator;
94    list->freelist = NULL;
95    list->blocks = block;
96    block->first_avail += APR_ALIGN_DEFAULT(sizeof(*list));
97
98    return list;
99}
100
101APU_DECLARE_NONSTD(void) apr_bucket_alloc_destroy(apr_bucket_alloc_t *list)
102{
103    if (list->pool) {
104        apr_pool_cleanup_kill(list->pool, list, alloc_cleanup);
105    }
106
107    apr_allocator_free(list->allocator, list->blocks);
108
109#if APR_POOL_DEBUG
110    if (list->pool && list->allocator != apr_pool_allocator_get(list->pool)) {
111        apr_allocator_destroy(list->allocator);
112    }
113#endif
114}
115
116APU_DECLARE_NONSTD(void *) apr_bucket_alloc(apr_size_t size,
117                                            apr_bucket_alloc_t *list)
118{
119    node_header_t *node;
120    apr_memnode_t *active = list->blocks;
121    char *endp;
122
123    size += SIZEOF_NODE_HEADER_T;
124    if (size <= SMALL_NODE_SIZE) {
125        if (list->freelist) {
126            node = list->freelist;
127            list->freelist = node->next;
128        }
129        else {
130            endp = active->first_avail + SMALL_NODE_SIZE;
131            if (endp >= active->endp) {
132                list->blocks = apr_allocator_alloc(list->allocator, ALLOC_AMT);
133                if (!list->blocks) {
134                    return NULL;
135                }
136                list->blocks->next = active;
137                active = list->blocks;
138                endp = active->first_avail + SMALL_NODE_SIZE;
139            }
140            node = (node_header_t *)active->first_avail;
141            node->alloc = list;
142            node->memnode = active;
143            node->size = SMALL_NODE_SIZE;
144            active->first_avail = endp;
145        }
146    }
147    else {
148        apr_memnode_t *memnode = apr_allocator_alloc(list->allocator, size);
149        if (!memnode) {
150            return NULL;
151        }
152        node = (node_header_t *)memnode->first_avail;
153        node->alloc = list;
154        node->memnode = memnode;
155        node->size = size;
156    }
157    return ((char *)node) + SIZEOF_NODE_HEADER_T;
158}
159
160#ifdef APR_BUCKET_DEBUG
161#if APR_HAVE_STDLIB_H
162#include <stdlib.h>
163#endif
164static void check_not_already_free(node_header_t *node)
165{
166    apr_bucket_alloc_t *list = node->alloc;
167    node_header_t *curr = list->freelist;
168
169    while (curr) {
170        if (node == curr) {
171            abort();
172        }
173        curr = curr->next;
174    }
175}
176#else
177#define check_not_already_free(node)
178#endif
179
180APU_DECLARE_NONSTD(void) apr_bucket_free(void *mem)
181{
182    node_header_t *node = (node_header_t *)((char *)mem - SIZEOF_NODE_HEADER_T);
183    apr_bucket_alloc_t *list = node->alloc;
184
185    if (node->size == SMALL_NODE_SIZE) {
186        check_not_already_free(node);
187        node->next = list->freelist;
188        list->freelist = node;
189    }
190    else {
191        apr_allocator_free(list->allocator, node->memnode);
192    }
193}
194