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 "apr_buckets.h"
18#define APR_WANT_MEMFUNC
19#include "apr_want.h"
20
21static apr_status_t pool_bucket_cleanup(void *data)
22{
23    apr_bucket_pool *p = data;
24
25    /*
26     * If the pool gets cleaned up, we have to copy the data out
27     * of the pool and onto the heap.  But the apr_buckets out there
28     * that point to this pool bucket need to be notified such that
29     * they can morph themselves into a regular heap bucket the next
30     * time they try to read.  To avoid having to manipulate
31     * reference counts and b->data pointers, the apr_bucket_pool
32     * actually _contains_ an apr_bucket_heap as its first element,
33     * so the two share their apr_bucket_refcount member, and you
34     * can typecast a pool bucket struct to make it look like a
35     * regular old heap bucket struct.
36     */
37    p->heap.base = apr_bucket_alloc(p->heap.alloc_len, p->list);
38    memcpy(p->heap.base, p->base, p->heap.alloc_len);
39    p->base = NULL;
40    p->pool = NULL;
41
42    return APR_SUCCESS;
43}
44
45static apr_status_t pool_bucket_read(apr_bucket *b, const char **str,
46                                     apr_size_t *len, apr_read_type_e block)
47{
48    apr_bucket_pool *p = b->data;
49    const char *base = p->base;
50
51    if (p->pool == NULL) {
52        /*
53         * pool has been cleaned up... masquerade as a heap bucket from now
54         * on. subsequent bucket operations will use the heap bucket code.
55         */
56        b->type = &apr_bucket_type_heap;
57        base = p->heap.base;
58    }
59    *str = base + b->start;
60    *len = b->length;
61    return APR_SUCCESS;
62}
63
64static void pool_bucket_destroy(void *data)
65{
66    apr_bucket_pool *p = data;
67
68    /* If the pool is cleaned up before the last reference goes
69     * away, the data is really now on the heap; heap_destroy() takes
70     * over.  free() in heap_destroy() thinks it's freeing
71     * an apr_bucket_heap, when in reality it's freeing the whole
72     * apr_bucket_pool for us.
73     */
74    if (p->pool) {
75        /* the shared resource is still in the pool
76         * because the pool has not been cleaned up yet
77         */
78        if (apr_bucket_shared_destroy(p)) {
79            apr_pool_cleanup_kill(p->pool, p, pool_bucket_cleanup);
80            apr_bucket_free(p);
81        }
82    }
83    else {
84        /* the shared resource is no longer in the pool, it's
85         * on the heap, but this reference still thinks it's a pool
86         * bucket.  we should just go ahead and pass control to
87         * heap_destroy() for it since it doesn't know any better.
88         */
89        apr_bucket_type_heap.destroy(p);
90    }
91}
92
93APU_DECLARE(apr_bucket *) apr_bucket_pool_make(apr_bucket *b,
94                      const char *buf, apr_size_t length, apr_pool_t *pool)
95{
96    apr_bucket_pool *p;
97
98    p = apr_bucket_alloc(sizeof(*p), b->list);
99
100    /* XXX: we lose the const qualifier here which indicates
101     * there's something screwy with the API...
102     */
103    /* XXX: why is this?  buf is const, p->base is const... what's
104     * the problem?  --jcw */
105    p->base = (char *) buf;
106    p->pool = pool;
107    p->list = b->list;
108
109    b = apr_bucket_shared_make(b, p, 0, length);
110    b->type = &apr_bucket_type_pool;
111
112    /* pre-initialize heap bucket member */
113    p->heap.alloc_len = length;
114    p->heap.base      = NULL;
115    p->heap.free_func = apr_bucket_free;
116
117    apr_pool_cleanup_register(p->pool, p, pool_bucket_cleanup,
118                              apr_pool_cleanup_null);
119    return b;
120}
121
122APU_DECLARE(apr_bucket *) apr_bucket_pool_create(const char *buf,
123                                                 apr_size_t length,
124                                                 apr_pool_t *pool,
125                                                 apr_bucket_alloc_t *list)
126{
127    apr_bucket *b = apr_bucket_alloc(sizeof(*b), list);
128
129    APR_BUCKET_INIT(b);
130    b->free = apr_bucket_free;
131    b->list = list;
132    return apr_bucket_pool_make(b, buf, length, pool);
133}
134
135APU_DECLARE_DATA const apr_bucket_type_t apr_bucket_type_pool = {
136    "POOL", 5, APR_BUCKET_DATA,
137    pool_bucket_destroy,
138    pool_bucket_read,
139    apr_bucket_setaside_noop, /* don't need to setaside thanks to the cleanup*/
140    apr_bucket_shared_split,
141    apr_bucket_shared_copy
142};
143