1 /*
2 +----------------------------------------------------------------------+
3 | PHP Version 5 |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 2006-2016 The PHP Group |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 3.01 of the PHP license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.php.net/license/3_01.txt |
11 | If you did not receive a copy of the PHP license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@php.net so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Authors: Georg Richter <georg@mysql.com> |
16 | Andrey Hristov <andrey@mysql.com> |
17 | Ulf Wendel <uwendel@mysql.com> |
18 +----------------------------------------------------------------------+
19 */
20
21 /* $Id$ */
22
23 #include "php.h"
24 #include "mysqlnd.h"
25 #include "mysqlnd_block_alloc.h"
26 #include "mysqlnd_debug.h"
27 #include "mysqlnd_priv.h"
28
29
30 /* {{{ mysqlnd_mempool_free_chunk */
31 static void
mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL_CHUNK * chunk TSRMLS_DC)32 mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL_CHUNK * chunk TSRMLS_DC)
33 {
34 MYSQLND_MEMORY_POOL * pool = chunk->pool;
35 DBG_ENTER("mysqlnd_mempool_free_chunk");
36 if (chunk->from_pool) {
37 /* Try to back-off and guess if this is the last block allocated */
38 if (chunk->ptr == (pool->arena + (pool->arena_size - pool->free_size - chunk->size))) {
39 /*
40 This was the last allocation. Lucky us, we can free
41 a bit of memory from the pool. Next time we will return from the same ptr.
42 */
43 pool->free_size += chunk->size;
44 }
45 pool->refcount--;
46 } else {
47 mnd_free(chunk->ptr);
48 }
49 mnd_free(chunk);
50 DBG_VOID_RETURN;
51 }
52 /* }}} */
53
54
55 /* {{{ mysqlnd_mempool_resize_chunk */
56 static enum_func_status
mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL_CHUNK * chunk,unsigned int size TSRMLS_DC)57 mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL_CHUNK * chunk, unsigned int size TSRMLS_DC)
58 {
59 DBG_ENTER("mysqlnd_mempool_resize_chunk");
60 if (chunk->from_pool) {
61 MYSQLND_MEMORY_POOL * pool = chunk->pool;
62 /* Try to back-off and guess if this is the last block allocated */
63 if (chunk->ptr == (pool->arena + (pool->arena_size - pool->free_size - chunk->size))) {
64 /*
65 This was the last allocation. Lucky us, we can free
66 a bit of memory from the pool. Next time we will return from the same ptr.
67 */
68 if ((chunk->size + pool->free_size) < size) {
69 zend_uchar *new_ptr;
70 new_ptr = mnd_malloc(size);
71 if (!new_ptr) {
72 DBG_RETURN(FAIL);
73 }
74 memcpy(new_ptr, chunk->ptr, chunk->size);
75 chunk->ptr = new_ptr;
76 pool->free_size += chunk->size;
77 chunk->size = size;
78 chunk->pool = NULL; /* now we have no pool memory */
79 pool->refcount--;
80 } else {
81 /* If the chunk is > than asked size then free_memory increases, otherwise decreases*/
82 pool->free_size += (chunk->size - size);
83 }
84 } else {
85 /* Not last chunk, if the user asks for less, give it to him */
86 if (chunk->size >= size) {
87 ; /* nop */
88 } else {
89 zend_uchar *new_ptr;
90 new_ptr = mnd_malloc(size);
91 if (!new_ptr) {
92 DBG_RETURN(FAIL);
93 }
94 memcpy(new_ptr, chunk->ptr, chunk->size);
95 chunk->ptr = new_ptr;
96 chunk->size = size;
97 chunk->pool = NULL; /* now we have non-pool memory */
98 pool->refcount--;
99 }
100 }
101 } else {
102 zend_uchar *new_ptr = mnd_realloc(chunk->ptr, size);
103 if (!new_ptr) {
104 DBG_RETURN(FAIL);
105 }
106 chunk->ptr = new_ptr;
107 }
108 DBG_RETURN(PASS);
109 }
110 /* }}} */
111
112
113 /* {{{ mysqlnd_mempool_get_chunk */
114 static
mysqlnd_mempool_get_chunk(MYSQLND_MEMORY_POOL * pool,unsigned int size TSRMLS_DC)115 MYSQLND_MEMORY_POOL_CHUNK * mysqlnd_mempool_get_chunk(MYSQLND_MEMORY_POOL * pool, unsigned int size TSRMLS_DC)
116 {
117 MYSQLND_MEMORY_POOL_CHUNK *chunk = NULL;
118 DBG_ENTER("mysqlnd_mempool_get_chunk");
119
120 chunk = mnd_malloc(sizeof(MYSQLND_MEMORY_POOL_CHUNK));
121 if (chunk) {
122 chunk->free_chunk = mysqlnd_mempool_free_chunk;
123 chunk->resize_chunk = mysqlnd_mempool_resize_chunk;
124 chunk->size = size;
125 /*
126 Should not go over MYSQLND_MAX_PACKET_SIZE, since we
127 expect non-arena memory in mysqlnd_wireprotocol.c . We
128 realloc the non-arena memory.
129 */
130 chunk->pool = pool;
131 if (size > pool->free_size) {
132 chunk->from_pool = FALSE;
133 chunk->ptr = mnd_malloc(size);
134 if (!chunk->ptr) {
135 chunk->free_chunk(chunk TSRMLS_CC);
136 chunk = NULL;
137 }
138 } else {
139 chunk->from_pool = TRUE;
140 ++pool->refcount;
141 chunk->ptr = pool->arena + (pool->arena_size - pool->free_size);
142 /* Last step, update free_size */
143 pool->free_size -= size;
144 }
145 }
146 DBG_RETURN(chunk);
147 }
148 /* }}} */
149
150
151 /* {{{ mysqlnd_mempool_create */
152 PHPAPI MYSQLND_MEMORY_POOL *
mysqlnd_mempool_create(size_t arena_size TSRMLS_DC)153 mysqlnd_mempool_create(size_t arena_size TSRMLS_DC)
154 {
155 /* We calloc, because we free(). We don't mnd_calloc() for a reason. */
156 MYSQLND_MEMORY_POOL * ret = mnd_calloc(1, sizeof(MYSQLND_MEMORY_POOL));
157 DBG_ENTER("mysqlnd_mempool_create");
158 if (ret) {
159 ret->get_chunk = mysqlnd_mempool_get_chunk;
160 ret->free_size = ret->arena_size = arena_size ? arena_size : 0;
161 ret->refcount = 0;
162 /* OOM ? */
163 ret->arena = mnd_malloc(ret->arena_size);
164 if (!ret->arena) {
165 mysqlnd_mempool_destroy(ret TSRMLS_CC);
166 ret = NULL;
167 }
168 }
169 DBG_RETURN(ret);
170 }
171 /* }}} */
172
173
174 /* {{{ mysqlnd_mempool_destroy */
175 PHPAPI void
mysqlnd_mempool_destroy(MYSQLND_MEMORY_POOL * pool TSRMLS_DC)176 mysqlnd_mempool_destroy(MYSQLND_MEMORY_POOL * pool TSRMLS_DC)
177 {
178 DBG_ENTER("mysqlnd_mempool_destroy");
179 /* mnd_free will reference LOCK_access and might crash, depending on the caller...*/
180 mnd_free(pool->arena);
181 mnd_free(pool);
182 DBG_VOID_RETURN;
183 }
184 /* }}} */
185
186
187 /*
188 * Local variables:
189 * tab-width: 4
190 * c-basic-offset: 4
191 * End:
192 * vim600: noet sw=4 ts=4 fdm=marker
193 * vim<600: noet sw=4 ts=4
194 */
195
