1 /*
2 +----------------------------------------------------------------------+
3 | PHP Version 7 |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 2006-2018 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: Andrey Hristov <andrey@php.net> |
16 | Ulf Wendel <uw@php.net> |
17 +----------------------------------------------------------------------+
18 */
19
20 #include "php.h"
21 #include "mysqlnd.h"
22 #include "mysqlnd_block_alloc.h"
23 #include "mysqlnd_debug.h"
24 #include "mysqlnd_priv.h"
25
26
27 /* {{{ mysqlnd_mempool_free_chunk */
28 static void
mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL * pool,MYSQLND_MEMORY_POOL_CHUNK * chunk)29 mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL * pool, MYSQLND_MEMORY_POOL_CHUNK * chunk)
30 {
31 DBG_ENTER("mysqlnd_mempool_free_chunk");
32 if (chunk->from_pool) {
33 /* Try to back-off and guess if this is the last block allocated */
34 if (chunk->ptr == (pool->arena + (pool->arena_size - pool->free_size - chunk->size))) {
35 /*
36 This was the last allocation. Lucky us, we can free
37 a bit of memory from the pool. Next time we will return from the same ptr.
38 */
39 pool->free_size += chunk->size;
40 }
41 } else {
42 mnd_efree(chunk->ptr);
43 }
44 mnd_efree(chunk);
45 DBG_VOID_RETURN;
46 }
47 /* }}} */
48
49
50 /* {{{ mysqlnd_mempool_resize_chunk */
51 static enum_func_status
mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL * pool,MYSQLND_MEMORY_POOL_CHUNK * chunk,unsigned int size)52 mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL * pool, MYSQLND_MEMORY_POOL_CHUNK * chunk, unsigned int size)
53 {
54 DBG_ENTER("mysqlnd_mempool_resize_chunk");
55 if (chunk->from_pool) {
56 /* Try to back-off and guess if this is the last block allocated */
57 if (chunk->ptr == (pool->arena + (pool->arena_size - pool->free_size - chunk->size))) {
58 /*
59 This was the last allocation. Lucky us, we can free
60 a bit of memory from the pool. Next time we will return from the same ptr.
61 */
62 if ((chunk->size + pool->free_size) < size) {
63 zend_uchar *new_ptr;
64 new_ptr = mnd_emalloc(size);
65 if (!new_ptr) {
66 DBG_RETURN(FAIL);
67 }
68 memcpy(new_ptr, chunk->ptr, chunk->size);
69 chunk->ptr = new_ptr;
70 pool->free_size += chunk->size;
71 chunk->size = size;
72 chunk->from_pool = FALSE; /* now we have no pool memory */
73 } else {
74 /* If the chunk is > than asked size then free_memory increases, otherwise decreases*/
75 pool->free_size += (chunk->size - size);
76 }
77 } else {
78 /* Not last chunk, if the user asks for less, give it to him */
79 if (chunk->size >= size) {
80 ; /* nop */
81 } else {
82 zend_uchar *new_ptr;
83 new_ptr = mnd_emalloc(size);
84 if (!new_ptr) {
85 DBG_RETURN(FAIL);
86 }
87 memcpy(new_ptr, chunk->ptr, chunk->size);
88 chunk->ptr = new_ptr;
89 chunk->size = size;
90 chunk->from_pool = FALSE; /* now we have non-pool memory */
91 }
92 }
93 } else {
94 zend_uchar *new_ptr = mnd_erealloc(chunk->ptr, size);
95 if (!new_ptr) {
96 DBG_RETURN(FAIL);
97 }
98 chunk->ptr = new_ptr;
99 }
100 DBG_RETURN(PASS);
101 }
102 /* }}} */
103
104
105 /* {{{ mysqlnd_mempool_get_chunk */
106 static
mysqlnd_mempool_get_chunk(MYSQLND_MEMORY_POOL * pool,unsigned int size)107 MYSQLND_MEMORY_POOL_CHUNK * mysqlnd_mempool_get_chunk(MYSQLND_MEMORY_POOL * pool, unsigned int size)
108 {
109 MYSQLND_MEMORY_POOL_CHUNK *chunk = NULL;
110 DBG_ENTER("mysqlnd_mempool_get_chunk");
111
112 chunk = mnd_emalloc(sizeof(MYSQLND_MEMORY_POOL_CHUNK));
113 if (chunk) {
114 chunk->size = size;
115 /*
116 Should not go over MYSQLND_MAX_PACKET_SIZE, since we
117 expect non-arena memory in mysqlnd_wireprotocol.c . We
118 realloc the non-arena memory.
119 */
120 if (size > pool->free_size) {
121 chunk->from_pool = FALSE;
122 chunk->ptr = mnd_emalloc(size);
123 if (!chunk->ptr) {
124 pool->free_chunk(pool, chunk);
125 chunk = NULL;
126 }
127 } else {
128 chunk->from_pool = TRUE;
129 chunk->ptr = pool->arena + (pool->arena_size - pool->free_size);
130 /* Last step, update free_size */
131 pool->free_size -= size;
132 }
133 }
134 DBG_RETURN(chunk);
135 }
136 /* }}} */
137
138
139 /* {{{ mysqlnd_mempool_create */
140 PHPAPI MYSQLND_MEMORY_POOL *
mysqlnd_mempool_create(size_t arena_size)141 mysqlnd_mempool_create(size_t arena_size)
142 {
143 /* We calloc, because we free(). We don't mnd_calloc() for a reason. */
144 MYSQLND_MEMORY_POOL * ret = mnd_ecalloc(1, sizeof(MYSQLND_MEMORY_POOL));
145 DBG_ENTER("mysqlnd_mempool_create");
146 if (ret) {
147 ret->get_chunk = mysqlnd_mempool_get_chunk;
148 ret->free_chunk = mysqlnd_mempool_free_chunk;
149 ret->resize_chunk = mysqlnd_mempool_resize_chunk;
150 ret->free_size = ret->arena_size = arena_size ? arena_size : 0;
151 /* OOM ? */
152 ret->arena = mnd_emalloc(ret->arena_size);
153 if (!ret->arena) {
154 mysqlnd_mempool_destroy(ret);
155 ret = NULL;
156 }
157 }
158 DBG_RETURN(ret);
159 }
160 /* }}} */
161
162
163 /* {{{ mysqlnd_mempool_destroy */
164 PHPAPI void
mysqlnd_mempool_destroy(MYSQLND_MEMORY_POOL * pool)165 mysqlnd_mempool_destroy(MYSQLND_MEMORY_POOL * pool)
166 {
167 DBG_ENTER("mysqlnd_mempool_destroy");
168 /* mnd_free will reference LOCK_access and might crash, depending on the caller...*/
169 mnd_efree(pool->arena);
170 mnd_efree(pool);
171 DBG_VOID_RETURN;
172 }
173 /* }}} */
174
175
176 /*
177 * Local variables:
178 * tab-width: 4
179 * c-basic-offset: 4
180 * End:
181 * vim600: noet sw=4 ts=4 fdm=marker
182 * vim<600: noet sw=4 ts=4
183 */
184
