1 /*
2 +----------------------------------------------------------------------+
3 | Zend OPcache |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 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 | https://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: Andi Gutmans <andi@php.net> |
16 | Zeev Suraski <zeev@php.net> |
17 | Stanislav Malyshev <stas@zend.com> |
18 | Dmitry Stogov <dmitry@php.net> |
19 +----------------------------------------------------------------------+
20 */
21
22 #include "zend_shared_alloc.h"
23
24 #ifdef USE_SHM
25
26 #if defined(__FreeBSD__)
27 # include <machine/param.h>
28 #endif
29 #include <sys/types.h>
30 #include <sys/shm.h>
31 #include <sys/ipc.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <unistd.h>
36 #include <errno.h>
37
38 #include <sys/stat.h>
39 #include <fcntl.h>
40
41 #ifndef MIN
42 # define MIN(x, y) ((x) > (y)? (y) : (x))
43 #endif
44
45 #define SEG_ALLOC_SIZE_MAX 32*1024*1024
46 #define SEG_ALLOC_SIZE_MIN 2*1024*1024
47
48 typedef struct {
49 zend_shared_segment common;
50 int shm_id;
51 } zend_shared_segment_shm;
52
create_segments(size_t requested_size,zend_shared_segment_shm *** shared_segments_p,int * shared_segments_count,const char ** error_in)53 static int create_segments(size_t requested_size, zend_shared_segment_shm ***shared_segments_p, int *shared_segments_count, const char **error_in)
54 {
55 int i;
56 size_t allocate_size = 0, remaining_bytes = requested_size, seg_allocate_size;
57 int first_segment_id = -1;
58 key_t first_segment_key = -1;
59 struct shmid_ds sds;
60 int shmget_flags;
61 zend_shared_segment_shm *shared_segments;
62
63 seg_allocate_size = SEG_ALLOC_SIZE_MAX;
64 /* determine segment size we _really_ need:
65 * no more than to include requested_size
66 */
67 while (requested_size * 2 <= seg_allocate_size && seg_allocate_size > SEG_ALLOC_SIZE_MIN) {
68 seg_allocate_size >>= 1;
69 }
70
71 shmget_flags = IPC_CREAT|SHM_R|SHM_W|IPC_EXCL;
72
73 /* try allocating this much, if not - try shrinking */
74 while (seg_allocate_size >= SEG_ALLOC_SIZE_MIN) {
75 allocate_size = MIN(requested_size, seg_allocate_size);
76 first_segment_id = shmget(first_segment_key, allocate_size, shmget_flags);
77 if (first_segment_id != -1) {
78 break;
79 }
80 seg_allocate_size >>= 1; /* shrink the allocated block */
81 }
82
83 if (first_segment_id == -1) {
84 *error_in = "shmget";
85 return ALLOC_FAILURE;
86 }
87
88 *shared_segments_count = ((requested_size - 1) / seg_allocate_size) + 1;
89 *shared_segments_p = (zend_shared_segment_shm **) calloc(1, (*shared_segments_count) * sizeof(zend_shared_segment_shm) + sizeof(void *) * (*shared_segments_count));
90 if (!*shared_segments_p) {
91 *error_in = "calloc";
92 return ALLOC_FAILURE;
93 }
94 shared_segments = (zend_shared_segment_shm *)((char *)(*shared_segments_p) + sizeof(void *) * (*shared_segments_count));
95 for (i = 0; i < *shared_segments_count; i++) {
96 (*shared_segments_p)[i] = shared_segments + i;
97 }
98
99 remaining_bytes = requested_size;
100 for (i = 0; i < *shared_segments_count; i++) {
101 allocate_size = MIN(remaining_bytes, seg_allocate_size);
102 if (i != 0) {
103 shared_segments[i].shm_id = shmget(IPC_PRIVATE, allocate_size, shmget_flags);
104 } else {
105 shared_segments[i].shm_id = first_segment_id;
106 }
107
108 if (shared_segments[i].shm_id == -1) {
109 return ALLOC_FAILURE;
110 }
111
112 shared_segments[i].common.p = shmat(shared_segments[i].shm_id, NULL, 0);
113 if (shared_segments[i].common.p == (void *)-1) {
114 *error_in = "shmat";
115 shmctl(shared_segments[i].shm_id, IPC_RMID, &sds);
116 return ALLOC_FAILURE;
117 }
118 shmctl(shared_segments[i].shm_id, IPC_RMID, &sds);
119
120 shared_segments[i].common.pos = 0;
121 shared_segments[i].common.size = allocate_size;
122 remaining_bytes -= allocate_size;
123 }
124 return ALLOC_SUCCESS;
125 }
126
detach_segment(zend_shared_segment_shm * shared_segment)127 static int detach_segment(zend_shared_segment_shm *shared_segment)
128 {
129 shmdt(shared_segment->common.p);
130 return 0;
131 }
132
segment_type_size(void)133 static size_t segment_type_size(void)
134 {
135 return sizeof(zend_shared_segment_shm);
136 }
137
138 const zend_shared_memory_handlers zend_alloc_shm_handlers = {
139 (create_segments_t)create_segments,
140 (detach_segment_t)detach_segment,
141 segment_type_size
142 };
143
144 #endif /* USE_SHM */
145
