xref: /f-stack/app/nginx-1.16.1/src/os/unix/ngx_shmem.c (revision 3da8d17d)
1 
2 /*
3  * Copyright (C) Igor Sysoev
4  * Copyright (C) Nginx, Inc.
5  */
6 
7 
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 
11 
12 #if (NGX_HAVE_MAP_ANON)
13 
14 ngx_int_t
ngx_shm_alloc(ngx_shm_t * shm)15 ngx_shm_alloc(ngx_shm_t *shm)
16 {
17     shm->addr = (u_char *) mmap(NULL, shm->size,
18                                 PROT_READ|PROT_WRITE,
19                                 MAP_ANON|MAP_SHARED, -1, 0);
20 
21     if (shm->addr == MAP_FAILED) {
22         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
23                       "mmap(MAP_ANON|MAP_SHARED, %uz) failed", shm->size);
24         return NGX_ERROR;
25     }
26 
27     return NGX_OK;
28 }
29 
30 
31 void
ngx_shm_free(ngx_shm_t * shm)32 ngx_shm_free(ngx_shm_t *shm)
33 {
34     if (munmap((void *) shm->addr, shm->size) == -1) {
35         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
36                       "munmap(%p, %uz) failed", shm->addr, shm->size);
37     }
38 }
39 
40 #elif (NGX_HAVE_MAP_DEVZERO)
41 
42 ngx_int_t
ngx_shm_alloc(ngx_shm_t * shm)43 ngx_shm_alloc(ngx_shm_t *shm)
44 {
45     ngx_fd_t  fd;
46 
47     fd = open("/dev/zero", O_RDWR);
48 
49     if (fd == -1) {
50         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
51                       "open(\"/dev/zero\") failed");
52         return NGX_ERROR;
53     }
54 
55     shm->addr = (u_char *) mmap(NULL, shm->size, PROT_READ|PROT_WRITE,
56                                 MAP_SHARED, fd, 0);
57 
58     if (shm->addr == MAP_FAILED) {
59         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
60                       "mmap(/dev/zero, MAP_SHARED, %uz) failed", shm->size);
61     }
62 
63     if (close(fd) == -1) {
64         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
65                       "close(\"/dev/zero\") failed");
66     }
67 
68     return (shm->addr == MAP_FAILED) ? NGX_ERROR : NGX_OK;
69 }
70 
71 
72 void
ngx_shm_free(ngx_shm_t * shm)73 ngx_shm_free(ngx_shm_t *shm)
74 {
75     if (munmap((void *) shm->addr, shm->size) == -1) {
76         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
77                       "munmap(%p, %uz) failed", shm->addr, shm->size);
78     }
79 }
80 
81 #elif (NGX_HAVE_SYSVSHM)
82 
83 #include <sys/ipc.h>
84 #include <sys/shm.h>
85 
86 
87 ngx_int_t
ngx_shm_alloc(ngx_shm_t * shm)88 ngx_shm_alloc(ngx_shm_t *shm)
89 {
90     int  id;
91 
92     id = shmget(IPC_PRIVATE, shm->size, (SHM_R|SHM_W|IPC_CREAT));
93 
94     if (id == -1) {
95         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
96                       "shmget(%uz) failed", shm->size);
97         return NGX_ERROR;
98     }
99 
100     ngx_log_debug1(NGX_LOG_DEBUG_CORE, shm->log, 0, "shmget id: %d", id);
101 
102     shm->addr = shmat(id, NULL, 0);
103 
104     if (shm->addr == (void *) -1) {
105         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "shmat() failed");
106     }
107 
108     if (shmctl(id, IPC_RMID, NULL) == -1) {
109         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
110                       "shmctl(IPC_RMID) failed");
111     }
112 
113     return (shm->addr == (void *) -1) ? NGX_ERROR : NGX_OK;
114 }
115 
116 
117 void
ngx_shm_free(ngx_shm_t * shm)118 ngx_shm_free(ngx_shm_t *shm)
119 {
120     if (shmdt(shm->addr) == -1) {
121         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,
122                       "shmdt(%p) failed", shm->addr);
123     }
124 }
125 
126 #endif
127