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 #include <ngx_channel.h>
11
12
13 ngx_int_t
ngx_write_channel(ngx_socket_t s,ngx_channel_t * ch,size_t size,ngx_log_t * log)14 ngx_write_channel(ngx_socket_t s, ngx_channel_t *ch, size_t size,
15 ngx_log_t *log)
16 {
17 ssize_t n;
18 ngx_err_t err;
19 struct iovec iov[1];
20 struct msghdr msg;
21
22 #if (NGX_HAVE_MSGHDR_MSG_CONTROL)
23
24 union {
25 struct cmsghdr cm;
26 char space[CMSG_SPACE(sizeof(int))];
27 } cmsg;
28
29 if (ch->fd == -1) {
30 msg.msg_control = NULL;
31 msg.msg_controllen = 0;
32
33 } else {
34 msg.msg_control = (caddr_t) &cmsg;
35 msg.msg_controllen = sizeof(cmsg);
36
37 ngx_memzero(&cmsg, sizeof(cmsg));
38
39 cmsg.cm.cmsg_len = CMSG_LEN(sizeof(int));
40 cmsg.cm.cmsg_level = SOL_SOCKET;
41 cmsg.cm.cmsg_type = SCM_RIGHTS;
42
43 /*
44 * We have to use ngx_memcpy() instead of simple
45 * *(int *) CMSG_DATA(&cmsg.cm) = ch->fd;
46 * because some gcc 4.4 with -O2/3/s optimization issues the warning:
47 * dereferencing type-punned pointer will break strict-aliasing rules
48 *
49 * Fortunately, gcc with -O1 compiles this ngx_memcpy()
50 * in the same simple assignment as in the code above
51 */
52
53 ngx_memcpy(CMSG_DATA(&cmsg.cm), &ch->fd, sizeof(int));
54 }
55
56 msg.msg_flags = 0;
57
58 #else
59
60 if (ch->fd == -1) {
61 msg.msg_accrights = NULL;
62 msg.msg_accrightslen = 0;
63
64 } else {
65 msg.msg_accrights = (caddr_t) &ch->fd;
66 msg.msg_accrightslen = sizeof(int);
67 }
68
69 #endif
70
71 iov[0].iov_base = (char *) ch;
72 iov[0].iov_len = size;
73
74 msg.msg_name = NULL;
75 msg.msg_namelen = 0;
76 msg.msg_iov = iov;
77 msg.msg_iovlen = 1;
78
79 n = sendmsg(s, &msg, 0);
80
81 if (n == -1) {
82 err = ngx_errno;
83 if (err == NGX_EAGAIN) {
84 return NGX_AGAIN;
85 }
86
87 ngx_log_error(NGX_LOG_ALERT, log, err, "sendmsg() failed");
88 return NGX_ERROR;
89 }
90
91 return NGX_OK;
92 }
93
94
95 ngx_int_t
ngx_read_channel(ngx_socket_t s,ngx_channel_t * ch,size_t size,ngx_log_t * log)96 ngx_read_channel(ngx_socket_t s, ngx_channel_t *ch, size_t size, ngx_log_t *log)
97 {
98 ssize_t n;
99 ngx_err_t err;
100 struct iovec iov[1];
101 struct msghdr msg;
102
103 #if (NGX_HAVE_MSGHDR_MSG_CONTROL)
104 union {
105 struct cmsghdr cm;
106 char space[CMSG_SPACE(sizeof(int))];
107 } cmsg;
108 #else
109 int fd;
110 #endif
111
112 iov[0].iov_base = (char *) ch;
113 iov[0].iov_len = size;
114
115 msg.msg_name = NULL;
116 msg.msg_namelen = 0;
117 msg.msg_iov = iov;
118 msg.msg_iovlen = 1;
119
120 #if (NGX_HAVE_MSGHDR_MSG_CONTROL)
121 msg.msg_control = (caddr_t) &cmsg;
122 msg.msg_controllen = sizeof(cmsg);
123 #else
124 msg.msg_accrights = (caddr_t) &fd;
125 msg.msg_accrightslen = sizeof(int);
126 #endif
127
128 n = recvmsg(s, &msg, 0);
129
130 if (n == -1) {
131 err = ngx_errno;
132 if (err == NGX_EAGAIN) {
133 return NGX_AGAIN;
134 }
135
136 ngx_log_error(NGX_LOG_ALERT, log, err, "recvmsg() failed");
137 return NGX_ERROR;
138 }
139
140 if (n == 0) {
141 ngx_log_debug0(NGX_LOG_DEBUG_CORE, log, 0, "recvmsg() returned zero");
142 return NGX_ERROR;
143 }
144
145 if ((size_t) n < sizeof(ngx_channel_t)) {
146 ngx_log_error(NGX_LOG_ALERT, log, 0,
147 "recvmsg() returned not enough data: %z", n);
148 return NGX_ERROR;
149 }
150
151 #if (NGX_HAVE_MSGHDR_MSG_CONTROL)
152
153 if (ch->command == NGX_CMD_OPEN_CHANNEL) {
154
155 if (cmsg.cm.cmsg_len < (socklen_t) CMSG_LEN(sizeof(int))) {
156 ngx_log_error(NGX_LOG_ALERT, log, 0,
157 "recvmsg() returned too small ancillary data");
158 return NGX_ERROR;
159 }
160
161 if (cmsg.cm.cmsg_level != SOL_SOCKET || cmsg.cm.cmsg_type != SCM_RIGHTS)
162 {
163 ngx_log_error(NGX_LOG_ALERT, log, 0,
164 "recvmsg() returned invalid ancillary data "
165 "level %d or type %d",
166 cmsg.cm.cmsg_level, cmsg.cm.cmsg_type);
167 return NGX_ERROR;
168 }
169
170 /* ch->fd = *(int *) CMSG_DATA(&cmsg.cm); */
171
172 ngx_memcpy(&ch->fd, CMSG_DATA(&cmsg.cm), sizeof(int));
173 }
174
175 if (msg.msg_flags & (MSG_TRUNC|MSG_CTRUNC)) {
176 ngx_log_error(NGX_LOG_ALERT, log, 0,
177 "recvmsg() truncated data");
178 }
179
180 #else
181
182 if (ch->command == NGX_CMD_OPEN_CHANNEL) {
183 if (msg.msg_accrightslen != sizeof(int)) {
184 ngx_log_error(NGX_LOG_ALERT, log, 0,
185 "recvmsg() returned no ancillary data");
186 return NGX_ERROR;
187 }
188
189 ch->fd = fd;
190 }
191
192 #endif
193
194 return n;
195 }
196
197
198 ngx_int_t
ngx_add_channel_event(ngx_cycle_t * cycle,ngx_fd_t fd,ngx_int_t event,ngx_event_handler_pt handler)199 ngx_add_channel_event(ngx_cycle_t *cycle, ngx_fd_t fd, ngx_int_t event,
200 ngx_event_handler_pt handler)
201 {
202 ngx_event_t *ev, *rev, *wev;
203 ngx_connection_t *c;
204
205 c = ngx_get_connection(fd, cycle->log);
206
207 if (c == NULL) {
208 return NGX_ERROR;
209 }
210
211 c->pool = cycle->pool;
212
213 rev = c->read;
214 wev = c->write;
215
216 #if (NGX_HAVE_FSTACK)
217 rev->belong_to_host = wev->belong_to_host = 1;
218 #endif
219
220 rev->log = cycle->log;
221 wev->log = cycle->log;
222
223 rev->channel = 1;
224 wev->channel = 1;
225
226 ev = (event == NGX_READ_EVENT) ? rev : wev;
227
228 ev->handler = handler;
229
230 #if (NGX_HAVE_FSTACK)
231 if (ngx_event_actions.add_conn && (ngx_event_flags & NGX_USE_EPOLL_EVENT) == 0) {
232 #else
233 if (ngx_add_conn && (ngx_event_flags & NGX_USE_EPOLL_EVENT) == 0) {
234 #endif
235 if (ngx_add_conn(c) == NGX_ERROR) {
236 ngx_free_connection(c);
237 return NGX_ERROR;
238 }
239
240 } else {
241 if (ngx_add_event(ev, event, 0) == NGX_ERROR) {
242 ngx_free_connection(c);
243 return NGX_ERROR;
244 }
245 }
246
247 return NGX_OK;
248 }
249
250
251 void
252 ngx_close_channel(ngx_fd_t *fd, ngx_log_t *log)
253 {
254 if (close(fd[0]) == -1) {
255 ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "close() channel failed");
256 }
257
258 if (close(fd[1]) == -1) {
259 ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "close() channel failed");
260 }
261 }
262