1 /*
2  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/stat.h>
20 #include <sys/socket.h>
21 #include <sys/uio.h>
22 #include <sys/un.h>
23 
24 #include <netinet/in.h>
25 #include <net/if.h>
26 
27 #include <errno.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 #include "log.h"
33 #include "kamid.h"
34 #include "control.h"
35 #include "listener.h"
36 
37 #define	CONTROL_BACKLOG	5
38 
39 struct {
40 	struct event	ev;
41 	struct event	evt;
42 	int		fd;
43 } control_state = {.fd = -1};
44 
45 struct ctl_conn {
46 	TAILQ_ENTRY(ctl_conn)	entry;
47 	struct imsgev		iev;
48 };
49 
50 TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
51 
52 struct ctl_conn	*control_connbyfd(int);
53 struct ctl_conn	*control_connbypid(pid_t);
54 void		 control_close(int);
55 
56 int
57 control_init(const char *path)
58 {
59 	struct sockaddr_un	 sun;
60 	int			 fd;
61 	mode_t			 old_umask;
62 
63 	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
64 	    0)) == -1) {
65 		log_warn("%s: socket", __func__);
66 		return (-1);
67 	}
68 
69 	memset(&sun, 0, sizeof(sun));
70 	sun.sun_family = AF_UNIX;
71 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
72 
73 	if (unlink(path) == -1)
74 		if (errno != ENOENT) {
75 			log_warn("%s: unlink %s", __func__, path);
76 			close(fd);
77 			return (-1);
78 		}
79 
80 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
81 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
82 		log_warn("%s: bind: %s", __func__, path);
83 		close(fd);
84 		umask(old_umask);
85 		return (-1);
86 	}
87 	umask(old_umask);
88 
89 	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
90 		log_warn("%s: chmod", __func__);
91 		close(fd);
92 		(void)unlink(path);
93 		return (-1);
94 	}
95 
96 	return (fd);
97 }
98 
99 int
100 control_listen(int fd)
101 {
102 	if (control_state.fd != -1)
103 		fatalx("%s: received unexpected controlsock", __func__);
104 
105 	control_state.fd = fd;
106 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
107 		log_warn("%s: listen", __func__);
108 		return (-1);
109 	}
110 
111 	event_set(&control_state.ev, control_state.fd, EV_READ,
112 	    control_accept, NULL);
113 	event_add(&control_state.ev, NULL);
114 	evtimer_set(&control_state.evt, control_accept, NULL);
115 
116 	return (0);
117 }
118 
119 void
120 control_accept(int listenfd, short event, void *bula)
121 {
122 	int			 connfd;
123 	socklen_t		 len;
124 	struct sockaddr_un	 sun;
125 	struct ctl_conn		*c;
126 
127 	event_add(&control_state.ev, NULL);
128 	if ((event & EV_TIMEOUT))
129 		return;
130 
131 	len = sizeof(sun);
132 	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
133 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
134 		/*
135 		 * Pause accept if we are out of file descriptors, or
136 		 * libevent will haunt us here too.
137 		 */
138 		if (errno == ENFILE || errno == EMFILE) {
139 			struct timeval evtpause = { 1, 0 };
140 
141 			event_del(&control_state.ev);
142 			evtimer_add(&control_state.evt, &evtpause);
143 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
144 		    errno != ECONNABORTED)
145 			log_warn("%s: accept4", __func__);
146 		return;
147 	}
148 
149 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
150 		log_warn("%s: calloc", __func__);
151 		close(connfd);
152 		return;
153 	}
154 
155 	imsg_init(&c->iev.ibuf, connfd);
156 	c->iev.handler = control_dispatch_imsg;
157 	c->iev.events = EV_READ;
158 	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
159 	    c->iev.handler, &c->iev);
160 	event_add(&c->iev.ev, NULL);
161 
162 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
163 }
164 
165 struct ctl_conn *
166 control_connbyfd(int fd)
167 {
168 	struct ctl_conn	*c;
169 
170 	TAILQ_FOREACH(c, &ctl_conns, entry) {
171 		if (c->iev.ibuf.fd == fd)
172 			break;
173 	}
174 
175 	return (c);
176 }
177 
178 struct ctl_conn *
179 control_connbypid(pid_t pid)
180 {
181 	struct ctl_conn	*c;
182 
183 	TAILQ_FOREACH(c, &ctl_conns, entry) {
184 		if (c->iev.ibuf.pid == pid)
185 			break;
186 	}
187 
188 	return (c);
189 }
190 
191 void
192 control_close(int fd)
193 {
194 	struct ctl_conn	*c;
195 
196 	if ((c = control_connbyfd(fd)) == NULL) {
197 		log_warnx("%s: fd %d: not found", __func__, fd);
198 		return;
199 	}
200 
201 	msgbuf_clear(&c->iev.ibuf.w);
202 	TAILQ_REMOVE(&ctl_conns, c, entry);
203 
204 	event_del(&c->iev.ev);
205 	close(c->iev.ibuf.fd);
206 
207 	/* Some file descriptors are available again. */
208 	if (evtimer_pending(&control_state.evt, NULL)) {
209 		evtimer_del(&control_state.evt);
210 		event_add(&control_state.ev, NULL);
211 	}
212 
213 	free(c);
214 }
215 
216 void
217 control_dispatch_imsg(int fd, short event, void *bula)
218 {
219 	struct ctl_conn	*c;
220 	struct imsg	 imsg;
221 	ssize_t		 n;
222 	int		 verbose;
223 
224 	if ((c = control_connbyfd(fd)) == NULL) {
225 		log_warnx("%s: fd %d: not found", __func__, fd);
226 		return;
227 	}
228 
229 	if (event & EV_READ) {
230 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
231 		    n == 0) {
232 			control_close(fd);
233 			return;
234 		}
235 	}
236 	if (event & EV_WRITE) {
237 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
238 			control_close(fd);
239 			return;
240 		}
241 	}
242 
243 	for (;;) {
244 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
245 			control_close(fd);
246 			return;
247 		}
248 		if (n == 0)
249 			break;
250 
251 		switch (imsg.hdr.type) {
252 		case IMSG_CTL_RELOAD:
253 			listener_imsg_compose_main(imsg.hdr.type, 0, NULL, 0);
254 			break;
255 		case IMSG_CTL_LOG_VERBOSE:
256 			if (IMSG_DATA_SIZE(imsg) != sizeof(verbose))
257 				break;
258 
259 			/* Forward to all other processes. */
260 			listener_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid,
261 			    imsg.data, IMSG_DATA_SIZE(imsg));
262 
263 			/* XXX: send to every client? */
264 
265 			memcpy(&verbose, imsg.data, sizeof(verbose));
266 			log_setverbose(verbose);
267 			break;
268 		default:
269 			log_debug("%s: error handling imsg %d", __func__,
270 			    imsg.hdr.type);
271 			break;
272 		}
273 		imsg_free(&imsg);
274 	}
275 
276 	imsg_event_add(&c->iev);
277 }
278 
279 int
280 control_imsg_relay(struct imsg *imsg)
281 {
282 	struct ctl_conn	*c;
283 
284 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
285 		return (0);
286 
287 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
288 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
289 }