1 /*	$OpenBSD: control.c,v 1.8 2021/03/02 04:10:07 jsg Exp $	*/
2 
3 /*
4  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/stat.h>
21 #include <sys/socket.h>
22 #include <sys/uio.h>
23 #include <sys/un.h>
24 
25 #include <netinet/in.h>
26 #include <net/if.h>
27 
28 #include <errno.h>
29 #include <event.h>
30 #include <imsg.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "amused.h"
36 #include "log.h"
37 #include "control.h"
38 #include "playlist.h"
39 
40 #define	CONTROL_BACKLOG	5
41 
42 struct {
43 	struct event	ev;
44 	struct event	evt;
45 	int		fd;
46 } control_state = {.fd = -1};
47 
48 struct ctl_conn {
49 	TAILQ_ENTRY(ctl_conn)	entry;
50 	struct imsgev		iev;
51 };
52 
53 TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
54 
55 struct ctl_conn	*control_connbyfd(int);
56 struct ctl_conn	*control_connbypid(pid_t);
57 void		 control_close(int);
58 
59 int
60 control_init(char *path)
61 {
62 	struct sockaddr_un	 sun;
63 	int			 fd;
64 	mode_t			 old_umask;
65 
66 	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
67 	    0)) == -1) {
68 		log_warn("%s: socket", __func__);
69 		return (-1);
70 	}
71 
72 	memset(&sun, 0, sizeof(sun));
73 	sun.sun_family = AF_UNIX;
74 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
75 
76 	if (unlink(path) == -1)
77 		if (errno != ENOENT) {
78 			log_warn("%s: unlink %s", __func__, path);
79 			close(fd);
80 			return (-1);
81 		}
82 
83 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
84 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
85 		log_warn("%s: bind: %s", __func__, path);
86 		close(fd);
87 		umask(old_umask);
88 		return (-1);
89 	}
90 	umask(old_umask);
91 
92 	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
93 		log_warn("%s: chmod", __func__);
94 		close(fd);
95 		(void)unlink(path);
96 		return (-1);
97 	}
98 
99 	return (fd);
100 }
101 
102 int
103 control_listen(int fd)
104 {
105 	if (control_state.fd != -1)
106 		fatalx("%s: received unexpected controlsock", __func__);
107 
108 	control_state.fd = fd;
109 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
110 		log_warn("%s: listen", __func__);
111 		return (-1);
112 	}
113 
114 	event_set(&control_state.ev, control_state.fd, EV_READ,
115 	    control_accept, NULL);
116 	event_add(&control_state.ev, NULL);
117 	evtimer_set(&control_state.evt, control_accept, NULL);
118 
119 	return (0);
120 }
121 
122 void
123 control_accept(int listenfd, short event, void *bula)
124 {
125 	int			 connfd;
126 	socklen_t		 len;
127 	struct sockaddr_un	 sun;
128 	struct ctl_conn		*c;
129 
130 	event_add(&control_state.ev, NULL);
131 	if ((event & EV_TIMEOUT))
132 		return;
133 
134 	len = sizeof(sun);
135 	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
136 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
137 		/*
138 		 * Pause accept if we are out of file descriptors, or
139 		 * libevent will haunt us here too.
140 		 */
141 		if (errno == ENFILE || errno == EMFILE) {
142 			struct timeval evtpause = { 1, 0 };
143 
144 			event_del(&control_state.ev);
145 			evtimer_add(&control_state.evt, &evtpause);
146 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
147 		    errno != ECONNABORTED)
148 			log_warn("%s: accept4", __func__);
149 		return;
150 	}
151 
152 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
153 		log_warn("%s: calloc", __func__);
154 		close(connfd);
155 		return;
156 	}
157 
158 	imsg_init(&c->iev.ibuf, connfd);
159 	c->iev.handler = control_dispatch_imsg;
160 	c->iev.events = EV_READ;
161 	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
162 	    c->iev.handler, &c->iev);
163 	event_add(&c->iev.ev, NULL);
164 
165 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
166 }
167 
168 struct ctl_conn *
169 control_connbyfd(int fd)
170 {
171 	struct ctl_conn	*c;
172 
173 	TAILQ_FOREACH(c, &ctl_conns, entry) {
174 		if (c->iev.ibuf.fd == fd)
175 			break;
176 	}
177 
178 	return (c);
179 }
180 
181 struct ctl_conn *
182 control_connbypid(pid_t pid)
183 {
184 	struct ctl_conn	*c;
185 
186 	TAILQ_FOREACH(c, &ctl_conns, entry) {
187 		if (c->iev.ibuf.pid == pid)
188 			break;
189 	}
190 
191 	return (c);
192 }
193 
194 void
195 control_close(int fd)
196 {
197 	struct ctl_conn	*c;
198 
199 	if ((c = control_connbyfd(fd)) == NULL) {
200 		log_warnx("%s: fd %d: not found", __func__, fd);
201 		return;
202 	}
203 
204 	msgbuf_clear(&c->iev.ibuf.w);
205 	TAILQ_REMOVE(&ctl_conns, c, entry);
206 
207 	event_del(&c->iev.ev);
208 	close(c->iev.ibuf.fd);
209 
210 	/* Some file descriptors are available again. */
211 	if (evtimer_pending(&control_state.evt, NULL)) {
212 		evtimer_del(&control_state.evt);
213 		event_add(&control_state.ev, NULL);
214 	}
215 
216 	free(c);
217 }
218 
219 void
220 control_dispatch_imsg(int fd, short event, void *bula)
221 {
222 	struct ctl_conn	*c;
223 	struct imsg	 imsg;
224 	ssize_t		 n;
225 
226 	if ((c = control_connbyfd(fd)) == NULL) {
227 		log_warnx("%s: fd %d: not found", __func__, fd);
228 		return;
229 	}
230 
231 	if (event & EV_READ) {
232 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
233 		    n == 0) {
234 			control_close(fd);
235 			return;
236 		}
237 	}
238 	if (event & EV_WRITE) {
239 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
240 			control_close(fd);
241 			return;
242 		}
243 	}
244 
245 	for (;;) {
246 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
247 			control_close(fd);
248 			return;
249 		}
250 		if (n == 0)
251 			break;
252 
253 		switch (imsg.hdr.type) {
254 		case IMSG_CTL_PLAY:
255 			switch (play_state) {
256 			case STATE_STOPPED:
257 				main_playlist_advance();
258 				break;
259 			case STATE_PLAYING:
260 				/* do nothing */
261 				break;
262 			case STATE_PAUSED:
263 				play_state = STATE_PLAYING;
264 				main_send_player(IMSG_RESUME, -1, NULL, 0);
265 				break;
266 			}
267 			break;
268 		case IMSG_CTL_TOGGLE_PLAY:
269 			switch (play_state) {
270 			case STATE_STOPPED:
271 				main_playlist_advance();
272 				break;
273 			case STATE_PLAYING:
274 				main_send_player(IMSG_PAUSE, -1, NULL, 0);
275 				break;
276 			case STATE_PAUSED:
277 				main_send_player(IMSG_RESUME, -1, NULL, 0);
278 				break;
279 			}
280 			break;
281 		case IMSG_CTL_PAUSE:
282 			if (play_state != STATE_PLAYING)
283 				break;
284 			play_state = STATE_PAUSED;
285 			main_send_player(IMSG_PAUSE, -1, NULL, 0);
286 			break;
287 		case IMSG_CTL_STOP:
288 			if (play_state == STATE_STOPPED)
289 				break;
290 			main_send_player(IMSG_STOP, -1, NULL, 0);
291 			break;
292 		case IMSG_CTL_RESTART:
293 			main_send_player(IMSG_STOP, -1, NULL, 0);
294 			main_restart_track();
295 			break;
296 		case IMSG_CTL_ADD:
297 			main_enqueue(&c->iev, &imsg);
298 			break;
299 		case IMSG_CTL_FLUSH:
300 			playlist_truncate();
301 			break;
302 		case IMSG_CTL_SHOW:
303 			main_send_playlist(&c->iev);
304 			break;
305 		default:
306 			log_debug("%s: error handling imsg %d", __func__,
307 			    imsg.hdr.type);
308 			break;
309 		}
310 		imsg_free(&imsg);
311 	}
312 
313 	imsg_event_add(&c->iev);
314 }
315 
316 int
317 control_imsg_relay(struct imsg *imsg)
318 {
319 	struct ctl_conn	*c;
320 
321 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
322 		return (0);
323 
324 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
325 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
326 }