1 /*	$OpenBSD: control.c,v 1.8 2021/03/02 04:10:07 jsg Exp $	*/
2 
3 /*
4  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
5  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include "config.h"
21 
22 #include <sys/stat.h>
23 #include <sys/socket.h>
24 #include <sys/un.h>
25 
26 #include <netinet/in.h>
27 #include <net/if.h>
28 
29 #include <errno.h>
30 #include <limits.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 #include "amused.h"
37 #include "log.h"
38 #include "control.h"
39 #include "playlist.h"
40 
41 #define	CONTROL_BACKLOG	5
42 
43 struct {
44 	struct event	ev;
45 	struct event	evt;
46 	int		fd;
47 	struct playlist	play;
48 	int		tx;
49 } control_state = {.fd = -1, .tx = -1};
50 
51 struct ctl_conn {
52 	TAILQ_ENTRY(ctl_conn)	entry;
53 	int			monitor; /* 1 if client is in monitor mode */
54 	struct imsgev		iev;
55 };
56 
57 TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
58 
59 struct ctl_conn	*control_connbyfd(int);
60 struct ctl_conn	*control_connbypid(pid_t);
61 void		 control_close(int);
62 
63 int
64 control_init(char *path)
65 {
66 	struct sockaddr_un	 sun;
67 	int			 fd;
68 	mode_t			 old_umask;
69 
70 	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
71 	    0)) == -1) {
72 		log_warn("%s: socket", __func__);
73 		return (-1);
74 	}
75 
76 	memset(&sun, 0, sizeof(sun));
77 	sun.sun_family = AF_UNIX;
78 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
79 
80 	if (unlink(path) == -1)
81 		if (errno != ENOENT) {
82 			log_warn("%s: unlink %s", __func__, path);
83 			close(fd);
84 			return (-1);
85 		}
86 
87 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
88 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
89 		log_warn("%s: bind: %s", __func__, path);
90 		close(fd);
91 		umask(old_umask);
92 		return (-1);
93 	}
94 	umask(old_umask);
95 
96 	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
97 		log_warn("%s: chmod", __func__);
98 		close(fd);
99 		(void)unlink(path);
100 		return (-1);
101 	}
102 
103 	return (fd);
104 }
105 
106 int
107 control_listen(int fd)
108 {
109 	if (control_state.fd != -1)
110 		fatalx("%s: received unexpected controlsock", __func__);
111 
112 	control_state.fd = fd;
113 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
114 		log_warn("%s: listen", __func__);
115 		return (-1);
116 	}
117 
118 	event_set(&control_state.ev, control_state.fd, EV_READ,
119 	    control_accept, NULL);
120 	event_add(&control_state.ev, NULL);
121 	evtimer_set(&control_state.evt, control_accept, NULL);
122 
123 	return (0);
124 }
125 
126 void
127 control_accept(int listenfd, short event, void *bula)
128 {
129 	int			 connfd;
130 	socklen_t		 len;
131 	struct sockaddr_un	 sun;
132 	struct ctl_conn		*c;
133 
134 	event_add(&control_state.ev, NULL);
135 	if ((event & EV_TIMEOUT))
136 		return;
137 
138 	len = sizeof(sun);
139 	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
140 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
141 		/*
142 		 * Pause accept if we are out of file descriptors, or
143 		 * libevent will haunt us here too.
144 		 */
145 		if (errno == ENFILE || errno == EMFILE) {
146 			struct timeval evtpause = { 1, 0 };
147 
148 			event_del(&control_state.ev);
149 			evtimer_add(&control_state.evt, &evtpause);
150 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
151 		    errno != ECONNABORTED)
152 			log_warn("%s: accept4", __func__);
153 		return;
154 	}
155 
156 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
157 		log_warn("%s: calloc", __func__);
158 		close(connfd);
159 		return;
160 	}
161 
162 	imsg_init(&c->iev.ibuf, connfd);
163 	c->iev.handler = control_dispatch_imsg;
164 	c->iev.events = EV_READ;
165 	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
166 	    c->iev.handler, &c->iev);
167 	event_add(&c->iev.ev, NULL);
168 
169 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
170 }
171 
172 struct ctl_conn *
173 control_connbyfd(int fd)
174 {
175 	struct ctl_conn	*c;
176 
177 	TAILQ_FOREACH(c, &ctl_conns, entry) {
178 		if (c->iev.ibuf.fd == fd)
179 			break;
180 	}
181 
182 	return (c);
183 }
184 
185 struct ctl_conn *
186 control_connbypid(pid_t pid)
187 {
188 	struct ctl_conn	*c;
189 
190 	TAILQ_FOREACH(c, &ctl_conns, entry) {
191 		if (c->iev.ibuf.pid == pid)
192 			break;
193 	}
194 
195 	return (c);
196 }
197 
198 void
199 control_close(int fd)
200 {
201 	struct ctl_conn	*c;
202 
203 	if ((c = control_connbyfd(fd)) == NULL) {
204 		log_warnx("%s: fd %d: not found", __func__, fd);
205 		return;
206 	}
207 
208 	/* abort the transaction if running by this user */
209 	if (control_state.tx != -1 && c->iev.ibuf.fd == control_state.tx) {
210 		playlist_free(&control_state.play);
211 		control_state.tx = -1;
212 	}
213 
214 	msgbuf_clear(&c->iev.ibuf.w);
215 	TAILQ_REMOVE(&ctl_conns, c, entry);
216 
217 	event_del(&c->iev.ev);
218 	close(c->iev.ibuf.fd);
219 
220 	/* Some file descriptors are available again. */
221 	if (evtimer_pending(&control_state.evt, NULL)) {
222 		evtimer_del(&control_state.evt);
223 		event_add(&control_state.ev, NULL);
224 	}
225 
226 	free(c);
227 }
228 
229 void
230 control_notify(int type)
231 {
232 	struct ctl_conn *c;
233 
234 	TAILQ_FOREACH(c, &ctl_conns, entry) {
235 		if (!c->monitor)
236 			continue;
237 
238 		imsg_compose_event(&c->iev, IMSG_CTL_MONITOR, 0, 0,
239 		    -1, &type, sizeof(type));
240 	}
241 }
242 
243 void
244 control_dispatch_imsg(int fd, short event, void *bula)
245 {
246 	struct ctl_conn		*c;
247 	struct imsg		 imsg;
248 	struct player_mode	 mode;
249 	struct player_seek	 seek;
250 	ssize_t		 	 n, off;
251 
252 	if ((c = control_connbyfd(fd)) == NULL) {
253 		log_warnx("%s: fd %d: not found", __func__, fd);
254 		return;
255 	}
256 
257 	if (event & EV_READ) {
258 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
259 		    n == 0) {
260 			control_close(fd);
261 			return;
262 		}
263 	}
264 	if (event & EV_WRITE) {
265 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
266 			control_close(fd);
267 			return;
268 		}
269 	}
270 
271 	for (;;) {
272 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
273 			control_close(fd);
274 			return;
275 		}
276 		if (n == 0)
277 			break;
278 
279 		switch (imsg.hdr.type) {
280 		case IMSG_CTL_PLAY:
281 			switch (play_state) {
282 			case STATE_STOPPED:
283 				main_playlist_resume();
284 				break;
285 			case STATE_PLAYING:
286 				/* do nothing */
287 				break;
288 			case STATE_PAUSED:
289 				play_state = STATE_PLAYING;
290 				main_send_player(IMSG_RESUME, -1, NULL ,0);
291 				break;
292 			}
293 			control_notify(imsg.hdr.type);
294 			break;
295 		case IMSG_CTL_TOGGLE_PLAY:
296 			switch (play_state) {
297 			case STATE_STOPPED:
298 				control_notify(IMSG_CTL_PLAY);
299 				main_playlist_resume();
300 				break;
301 			case STATE_PLAYING:
302 				control_notify(IMSG_CTL_PAUSE);
303 				play_state = STATE_PAUSED;
304 				main_send_player(IMSG_PAUSE, -1, NULL, 0);
305 				break;
306 			case STATE_PAUSED:
307 				control_notify(IMSG_CTL_PLAY);
308 				play_state = STATE_PLAYING;
309 				main_send_player(IMSG_RESUME, -1, NULL, 0);
310 				break;
311 			}
312 			break;
313 		case IMSG_CTL_PAUSE:
314 			if (play_state != STATE_PLAYING)
315 				break;
316 			play_state = STATE_PAUSED;
317 			main_send_player(IMSG_PAUSE, -1, NULL, 0);
318 			control_notify(imsg.hdr.type);
319 			break;
320 		case IMSG_CTL_STOP:
321 			if (play_state == STATE_STOPPED)
322 				break;
323 			play_state = STATE_STOPPED;
324 			main_send_player(IMSG_STOP, -1, NULL, 0);
325 			control_notify(imsg.hdr.type);
326 			break;
327 		case IMSG_CTL_FLUSH:
328 			playlist_truncate();
329 			control_notify(IMSG_CTL_COMMIT);
330 			break;
331 		case IMSG_CTL_SHOW:
332 			main_send_playlist(&c->iev);
333 			break;
334 		case IMSG_CTL_STATUS:
335 			main_send_status(&c->iev);
336 			break;
337 		case IMSG_CTL_NEXT:
338 			control_notify(imsg.hdr.type);
339 			main_send_player(IMSG_STOP, -1, NULL, 0);
340 			main_playlist_advance();
341 			break;
342 		case IMSG_CTL_PREV:
343 			control_notify(imsg.hdr.type);
344 			main_send_player(IMSG_STOP, -1, NULL, 0);
345 			main_playlist_previous();
346 			break;
347 		case IMSG_CTL_JUMP:
348 			main_playlist_jump(&c->iev, &imsg);
349 			break;
350 		case IMSG_CTL_MODE:
351 			if (IMSG_DATA_SIZE(imsg) != sizeof(mode)) {
352 				log_warnx("%s: got wrong size", __func__);
353 				break;
354 			}
355 			memcpy(&mode, imsg.data, sizeof(mode));
356 			if (mode.repeat_all != -1)
357 				repeat_all = mode.repeat_all;
358 			if (mode.repeat_one != -1)
359 				repeat_one = mode.repeat_one;
360 			if (mode.consume != -1)
361 				consume = mode.consume;
362 			control_notify(imsg.hdr.type);
363 			break;
364 		case IMSG_CTL_BEGIN:
365 			if (control_state.tx != -1) {
366 				main_senderr(&c->iev, "locked");
367 				break;
368 			}
369 			control_state.tx = c->iev.ibuf.fd;
370 			imsg_compose_event(&c->iev, IMSG_CTL_BEGIN, 0, 0, -1,
371 			    NULL, 0);
372 			break;
373 		case IMSG_CTL_ADD:
374 			if (control_state.tx != -1 &&
375 			    control_state.tx != c->iev.ibuf.fd) {
376 				main_senderr(&c->iev, "locked");
377 				break;
378 			}
379 			main_enqueue(control_state.tx != -1,
380 			   &control_state.play,&c->iev, &imsg);
381 			if (control_state.tx == -1)
382 				control_notify(imsg.hdr.type);
383 			break;
384 		case IMSG_CTL_COMMIT:
385 			if (control_state.tx != c->iev.ibuf.fd) {
386 				main_senderr(&c->iev, "locked");
387 				break;
388 			}
389 			if (IMSG_DATA_SIZE(imsg) != sizeof(off)) {
390 				main_senderr(&c->iev, "wrong size");
391 				break;
392 			}
393 			memcpy(&off, imsg.data, sizeof(off));
394 			playlist_swap(&control_state.play, off);
395 			memset(&control_state.play, 0,
396 			    sizeof(control_state.play));
397 			control_state.tx = -1;
398 			imsg_compose_event(&c->iev, IMSG_CTL_COMMIT, 0, 0, -1,
399 			    NULL, 0);
400 			control_notify(imsg.hdr.type);
401 			break;
402 		case IMSG_CTL_MONITOR:
403 			c->monitor = 1;
404 			break;
405 		case IMSG_CTL_SEEK:
406 			if (IMSG_DATA_SIZE(imsg) != sizeof(seek)) {
407 				main_senderr(&c->iev, "wrong size");
408 				break;
409 			}
410 			memcpy(&seek, imsg.data, sizeof(seek));
411 			main_seek(&seek);
412 			break;
413 		default:
414 			log_debug("%s: error handling imsg %d", __func__,
415 			    imsg.hdr.type);
416 			break;
417 		}
418 		imsg_free(&imsg);
419 	}
420 
421 	imsg_event_add(&c->iev);
422 }
423 
424 int
425 control_imsg_relay(struct imsg *imsg)
426 {
427 	struct ctl_conn	*c;
428 
429 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
430 		return (0);
431 
432 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
433 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
434 }