1 /*	$OpenBSD: control.c,v 1.8 2021/03/02 04:10:07 jsg Exp $	*/
2 
3 /*
4  * Copyright (c) 2022, 2023 Omar Polo <op@omarpolo.com>
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 <fcntl.h>
31 #include <limits.h>
32 #include <poll.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37 
38 #include "amused.h"
39 #include "ev.h"
40 #include "log.h"
41 #include "control.h"
42 #include "playlist.h"
43 
44 #define	CONTROL_BACKLOG	5
45 
46 struct {
47 	int		fd;
48 	struct playlist	play;
49 	int		tx;
50 } control_state = {.fd = -1, .tx = -1};
51 
52 struct ctl_conn {
53 	TAILQ_ENTRY(ctl_conn)	entry;
54 	int			monitor; /* 1 if client is in monitor mode */
55 	struct imsgev		iev;
56 };
57 
58 TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
59 
60 struct ctl_conn	*control_connbyfd(int);
61 struct ctl_conn	*control_connbypid(pid_t);
62 void		 control_close(int);
63 
64 int
65 control_init(char *path)
66 {
67 	struct sockaddr_un	 sun;
68 	int			 fd, flags;
69 	mode_t			 old_umask;
70 
71 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
72 		log_warn("%s: socket", __func__);
73 		return (-1);
74 	}
75 
76 	if ((flags = fcntl(fd, F_GETFL)) == -1 ||
77 	    fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
78 		fatal("fcntl(O_NONBLOCK)");
79 
80 	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
81 		fatal("fcntl(CLOEXEC)");
82 
83 	memset(&sun, 0, sizeof(sun));
84 	sun.sun_family = AF_UNIX;
85 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
86 
87 	if (unlink(path) == -1)
88 		if (errno != ENOENT) {
89 			log_warn("%s: unlink %s", __func__, path);
90 			close(fd);
91 			return (-1);
92 		}
93 
94 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
95 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
96 		log_warn("%s: bind: %s", __func__, path);
97 		close(fd);
98 		umask(old_umask);
99 		return (-1);
100 	}
101 	umask(old_umask);
102 
103 	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
104 		log_warn("%s: chmod", __func__);
105 		close(fd);
106 		(void)unlink(path);
107 		return (-1);
108 	}
109 
110 	return (fd);
111 }
112 
113 static void
114 enable_accept(int fd, int ev, void *bula)
115 {
116 	ev_add(control_state.fd, POLLIN, control_accept, NULL);
117 }
118 
119 int
120 control_listen(int fd)
121 {
122 	if (control_state.fd != -1)
123 		fatalx("%s: received unexpected controlsock", __func__);
124 
125 	control_state.fd = fd;
126 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
127 		log_warn("%s: listen", __func__);
128 		return (-1);
129 	}
130 
131 	enable_accept(-1, 0, NULL);
132 	return (0);
133 }
134 
135 void
136 control_accept(int listenfd, int event, void *bula)
137 {
138 	int			 connfd, flags;
139 	socklen_t		 len;
140 	struct sockaddr_un	 sun;
141 	struct ctl_conn		*c;
142 
143 	len = sizeof(sun);
144 	if ((connfd = accept(listenfd, (struct sockaddr *)&sun, &len)) == -1) {
145 		/*
146 		 * Pause accept if we are out of file descriptors, or
147 		 * libevent will haunt us here too.
148 		 */
149 		if (errno == ENFILE || errno == EMFILE) {
150 			struct timeval evtpause = { 1, 0 };
151 
152 			ev_del(control_state.fd);
153 			ev_timer(&evtpause, enable_accept, NULL);
154 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
155 		    errno != ECONNABORTED)
156 			log_warn("%s: accept4", __func__);
157 		return;
158 	}
159 
160 	if ((flags = fcntl(connfd, F_GETFL)) == -1 ||
161 	    fcntl(connfd, F_SETFL, flags | O_NONBLOCK) == -1)
162 		fatal("fcntl(O_NONBLOCK)");
163 	if (fcntl(connfd, F_SETFD, FD_CLOEXEC) == -1)
164 		fatal("fcntl(CLOEXEC)");
165 
166 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
167 		log_warn("%s: calloc", __func__);
168 		close(connfd);
169 		return;
170 	}
171 
172 	imsg_init(&c->iev.ibuf, connfd);
173 	c->iev.handler = control_dispatch_imsg;
174 	c->iev.events = POLLIN;
175 	ev_add(c->iev.ibuf.fd, c->iev.events, c->iev.handler, &c->iev);
176 
177 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
178 }
179 
180 struct ctl_conn *
181 control_connbyfd(int fd)
182 {
183 	struct ctl_conn	*c;
184 
185 	TAILQ_FOREACH(c, &ctl_conns, entry) {
186 		if (c->iev.ibuf.fd == fd)
187 			break;
188 	}
189 
190 	return (c);
191 }
192 
193 struct ctl_conn *
194 control_connbypid(pid_t pid)
195 {
196 	struct ctl_conn	*c;
197 
198 	TAILQ_FOREACH(c, &ctl_conns, entry) {
199 		if (c->iev.ibuf.pid == pid)
200 			break;
201 	}
202 
203 	return (c);
204 }
205 
206 void
207 control_close(int fd)
208 {
209 	struct ctl_conn	*c;
210 
211 	if ((c = control_connbyfd(fd)) == NULL) {
212 		log_warnx("%s: fd %d: not found", __func__, fd);
213 		return;
214 	}
215 
216 	/* abort the transaction if running by this user */
217 	if (control_state.tx != -1 && c->iev.ibuf.fd == control_state.tx) {
218 		playlist_free(&control_state.play);
219 		control_state.tx = -1;
220 	}
221 
222 	msgbuf_clear(&c->iev.ibuf.w);
223 	TAILQ_REMOVE(&ctl_conns, c, entry);
224 
225 	ev_del(c->iev.ibuf.fd);
226 	close(c->iev.ibuf.fd);
227 
228 	/* Some file descriptors are available again. */
229 	if (ev_timer_pending()) {
230 		ev_timer(NULL, NULL, NULL);
231 		ev_add(control_state.fd, POLLIN, control_accept, NULL);
232 	}
233 
234 	free(c);
235 }
236 
237 void
238 control_notify(int type)
239 {
240 	struct ctl_conn *c;
241 	struct player_event ev;
242 
243 	memset(&ev, 0, sizeof(ev));
244 	ev.event = type;
245 	ev.position = current_position;
246 	ev.duration = current_duration;
247 	ev.mode.repeat_one = repeat_one;
248 	ev.mode.repeat_all = repeat_all;
249 	ev.mode.consume = consume;
250 
251 	TAILQ_FOREACH(c, &ctl_conns, entry) {
252 		if (!c->monitor)
253 			continue;
254 
255 		imsg_compose_event(&c->iev, IMSG_CTL_MONITOR, 0, 0,
256 		    -1, &ev, sizeof(ev));
257 	}
258 }
259 
260 static int
261 new_mode(int val, int newval)
262 {
263 	if (newval == MODE_UNDEF)
264 		return val;
265 	if (newval == MODE_TOGGLE)
266 		return !val;
267 	return !!newval;
268 }
269 
270 void
271 control_dispatch_imsg(int fd, int event, void *bula)
272 {
273 	struct ctl_conn		*c;
274 	struct imsg		 imsg;
275 	struct player_mode	 mode;
276 	struct player_seek	 seek;
277 	ssize_t		 	 n, off;
278 
279 	if ((c = control_connbyfd(fd)) == NULL) {
280 		log_warnx("%s: fd %d: not found", __func__, fd);
281 		return;
282 	}
283 
284 	if (event & POLLIN) {
285 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
286 		    n == 0) {
287 			control_close(fd);
288 			return;
289 		}
290 	}
291 	if (event & POLLOUT) {
292 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
293 			control_close(fd);
294 			return;
295 		}
296 	}
297 
298 	for (;;) {
299 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
300 			control_close(fd);
301 			return;
302 		}
303 		if (n == 0)
304 			break;
305 
306 		switch (imsg.hdr.type) {
307 		case IMSG_CTL_PLAY:
308 			switch (play_state) {
309 			case STATE_STOPPED:
310 				main_playlist_resume();
311 				break;
312 			case STATE_PLAYING:
313 				/* do nothing */
314 				break;
315 			case STATE_PAUSED:
316 				play_state = STATE_PLAYING;
317 				main_send_player(IMSG_RESUME, -1, NULL ,0);
318 				break;
319 			}
320 			control_notify(imsg.hdr.type);
321 			break;
322 		case IMSG_CTL_TOGGLE_PLAY:
323 			switch (play_state) {
324 			case STATE_STOPPED:
325 				control_notify(IMSG_CTL_PLAY);
326 				main_playlist_resume();
327 				break;
328 			case STATE_PLAYING:
329 				control_notify(IMSG_CTL_PAUSE);
330 				play_state = STATE_PAUSED;
331 				main_send_player(IMSG_PAUSE, -1, NULL, 0);
332 				break;
333 			case STATE_PAUSED:
334 				control_notify(IMSG_CTL_PLAY);
335 				play_state = STATE_PLAYING;
336 				main_send_player(IMSG_RESUME, -1, NULL, 0);
337 				break;
338 			}
339 			break;
340 		case IMSG_CTL_PAUSE:
341 			if (play_state != STATE_PLAYING)
342 				break;
343 			play_state = STATE_PAUSED;
344 			main_send_player(IMSG_PAUSE, -1, NULL, 0);
345 			control_notify(imsg.hdr.type);
346 			break;
347 		case IMSG_CTL_STOP:
348 			if (play_state == STATE_STOPPED)
349 				break;
350 			play_state = STATE_STOPPED;
351 			main_send_player(IMSG_STOP, -1, NULL, 0);
352 			control_notify(imsg.hdr.type);
353 			break;
354 		case IMSG_CTL_FLUSH:
355 			playlist_truncate();
356 			control_notify(IMSG_CTL_COMMIT);
357 			break;
358 		case IMSG_CTL_SHOW:
359 			main_send_playlist(&c->iev);
360 			break;
361 		case IMSG_CTL_STATUS:
362 			main_send_status(&c->iev);
363 			break;
364 		case IMSG_CTL_NEXT:
365 			control_notify(imsg.hdr.type);
366 			main_send_player(IMSG_STOP, -1, NULL, 0);
367 			main_playlist_advance();
368 			break;
369 		case IMSG_CTL_PREV:
370 			control_notify(imsg.hdr.type);
371 			main_send_player(IMSG_STOP, -1, NULL, 0);
372 			main_playlist_previous();
373 			break;
374 		case IMSG_CTL_JUMP:
375 			main_playlist_jump(&c->iev, &imsg);
376 			break;
377 		case IMSG_CTL_MODE:
378 			if (IMSG_DATA_SIZE(imsg) != sizeof(mode)) {
379 				log_warnx("%s: got wrong size", __func__);
380 				break;
381 			}
382 			memcpy(&mode, imsg.data, sizeof(mode));
383 			consume = new_mode(consume, mode.consume);
384 			repeat_all = new_mode(repeat_all, mode.repeat_all);
385 			repeat_one = new_mode(repeat_one, mode.repeat_one);
386 			control_notify(imsg.hdr.type);
387 			break;
388 		case IMSG_CTL_BEGIN:
389 			if (control_state.tx != -1) {
390 				main_senderr(&c->iev, "locked");
391 				break;
392 			}
393 			control_state.tx = c->iev.ibuf.fd;
394 			imsg_compose_event(&c->iev, IMSG_CTL_BEGIN, 0, 0, -1,
395 			    NULL, 0);
396 			break;
397 		case IMSG_CTL_ADD:
398 			if (control_state.tx != -1 &&
399 			    control_state.tx != c->iev.ibuf.fd) {
400 				main_senderr(&c->iev, "locked");
401 				break;
402 			}
403 			main_enqueue(control_state.tx != -1,
404 			   &control_state.play,&c->iev, &imsg);
405 			if (control_state.tx == -1)
406 				control_notify(imsg.hdr.type);
407 			break;
408 		case IMSG_CTL_COMMIT:
409 			if (control_state.tx != c->iev.ibuf.fd) {
410 				main_senderr(&c->iev, "locked");
411 				break;
412 			}
413 			if (IMSG_DATA_SIZE(imsg) != sizeof(off)) {
414 				main_senderr(&c->iev, "wrong size");
415 				break;
416 			}
417 			memcpy(&off, imsg.data, sizeof(off));
418 			playlist_swap(&control_state.play, off);
419 			memset(&control_state.play, 0,
420 			    sizeof(control_state.play));
421 			control_state.tx = -1;
422 			imsg_compose_event(&c->iev, IMSG_CTL_COMMIT, 0, 0, -1,
423 			    NULL, 0);
424 			control_notify(imsg.hdr.type);
425 			break;
426 		case IMSG_CTL_MONITOR:
427 			c->monitor = 1;
428 			break;
429 		case IMSG_CTL_SEEK:
430 			if (IMSG_DATA_SIZE(imsg) != sizeof(seek)) {
431 				main_senderr(&c->iev, "wrong size");
432 				break;
433 			}
434 			memcpy(&seek, imsg.data, sizeof(seek));
435 			main_seek(&seek);
436 			break;
437 		default:
438 			log_debug("%s: error handling imsg %d", __func__,
439 			    imsg.hdr.type);
440 			break;
441 		}
442 		imsg_free(&imsg);
443 	}
444 
445 	imsg_event_add(&c->iev);
446 }
447 
448 int
449 control_imsg_relay(struct imsg *imsg)
450 {
451 	struct ctl_conn	*c;
452 
453 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
454 		return (0);
455 
456 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
457 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
458 }