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 <limits.h>
31 #include <poll.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <unistd.h>
36 
37 #include "amused.h"
38 #include "ev.h"
39 #include "log.h"
40 #include "control.h"
41 #include "playlist.h"
42 
43 #define	CONTROL_BACKLOG	5
44 
45 struct {
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 static void
107 enable_accept(int fd, int ev, void *bula)
108 {
109 	ev_add(control_state.fd, POLLIN, control_accept, NULL);
110 }
111 
112 int
113 control_listen(int fd)
114 {
115 	if (control_state.fd != -1)
116 		fatalx("%s: received unexpected controlsock", __func__);
117 
118 	control_state.fd = fd;
119 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
120 		log_warn("%s: listen", __func__);
121 		return (-1);
122 	}
123 
124 	enable_accept(-1, 0, NULL);
125 	return (0);
126 }
127 
128 void
129 control_accept(int listenfd, int event, void *bula)
130 {
131 	int			 connfd;
132 	socklen_t		 len;
133 	struct sockaddr_un	 sun;
134 	struct ctl_conn		*c;
135 
136 	len = sizeof(sun);
137 	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
138 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
139 		/*
140 		 * Pause accept if we are out of file descriptors, or
141 		 * libevent will haunt us here too.
142 		 */
143 		if (errno == ENFILE || errno == EMFILE) {
144 			struct timeval evtpause = { 1, 0 };
145 
146 			ev_del(control_state.fd);
147 			ev_timer(&evtpause, enable_accept, NULL);
148 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
149 		    errno != ECONNABORTED)
150 			log_warn("%s: accept4", __func__);
151 		return;
152 	}
153 
154 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
155 		log_warn("%s: calloc", __func__);
156 		close(connfd);
157 		return;
158 	}
159 
160 	imsg_init(&c->iev.ibuf, connfd);
161 	c->iev.handler = control_dispatch_imsg;
162 	c->iev.events = POLLIN;
163 	ev_add(c->iev.ibuf.fd, c->iev.events, c->iev.handler, &c->iev);
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 	/* abort the transaction if running by this user */
205 	if (control_state.tx != -1 && c->iev.ibuf.fd == control_state.tx) {
206 		playlist_free(&control_state.play);
207 		control_state.tx = -1;
208 	}
209 
210 	msgbuf_clear(&c->iev.ibuf.w);
211 	TAILQ_REMOVE(&ctl_conns, c, entry);
212 
213 	ev_del(c->iev.ibuf.fd);
214 	close(c->iev.ibuf.fd);
215 
216 	/* Some file descriptors are available again. */
217 	if (ev_timer_pending()) {
218 		ev_timer(NULL, NULL, NULL);
219 		ev_add(control_state.fd, POLLIN, control_accept, NULL);
220 	}
221 
222 	free(c);
223 }
224 
225 void
226 control_notify(int type)
227 {
228 	struct ctl_conn *c;
229 	struct player_event ev;
230 
231 	memset(&ev, 0, sizeof(ev));
232 	ev.event = type;
233 	ev.position = current_position;
234 	ev.duration = current_duration;
235 	ev.mode.repeat_one = repeat_one;
236 	ev.mode.repeat_all = repeat_all;
237 	ev.mode.consume = consume;
238 
239 	TAILQ_FOREACH(c, &ctl_conns, entry) {
240 		if (!c->monitor)
241 			continue;
242 
243 		imsg_compose_event(&c->iev, IMSG_CTL_MONITOR, 0, 0,
244 		    -1, &ev, sizeof(ev));
245 	}
246 }
247 
248 static int
249 new_mode(int val, int newval)
250 {
251 	if (newval == MODE_UNDEF)
252 		return val;
253 	if (newval == MODE_TOGGLE)
254 		return !val;
255 	return !!newval;
256 }
257 
258 void
259 control_dispatch_imsg(int fd, int event, void *bula)
260 {
261 	struct ctl_conn		*c;
262 	struct imsg		 imsg;
263 	struct player_mode	 mode;
264 	struct player_seek	 seek;
265 	ssize_t		 	 n, off;
266 
267 	if ((c = control_connbyfd(fd)) == NULL) {
268 		log_warnx("%s: fd %d: not found", __func__, fd);
269 		return;
270 	}
271 
272 	if (event & POLLIN) {
273 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
274 		    n == 0) {
275 			control_close(fd);
276 			return;
277 		}
278 	}
279 	if (event & POLLOUT) {
280 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
281 			control_close(fd);
282 			return;
283 		}
284 	}
285 
286 	for (;;) {
287 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
288 			control_close(fd);
289 			return;
290 		}
291 		if (n == 0)
292 			break;
293 
294 		switch (imsg.hdr.type) {
295 		case IMSG_CTL_PLAY:
296 			switch (play_state) {
297 			case STATE_STOPPED:
298 				main_playlist_resume();
299 				break;
300 			case STATE_PLAYING:
301 				/* do nothing */
302 				break;
303 			case STATE_PAUSED:
304 				play_state = STATE_PLAYING;
305 				main_send_player(IMSG_RESUME, -1, NULL ,0);
306 				break;
307 			}
308 			control_notify(imsg.hdr.type);
309 			break;
310 		case IMSG_CTL_TOGGLE_PLAY:
311 			switch (play_state) {
312 			case STATE_STOPPED:
313 				control_notify(IMSG_CTL_PLAY);
314 				main_playlist_resume();
315 				break;
316 			case STATE_PLAYING:
317 				control_notify(IMSG_CTL_PAUSE);
318 				play_state = STATE_PAUSED;
319 				main_send_player(IMSG_PAUSE, -1, NULL, 0);
320 				break;
321 			case STATE_PAUSED:
322 				control_notify(IMSG_CTL_PLAY);
323 				play_state = STATE_PLAYING;
324 				main_send_player(IMSG_RESUME, -1, NULL, 0);
325 				break;
326 			}
327 			break;
328 		case IMSG_CTL_PAUSE:
329 			if (play_state != STATE_PLAYING)
330 				break;
331 			play_state = STATE_PAUSED;
332 			main_send_player(IMSG_PAUSE, -1, NULL, 0);
333 			control_notify(imsg.hdr.type);
334 			break;
335 		case IMSG_CTL_STOP:
336 			if (play_state == STATE_STOPPED)
337 				break;
338 			play_state = STATE_STOPPED;
339 			main_send_player(IMSG_STOP, -1, NULL, 0);
340 			control_notify(imsg.hdr.type);
341 			break;
342 		case IMSG_CTL_FLUSH:
343 			playlist_truncate();
344 			control_notify(IMSG_CTL_COMMIT);
345 			break;
346 		case IMSG_CTL_SHOW:
347 			main_send_playlist(&c->iev);
348 			break;
349 		case IMSG_CTL_STATUS:
350 			main_send_status(&c->iev);
351 			break;
352 		case IMSG_CTL_NEXT:
353 			control_notify(imsg.hdr.type);
354 			main_send_player(IMSG_STOP, -1, NULL, 0);
355 			main_playlist_advance();
356 			break;
357 		case IMSG_CTL_PREV:
358 			control_notify(imsg.hdr.type);
359 			main_send_player(IMSG_STOP, -1, NULL, 0);
360 			main_playlist_previous();
361 			break;
362 		case IMSG_CTL_JUMP:
363 			main_playlist_jump(&c->iev, &imsg);
364 			break;
365 		case IMSG_CTL_MODE:
366 			if (IMSG_DATA_SIZE(imsg) != sizeof(mode)) {
367 				log_warnx("%s: got wrong size", __func__);
368 				break;
369 			}
370 			memcpy(&mode, imsg.data, sizeof(mode));
371 			consume = new_mode(consume, mode.consume);
372 			repeat_all = new_mode(repeat_all, mode.repeat_all);
373 			repeat_one = new_mode(repeat_one, mode.repeat_one);
374 			control_notify(imsg.hdr.type);
375 			break;
376 		case IMSG_CTL_BEGIN:
377 			if (control_state.tx != -1) {
378 				main_senderr(&c->iev, "locked");
379 				break;
380 			}
381 			control_state.tx = c->iev.ibuf.fd;
382 			imsg_compose_event(&c->iev, IMSG_CTL_BEGIN, 0, 0, -1,
383 			    NULL, 0);
384 			break;
385 		case IMSG_CTL_ADD:
386 			if (control_state.tx != -1 &&
387 			    control_state.tx != c->iev.ibuf.fd) {
388 				main_senderr(&c->iev, "locked");
389 				break;
390 			}
391 			main_enqueue(control_state.tx != -1,
392 			   &control_state.play,&c->iev, &imsg);
393 			if (control_state.tx == -1)
394 				control_notify(imsg.hdr.type);
395 			break;
396 		case IMSG_CTL_COMMIT:
397 			if (control_state.tx != c->iev.ibuf.fd) {
398 				main_senderr(&c->iev, "locked");
399 				break;
400 			}
401 			if (IMSG_DATA_SIZE(imsg) != sizeof(off)) {
402 				main_senderr(&c->iev, "wrong size");
403 				break;
404 			}
405 			memcpy(&off, imsg.data, sizeof(off));
406 			playlist_swap(&control_state.play, off);
407 			memset(&control_state.play, 0,
408 			    sizeof(control_state.play));
409 			control_state.tx = -1;
410 			imsg_compose_event(&c->iev, IMSG_CTL_COMMIT, 0, 0, -1,
411 			    NULL, 0);
412 			control_notify(imsg.hdr.type);
413 			break;
414 		case IMSG_CTL_MONITOR:
415 			c->monitor = 1;
416 			break;
417 		case IMSG_CTL_SEEK:
418 			if (IMSG_DATA_SIZE(imsg) != sizeof(seek)) {
419 				main_senderr(&c->iev, "wrong size");
420 				break;
421 			}
422 			memcpy(&seek, imsg.data, sizeof(seek));
423 			main_seek(&seek);
424 			break;
425 		default:
426 			log_debug("%s: error handling imsg %d", __func__,
427 			    imsg.hdr.type);
428 			break;
429 		}
430 		imsg_free(&imsg);
431 	}
432 
433 	imsg_event_add(&c->iev);
434 }
435 
436 int
437 control_imsg_relay(struct imsg *imsg)
438 {
439 	struct ctl_conn	*c;
440 
441 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
442 		return (0);
443 
444 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
445 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
446 }