xref: /freebsd/lib/libmixer/mixer.c (revision 43a5ec4eb41567cc92586503212743d89686d78f) 
1 /*-
2  * Copyright (c) 2021 Christos Margiolis <christos@FreeBSD.org>
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a copy
5  * of this software and associated documentation files (the "Software"), to deal
6  * in the Software without restriction, including without limitation the rights
7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8  * copies of the Software, and to permit persons to whom the Software is
9  * furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20  * THE SOFTWARE.
21  *
22  * $FreeBSD$
23  */
24 
25 #include <sys/types.h>
26 #include <sys/ioctl.h>
27 #include <sys/sysctl.h>
28 
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 #include "mixer.h"
37 
38 #define	BASEPATH "/dev/mixer"
39 
40 static int _mixer_readvol(struct mixer *, struct mix_dev *);
41 
42 /*
43  * Fetch volume from the device.
44  */
45 static int
46 _mixer_readvol(struct mixer *m, struct mix_dev *dev)
47 {
48 	int v;
49 
50 	if (ioctl(m->fd, MIXER_READ(dev->devno), &v) < 0)
51 		return (-1);
52 	dev->vol.left = MIX_VOLNORM(v & 0x00ff);
53 	dev->vol.right = MIX_VOLNORM((v >> 8) & 0x00ff);
54 
55 	return (0);
56 }
57 
58 /*
59  * Open a mixer device in `/dev/mixerN`, where N is the number of the mixer.
60  * Each device maps to an actual pcm audio card, so `/dev/mixer0` is the
61  * mixer for pcm0, and so on.
62  *
63  * @param name		path to mixer device. NULL or "/dev/mixer" for the
64  *			the default mixer (i.e `hw.snd.default_unit`).
65  */
66 struct mixer *
67 mixer_open(const char *name)
68 {
69 	struct mixer *m = NULL;
70 	struct mix_dev *dp;
71 	const char *names[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_NAMES;
72 	int i;
73 
74 	if ((m = calloc(1, sizeof(struct mixer))) == NULL)
75 		goto fail;
76 
77 	if (name != NULL) {
78 		/* `name` does not start with "/dev/mixer". */
79 		if (strncmp(name, BASEPATH, strlen(BASEPATH)) != 0) {
80 			m->unit = -1;
81 		} else {
82 			/* `name` is "/dev/mixer" so, we'll use the default unit. */
83 			if (strncmp(name, BASEPATH, strlen(name)) == 0)
84 				goto dunit;
85 			m->unit = strtol(name + strlen(BASEPATH), NULL, 10);
86 		}
87 		(void)strlcpy(m->name, name, sizeof(m->name));
88 	} else {
89 dunit:
90 		if ((m->unit = mixer_get_dunit()) < 0)
91 			goto fail;
92 		(void)snprintf(m->name, sizeof(m->name), "/dev/mixer%d", m->unit);
93 	}
94 
95 	if ((m->fd = open(m->name, O_RDWR)) < 0)
96 		goto fail;
97 
98 	m->devmask = m->recmask = m->recsrc = 0;
99 	m->f_default = m->unit == mixer_get_dunit();
100 	m->mode = mixer_get_mode(m->unit);
101 	/* The unit number _must_ be set before the ioctl. */
102 	m->mi.dev = m->unit;
103 	m->ci.card = m->unit;
104 	if (ioctl(m->fd, SNDCTL_MIXERINFO, &m->mi) < 0) {
105 		memset(&m->mi, 0, sizeof(m->mi));
106 		strlcpy(m->mi.name, m->name, sizeof(m->mi.name));
107 	}
108 	if (ioctl(m->fd, SNDCTL_CARDINFO, &m->ci) < 0)
109 		memset(&m->ci, 0, sizeof(m->ci));
110 	if (ioctl(m->fd, SOUND_MIXER_READ_DEVMASK, &m->devmask) < 0 ||
111 	    ioctl(m->fd, SOUND_MIXER_READ_MUTE, &m->mutemask) < 0 ||
112 	    ioctl(m->fd, SOUND_MIXER_READ_RECMASK, &m->recmask) < 0 ||
113 	    ioctl(m->fd, SOUND_MIXER_READ_RECSRC, &m->recsrc) < 0)
114 		goto fail;
115 
116 	TAILQ_INIT(&m->devs);
117 	for (i = 0; i < SOUND_MIXER_NRDEVICES; i++) {
118 		if (!MIX_ISDEV(m, i))
119 			continue;
120 		if ((dp = calloc(1, sizeof(struct mix_dev))) == NULL)
121 			goto fail;
122 		dp->parent_mixer = m;
123 		dp->devno = i;
124 		dp->nctl = 0;
125 		if (_mixer_readvol(m, dp) < 0)
126 			goto fail;
127 		(void)strlcpy(dp->name, names[i], sizeof(dp->name));
128 		TAILQ_INIT(&dp->ctls);
129 		TAILQ_INSERT_TAIL(&m->devs, dp, devs);
130 		m->ndev++;
131 	}
132 
133 	/* The default device is always "vol". */
134 	m->dev = TAILQ_FIRST(&m->devs);
135 
136 	return (m);
137 fail:
138 	if (m != NULL)
139 		(void)mixer_close(m);
140 
141 	return (NULL);
142 }
143 
144 /*
145  * Free resources and close the mixer.
146  */
147 int
148 mixer_close(struct mixer *m)
149 {
150 	struct mix_dev *dp;
151 	int r;
152 
153 	r = close(m->fd);
154 	while (!TAILQ_EMPTY(&m->devs)) {
155 		dp = TAILQ_FIRST(&m->devs);
156 		TAILQ_REMOVE(&m->devs, dp, devs);
157 		while (!TAILQ_EMPTY(&dp->ctls))
158 			(void)mixer_remove_ctl(TAILQ_FIRST(&dp->ctls));
159 		free(dp);
160 	}
161 	free(m);
162 
163 	return (r);
164 }
165 
166 /*
167  * Select a mixer device. The mixer structure keeps a list of all the devices
168  * the mixer has, but only one can be manipulated at a time -- this is what
169  * the `dev` in the mixer structure field is for. Each time a device is to be
170  * manipulated, `dev` has to point to it first.
171  *
172  * The caller must manually assign the return value to `m->dev`.
173  */
174 struct mix_dev *
175 mixer_get_dev(struct mixer *m, int dev)
176 {
177 	struct mix_dev *dp;
178 
179 	if (dev < 0 || dev >= m->ndev) {
180 		errno = ERANGE;
181 		return (NULL);
182 	}
183 	TAILQ_FOREACH(dp, &m->devs, devs) {
184 		if (dp->devno == dev)
185 			return (dp);
186 	}
187 	errno = EINVAL;
188 
189 	return (NULL);
190 }
191 
192 /*
193  * Select a device by name.
194  *
195  * @param name		device name (e.g vol, pcm, ...)
196  */
197 struct mix_dev *
198 mixer_get_dev_byname(struct mixer *m, const char *name)
199 {
200 	struct mix_dev *dp;
201 
202 	TAILQ_FOREACH(dp, &m->devs, devs) {
203 		if (!strncmp(dp->name, name, sizeof(dp->name)))
204 			return (dp);
205 	}
206 	errno = EINVAL;
207 
208 	return (NULL);
209 }
210 
211 /*
212  * Add a mixer control to a device.
213  */
214 int
215 mixer_add_ctl(struct mix_dev *parent_dev, int id, const char *name,
216     int (*mod)(struct mix_dev *, void *),
217     int (*print)(struct mix_dev *, void *))
218 {
219 	struct mix_dev *dp;
220 	mix_ctl_t *ctl, *cp;
221 
222 	/* XXX: should we accept NULL name? */
223 	if (parent_dev == NULL) {
224 		errno = EINVAL;
225 		return (-1);
226 	}
227 	if ((ctl = calloc(1, sizeof(mix_ctl_t))) == NULL)
228 		return (-1);
229 	ctl->parent_dev = parent_dev;
230 	ctl->id = id;
231 	if (name != NULL)
232 		(void)strlcpy(ctl->name, name, sizeof(ctl->name));
233 	ctl->mod = mod;
234 	ctl->print = print;
235 	dp = ctl->parent_dev;
236 	/* Make sure the same ID or name doesn't exist already. */
237 	TAILQ_FOREACH(cp, &dp->ctls, ctls) {
238 		if (!strncmp(cp->name, name, sizeof(cp->name)) || cp->id == id) {
239 			errno = EINVAL;
240 			return (-1);
241 		}
242 	}
243 	TAILQ_INSERT_TAIL(&dp->ctls, ctl, ctls);
244 	dp->nctl++;
245 
246 	return (0);
247 }
248 
249 /*
250  * Same as `mixer_add_ctl`.
251  */
252 int
253 mixer_add_ctl_s(mix_ctl_t *ctl)
254 {
255 	if (ctl == NULL)
256 		return (-1);
257 
258 	return (mixer_add_ctl(ctl->parent_dev, ctl->id, ctl->name,
259 	    ctl->mod, ctl->print));
260 }
261 
262 /*
263  * Remove a mixer control from a device.
264  */
265 int
266 mixer_remove_ctl(mix_ctl_t *ctl)
267 {
268 	struct mix_dev *p;
269 
270 	if (ctl == NULL) {
271 		errno = EINVAL;
272 		return (-1);
273 	}
274 	p = ctl->parent_dev;
275 	if (!TAILQ_EMPTY(&p->ctls)) {
276 		TAILQ_REMOVE(&p->ctls, ctl, ctls);
277 		free(ctl);
278 	}
279 
280 	return (0);
281 }
282 
283 /*
284  * Get a mixer control by id.
285  */
286 mix_ctl_t *
287 mixer_get_ctl(struct mix_dev *d, int id)
288 {
289 	mix_ctl_t *cp;
290 
291 	TAILQ_FOREACH(cp, &d->ctls, ctls) {
292 		if (cp->id == id)
293 			return (cp);
294 	}
295 	errno = EINVAL;
296 
297 	return (NULL);
298 }
299 
300 /*
301  * Get a mixer control by name.
302  */
303 mix_ctl_t *
304 mixer_get_ctl_byname(struct mix_dev *d, const char *name)
305 {
306 	mix_ctl_t *cp;
307 
308 	TAILQ_FOREACH(cp, &d->ctls, ctls) {
309 		if (!strncmp(cp->name, name, sizeof(cp->name)))
310 			return (cp);
311 	}
312 	errno = EINVAL;
313 
314 	return (NULL);
315 }
316 
317 /*
318  * Change the mixer's left and right volume. The allowed volume values are
319  * between MIX_VOLMIN and MIX_VOLMAX. The `ioctl` for volume change requires
320  * an integer value between 0 and 100 stored as `lvol | rvol << 8` --  for
321  * that reason, we de-normalize the 32-bit float volume value, before
322  * we pass it to the `ioctl`.
323  *
324  * Volume clumping should be done by the caller.
325  */
326 int
327 mixer_set_vol(struct mixer *m, mix_volume_t vol)
328 {
329 	int v;
330 
331 	if (vol.left < MIX_VOLMIN || vol.left > MIX_VOLMAX ||
332 	    vol.right < MIX_VOLMIN || vol.right > MIX_VOLMAX) {
333 		errno = ERANGE;
334 		return (-1);
335 	}
336 	v = MIX_VOLDENORM(vol.left) | MIX_VOLDENORM(vol.right) << 8;
337 	if (ioctl(m->fd, MIXER_WRITE(m->dev->devno), &v) < 0)
338 		return (-1);
339 	if (_mixer_readvol(m, m->dev) < 0)
340 		return (-1);
341 
342 	return (0);
343 }
344 
345 /*
346  * Manipulate a device's mute.
347  *
348  * @param opt		MIX_MUTE mute device
349  *			MIX_UNMUTE unmute device
350  *			MIX_TOGGLEMUTE toggle device's mute
351  */
352 int
353 mixer_set_mute(struct mixer *m, int opt)
354 {
355 	switch (opt) {
356 	case MIX_MUTE:
357 		m->mutemask |= (1 << m->dev->devno);
358 		break;
359 	case MIX_UNMUTE:
360 		m->mutemask &= ~(1 << m->dev->devno);
361 		break;
362 	case MIX_TOGGLEMUTE:
363 		m->mutemask ^= (1 << m->dev->devno);
364 		break;
365 	default:
366 		errno = EINVAL;
367 		return (-1);
368 	}
369 	if (ioctl(m->fd, SOUND_MIXER_WRITE_MUTE, &m->mutemask) < 0)
370 		return (-1);
371 	if (ioctl(m->fd, SOUND_MIXER_READ_MUTE, &m->mutemask) < 0)
372 		return (-1);
373 
374 	return 0;
375 }
376 
377 /*
378  * Modify a recording device. The selected device has to be a recording device,
379  * otherwise the function will fail.
380  *
381  * @param opt		MIX_ADDRECSRC add device to recording sources
382  *			MIX_REMOVERECSRC remove device from recording sources
383  *			MIX_SETRECSRC set device as the only recording source
384  *			MIX_TOGGLERECSRC toggle device from recording sources
385  */
386 int
387 mixer_mod_recsrc(struct mixer *m, int opt)
388 {
389 	if (!m->recmask || !MIX_ISREC(m, m->dev->devno)) {
390 		errno = ENODEV;
391 		return (-1);
392 	}
393 	switch (opt) {
394 	case MIX_ADDRECSRC:
395 		m->recsrc |= (1 << m->dev->devno);
396 		break;
397 	case MIX_REMOVERECSRC:
398 		m->recsrc &= ~(1 << m->dev->devno);
399 		break;
400 	case MIX_SETRECSRC:
401 		m->recsrc = (1 << m->dev->devno);
402 		break;
403 	case MIX_TOGGLERECSRC:
404 		m->recsrc ^= (1 << m->dev->devno);
405 		break;
406 	default:
407 		errno = EINVAL;
408 		return (-1);
409 	}
410 	if (ioctl(m->fd, SOUND_MIXER_WRITE_RECSRC, &m->recsrc) < 0)
411 		return (-1);
412 	if (ioctl(m->fd, SOUND_MIXER_READ_RECSRC, &m->recsrc) < 0)
413 		return (-1);
414 
415 	return (0);
416 }
417 
418 /*
419  * Get default audio card's number. This is used to open the default mixer
420  * and set the mixer structure's `f_default` flag.
421  */
422 int
423 mixer_get_dunit(void)
424 {
425 	size_t size;
426 	int unit;
427 
428 	size = sizeof(int);
429 	if (sysctlbyname("hw.snd.default_unit", &unit, &size, NULL, 0) < 0)
430 		return (-1);
431 
432 	return (unit);
433 }
434 
435 /*
436  * Change the default audio card. This is normally _not_ a mixer feature, but
437  * it's useful to have, so the caller can avoid having to manually use
438  * the sysctl API.
439  *
440  * @param unit		the audio card number (e.g pcm0, pcm1, ...).
441  */
442 int
443 mixer_set_dunit(struct mixer *m, int unit)
444 {
445 	size_t size;
446 
447 	size = sizeof(int);
448 	if (sysctlbyname("hw.snd.default_unit", NULL, 0, &unit, size) < 0)
449 		return (-1);
450 	/* XXX: how will other mixers get updated? */
451 	m->f_default = m->unit == unit;
452 
453 	return (0);
454 }
455 
456 /*
457  * Get sound device mode (none, play, rec, play+rec). Userland programs can
458  * use the MIX_MODE_* flags to determine the mode of the device.
459  */
460 int
461 mixer_get_mode(int unit)
462 {
463 	char buf[64];
464 	size_t size;
465 	unsigned int mode;
466 
467 	(void)snprintf(buf, sizeof(buf), "dev.pcm.%d.mode", unit);
468 	size = sizeof(unsigned int);
469 	if (sysctlbyname(buf, &mode, &size, NULL, 0) < 0)
470 		return (0);
471 
472 	return (mode);
473 }
474 
475 /*
476  * Get the total number of mixers in the system.
477  */
478 int
479 mixer_get_nmixers(void)
480 {
481 	struct mixer *m;
482 	oss_sysinfo si;
483 
484 	/*
485 	 * Open a dummy mixer because we need the `fd` field for the
486 	 * `ioctl` to work.
487 	 */
488 	if ((m = mixer_open(NULL)) == NULL)
489 		return (-1);
490 	if (ioctl(m->fd, OSS_SYSINFO, &si) < 0) {
491 		(void)mixer_close(m);
492 		return (-1);
493 	}
494 	(void)mixer_close(m);
495 
496 	return (si.nummixers);
497 }
498