alsa-utils/salsa.c

/* Copyright 2005 Red Hat, Inc.
 *
 * Portions extraced from various ALSA code:
 *  Copyright (c) by Abramo Bagnara <abramo@alsa-project.org>
 *                   Jaroslav Kysela <perex@suse.cz>
 *
 * This software may be freely redistributed under the terms of the GNU
 * public license.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <alsa/asoundlib.h>

#define ALSA_CONFIG_PATH	"/etc/asound.state"

int get_card_number()
{
	char *devname, *action;
	
	action = getenv("ACTION");
	if (!action || strcmp(action,"add"))
		return -1;
	devname = getenv("DEVNAME");
	if (!devname)
		return -1;
	if (!strncmp(devname,"/dev/snd/controlC",17))
		return atoi(devname+17);
	if (!strncmp(devname,"/dev/snd/pcmC",13))
		return atoi(devname+13);
	return -1;
}

int has_config(int index)
{
	int rc = 0;
	snd_config_t *config, *control;
	snd_input_t *in;
	snd_ctl_t *handle;
        snd_ctl_card_info_t *info;
	const char *id;
	char path[32];
	
	rc = snd_config_top(&config);
	if (rc < 0)
		goto out;
	rc = snd_input_stdio_open(&in, ALSA_CONFIG_PATH, "r");
	if (rc >= 0) {
		rc = snd_config_load(config, in);
		snd_input_close(in);
		if (rc < 0)
			goto out;
	}
	sprintf(path, "hw:%d", index);
	rc = snd_ctl_open(&handle, path, 0);
	if (rc < 0) 
		goto out;
	snd_ctl_card_info_alloca(&info);
	rc = snd_ctl_card_info(handle, info);
	if (rc < 0)
		goto out_close;
	id = snd_ctl_card_info_get_id(info);
	rc = snd_config_searchv(config, &control, "state", id, "control", 0);
out_close:
	snd_ctl_close(handle);
out:
	return !rc;
	
}

int run_alsactl(int index)
{
	char *args[] = { "/sbin/alsactl", "restore", NULL, NULL };
	char num[10];
	
	sprintf(num,"%d",index);
	args[2] = num;
	execv(args[0],args);
        return 1;
}

int frob_mixer(int index)
{
	int rc = 0;
	char card[32];
	snd_mixer_t *handle;
	snd_mixer_selem_id_t *sid;
	snd_mixer_elem_t *elem;
	snd_mixer_selem_id_alloca(&sid);
	
	sprintf(card,"hw:%d",index);
	if ((rc = snd_mixer_open(&handle, 0)) < 0) {
		return rc;
	}
	if ((rc = snd_mixer_attach(handle, card)) < 0) {
		goto out;
	}
	if ((rc = snd_mixer_selem_register(handle, NULL, NULL)) < 0) {
		goto out;
	}
	rc = snd_mixer_load(handle);
	if (rc < 0) {
		goto out;
	}
	for (elem = snd_mixer_first_elem(handle); elem; elem = snd_mixer_elem_next(elem)) {
		long pmin, pmax;
		int c;
		
		snd_mixer_selem_get_id(elem, sid);
		snd_mixer_selem_get_playback_volume_range(elem, &pmin, &pmax);
		for (c = 0; c < SND_MIXER_SCHN_LAST; c++) {
			if (snd_mixer_selem_has_capture_channel(elem, c)) {
				if (snd_mixer_selem_has_capture_volume(elem))
					snd_mixer_selem_set_capture_volume(elem, c, 0);
				if (!strcmp(snd_mixer_selem_id_get_name(sid),"CD")) {
					if (snd_mixer_selem_has_capture_switch(elem))
						snd_mixer_selem_set_capture_switch(elem, c, 1);
				} else {
					if (snd_mixer_selem_has_capture_switch(elem))
						snd_mixer_selem_set_capture_switch(elem, c, 0);
					if (snd_mixer_selem_has_playback_switch(elem))
						snd_mixer_selem_set_playback_switch(elem, c, 0);
					if (snd_mixer_selem_has_playback_volume(elem))
						snd_mixer_selem_set_playback_volume(elem, c, 0);
				} 
			}
			if (snd_mixer_selem_has_playback_channel(elem, c)) {
				if (!snd_mixer_selem_has_capture_channel(elem, c) ||
				    !strcmp(snd_mixer_selem_id_get_name(sid),"CD") ||
				    !strcmp(snd_mixer_selem_id_get_name(sid),"Wave")) {
					if (snd_mixer_selem_has_playback_switch(elem))
						snd_mixer_selem_set_playback_switch(elem, c, 1);
					if (snd_mixer_selem_has_playback_volume(elem))
						snd_mixer_selem_set_playback_volume(elem, c, pmin + (pmax - pmin) * 0.75);
				}
			}
		}
	}
out:
	snd_mixer_close(handle);
	return rc;
}

int main(int argc, char **argv)
{
	int i;
	
	i = get_card_number();
	if (i < 0)
		return 0;
	if (has_config(i))
		return run_alsactl(i);
	else
		return frob_mixer(i);
}