alsactl: Add monitor command

With monitor command, you can monitor the events received from the
given control device.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

4 files changed, 86 insertions, 2 deletions

diff --git a/alsactl/Makefile.am b/alsactl/Makefile.am
index bac84eb..b05b09c 100644
--- a/alsactl/Makefile.am
+++ b/alsactl/Makefile.am
@@ -7,7 +7,7 @@ man_MANS += alsactl_init.7
 endif
 EXTRA_DIST=alsactl.1 alsactl_init.xml
 
-alsactl_SOURCES=alsactl.c state.c lock.c utils.c init_parse.c daemon.c
+alsactl_SOURCES=alsactl.c state.c lock.c utils.c init_parse.c daemon.c monitor.c
 alsactl_CFLAGS=$(AM_CFLAGS) -D__USE_GNU -DSYS_ASOUNDRC=\"$(ASOUND_STATE_DIR)/asound.state\" -DSYS_PIDFILE=\"$(ALSACTL_PIDFILE_DIR)/alsactl.pid\"
 noinst_HEADERS=alsactl.h list.h init_sysdeps.c init_utils_string.c init_utils_run.c init_sysfs.c
 
diff --git a/alsactl/alsactl.1 b/alsactl/alsactl.1
index 45ac8a6..a11c17c 100644
--- a/alsactl/alsactl.1
+++ b/alsactl/alsactl.1
@@ -6,6 +6,8 @@ alsactl \- advanced controls for ALSA soundcard driver
 
 \fBalsactl\fP [\fIoptions\fP] [\fIstore\fP|\fIrestore\fP|\fIinit\fP] <card # or id or device>
 
+\fBalsactl\fP \fImonitor\fP <card # or id>
+
 .SH DESCRIPTION
 \fBalsactl\fP is used to control advanced settings for the ALSA
 soundcard drivers. It supports multiple soundcards. If your card has
@@ -34,8 +36,12 @@ is not known, error code 99 is returned.
 \fIkill\fP notifies the daemon to do the specified operation (quit,
 rescan, save_and_quit).
 
+\fImonitor\fP is for monitoring the events received from the given
+control device.
+
 If no soundcards are specified, setup for all cards will be saved or
-loaded.
+loaded (except for \fImonitor\fP command that can handle only a single
+card; it selects the card "default" when unspecified).
 
 .SH OPTIONS
 
diff --git a/alsactl/alsactl.c b/alsactl/alsactl.c
index 75baad8..6bc013f 100644
--- a/alsactl/alsactl.c
+++ b/alsactl/alsactl.c
@@ -100,6 +100,7 @@ static struct arg args[] = {
 { CARDCMD, "daemon", "store state periodically for one or each soundcards" },
 { CARDCMD, "rdaemon", "like daemon but do the state restore at first" },
 { KILLCMD, "kill", "notify daemon to quit, rescan or save_and_quit" },
+{ CARDCMD, "monitor", "monitor control events" },
 { 0, NULL, NULL }
 };
 
@@ -363,6 +364,8 @@ int main(int argc, char *argv[])
 		res = state_daemon(cfgfile, cardname, period, pidfile);
 	} else if (!strcmp(cmd, "kill")) {
 		res = state_daemon_kill(pidfile, cardname);
+	} else if (!strcmp(cmd, "monitor")) {
+		res = monitor(cardname);
 	} else {
 		fprintf(stderr, "alsactl: Unknown command '%s'...\n", cmd);
 		res = -ENODEV;
diff --git a/alsactl/monitor.c b/alsactl/monitor.c
new file mode 100644
index 0000000..12d2450
--- /dev/null
+++ b/alsactl/monitor.c
@@ -0,0 +1,75 @@
+/*
+ *  Advanced Linux Sound Architecture Control Program
+ *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include "aconfig.h"
+#include "version.h"
+#include <stdio.h>
+#include <alsa/asoundlib.h>
+
+int monitor(const char *name)
+{
+	snd_ctl_t *ctl;
+	snd_ctl_event_t *event;
+	int err;
+
+	if (!name)
+		name = "default";
+
+	err = snd_ctl_open(&ctl, name, SND_CTL_READONLY);
+	if (err < 0) {
+		fprintf(stderr, "Cannot open ctl %s\n", name);
+		return err;
+	}
+	err = snd_ctl_subscribe_events(ctl, 1);
+	if (err < 0) {
+		fprintf(stderr, "Cannot open subscribe events to ctl %s\n", name);
+		snd_ctl_close(ctl);
+		return err;
+	}
+	snd_ctl_event_alloca(&event);
+	while (snd_ctl_read(ctl, event) > 0) {
+		unsigned int mask;
+
+		if (snd_ctl_event_get_type(event) != SND_CTL_EVENT_ELEM)
+			continue;
+
+		printf("#%d (%i,%i,%i,%s,%i)",
+		       snd_ctl_event_elem_get_numid(event),
+		       snd_ctl_event_elem_get_interface(event),
+		       snd_ctl_event_elem_get_device(event),
+		       snd_ctl_event_elem_get_subdevice(event),
+		       snd_ctl_event_elem_get_name(event),
+		       snd_ctl_event_elem_get_index(event));
+
+		mask = snd_ctl_event_elem_get_mask(event);
+		if (mask & SND_CTL_EVENT_MASK_VALUE)
+			printf(" VALUE");
+		if (mask & SND_CTL_EVENT_MASK_INFO)
+			printf(" INFO");
+		if (mask & SND_CTL_EVENT_MASK_ADD)
+			printf(" ADD");
+		if (mask & SND_CTL_EVENT_MASK_TLV)
+			printf(" TLV");
+		if (mask == SND_CTL_EVENT_MASK_REMOVE)
+			printf(" REMOVE");
+		printf("\n");
+	}
+	snd_ctl_close(ctl);
+	return 0;
+}