OSS: handle device disconnects and reconnects (w/o needing a mpd restart)

Like the ALSA patches, this allows OSS devices to be disconnected
during playback and MPD will be able to reopen and reuse them without
restarting.

git-svn-id: https://svn.musicpd.org/mpd/trunk@4366 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/audioOutputs/audioOutput_oss.c

@@ -421,6 +421,12 @@ static int setParam(OssData * od, int param, int * value) {
 	return 0;
 }
 
+static void oss_close(OssData * od)
+{
+	if(od->fd >= 0) while (close(od->fd) && errno == EINTR);
+	od->fd = -1;
+}
+
 static int oss_open(AudioOutput * audioOutput) {
 	int tmp;
 	OssData * od = audioOutput->data;
@@ -468,7 +474,7 @@ static int oss_open(AudioOutput * audioOutput) {
 	return 0;
 
 fail:
-	if(od->fd >= 0) close(od->fd);
+	oss_close(od);
 	audioOutput->open = 0;
 	return -1;
 }
@@ -483,7 +489,8 @@ static int oss_openDevice(AudioOutput * audioOutput)
 	od->sampleRate = audioFormat->sampleRate;
 	od->bits = audioFormat->bits;
 
-	ret = oss_open(audioOutput);
+	if ((ret = oss_open(audioOutput)) < 0)
+		return ret;
 
 	audioFormat->channels = od->channels;
 	audioFormat->sampleRate = od->sampleRate;
@@ -496,11 +503,6 @@ static int oss_openDevice(AudioOutput * audioOutput)
 	return ret;
 }
 
-static void oss_close(OssData * od) {
-	if(od->fd >= 0) close(od->fd);
-	od->fd = -1;
-}
-
 static void oss_closeDevice(AudioOutput * audioOutput) {
 	OssData * od = audioOutput->data;
 
@@ -516,8 +518,6 @@ static void oss_dropBufferedAudio(AudioOutput * audioOutput) {
 		ioctl(od->fd, SNDCTL_DSP_RESET, 0);
 		oss_close(od);
 	}
-
-	/*oss_open(audioOutput);*/
 }
 
 static int oss_playAudio(AudioOutput * audioOutput, char * playChunk, 
@@ -527,7 +527,8 @@ static int oss_playAudio(AudioOutput * audioOutput, char * playChunk,
 	int ret;
 
 	/* reopen the device since it was closed by dropBufferedAudio */
-	if(od->fd < 0) oss_open(audioOutput);
+	if(od->fd < 0 && oss_open(audioOutput) < 0)
+		return -1;
 
 	while (size > 0) {
 		ret = write(od->fd, playChunk, size);

src/volume.c

@@ -64,7 +64,7 @@ static char * volume_mixerDevice = VOLUME_MIXER_DEVICE_DEFAULT;
 static int volume_softwareSet = 100;
 
 #ifdef HAVE_OSS
-static int volume_ossFd;
+static int volume_ossFd = -1;
 static int volume_ossControl = SOUND_MIXER_PCM;
 #endif
 
@@ -77,8 +77,14 @@ static int volume_alsaSet = -1;
 #endif
 
 #ifdef HAVE_OSS
+
+static void closeOssMixer(void)
+{
+	while (close(volume_ossFd) && errno == EINTR);
+	volume_ossFd = -1;
+}
+
 static int prepOssMixer(char * device) {
-	int devmask = 0;
 	ConfigParam * param;
 
 	if((volume_ossFd = open(device,O_RDONLY))<0) {
@@ -92,10 +98,11 @@ static int prepOssMixer(char * device) {
 		char * labels[SOUND_MIXER_NRDEVICES] = SOUND_DEVICE_LABELS;
 		char * dup;
 		int i,j;
+		int devmask = 0;
 
 		if(ioctl(volume_ossFd,SOUND_MIXER_READ_DEVMASK,&devmask)<0) {
 			WARNING("errors getting read_devmask for oss mixer\n");
-			close(volume_ossFd);
+			closeOssMixer();
 			return -1;
 		}
 
@@ -114,13 +121,13 @@ static int prepOssMixer(char * device) {
 		if(i>=SOUND_MIXER_NRDEVICES) {
 			WARNING("mixer control \"%s\" not found at line %i\n",
 					        param->value, param->line);
-			close(volume_ossFd);
+			closeOssMixer();
 			return -1;
 		}
 		else if(!( ( 1 << i ) & devmask )) {
 			WARNING("mixer control \"%s\" not usable at line %i\n",
 					        param->value, param->line);
-			close(volume_ossFd);
+			closeOssMixer();
 			return -1;
 		}
 
@@ -130,14 +137,21 @@ static int prepOssMixer(char * device) {
 	return 0;
 }
 
-static void closeOssMixer() {
+static int ensure_oss_open(void)
-	close(volume_ossFd);
+{
+	if ((volume_ossFd < 0 && prepOssMixer(volume_mixerDevice) < 0))
+		return -1;
+	return 0;
 }
 
 static int getOssVolumeLevel() {
 	int left, right, level;
 
+	if (ensure_oss_open() < 0)
+		return -1;
+
 	if(ioctl(volume_ossFd,MIXER_READ(volume_ossControl),&level) < 0) {
+		closeOssMixer();
 		WARNING("unable to read volume\n");
 		return -1;
 	}
@@ -166,8 +180,11 @@ static int changeOssVolumeLevel(FILE * fp, int change, int rel) {
 		}
 
 		new = current+change;
+	} else {
+		if (ensure_oss_open() < 0)
+			return -1;
+		new = change;
 	}
-	else new = change;
 
 	if(new<0) new = 0;
 	else if(new>100) new = 100;
@@ -175,6 +192,7 @@ static int changeOssVolumeLevel(FILE * fp, int change, int rel) {
 	level = (new << 8) + new;
 
 	if(ioctl(volume_ossFd,MIXER_WRITE(volume_ossControl),&level) < 0) {
+		closeOssMixer();
 		commandError(fp, ACK_ERROR_SYSTEM, "problems setting volume",
 				NULL);
 		return -1;