mixer: check param==NULL in the alsa and oss mixer code

When MPD starts without audio output configuration, the "param" variable is NULL. This triggers a segmentation fault in both mixer plugins.

mixer: check param==NULL in the alsa and oss mixer code
b12b5130 · Max Kellermann · b533307d · b12b5130 · b12b5130
Commit b12b5130 authored Jan 16, 2009 by Max Kellermann
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alsa_mixer.c src/mixer/alsa_mixer.c +3 -0

oss_mixer.c src/mixer/oss_mixer.c +4 -0

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--- a/src/mixer/alsa_mixer.c
+++ b/src/mixer/alsa_mixer.c
@@ -49,6 +49,9 @@ alsa_mixer_configure(struct mixer_data *data, ConfigParam *param)
 	struct alsa_mixer *am = (struct alsa_mixer *)data;
 	BlockParam *bp;

+	if (param == NULL)
+		return;
+
 	if ((bp = getBlockParam(param, "mixer_device"))) {
 		if (am->device)
 			g_free(am->device);

--- a/src/mixer/oss_mixer.c
+++ b/src/mixer/oss_mixer.c
@@ -52,6 +52,10 @@ oss_mixer_configure(struct mixer_data *data, ConfigParam *param)
 {
 	struct oss_mixer *om = (struct oss_mixer *) data;
 	BlockParam *bp;
+
+	if (param == NULL)
+		return;
+
 	bp = getBlockParam(param, "mixer_device");
 	if (bp) {
 		if (om->device)