Support mixer_idx with OSS

make mixer_idx load the default mixer

man/i3status.man

@@ -312,9 +312,10 @@ details on the format string.
 Outputs the volume of the specified mixer on the specified device. Works only
 on Linux because it uses ALSA.
 A simplified configuration can be used on FreeBSD and OpenBSD due to
-the lack of ALSA,  the +device+, +mixer+ and +mixder_idx+ options can be
+the lack of ALSA,  the +device+ and +mixer+ options can be
 ignored on these systems. On these systems the OSS API is used instead to
-query +/dev/mixer+ directly.
+query +/dev/mixer+ directly if +mixer_dix+ is -1, otherwise
++/dev/mixer++mixer_idx+.
 
 *Example order*: +volume master+
 

src/print_volume.c

@@ -175,12 +175,22 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
 	}
 #endif
 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
-        char mixerpath[] = "/dev/mixer";
+        char *mixerpath;
+        char defaultmixer[] = "/dev/mixer";
         int mixfd, vol, devmask = 0;
         pbval = 1;
 
+        if (mixer_idx > 0)
+                asprintf(&mixerpath, "/dev/mixer%d", mixer_idx);
+        else
+                mixerpath = defaultmixer;
+
         if ((mixfd = open(mixerpath, O_RDWR)) < 0)
                 return;
+
+        if (mixer_idx > 0)
+                free(mixerpath);
+
         if (ioctl(mixfd, SOUND_MIXER_READ_DEVMASK, &devmask) == -1)
                 return;
         if (ioctl(mixfd, MIXER_READ(0),&vol) == -1)