Mixer load: don't upload empty mixers from non-existing files

src/modules/systemlib/mixer/mixer_load.c

@@ -52,7 +52,8 @@ int load_mixer_file(const char *fname, char *buf, unsigned maxlen)
 	/* open the mixer definition file */
 	fp = fopen(fname, "r");
 	if (fp == NULL) {
-		return 1;
+		warnx("file not found");
+		return -1;
 	}
 
 	/* read valid lines from the file into a buffer */
@@ -88,7 +89,8 @@ int load_mixer_file(const char *fname, char *buf, unsigned maxlen)
 
 		/* if the line is too long to fit in the buffer, bail */
 		if ((strlen(line) + strlen(buf) + 1) >= maxlen) {
-			return 1;
+			warnx("line too long");
+			return -1;
 		}
 
 		/* add the line to the buffer */

src/systemcmds/mixer/mixer.cpp

@@ -102,7 +102,8 @@ load(const char *devname, const char *fname)
 	if (ioctl(dev, MIXERIOCRESET, 0))
 		err(1, "can't reset mixers on %s", devname);
 
-	load_mixer_file(fname, &buf[0], sizeof(buf));
+	if (load_mixer_file(fname, &buf[0], sizeof(buf)) < 0)
+		err(1, "can't load mixer: %s", fname);
 
 	/* XXX pass the buffer to the device */
 	int ret = ioctl(dev, MIXERIOCLOADBUF, (unsigned long)buf);