tools:iio:lsiio: add error handling

Add error handling to calls which can indicate a major problem by
returning an error code.
This also involves to change the type of dump_devices() from void to int.
Signed-off-by: NHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

tools/iio/lsiio.c

@@ -69,7 +69,10 @@ static int dump_one_device(const char *dev_dir_name)
 			"%i", &dev_idx);
 	if (retval != 1)
 		return -EINVAL;
-	read_sysfs_string("name", dev_dir_name, name);
+	retval = read_sysfs_string("name", dev_dir_name, name);
+	if (retval)
+		return retval;
+
 	printf("Device %03d: %s\n", dev_idx, name);
 
 	if (verblevel >= VERBLEVEL_SENSORS)
@@ -87,20 +90,24 @@ static int dump_one_trigger(const char *dev_dir_name)
 			"%i", &dev_idx);
 	if (retval != 1)
 		return -EINVAL;
-	read_sysfs_string("name", dev_dir_name, name);
+	retval = read_sysfs_string("name", dev_dir_name, name);
+	if (retval)
+		return retval;
+
 	printf("Trigger %03d: %s\n", dev_idx, name);
 	return 0;
 }
 
-static void dump_devices(void)
+static int dump_devices(void)
 {
 	const struct dirent *ent;
+	int ret;
 	DIR *dp;
 
 	dp = opendir(iio_dir);
 	if (dp == NULL) {
 		printf("No industrial I/O devices available\n");
-		return;
+		return -ENODEV;
 	}
 
 	while (ent = readdir(dp), ent != NULL) {
@@ -109,11 +116,16 @@ static void dump_devices(void)
 
 			if (asprintf(&dev_dir_name, "%s%s", iio_dir,
 				     ent->d_name) < 0) {
-				printf("Memory allocation failed\n");
+				ret = -ENOMEM;
+				goto error_close_dir;
+			}
+
+			ret = dump_one_device(dev_dir_name);
+			if (ret) {
+				free(dev_dir_name);
 				goto error_close_dir;
 			}
 
-			dump_one_device(dev_dir_name);
 			free(dev_dir_name);
 			if (verblevel >= VERBLEVEL_SENSORS)
 				printf("\n");
@@ -126,16 +138,26 @@ static void dump_devices(void)
 
 			if (asprintf(&dev_dir_name, "%s%s", iio_dir,
 				     ent->d_name) < 0) {
-				printf("Memory allocation failed\n");
+				ret = -ENOMEM;
+				goto error_close_dir;
+			}
+
+			ret = dump_one_trigger(dev_dir_name);
+			if (ret) {
+				free(dev_dir_name);
 				goto error_close_dir;
 			}
 
-			dump_one_trigger(dev_dir_name);
 			free(dev_dir_name);
 		}
 	}
+	return (closedir(dp) == -1) ? -errno : 0;
+
 error_close_dir:
-	closedir(dp);
+	if (closedir(dp) == -1)
+		perror("dump_devices(): Failed to close directory");
+
+	return ret;
 }
 
 int main(int argc, char **argv)
@@ -163,7 +185,5 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
-	dump_devices();
-
-	return 0;
+	return dump_devices();
 }