[3/5] btrfs-progs: property: set/get/print label property

Commit Message

Su Yue Nov. 2, 2017, 3:23 a.m. UTC

Introduce set_prop_label(), get_prop_label(), print_prop_label()
to set/get/print label.

Signed-off-by: Su Yue <[e-mail]>
---
 props.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 55 insertions(+), 9 deletions(-)

Patch

diff --git a/props.c b/props.c
index da69f6e9314c..28a81b6bdc81 100644
--- a/props.c
+++ b/props.c
@@ -145,23 +145,68 @@  out:
 	return ret;
 }
 
-static int prop_label(enum prop_object_type type,
-		      const char *object,
-		      const char *name,
-		      const char *value)
+static ssize_t prop_label(enum prop_object_type type, const char *object,
+		  const char *name, char *value, enum prop_operation operation)
 {
-	int ret;
+	ssize_t ret;
 
-	if (value) {
+	if (operation == set_prop) {
 		ret = set_label((char *) object, (char *) value);
 	} else {
 		char label[BTRFS_LABEL_SIZE];
 
 		ret = get_label((char *) object, label);
-		if (!ret)
-			fprintf(stdout, "label=%s\n", label);
+		if (ret)
+			goto out;
+
+		if (!value)
+			ret = strlen(label);
+		else
+			memcpy(value, label, strlen(label));
+	}
+out:
+	return ret;
+}
+
+static int set_prop_label(enum prop_object_type type, const char *object,
+			  const char *name, const char *value)
+{
+	return prop_label(type, object, name, (char *)value, set_prop);
+}
+
+static ssize_t get_prop_label(enum prop_object_type type, const char *object,
+			      const char *name, char *value)
+{
+	return prop_label(type, object, name, value, get_prop);
+}
+
+static int print_prop_label(enum prop_object_type type, const char *object,
+			    const char *name)
+{
+	int ret;
+	ssize_t len;
+	char *value = NULL;
+
+	len = get_prop_label(type, object, name, NULL);
+	if (len < 0) {
+		ret = len;
+		goto out;
 	}
 
+	value = malloc(len + 1);
+	if (!value) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	ret = get_prop_label(type, object, name, value);
+	if (ret)
+		goto out;
+
+	value[len] = '\0';
+	printf("label=%s\n", value);
+out:
+	if (value)
+		free(value);
 	return ret;
 }
 
@@ -243,7 +288,8 @@  const struct prop_handler prop_handlers[] = {
 	 set_prop_read_only, get_prop_read_only, print_prop_read_only},
 
 	{"label", "Set/get label of device.", 0,
-	 prop_object_dev | prop_object_root, NULL, NULL, NULL},
+	 prop_object_dev | prop_object_root,
+	 set_prop_label, get_prop_label, print_prop_label},
 
 	{"compression", "Set/get compression for a file or directory", 0,
 	 prop_object_inode, NULL, NULL, NULL},