tree: loop address may be NULL

Return an empty string in nvme_ctrl_get_address() and not a NULL
to get a better output.

Signed-off-by: Hannes Reinecke <[email protected]>

Author: hreinecke

src/nvme/tree.c

@@ -669,7 +669,7 @@ const char *nvme_ctrl_get_subsysnqn(nvme_ctrl_t c)
 
 const char *nvme_ctrl_get_address(nvme_ctrl_t c)
 {
-	return c->address;
+	return c->address ? c->address : "";
 }
 
 const char *nvme_ctrl_get_firmware(nvme_ctrl_t c)

src/nvme/tree.h

@@ -735,7 +735,8 @@ const char *nvme_ctrl_get_sysfs_dir(nvme_ctrl_t c);
  * nvme_ctrl_get_address() - Address string of an nvme_ctrl_t
  * @c: nvme_ctrl_t object
  *
- * Return: NVMe-over-Fabrics address string of @c
+ * Return: NVMe-over-Fabrics address string of @c or empty string
+ * of no address is present.
  */
 const char *nvme_ctrl_get_address(nvme_ctrl_t c);