[PATCH v3 01/12] libmultipath: signal device with no table in libmp_mapinfo

[Benjamin Marzinski <bmarzins@xxxxxxxxxx>]

if libmp_mapinfo() is run on a device that has no active table,
it will now return with a new exit code, DMP_EMPTY, to signal this.
Currently all code paths treat this identically to DMP_NOT_FOUND.

Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
Reviewed-by: Martin Wilck <mwilck@xxxxxxxx>
---
 libmultipath/devmapper.c | 6 ++++--
 libmultipath/devmapper.h | 7 ++++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 224be512..33425d02 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -86,6 +86,7 @@ const char *dmp_errstr(int rc)
 		[DMP_OK] = "success",
 		[DMP_NOT_FOUND] = "not found",
 		[DMP_NO_MATCH] = "target type mismatch",
+		[DMP_EMPTY] = "no target",
 		[DMP_LAST__] = "**invalid**",
 	};
 	if (rc < 0 || rc > DMP_LAST__)
@@ -747,9 +748,9 @@ static int libmp_mapinfo__(int flags, mapid_t id, mapinfo_t info, const char *ma
 			condlog(lvl, "%s: map %s has multiple targets", fname__, map_id);
 			return DMP_NO_MATCH;
 		}
-		if (!params) {
+		if (!params || !target_type) {
 			condlog(lvl, "%s: map %s has no targets", fname__, map_id);
-			return DMP_NOT_FOUND;
+			return DMP_EMPTY;
 		}
 		if (flags & MAPINFO_TGT_TYPE__) {
 			const char *tgt_type = flags & MAPINFO_MPATH_ONLY ? TGT_MPATH : TGT_PART;
@@ -873,6 +874,7 @@ int dm_is_mpath(const char *name)
 		return DM_IS_MPATH_YES;
 	case DMP_NOT_FOUND:
 	case DMP_NO_MATCH:
+	case DMP_EMPTY:
 		return DM_IS_MPATH_NO;
 	case DMP_ERR:
 	default:
diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
index 6b3bbad9..23926e3f 100644
--- a/libmultipath/devmapper.h
+++ b/libmultipath/devmapper.h
@@ -35,6 +35,7 @@ enum {
 	DMP_OK,
 	DMP_NOT_FOUND,
 	DMP_NO_MATCH,
+	DMP_EMPTY,
 	DMP_LAST__,
 };
 
@@ -105,7 +106,11 @@ typedef struct libmp_map_info {
  * @returns:
  *     DMP_OK if successful.
  *     DMP_NOT_FOUND if the map wasn't found, or has no or multiple targets.
- *     DMP_NO_MATCH if the map didn't match @tgt_type (see above).
+ *     DMP_NO_MATCH if the map didn't match @tgt_type (see above) or didn't
+ *                  have a multipath uuid prefix.
+ *     DMP_EMPTY if the map has no table. Note. The check for matching uuid
+ *               prefix will happen first, but the check for matching
+ *               tgt_type will happen afterwards.
  *     DMP_ERR if some other error occurred.
  *
  * This function obtains the requested information for the device-mapper map
-- 
2.46.2