From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Tue, 23 Jun 2020 22:17:31 -0500
Subject: [PATCH] libmultipath: make dm_get_map/status return codes symbolic

dm_get_map() and dm_get_status() now use symbolic return codes. They
also differentiate between failing to get information from device-mapper
and not finding the requested device. These symboilc return codes are
also used by update_multipath_* functions.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmultipath/devmapper.c   | 51 +++++++++++++++++++++++++-------------
 libmultipath/devmapper.h   |  6 +++++
 libmultipath/structs_vec.c | 45 +++++++++++++++++++--------------
 multipathd/main.c          | 12 ++++-----
 4 files changed, 72 insertions(+), 42 deletions(-)

diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 13a1cf53..f6204e5f 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -525,36 +525,43 @@ int dm_map_present(const char * str)
 
 int dm_get_map(const char *name, unsigned long long *size, char *outparams)
 {
-	int r = 1;
+	int r = DMP_ERR;
 	struct dm_task *dmt;
 	uint64_t start, length;
 	char *target_type = NULL;
 	char *params = NULL;
 
 	if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))
-		return 1;
+		return r;
 
 	if (!dm_task_set_name(dmt, name))
 		goto out;
 
 	dm_task_no_open_count(dmt);
 
-	if (!dm_task_run(dmt))
+	errno = 0;
+	if (!dm_task_run(dmt)) {
+		if (dm_task_get_errno(dmt) == ENXIO)
+			r = DMP_NOT_FOUND;
 		goto out;
+	}
 
+	r = DMP_NOT_FOUND;
 	/* Fetch 1st target */
-	dm_get_next_target(dmt, NULL, &start, &length,
-			   &target_type, &params);
+	if (dm_get_next_target(dmt, NULL, &start, &length,
+			       &target_type, &params) != NULL)
+		/* more than one target */
+		goto out;
 
 	if (size)
 		*size = length;
 
 	if (!outparams) {
-		r = 0;
+		r = DMP_OK;
 		goto out;
 	}
 	if (snprintf(outparams, PARAMS_SIZE, "%s", params) <= PARAMS_SIZE)
-		r = 0;
+		r = DMP_OK;
 out:
 	dm_task_destroy(dmt);
 	return r;
@@ -628,35 +635,45 @@ is_mpath_part(const char *part_name, const char *map_name)
 
 int dm_get_status(const char *name, char *outstatus)
 {
-	int r = 1;
+	int r = DMP_ERR;
 	struct dm_task *dmt;
 	uint64_t start, length;
 	char *target_type = NULL;
 	char *status = NULL;
 
 	if (!(dmt = libmp_dm_task_create(DM_DEVICE_STATUS)))
-		return 1;
+		return r;
 
 	if (!dm_task_set_name(dmt, name))
 		goto out;
 
 	dm_task_no_open_count(dmt);
 
-	if (!dm_task_run(dmt))
+	errno = 0;
+	if (!dm_task_run(dmt)) {
+		if (dm_task_get_errno(dmt) == ENXIO)
+			r = DMP_NOT_FOUND;
 		goto out;
+	}
 
+	r = DMP_NOT_FOUND;
 	/* Fetch 1st target */
-	dm_get_next_target(dmt, NULL, &start, &length,
-			   &target_type, &status);
+	if (dm_get_next_target(dmt, NULL, &start, &length,
+			       &target_type, &status) != NULL)
+		goto out;
+
+	if (!target_type || strcmp(target_type, TGT_MPATH) != 0)
+		goto out;
+
 	if (!status) {
 		condlog(2, "get null status.");
 		goto out;
 	}
 
 	if (snprintf(outstatus, PARAMS_SIZE, "%s", status) <= PARAMS_SIZE)
-		r = 0;
+		r = DMP_OK;
 out:
-	if (r)
+	if (r != DMP_OK)
 		condlog(0, "%s: error getting map status string", name);
 
 	dm_task_destroy(dmt);
@@ -866,7 +883,7 @@ int _dm_flush_map (const char * mapname, int need_sync, int deferred_remove,
 			return 1;
 
 	if (need_suspend &&
-	    !dm_get_map(mapname, &mapsize, params) &&
+	    dm_get_map(mapname, &mapsize, params) == DMP_OK &&
 	    strstr(params, "queue_if_no_path")) {
 		if (!dm_queue_if_no_path(mapname, 0))
 			queue_if_no_path = 1;
@@ -1075,7 +1092,7 @@ struct multipath *dm_get_multipath(const char *name)
 	if (!mpp->alias)
 		goto out;
 
-	if (dm_get_map(name, &mpp->size, NULL))
+	if (dm_get_map(name, &mpp->size, NULL) != DMP_OK)
 		goto out;
 
 	dm_get_uuid(name, mpp->wwid, WWID_SIZE);
@@ -1259,7 +1276,7 @@ do_foreach_partmaps (const char * mapname,
 		    /*
 		     * and we can fetch the map table from the kernel
 		     */
-		    !dm_get_map(names->name, &size, &params[0]) &&
+		    dm_get_map(names->name, &size, &params[0]) == DMP_OK &&
 
 		    /*
 		     * and the table maps over the multipath map
diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
index 7557a86b..adb55000 100644
--- a/libmultipath/devmapper.h
+++ b/libmultipath/devmapper.h
@@ -27,6 +27,12 @@
 #define UUID_PREFIX "mpath-"
 #define UUID_PREFIX_LEN (sizeof(UUID_PREFIX) - 1)
 
+enum {
+	DMP_ERR,
+	DMP_OK,
+	DMP_NOT_FOUND,
+};
+
 void dm_init(int verbosity);
 void libmp_dm_init(void);
 void libmp_udev_set_sync_support(int on);
diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
index 077f2e42..8137ea21 100644
--- a/libmultipath/structs_vec.c
+++ b/libmultipath/structs_vec.c
@@ -196,43 +196,47 @@ extract_hwe_from_path(struct multipath * mpp)
 int
 update_multipath_table (struct multipath *mpp, vector pathvec, int is_daemon)
 {
+	int r = DMP_ERR;
 	char params[PARAMS_SIZE] = {0};
 
 	if (!mpp)
-		return 1;
+		return r;
 
-	if (dm_get_map(mpp->alias, &mpp->size, params)) {
-		condlog(3, "%s: cannot get map", mpp->alias);
-		return 1;
+	r = dm_get_map(mpp->alias, &mpp->size, params);
+	if (r != DMP_OK) {
+		condlog(3, "%s: %s", mpp->alias, (r == DMP_ERR)? "error getting table" : "map not present");
+		return r;
 	}
 
 	if (disassemble_map(pathvec, params, mpp, is_daemon)) {
 		condlog(3, "%s: cannot disassemble map", mpp->alias);
-		return 1;
+		return DMP_ERR;
 	}
 
-	return 0;
+	return DMP_OK;
 }
 
 int
 update_multipath_status (struct multipath *mpp)
 {
+	int r = DMP_ERR;
 	char status[PARAMS_SIZE] = {0};
 
 	if (!mpp)
-		return 1;
+		return r;
 
-	if (dm_get_status(mpp->alias, status)) {
-		condlog(3, "%s: cannot get status", mpp->alias);
-		return 1;
+	r = dm_get_status(mpp->alias, status);
+	if (r != DMP_OK) {
+		condlog(3, "%s: %s", mpp->alias, (r == DMP_ERR)? "error getting status" : "map not present");
+		return r;
 	}
 
 	if (disassemble_status(status, mpp)) {
 		condlog(3, "%s: cannot disassemble status", mpp->alias);
-		return 1;
+		return DMP_ERR;
 	}
 
-	return 0;
+	return DMP_OK;
 }
 
 void sync_paths(struct multipath *mpp, vector pathvec)
@@ -264,10 +268,10 @@ int
 update_multipath_strings(struct multipath *mpp, vector pathvec, int is_daemon)
 {
 	struct pathgroup *pgp;
-	int i;
+	int i, r = DMP_ERR;
 
 	if (!mpp)
-		return 1;
+		return r;
 
 	update_mpp_paths(mpp, pathvec);
 	condlog(4, "%s: %s", mpp->alias, __FUNCTION__);
@@ -276,18 +280,21 @@ update_multipath_strings(struct multipath *mpp, vector pathvec, int is_daemon)
 	free_pgvec(mpp->pg, KEEP_PATHS);
 	mpp->pg = NULL;
 
-	if (update_multipath_table(mpp, pathvec, is_daemon))
-		return 1;
+	r = update_multipath_table(mpp, pathvec, is_daemon);
+	if (r != DMP_OK)
+		return r;
+
 	sync_paths(mpp, pathvec);
 
-	if (update_multipath_status(mpp))
-		return 1;
+	r = update_multipath_status(mpp);
+	if (r != DMP_OK)
+		return r;
 
 	vector_foreach_slot(mpp->pg, pgp, i)
 		if (pgp->paths)
 			path_group_prio_update(pgp);
 
-	return 0;
+	return DMP_OK;
 }
 
 static void enter_recovery_mode(struct multipath *mpp)
diff --git a/multipathd/main.c b/multipathd/main.c
index 6b7db2c0..e3427d3d 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -414,7 +414,7 @@ int __setup_multipath(struct vectors *vecs, struct multipath *mpp,
 		goto out;
 	}
 
-	if (update_multipath_strings(mpp, vecs->pathvec, 1)) {
+	if (update_multipath_strings(mpp, vecs->pathvec, 1) != DMP_OK) {
 		condlog(0, "%s: failed to setup multipath", mpp->alias);
 		goto out;
 	}
@@ -553,9 +553,9 @@ add_map_without_path (struct vectors *vecs, const char *alias)
 	mpp->mpe = find_mpe(conf->mptable, mpp->wwid);
 	put_multipath_config(conf);
 
-	if (update_multipath_table(mpp, vecs->pathvec, 1))
+	if (update_multipath_table(mpp, vecs->pathvec, 1) != DMP_OK)
 		goto out;
-	if (update_multipath_status(mpp))
+	if (update_multipath_status(mpp) != DMP_OK)
 		goto out;
 
 	if (!vector_alloc_slot(vecs->mpvec))
@@ -1346,8 +1346,8 @@ map_discovery (struct vectors * vecs)
 		return 1;
 
 	vector_foreach_slot (vecs->mpvec, mpp, i)
-		if (update_multipath_table(mpp, vecs->pathvec, 1) ||
-		    update_multipath_status(mpp)) {
+		if (update_multipath_table(mpp, vecs->pathvec, 1) != DMP_OK ||
+		    update_multipath_status(mpp) != DMP_OK) {
 			remove_map(mpp, vecs, 1);
 			i--;
 		}
@@ -2087,7 +2087,7 @@ check_path (struct vectors * vecs, struct path * pp, unsigned int ticks)
 	/*
 	 * Synchronize with kernel state
 	 */
-	if (update_multipath_strings(pp->mpp, vecs->pathvec, 1)) {
+	if (update_multipath_strings(pp->mpp, vecs->pathvec, 1) != DMP_OK) {
 		condlog(1, "%s: Could not synchronize with kernel state",
 			pp->dev);
 		pp->dmstate = PSTATE_UNDEF;
-- 
2.17.2