Fix userland resource leaks

Coverity caught these. With the exception of the file descriptor leak in
tests/zfs-tests/cmd/draid.c, they are all memory leaks.

Also, there is a piece of dead code in zfs_get_enclosure_sysfs_path().
We delete it as cleanup.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13921

cmd/zdb/zdb.c

@@ -1137,6 +1137,8 @@ dump_uint64(objset_t *os, uint64_t object, void *data, size_t size)
 	}
 
 	if (size == 0) {
+		if (data == NULL)
+			kmem_free(arr, oursize);
 		(void) printf("\t\t[]\n");
 		return;
 	}
@@ -7062,8 +7064,11 @@ import_checkpointed_state(char *target, nvlist_t *cfg, char **new_path)
 		freecfg = B_TRUE;
 	}
 
-	if (asprintf(&bogus_name, "%s%s", poolname, BOGUS_SUFFIX) == -1)
+	if (asprintf(&bogus_name, "%s%s", poolname, BOGUS_SUFFIX) == -1) {
+		if (target != poolname)
+			free(poolname);
 		return (NULL);
+	}
 	fnvlist_add_string(cfg, ZPOOL_CONFIG_POOL_NAME, bogus_name);
 
 	error = spa_import(bogus_name, cfg, NULL,
@@ -7078,6 +7083,7 @@ import_checkpointed_state(char *target, nvlist_t *cfg, char **new_path)
 
 	if (new_path != NULL && path_start != NULL) {
 		if (asprintf(new_path, "%s%s", bogus_name, path_start) == -1) {
+			free(bogus_name);
 			if (path_start != NULL)
 				free(poolname);
 			return (NULL);
@@ -8198,8 +8204,7 @@ zdb_read_block(char *thing, spa_t *spa)
 	vd = zdb_vdev_lookup(spa->spa_root_vdev, vdev);
 	if (vd == NULL) {
 		(void) printf("***Invalid vdev: %s\n", vdev);
-		free(dup);
-		return;
+		goto done;
 	} else {
 		if (vd->vdev_path)
 			(void) fprintf(stderr, "Found vdev: %s\n",

cmd/zfs/zfs_main.c

@@ -7395,8 +7395,11 @@ unshare_unmount(int op, int argc, char **argv)
 		    ((tree = uu_avl_create(pool, NULL, UU_DEFAULT)) == NULL))
 			nomem();
 
-		if ((mnttab = fopen(MNTTAB, "re")) == NULL)
+		if ((mnttab = fopen(MNTTAB, "re")) == NULL) {
+			uu_avl_destroy(tree);
+			uu_avl_pool_destroy(pool);
 			return (ENOENT);
+		}
 
 		while (getmntent(mnttab, &entry) == 0) {
 

cmd/zhack.c

@@ -295,6 +295,8 @@ zhack_do_feature_enable(int argc, char **argv)
 			feature.fi_flags |= ZFEATURE_FLAG_READONLY_COMPAT;
 			break;
 		case 'd':
+			if (desc != NULL)
+				free(desc);
 			desc = strdup(optarg);
 			break;
 		default:

cmd/zpool/zpool_main.c

@@ -1196,6 +1196,7 @@ zpool_do_remove(int argc, char **argv)
 		return (1);
 
 	if (stop && noop) {
+		zpool_close(zhp);
 		(void) fprintf(stderr, gettext("stop request ignored\n"));
 		return (0);
 	}