OpenZFS 4521 - zfstest is trying to execute evil "zfs unmount -a"

Authored by: Yuri Pankov <[email protected]>
Reviewed by: Andriy Gapon <[email protected]>
Reviewed by: Dan McDonald <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: John Kennedy <[email protected]>
Approved by: Robert Mustacchi <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Ported-by: Giuseppe Di Natale <[email protected]>

Porting Notes:
- Correctly set __ZFS_POOL_RESTRICT in inherit_001_pos

OpenZFS-issue: https://www.illumos.org/issues/4521
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/8808ac5
Closes #5674  

2 files changed, 35 insertions, 11 deletions

diff --git a/lib/libzfs/libzfs_config.c b/lib/libzfs/libzfs_config.c
index 4585a2b77..67379d072 100644
--- a/lib/libzfs/libzfs_config.c
+++ b/lib/libzfs/libzfs_config.c
@@ -27,6 +27,7 @@
 /*
  * Copyright (c) 2012 by Delphix. All rights reserved.
  * Copyright (c) 2015 by Syneto S.R.L. All rights reserved.
+ * Copyright 2016 Nexenta Systems, Inc.
  */
 
 /*
@@ -326,33 +327,47 @@ zpool_refresh_stats(zpool_handle_t *zhp, boolean_t *missing)
 }
 
 /*
- * If the __ZFS_POOL_RESTRICT environment variable is set we only iterate over
- * pools it lists.
+ * The following environment variables are undocumented
+ * and should be used for testing purposes only:
  *
- * This is an undocumented feature for use during testing only.
+ * __ZFS_POOL_EXCLUDE - don't iterate over the pools it lists
+ * __ZFS_POOL_RESTRICT - iterate only over the pools it lists
  *
  * This function returns B_TRUE if the pool should be skipped
  * during iteration.
  */
-static boolean_t
-check_restricted(const char *poolname)
+boolean_t
+zpool_skip_pool(const char *poolname)
 {
 	static boolean_t initialized = B_FALSE;
-	static char *restricted = NULL;
+	static const char *exclude = NULL;
+	static const char *restricted = NULL;
 
 	const char *cur, *end;
-	int len, namelen;
+	int len;
+	int namelen = strlen(poolname);
 
 	if (!initialized) {
 		initialized = B_TRUE;
+		exclude = getenv("__ZFS_POOL_EXCLUDE");
 		restricted = getenv("__ZFS_POOL_RESTRICT");
 	}
 
+	if (exclude != NULL) {
+		cur = exclude;
+		do {
+			end = strchr(cur, ' ');
+			len = (NULL == end) ? strlen(cur) : (end - cur);
+			if (len == namelen && 0 == strncmp(cur, poolname, len))
+				return (B_TRUE);
+			cur += (len + 1);
+		} while (NULL != end);
+	}
+
 	if (NULL == restricted)
 		return (B_FALSE);
 
 	cur = restricted;
-	namelen = strlen(poolname);
 	do {
 		end = strchr(cur, ' ');
 		len = (NULL == end) ? strlen(cur) : (end - cur);
@@ -390,7 +405,7 @@ zpool_iter(libzfs_handle_t *hdl, zpool_iter_f func, void *data)
 	for (cn = uu_avl_first(hdl->libzfs_ns_avl); cn != NULL;
 	    cn = uu_avl_next(hdl->libzfs_ns_avl, cn)) {
 
-		if (check_restricted(cn->cn_name))
+		if (zpool_skip_pool(cn->cn_name))
 			continue;
 
 		if (zpool_open_silent(hdl, cn->cn_name, &zhp) != 0) {
@@ -428,7 +443,7 @@ zfs_iter_root(libzfs_handle_t *hdl, zfs_iter_f func, void *data)
 	for (cn = uu_avl_first(hdl->libzfs_ns_avl); cn != NULL;
 	    cn = uu_avl_next(hdl->libzfs_ns_avl, cn)) {
 
-		if (check_restricted(cn->cn_name))
+		if (zpool_skip_pool(cn->cn_name))
 			continue;
 
 		if ((zhp = make_dataset_handle(hdl, cn->cn_name)) == NULL)
diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index 7c3ef744d..79c9dae6e 100644
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -27,7 +27,7 @@
  * Copyright (c) 2012 Pawel Jakub Dawidek <[email protected]>.
  * Copyright (c) 2013 Martin Matuska. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
- * Copyright 2013 Nexenta Systems, Inc. All rights reserved.
+ * Copyright 2016 Nexenta Systems, Inc.
  */
 
 #include <ctype.h>
@@ -3053,6 +3053,15 @@ zfs_get_name(const zfs_handle_t *zhp)
 }
 
 /*
+ * Returns the name of the parent pool for the given zfs handle.
+ */
+const char *
+zfs_get_pool_name(const zfs_handle_t *zhp)
+{
+	return (zhp->zpool_hdl->zpool_name);
+}
+
+/*
  * Returns the type of the given zfs handle.
  */
 zfs_type_t