Check for trailing '/' in mount.zfs

When run with a root '/' cwd the mount.zfs helper would strip not
only the '/' but also the next character from the dataset name.
For example, '/tank' was changed to 'ank' instead of just 'tank'.
Originally, this was done for the '/tmp' cwd case where we needed
to strip the '/' following the cwd.  For example '/tmp/tank' needed
to remove the '/tmp' cwd plus 1 character for the '/'.

This change fixes the problem by checking the cwd and if it ends in
a '/' it does not strip and extra character.  Otherwise it will strip
the next character.  I believe this should only ever be true for the
root directory.

Closes #148

1 files changed, 6 insertions, 2 deletions

diff --git a/cmd/mount_zfs/mount_zfs.c b/cmd/mount_zfs/mount_zfs.c
index 32f092199..fbb954acd 100644
--- a/cmd/mount_zfs/mount_zfs.c
+++ b/cmd/mount_zfs/mount_zfs.c
@@ -218,10 +218,14 @@ static char *
 parse_dataset(char *dataset)
 {
 	char cwd[PATH_MAX];
+	int len;
 
 	(void) getcwd(cwd, PATH_MAX);
-	if (!strncmp(cwd, dataset, strlen(cwd)))
-		return (dataset + strlen(cwd) + 1);
+	len = strlen(cwd);
+
+	/* Do not add one when cwd already ends in a trailing '/' */
+	if (!strncmp(cwd, dataset, len))
+		return (dataset + len + (cwd[len-1] != '/'));
 
 	return (dataset);
 }