[dpdk-stable] [PATCH v2] examples/vhost_blk: fix the TOCTOU

[Jin Yu <jin.yu@intel.com>]

Fix the time of check time of use warning in example code.
Ignore the errno of unlink failure. There are two situations.
The first one is that file doesn't exist the unlink fails and
it's ok to ignore. The second one is that unlink fails to remove
file but the next bind() would fail too.

Coverity issue: 350589 158663
Fixes: c19beb3f38cd ("examples/vhost_blk: introduce vhost storage sample")
Cc: stable@dpdk.org

Signed-off-by: Jin Yu <jin.yu@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
V2 - complement the commit message.
---
 examples/vhost_blk/vhost_blk.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/examples/vhost_blk/vhost_blk.c b/examples/vhost_blk/vhost_blk.c
index e1036bf3a..74c82a900 100644
--- a/examples/vhost_blk/vhost_blk.c
+++ b/examples/vhost_blk/vhost_blk.c
@@ -994,11 +994,7 @@ vhost_blk_ctrlr_construct(const char *ctrlr_name)
 	}
 	snprintf(dev_pathname, sizeof(dev_pathname), "%s/%s", path, ctrlr_name);
 
-	if (access(dev_pathname, F_OK) != -1) {
-		if (unlink(dev_pathname) != 0)
-			rte_exit(EXIT_FAILURE, "Cannot remove %s.\n",
-				 dev_pathname);
-	}
+	unlink(dev_pathname);
 
 	if (rte_vhost_driver_register(dev_pathname, 0) != 0) {
 		fprintf(stderr, "socket %s already exists\n", dev_pathname);
@@ -1041,8 +1037,7 @@ signal_handler(__rte_unused int signum)
 {
 	struct vhost_blk_ctrlr *ctrlr;
 
-	if (access(dev_pathname, F_OK) == 0)
-		unlink(dev_pathname);
+	unlink(dev_pathname);
 
 	if (g_should_stop != -1) {
 		g_should_stop = 1;
-- 
2.17.2