[PATCH] net/failsafe: fix exec parameter parsing error flow

[Matan Azrad <matan@mellanox.com>]

The corrupted code returns success value in case of the
execution process output stream is empty(EOF).
It causes to segmentation fault while failsafe polls
this command line again, than gets success and tries to
do hotplug add to the sub device by uninitialized pointer
dereferencing.

Morever, when the output is not empty but uncorrect, failsafe
returns error for its probe function while the expected
behavior is to do polling until the output is correct.

The fix changes the return value to be -ENODEV for this
sub device in the two cases.
By this way, failsafe tries to parse this sub device parameter
by exec method until the output is correct.

Fixes: a0194d828100 ("net/failsafe: add flexible device definition")
Fixes: 35ffe4208140 ("net/failsafe: fix missing pclose after popen")
Cc: stable@dpdk.org

Signed-off-by: Matan Azrad <matan@mellanox.com>
---
 drivers/net/failsafe/failsafe_args.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
index 645c885..61c55df 100644
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -157,12 +157,16 @@ fs_execute_cmd(struct sub_device *sdev, char *cmdline)
 	ret = fs_parse_device(sdev, output);
 	if (ret) {
 		ERROR("Parsing device '%s' failed", output);
+		ret = -ENODEV;
 		goto ret_pclose;
 	}
 ret_pclose:
 	pclose_ret = pclose(fp);
 	if (pclose_ret) {
-		pclose_ret = errno;
+		if (errno == 0)
+			errno = -(pclose_ret = ret);
+		else
+			pclose_ret = errno;
 		ERROR("pclose: %s", strerror(errno));
 		errno = old_err;
 		return pclose_ret;
-- 
2.7.4