[dpdk-dev] [PATCH v2] net/failsafe: fix blank line parsing

[Gaetan Rivet <gaetan.rivet@6wind.com>]

When the output of an exec() slave definition is only a single newline
character, the fail-safe currently fails to parse the device with the
value returned by the rte_devargs library.

This behavior is incorrect, because the fail-safe should make a
difference between the absence of a device, and an erroneous device
declaration.

Fix the output sanitization in the case where no newline was at its end
and detect the special case of an absent device. The correct error code
is then returned.

Fixes: a0194d828100 ("net/failsafe: add flexible device definition")

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---

This patch depends on:

net/failsafe: fix for missing pclose after popen
http://dpdk.org/ml/archives/dev/2017-August/072429.html

v2:

  - Remove useless, unposix use of strnlen

 drivers/net/failsafe/failsafe_args.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
index 3f92a77..1f22416 100644
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -101,10 +101,11 @@ fs_parse_device(struct sub_device *sdev, char *args)
 static void
 fs_sanitize_cmdline(char *args)
 {
-	size_t len;
+	char *nl;
 
-	len = strnlen(args, DEVARGS_MAXLEN);
-	args[len - 1] = '\0';
+	nl = strrchr(args, '\n');
+	if (nl)
+		nl[0] = '\0';
 }
 
 static int
@@ -149,6 +150,10 @@ fs_execute_cmd(struct sub_device *sdev, char *cmdline)
 		goto ret_pclose;
 	}
 	fs_sanitize_cmdline(output);
+	if (output[0] == '\0') {
+		ret = -ENODEV;
+		goto ret_pclose;
+	}
 	ret = fs_parse_device(sdev, output);
 	if (ret) {
 		ERROR("Parsing device '%s' failed", output);
-- 
2.1.4