[LTP] [PATCH v2 1/2] network/in6_02: Don't use default value for LHOST_IFACES

[Petr Vorel]

In case of LHOST_IFACES not being defined was 'eth0' used as default.
Although eth0 is common iface, we cannot guarantee it, therefore skip
testing it.

Also check sscanf return value to catch whitespace only.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Changes v1->v2:
* Add check before rewriting into new API.
* Check sscanf return value to catch whitespace only.

NOTE: with LHOST_IFACES="lo" (or other from n2i) it's tested twice, but
I ignore it.
---
Not sure if I need to put all longer strings in tst_res on new line.
---
 testcases/network/lib6/in6_02.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/testcases/network/lib6/in6_02.c b/testcases/network/lib6/in6_02.c
index 7cb362666..e1a71d987 100644
--- a/testcases/network/lib6/in6_02.c
+++ b/testcases/network/lib6/in6_02.c
@@ -34,7 +34,7 @@ static struct {
 	int nonzero;
 } n2i[] = {
 	{ "lo", 1 },
-	{ "eth0", 1 },
+	{ NULL, 1 },
 	{ "hoser75", 0 },
 	{ "6", 0 },
 };
@@ -80,6 +80,11 @@ void n2itest(void)
 	char ifname[IF_NAMESIZE], *pifn;
 
 	for (i = 0; i < N2I_COUNT; ++i) {
+		if (n2i[i].name == NULL) {
+			tst_resm(TCONF, "LHOST_IFACES not defined or invalid, skip testing it");
+			return;
+		}
+
 		TEST(if_nametoindex(n2i[i].name));
 		if (!TEST_RETURN != !n2i[i].nonzero) {
 			tst_resm(TFAIL, "if_nametoindex(\"%s\") %ld "
@@ -256,22 +261,17 @@ void setup(void)
 {
 	TEST_PAUSE;
 
-	tst_resm(TINFO, "get interface name from LHOST_IFACES var");
-
 	char *ifnames = getenv("LHOST_IFACES");
-
-	if (!ifnames) {
-		tst_resm(TWARN, "LHOST_IFACES not defined, default to eth0");
+	if (!ifnames)
 		return;
-	}
 
 	static char name[256];
+	int ret;
 
-	sscanf(ifnames, "%255s", name);
-
-	if (!strcmp(name, n2i[1].name))
+	ret = sscanf(ifnames, "%255s", name);
+	if (ret == -1)
 		return;
 
-	tst_resm(TINFO, "change default 'eth0' name to '%s'", name);
+	tst_resm(TINFO, "get interface name from LHOST_IFACES: '%s'", name);
 	n2i[1].name = name;
 }
-- 
2.16.3