[PATCH 1/2] selftests: watchdog: Validate optional file argument

From: Eugeniu Rosca
Date: Sat Sep 07 2019 - 05:00:01 EST


From: "George G. Davis" <george_davis@xxxxxxxxxx>

As reported by Eugeniu Rosca, the newly added optional file
argument does not validate if the file is indeed a watchdog, e.g.:

./watchdog-test -f /dev/zero
Watchdog Ticking Away!

Fix it by confirming that the WDIOC_GETSUPPORT ioctl succeeds.

Reported-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
---
v1: Applied/tested on commit ce54eab71e210f ("kunit: fix failure to build without printk") of
https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=next

tools/testing/selftests/watchdog/watchdog-test.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/tools/testing/selftests/watchdog/watchdog-test.c b/tools/testing/selftests/watchdog/watchdog-test.c
index afff120c7be6..6ed822dc2222 100644
--- a/tools/testing/selftests/watchdog/watchdog-test.c
+++ b/tools/testing/selftests/watchdog/watchdog-test.c
@@ -97,6 +97,7 @@ int main(int argc, char *argv[])
int c;
int oneshot = 0;
char *file = "/dev/watchdog";
+ struct watchdog_info info;

setbuf(stdout, NULL);

@@ -118,6 +119,16 @@ int main(int argc, char *argv[])
exit(-1);
}

+ /*
+ * Validate that `file` is a watchdog device
+ */
+ ret = ioctl(fd, WDIOC_GETSUPPORT, &info);
+ if (ret) {
+ printf("WDIOC_GETSUPPORT error '%s'\n", strerror(errno));
+ close(fd);
+ exit(ret);
+ }
+
optind = 0;

while ((c = getopt_long(argc, argv, sopts, lopts, NULL)) != -1) {
--
2.23.0