[PATCH driver-core 2/2] test_firmware: fix setting old custom fw path back on exit, second try

From: Ben Hutchings
Date: Wed Apr 04 2018 - 16:38:57 EST


Commit 65c79230576 tried to clear the custom firmware path on exit by
writing a single space to the firmware_class.path parameter. This
doesn't work because nothing strips this space from the value stored
and fw_get_filesystem_firmware() only ignores zero-length paths.

Instead, write a null byte.

Fixes: 0a8adf58475 ("test: add firmware_class loader test")
Fixes: 65c79230576 ("test_firmware: fix setting old custom fw path back on exit")
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
---
tools/testing/selftests/firmware/fw_lib.sh | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/firmware/fw_lib.sh b/tools/testing/selftests/firmware/fw_lib.sh
index 9ea31b57d71a..962d7f4ac627 100755
--- a/tools/testing/selftests/firmware/fw_lib.sh
+++ b/tools/testing/selftests/firmware/fw_lib.sh
@@ -154,11 +154,13 @@ test_finish()
if [ "$HAS_FW_LOADER_USER_HELPER" = "yes" ]; then
echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
fi
- if [ "$OLD_FWPATH" = "" ]; then
- OLD_FWPATH=" "
- fi
if [ "$TEST_REQS_FW_SET_CUSTOM_PATH" = "yes" ]; then
- echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path
+ if [ "$OLD_FWPATH" = "" ]; then
+ # A zero-length write won't work; write a null byte
+ printf '\000' >/sys/module/firmware_class/parameters/path
+ else
+ echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path
+ fi
fi
if [ -f $FW ]; then
rm -f "$FW"
--
2.16.2