[PATCH 1/2] selftests/cpu-hotplug: Use $(id -u) instead of $UID for root check

[Darren Chang <chihsheng@google.com>]

$UID is a bash-specific variable and is not defined in other shells such
as Android's /system/bin/sh (mksh) or POSIX sh. When running this test
on environments without bash (e.g. Android), $UID is unset and
'[ $UID != 0 ]' expands to '[ != 0 ]', causing a syntax error.

Replace $UID with "$(id -u)" so the root privilege check works across
different shells.

Signed-off-by: Darren Chang <chihsheng@google.com>
---
 tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh b/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
index 287cfd5809f6..6653507b9348 100755
--- a/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
+++ b/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
@@ -10,7 +10,7 @@ prerequisite()
 {
 	msg="skip all tests:"
 
-	if [ $UID != 0 ]; then
+	if [ "$(id -u)" -ne 0 ]; then
 		echo $msg must be run as root >&2
 		exit $ksft_skip
 	fi
-- 
2.56.0.257.gf7497c7d27-goog