[PATCH v4 6/6] test_sysctl: Add range clamping test

[Waiman Long]

Add a range clamping test for the msgmni sysctl parameter to verify
that the input value will be clamped if it exceeds the builtin maximum
or minimum value.

Below is the expected test run result:

Running test: sysctl_test_0006 - run #0
Checking range minimum clamping ... ok
Checking range maximum clamping ... ok

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
 tools/testing/selftests/sysctl/sysctl.sh | 43 ++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
index ec232c3..fbf9d73 100755
--- a/tools/testing/selftests/sysctl/sysctl.sh
+++ b/tools/testing/selftests/sysctl/sysctl.sh
@@ -34,6 +34,7 @@ ALL_TESTS="$ALL_TESTS 0002:1:1"
 ALL_TESTS="$ALL_TESTS 0003:1:1"
 ALL_TESTS="$ALL_TESTS 0004:1:1"
 ALL_TESTS="$ALL_TESTS 0005:3:1"
+ALL_TESTS="$ALL_TESTS 0006:1:1"
 
 test_modprobe()
 {
@@ -62,6 +63,9 @@ function allow_user_defaults()
 	if [ -z $WRITES_STRICT ]; then
 		WRITES_STRICT="${PROD_SYSCTL}/kernel/sysctl_writes_strict"
 	fi
+	if [ -z $MSGMNI ]; then
+		MSGMNI="${PROD_SYSCTL}/kernel/msgmni"
+	fi
 }
 
 function check_production_sysctl_writes_strict()
@@ -543,6 +547,34 @@ run_stringtests()
 	test_rc
 }
 
+# TARGET, BEYOND_MIN & BEYOND_MAX need to be defined before running test.
+run_range_clamping_test()
+{
+	echo -n "Checking range minimum clamping ... "
+	echo $BEYOND_MIN > "$TARGET" > /dev/null 2>&1
+	EXITVAL=$?
+	NEWVAL=$(cat "$TARGET")
+	if [[ $EXITVAL -ne 0 || $NEWVAL -le $BEYOND_MIN ]]; then
+		echo "FAIL" >&2
+		rc=1
+	else
+		echo "ok"
+	fi
+
+	echo -n "Checking range maximum clamping ... "
+	echo $BEYOND_MAX > "$TARGET" > /dev/null 2>&1
+	EXITVAL=$?
+	NEWVAL=$(cat "$TARGET")
+	if [[ $EXITVAL -ne 0 || $NEWVAL -ge $BEYOND_MAX ]]; then
+		echo "FAIL" >&2
+		rc=1
+	else
+		echo "ok"
+	fi
+
+	test_rc
+}
+
 sysctl_test_0001()
 {
 	TARGET="${SYSCTL}/int_0001"
@@ -600,6 +632,17 @@ sysctl_test_0005()
 	run_limit_digit_int_array
 }
 
+sysctl_test_0006()
+{
+	TARGET="${MSGMNI}"
+	ORIG=$(cat "${TARGET}")
+	BEYOND_MIN=-1
+	BEYOND_MAX=1000000000
+
+	run_range_clamping_test
+	set_orig
+}
+
 list_tests()
 {
 	echo "Test ID list:"
-- 
1.8.3.1