Add global sensitive props scripts (#57)

Please see
https://github.com/osm0sis/PlayIntegrityFork/tree/main/module
and
https://github.com/Displax/safetynet-fix/tree/dev/magisk
for full commit history and attribution/authorship

module/template/common_func.sh

@@ -0,0 +1,17 @@
+# resetprop_if_diff <prop name> <expected value>
+resetprop_if_diff() {
+    local NAME="$1"
+    local EXPECTED="$2"
+    local CURRENT="$(resetprop "$NAME")"
+
+    [ -z "$CURRENT" ] || [ "$CURRENT" = "$EXPECTED" ] || resetprop -n "$NAME" "$EXPECTED"
+}
+
+# resetprop_if_match <prop name> <value match string> <new value>
+resetprop_if_match() {
+    local NAME="$1"
+    local CONTAINS="$2"
+    local VALUE="$3"
+
+    [[ "$(resetprop "$NAME")" = *"$CONTAINS"* ]] && resetprop -n "$NAME" "$VALUE"
+}