exit bash API-download script immediately if sensor is already running

Makes the script do nothing if the sensor is already installed and running.
This makes it more suitable to run from AWS SSM State Manager.

Agent-Install-Examples/bash/API-download/install.sh

@@ -25,12 +25,24 @@ main() {
         print_usage
         exit 1
     fi
+
     echo -n 'Falcon Sensor Install  ... '; cs_sensor_install;  echo '[ Ok ]'
     echo -n 'Falcon Sensor Register ... '; cs_sensor_register; echo '[ Ok ]'
     echo -n 'Falcon Sensor Restart  ... '; cs_sensor_restart;  echo '[ Ok ]'
     echo 'Falcon Sensor deployed successfully.'
 }
 
+cs_sensor_exit_if_sensor_running() {
+    if type service >/dev/null 2>&1; then
+         service falcon-sensor status >/dev/null 2>&1
+    elif type systemctl >/dev/null 2>&1; then
+        systemctl -q is-active falcon-sensor
+    fi
+    if [ $? -eq 0 ]; then
+        exit 0;
+    fi
+}
+
 cs_sensor_register() {
     /opt/CrowdStrike/falconctl -s -f --cid="${cs_falcon_cid}"
 }
@@ -303,6 +315,8 @@ EOF
 }
 
 
+cs_sensor_exit_if_sensor_running;
+
 set -e