replace proccess check to filelock, tanks @themactep

general/overlay/usr/sbin/sysupgrade

@@ -3,11 +3,6 @@
 # OpenIPC.org | v.20220722
 #
 
-if [ $(pidof sysupgrade) ]; then
-	echo "Sysupgrade script already running!"
-	exit 1
-fi
-
 set -e
 
 echo_c() {
@@ -111,6 +106,11 @@ free_resources() {
 	sync; echo 3 > /proc/sys/vm/drop_caches
 }
 
+create_lock() {
+  [ -f /tmp/sysupgrade.lock ] && echo -e "\e[1;31m\nAnother sysupgrade process already running!\e[0m\n" && exit 1
+  touch /tmp/sysupgrade.lock
+}
+
 get_device() {
 	echo -n "/dev/$(grep "\"$1\"" /proc/mtd | cut -d: -f1)"
 }
@@ -249,6 +249,8 @@ print_sysinfo
 echo_c 97 "\nTry '$(basename "$0") --help' for options." && \
 exit 0
 
+create_lock
+
 free_resources
 [ "$remote_update" -eq 1 ] && download_firmware
 [ "$update_kernel" -eq 1 ] && do_update_kernel "$kernel_file"