chore(base): add source support

Author: duanhongyi

debootstrap/bullseye/rootfs/usr/bin/init-stack

@@ -1,5 +1,13 @@
 #!/bin/bash
 
+# check to see if this file is being run or sourced from another script
+_is_sourced() {
+	# https://unix.stackexchange.com/a/215279
+	[ "${#FUNCNAME[@]}" -ge 2 ] \
+		&& [ "${FUNCNAME[0]}" = '_is_sourced' ] \
+		&& [ "${FUNCNAME[1]}" = 'source' ]
+}
+
 env_list=$(find /opt/drycc/*/env/* 2>/dev/null || echo "")
 for env in ${env_list}
 do
@@ -31,8 +39,10 @@ do
   "${_exec}"
 done
 
-if [[ "$$" == "1" ]] ; then
-  exec tini -g -- "$@"
-else
-  exec tini -sg -- "$@"
+if ! _is_sourced; then
+  if [[ "$$" == "1" ]] ; then
+    exec tini -g -- "$@"
+  else
+    exec tini -sg -- "$@"
+  fi
 fi