Change the ownership of the pid folder when using a sub-folder

This is an alternative to the fix made in 3b52909 which removed the
chown call entirely.

Prior to 3b52909, the ownership of $PID_FOLDER was always changed even
when its value was /var/run. This was problematic as it could prevent
other services from creating their pid folder or file.

When a sub-folder is used, changing its ownership so that it’s owned by
the user that will run the app is desirable as it limits access to the
folder. Rather than removing the chown call entirely, this commit
ensures that it only happens when a sub-folder is being used to hold the
pid file.

Closes gh-6532

spring-boot-tools/spring-boot-loader-tools/src/main/resources/org/springframework/boot/loader/tools/launch.script

@@ -106,6 +106,7 @@ fi
 # Build the pid and log filenames
 if [[ "$identity" == "$init_script" ]] || [[ "$identity" == "$APP_NAME" ]]; then
   PID_FOLDER="$PID_FOLDER/${identity}"
+  pid_subfolder=$PID_FOLDER
 fi
 pid_file="$PID_FOLDER/${identity}.pid"
 log_file="$LOG_FOLDER/$LOG_FILENAME"
@@ -143,6 +144,9 @@ do_start() {
   mkdir "$PID_FOLDER" &> /dev/null
   if [[ -n "$run_user" ]]; then
     checkPermissions || return $?
+    if [[ -z "$pid_subfolder" ]]; then
+      chown "$run_user" "$pid_subfolder"
+    fi
     chown "$run_user" "$pid_file"
     chown "$run_user" "$log_file"
     if [ $USE_START_STOP_DAEMON = true ] && type start-stop-daemon > /dev/null 2>&1; then