The new `%s` comes can only come from constants, not user input, so that side should be safe.
The first `%s` comes from the configuration, whatever is defined by the user for a services `pid_file`.  This could potentially be anything, but a user who has access to the configuration can basically already run any command they'd like from the `command` field, so I don't think this is really allowing for increased access. Any security comes from standard user permissions.