lockhinter, a standalone tool for setting and clearing LockedHint

This program is a simple tool designed to manage the LockedHint state of a logind session (whether when used as part of systemd or a fork, such as elogind).

Normally, the desktop environment (such as GNOME or Plasma) would set LockedHint whenever a session is locked or unlocked in order to indicate the session's state to the login manager. In addition, certain utilities query that state themselves, usually to make sure that sensitive operations can only be performed while the session is unlocked.

More lightweight desktop environments, window managers and Wayland compositors, however, do not do that, and the session is always treated as if it is unlocked. The decision to not add this functionality is usually justified by a desire to not add extra functionality or not add a dependency on systemd.

To solve this problem, lockhinter functions as an in-between utility. When launched with command-line arguments including a locker program's name and its arguments, lockhinter launches the locker, then sets LockedHint to true, waiting until the locker terminates. If it terminates gracefully and returns a code of 0 (no errors), LockedHint is then set to false, otherwise it is not reset. (This is to make sure that lockhinter or the locker program crashing doesn't cause the login manager or programs reading LockedHint to think a session was unlocked even though it wasn't.)

Installation

Right now, the best way to install the program is via cargo:

$ cargo install lockhinter

You will likely also need to add $HOME/.cargo/bin to your PATH environment variable, for example by editing the .profile file in your home directory to say:

export PATH=$HOME/.cargo/bin:$PATH

If any Linux distro maintainers decide to add this utility to their repositories, then installing via package manager will be the preferred way, as it would provide a system-wide installation that doesn't require editing $PATH, as well as automatic updates.

Usage

lockhinter has two modes of operation. The primary one is using it to run another locker utility (such as swaylock), in which case it will keep the LockedHint property set for as long as the locker is running. Parameters for running the locker should be specified immediately, or after the -- separator.

$ lockhinter -- swaylock -c 3d3846

or

$ lockhinter swaylock -c 3d3846

By default, if the LockedHint property is already set on a session, lockhinter will terminate immediately and not change it, but this can be overridden with the -f or `--force`` parameter:

$ lockhinter -f -- swaylock -c 3d3846

That way, the program will start the locker again and clear the LockedHint property once the locker closes properly.

If the -c parameter is specified, then lockhinter will simply check the LockedHint property's state, output FALSE or TRUE to standard output and terminate with a code of 0 or 1 respectively.

$ lockhinter -c
FALSE