How the Daemon Works

Documentation / Contents - Removable Media

• Overview of Removable Media
  • What It Is Not
  • The Two Programs
  • In This Book
• Setting Up the Daemon
  • What You Need
  • Build and Install
  • Privilege Hop
  • Media Directories
  • Start the Daemon
  • Check That It Works
  • Common Mistakes
• How the Daemon Works
  • What It Does Each Poll
  • Pidfile and One Instance
  • Without Privilege
  • Stopping
• Commands
  • Everyday Commands
  • Mount Eject and Chest
  • Environment
• CyDrive
  • Opening CyDrive
  • The List
  • Open Mount Eject
• Files and Paths
  • The Ledger
  • Mount Points
  • Helper
• Copyright

How the Daemon Works

cymount --daemon is a user-session process. It is not a system service and not a Motif window. startcyanotype starts it when the binary exists; you can also start it by hand after Setting Up the Daemon.

What It Does Each Poll

About every two seconds:

1. If privilege was missing at start, re-check occasionally so a mid-session fix can turn automount back on without a restart. 2. Lock and load the volume ledger. 3. If privilege is ok: discover removable candidates, automount allowlisted filesystems, prune stale rows, save the ledger. New mounts may play the desktop Mount sound when DISPLAY is set. 4. If privilege is not ok: only import already-mounted media into the ledger (no new automount). Warnings go to stderr.

CyDrive and other clients re-read the ledger file; they do not need a private wire to the daemon.

Pidfile and One Instance

While running, the daemon claims:

~/.cyanotype/run/cymount.pid

Only one daemon per user should hold it. A second cymount --daemon exits with an error if another live cymount already owns the file. On clean exit the pidfile is released.

Without Privilege

The process still runs so status and list can reflect the world, but automount is off. stderr says so. Fix the hop (setup-privilege), then either wait for the periodic re-check or restart the daemon.

Stopping

• Full desktop stop: startcyanotype (or your session script) stops cymount with the other services.
• Hand-started: Ctrl-C or SIGTERM. The process writes "daemon exit" and drops the pidfile.

Do not confuse "kill -9" with a clean stop; if you force-kill, check the pidfile before starting again.

Related Commands

cymount --notify   one scan cycle (same work as scan)
cymount scan       same, with a printed summary
cymount status     privilege, media roots, daemon alive or not