Autofs State Machine

Autofs uses 5 states:

State Enter Trigger Leave Trigger Behaviour

ST_READY SIGTERM, SIGUSR1, SIGUSR2, SIGALRM Reads from kernel pipe and state-change pipe. All signals enabled

ST_PRUNE SIGUSR1 SIGCHLD: prune process finishes Prune unused autofs filesystems; reads from kernel and state pipe. All signals but SIGCHLD are blocked.

ST_EXPIRE SIGALRM SIGCHLD: expire process finishes Expire idle autofs filesystems; reads from kernel and state pipe. All signals but SIGCHLD are blocked.

ST_SHUTDOWN_PENDING SIGTERM, SIGUSR2 SIGCHLD: prune process finishes. If successful, goes to ST_SHUTDOWN; otherwise returns to ST_READY Prunes unused autofs filesystems. Reads from kernel message pipe. All signals but SIGCHLD are blocked. Kills whole process group (all children) with SIGTERM to abort any pending mounts.

ST_SHUTDOWN ST_SHUTDOWN_PENDING expires all filesystems All child processes die Daemon exits

Back to autofs

State	Enter Trigger	Leave Trigger	Behaviour
ST_READY		SIGTERM, SIGUSR1, SIGUSR2, SIGALRM	Reads from kernel pipe and state-change pipe. All signals enabled
ST_PRUNE	SIGUSR1	SIGCHLD: prune process finishes	Prune unused autofs filesystems; reads from kernel and state pipe. All signals but SIGCHLD are blocked.
ST_EXPIRE	SIGALRM	SIGCHLD: expire process finishes	Expire idle autofs filesystems; reads from kernel and state pipe. All signals but SIGCHLD are blocked.
ST_SHUTDOWN_PENDING	SIGTERM, SIGUSR2	SIGCHLD: prune process finishes. If successful, goes to ST_SHUTDOWN; otherwise returns to ST_READY	Prunes unused autofs filesystems. Reads from kernel message pipe. All signals but SIGCHLD are blocked. Kills whole process group (all children) with SIGTERM to abort any pending mounts.
ST_SHUTDOWN	ST_SHUTDOWN_PENDING expires all filesystems	All child processes die	Daemon exits