Timing

Every worker acquires resources at certain timings and holds it during an interval. For example, /usr/local linker holds the resource during the interval FROM_ENABLE_TO_DISABLE, which means it acquires resource at WHEN_ENABLE and releases it at WHEN_DISABLE. The timings are listed and explained below:

timing descrioption when Failure
WHEN_PREINST before preinst abort installation, rollback, show alert message on UI
WHEN_POSTINST before postinst finish installation, show alert message on UI
WHEN_ENABLE before WHEN_STARTUP, won't process during bootup abort startup, rollback, show alert message on UI
WHEN_STARTUP before start abort startup, rollback, show alert message on UI
WHEN_PREUNINST after preuninst finish uninstallation, show alert message on UI
WHEN_POSTUNINST before postuninst finish uninstallation, show alert message on UI
WHEN_DISABLE after WHEN_HALT, won't process during shutdown ignore
WHEN_HALT after stop ignore

NOTE To let the package itself decide whether uninstallation should continue or not, WHEN_PREUNINST is processed after the preuninst script.