#! /bin/sh

##
## Signal handler for runit
##

if [ $PPID != 1 ]; then
    echo "This program should only be invoked by PID 1."
    # The reason is that killall5 won't kill anything in the same
    # process group.  That means it won't kill your invoking shell,
    # getty, or svrun.  That in turn prevents filesystems from
    # unmounting, or even being remounted ro, since svrun (at least) has
    # a FIFO open for writes.  And if we reboot without unmounting
    # filesystems, that's bad.

    echo "Feel free to read $0 to learn why :)"
    exit 1
fi

waitall () {
    for i in $(seq 50); do
        # If all processes are in group 0, we're done
        awk '($5){exit 1;}' /proc/[0-9]*/stat && return 0
        usleep 200000
    done
    return 1
}

cleanup () {
    echo "Stopping services..."
    sv stop /service/*
    echo "Asking processes to exit..."
    killall5 -HUP
    killall5 -TERM
    if waitall; then
        echo "Forcing processes to exit..."
        killall5 -KILL
        waitall
    fi
    echo "Unmounting file systems..."
    umount -a -r
        
    # Sometimes when we reach here we still haven't been able to umount
    # everything.  Not much more we can do about that, other than flush
    # write buffers and hope for the best.
    sync
}

case $1 in
    1)                          # SIGHUP
        ;;
    15)                         # SIGTERM: reboot
        cleanup
        echo "Rebooting..."
        reboot -f
        ;;
    10)                         # SIGUSR1: halt
        cleanup
        echo "Halting..."
        halt -f
        ;;
    12)                         # SIGUSR2: power
        cleanup
        echo "Shutting down..."
        poweroff -f
        ;;
    *)                          # Everything else
        ;;
esac