busybox/examples/shutdown-1.0/script/stop_tasks

#!/bin/sh
# We are trying to be nice.
# TERM everybody. Give them some time to die.
# KILL might make some filesystems non-unmountable,
# so we'll do it in stop_storage instead.

killcnt=30

PATH=/sbin:/usr/sbin:/bin:/usr/bin

echo "<*> `date '+%Y-%m-%d %H:%M:%S'` Executing '$0 $*'"

showps() {
	# sleep 1 ensures that xargs will have time to start up.
	# This makes pslist less prone to random jitter.
	pslist=`{ sleep 1; ps -A -o comm=; } | sort | xargs`
	pscnt=$(( `echo "$pslist" | wc -w` + 0 ))
	if test x"$VERBOSE" = x; then
		echo "* `date '+%H:%M:%S'` $pscnt processes"
	else
		echo "* `date '+%H:%M:%S'` Processes ($pscnt): $pslist"
	fi
}

# Sync.
# Rationale: sometimes buggy root processes can
# hang the system when killed (X for example may have problems
# with restoring text mode on a poorly supported hardware).
# These are bugs and must be fixed, but until then users will lose
# dirty data on shutdown! Let's make that less likely.
sync &

# Send SIGTERMs. If list of processes changes, proceed slower.
# If it has stabilised (all who wanted to, exited), proceed faster.
showps
i="$killcnt"
while test "$i" -gt 0; do
	echo "* `date '+%H:%M:%S'` Sending CONT, TERM" #, HUP"
	# I've seen "killall5 2.86" which doesn't grok signal names!
	killall5 -18
	killall5 -15
	#killall5 -1    # HUP: because interactive bash does not die on TERM...
	# but init will reread /etc/inittab on HUP and my /etc is on non root fs!
	# -> umounts will complain.
	oldpslist="$pslist"
	showps
	if test x"$pslist" = x"$oldpslist"; then
		i=$((i-8))
	fi
	i=$((i-2))
done

echo "* `date '+%H:%M:%S'` Turning off swap"
swapoff -a
cat /proc/swaps | grep -v ^Filename | cut -d ' ' -f1 \
| while read -r line; do
	test "$line" && {
		echo swapoff "$line"
		swapoff "$line"
	}
done

echo "* /proc/swaps:"
cat /proc/swaps
echo "* /proc/mounts:"
cat /proc/mounts
echo "* ps -A e:"
ps -A e
echo "* top -bn1:"
top -bn1