#!/bin/sh
# Kill the pid referenced by a pidfile, if any.

log() {
  echo "$@" >&2
}


die() {
  log "Fatal:" "$@"
  exit 1
}


pidfile=$1
if [ -z "$pidfile" ]; then
  log "Usage: $0 <pidfile>"
  exit 99
fi

[ -e "$pidfile" ] || exit 0

read pid junk <"$pidfile"

[ -n "$pid" ] || die "'$pidfile' exists but has no pid inside"
[ "$pid" -gt 1 ] || die "'$pidfile' pid is '$pid'; must be > 1"

kill -15 "$pid" 2>/dev/null
for d in $(seq 20); do
  kill -0 "$pid" 2>/dev/null || break
  msleep 100
done
kill -9 "$pid" 2>/dev/null

# return an error if the process *does* exist
! kill -0 "$pid" 2>/dev/null