#!/bin/ksh
# @(#) chkdaemon.ksh 1.0 97/07/18
# 96/05/19 john h. dubois iii
# 97/07/18 Improved help.

# This utility shouldn't be neccessary, but some daemons have no option to
# not fork & run in the background, so they can't be run from inittab w/respawn

name=${0##*/}
Usage="Usage: $name [-hvV] [-m<PID>] <daemon-name> <PID-file> ..."
Verbose=false
ExtraVerbose=false
defMinPID=8
typeset -i minPID=$defMinPID
typeset -i pid

while getopts hm:vV opt; do
    case $opt in
    h)
	echo \
"$name: restart daemons which have died.
<daemon-name> is the name of a process that should be running.
<PID-file> is the name of a file that contains the process ID of the daemon
as an ASCII number.  The file should contain nothing but the PID and optional
whitespace.  A PID-file must be given for each daemon-name, so there must
always be an even number of non-option arguments.
For each pair of arguments, if the PID read from the file is no longer running,
the associated daemon-name is run.  No check is done for whether the process
name for the PID is the same as daemon-name; daemon-name is used only as the
command to run to restart the process.  daemon-name should generally include a
full path.  If options are given, the command name and options should be quoted
so that they are passed to $name as a single argument.
Example:
$name -v /etc/named /etc/named.pid
$Usage
Options:
-h: Print this help.
-m<PID>: Set the minimum PID that will be believed to <PID>.  The default is
    $defMinPID.  If the PID read from the PID-file is less than this, a
    complaint will be printed and no other action will be taken.
-v: Print a report to the standard output any time a daemon is restarted.
    If $name is run from cron, cron will mail the report to the cron job
    owner.
-V: Print a report to the standard output telling whether or not each
    daemon was restarted."
	exit 0
	;;
    m)
	minPID=$OPTARG || exit 1
	;;
    v)
	Verbose=true
	;;
    V)
	ExtraVerbose=true
	Verbose=true
	;;
    ?)
	print -u2 "Use -h for help."
	exit 1
	;;
    esac
done

# remove args that were options
let OPTIND=OPTIND-1
shift $OPTIND

if [ $# -lt 2 ]; then
    print -u2 "$Usage\nUse -h for help."
    exit 1
fi
if [ $(( $# % 2 )) -ne 0 ]; then
    print -u2 \
    "$name: must give an even number of parameters.  Use -h for help."
    exit 1
fi

while [ $# -gt 0 ]; do
    daemon=$1
    pidFile=$2

    if [ ! -f "$pidFile" ]; then
	$daemon &
	$Verbose && print \
	"$name: Restarted daemon (PID file $pidFile did not exist): $daemon"
    elif pid=$(<$pidFile); then
	if [ "$pid" -lt $minPID ]; then
	    print -u2 \
	    "$name: Bad PID for daemon $daemon read from PID file $pidFile"
	elif ! kill -0 "$pid" 2>/dev/null; then
	    "$daemon" &
	    $Verbose && print \
	    "$name: Restarted daemon (dead PID read from PID file): $daemon"
	else
	    $ExtraVerbose &&
	    print \
	    "$name: Did not restart daemon $daemon; still running (PID=$pid)"
	fi
    fi
    shift 2
done