#!/bin/sh
#########################################
## Test an IP or domain name for web service, return false if connection(s) fail
## Usage: poke [-av] target[:port] [target[:port] ...]
##   -a      Report all failures instead of quitting after first (takes longer)
##   -v      Verbose mode.  Reports success or failure (only first failure)
##   -2      Run again after 30s and report only target(s) that fail twice
##   target  Any IP address or domain name, like 192.168.0.1 or www.google.com
##   port    Check connections on specified port instead of 80 (www)
## 
## poke 0.8, (c) 2007-8 by Adam Katz <scriptsATkhopiscom>, LGPL v2+
#########################################
### poke changelog
### 0.8 (2008-05-08) - netcat (nc) is simpler, better, more reliable than nmap

say=true
ALL() { false; }
filter() { echo "$*"; }

if type nc >/dev/null 2>&1
  then poker() { nc -z -w1 "$1" $2 >/dev/null 2>&1; } # test port w/ 1 sec timeout
  else
    # nmap with timeouts (version 4+) is awesome!  ... 1s is unreliable
    my_nmap() { nmap -P0 -sT -T4 --host-timeout=1501 -p "$@" 2>&1; }
    # fall back to telnet if nmap doesn't report on the requested port
    if [ -n "`my_nmap 25 localhost |grep '^25/'`" ] 
      then poker() { p=`my_nmap "$2" "$1" |grep "^$2.*open"`; [ -n "$p" ]; }
      else poker() { echo X |telnet -e X "$1" $2 >/dev/null 2>&1; }
    fi 
fi

help() { sed -e '/^## /!d' -e 's///' "`which $0 || echo $0`"; }

while [ -n "$1" ]; do
 target="${1%%[:/]*}"
 port="${1##*:}"
 [ "$port" = 0 ] && port=6000 # assume host:0 is X11 on display 0
 [ "$1" = "$port" ] && port=80 || altport=":$port"
 if [ "$port" -ge 0 ] 2>/dev/null; then true; else # in case error won't reverse
   s='[	 ]'
   port=`grep "^[^#]*$port$s" /etc/services 2>/dev/null \
          |sed -e "s:/.*::g" -e "s/^.*$s//g" -e 1q` # get port number
   [ "$port" -gt 0 ] 2>/dev/null || $say "poke: invalid port '${1##*:}'" >&2
 fi
 case "$target" in
  -2* | -a*2* )	shift; say=true;
  		set placeholder -a "$@" --pause "$@" # do it twice!
  		# filter for dups only; anything that fails only once is okay
  		filter() { echo "$*" |sed 's/ /\n/g' |sort |uniq -d; } ;;
  --pause* )	sleep 3 ;;
  -va* | -av*)	shift; set placeholder -v -a "$@" ;;
  -v* | --v* )	say=echo ;;
  -a* | --a* )	ALL() { [ -n "$*" ] && printf "$*"; true; } ;;
  -h* | --h* )	help; exit 0 ;;
  -*  | --*  )	echo "poke: invalid argument \`$target'" >&2
 		help|grep ^Usage; exit 2 ;;
  * ) 		if poker "$target" $port
 		  then hits="$hits $target$altport"
 		       ALL && $say "poke: $target is listening on port $port"
 		  else misses="$misses $target$altport"
 		       $say "poke: could not connect to $target$altport" 
 		       (! ALL) && exit 1
 		fi ;;
 esac
 shift
 unset altport
done

if [ -z "$hits$misses" ]; then 
  echo "poke: too few arguments" >&2
  echo "Try \`poke --help' for more information." >&2
  exit 2
fi

(! ALL) && $say "poke: successfully connected to each of: $hits"

misses=`filter $misses`
[ -n "$misses" ] && ALL "poke: failed to connect to: $misses\n" \
  && exit 1 || exit 0