#!/bin/sh
#
# Stupid little program to find the socket of stdin of the parent
# of the specified process. Normally this is used for the 
# login shell to determine to which of several virtual hosts the
# user connected.

if [ $# -eq 0 ]
then
	echo "Usage: $0 <pid of login shell>" >&2
	exit 1
fi

pid=$1

ppid=`ps -ef | awk -v pid=$pid '$2 == pid { print $3 }'`

sock=`lsof -p $ppid 2>/dev/null | awk '$4 == "0u" && $5 == "inet" { print $9 }'`
echo $sock