Re-use existing ssh-agent

Saturday, 03 April 2010 12:40

// dot this script, don't just run it as a script (which would run it in its own sub-shell) because you need the variables to be set in the context of your current shell.



#!/bin/bash



for FILE in $(find /tmp/ssh-???*[0-9]* -type s -user ${LOGNAME} -name "agent.[0-9]*")

do



    GOT_AGENT=0



    SOCK_PID=${FILE##*.}



    PID=$(ps -fu${LOGNAME}|awk '/ssh-agent/ && ( $2=='${SOCK_PID}' || $3=='${SOCK_PID}' || $2=='${SOCK_PID}' +1 ) {print $2}')



    SOCK_FILE=${FILE}



    SSH_AUTH_SOCK=${SOCK_FILE}; export SSH_AUTH_SOCK;

    SSH_AGENT_PID=${PID}; export SSH_AGENT_PID;



    ssh-add -l | grep : > /dev/null

    if [ $? = 0 ]

    then

        GOT_AGENT=1

        echo "Agent pid ${PID}"

        break

    fi

    echo "Skipping pid ${PID}"



done



if [ $GOT_AGENT = 0 ]

then

    ssh-add

fi

Before I used the find I was using this, but it's not as accurate, and the socket file is more important than the PID when you're trying to connect to an existing agent, so it makes sense to me to start with that.
(unless your find would be horribly slow for some reason)



for PID in $(ps -furoot | awk '/ssh-agent/{print $2}')

do

    let SOCK_PID=PID-1

    SOCK_FILE=$(ls -d /tmp/ssh-???*${SOCK_PID}/agent.${SOCK_PID})