connect with gpg-agent (with ssh) at all costs

connect-to-agent.sh

# Tries to connect to a running gpg-agent or starts one itself. It tries connecting to: 
#    1. the agent currently designated in the environment,
#    2. the agent designated in the $HOME/.gnupg/gpg-agent-info file,
#    3. the most recently started running gpg-agent process, or last
#    4. a new gpg-agent process, with ssh support and, if applicable, x11 support.
# 
# Step no. 3 requires the "pgrep" and "sockstat" utilities (available on FreeBSD)

CONNECTGPG=$(which gpg-connect-agent)
if [ -x $CONNECTGPG ] ; then
    agent_info=$HOME/.gnupg/gpg-agent-info
    validate_agent () {
        if env GPG_AGENT_INFO=$GPG_AGENT_INFO \
            $CONNECTGPG /bye >/dev/null 2>&1 ; then
           export GPG_AGENT_INFO SSH_AUTH_SOCK \
                  SSH_AGENT_PID GPG_TTY=$(tty)
           return 0
        fi
        return 1
    }
    for _ in "" ; do
        validate_agent && break
        if [ -f $agent_info ] ; then
            . $agent_info
            validate_agent && break
        fi
        agent_pid=""
        if [ -x $(which pgrep) ] ; then
            agent_pid=$(pgrep -o gpg-agent)
        fi
        if [ -n "$agent_pid" -a -x $(which sockstat) ] ; then
            sockstat -u | grep "$agent_pid" | sed -e 's/.* //' \
                -e "s/.*gpg-agent\$/GPG_AGENT_INFO=&:$agent_pid:1/" \
                -e 's/.*gpg-agent.ssh$/SSH_AUTH_SOCK=&/' > $agent_info
            echo "SSH_AGENT_PID=$agent_pid" >> $agent_info
            . $agent_info
            validate_agent && break
        fi
        eval $(gpg-agent --sh --daemon ${DISPLAY:+--display $DISPLAY} \
            --enable-ssh-support \
            --write-env-file ${HOME}/.gnupg/gpg-agent-info)
        validate_agent && break
    done
    unset agent_info agent_pid
    unset -f validate_agent
fi
unset CONNECTGPG