path: root/bashrc/common/ssh-agent-forwarding.sh

wipe_removed_sockets() {
    TMPFILE=$(mktemp)

    # cleanup old agent-sockets
    if [ -r "${HOME}/.ssh-agent-forwarding" ]; then
        cut -d" " -f2 "${HOME}/.ssh-agent-forwarding" | \
            xargs ls -a 2>/dev/null | \
            grep -f - "${HOME}/.ssh-agent-forwarding" | \
            sort -n > "${TMPFILE}"
    
        mv "${TMPFILE}" "${HOME}/.ssh-agent-forwarding"
    fi
}

fixssh() {
    # if the symlinked socket, does not exists
    # find latest connection, that is still alive
    wipe_removed_sockets
    
    if [ ! -e "${HOME}/.ssh-agent-forwarded-sock" ]; then
	LATEST_SOCK=$(tail -n 1 "${HOME}/.ssh-agent-forwarding" | cut -d" " -f2)

	if [ -n "$LATEST_SOCK" ]; then
	    ln -sf "${LATEST_SOCK}" "${HOME}/.ssh-agent-forwarded-sock"
	fi
    fi
}

wipe_removed_sockets

# if this login is via ssh and ssh-agent is forwarded
if [ -n "$SSH_AUTH_SOCK" -a -n "$SSH_CLIENT" -a "$SSH_AUTH_SOCK" != "${HOME}/.ssh-agent-forwarded-sock" ]; then

    # add current socket
    echo "$(date +%s) $SSH_AUTH_SOCK $SSH_CLIENT" >> "${HOME}/.ssh-agent-forwarding"

    # remove old symlink
    if [ -L "${HOME}/.ssh-agent-forwarded-sock" ]; then
	rm -f "${HOME}/.ssh-agent-forwarded-sock"
    fi

    # create static symlink to socket
    if [ ! -e "${HOME}/.ssh-agent-forwarded-sock" ]; then
	ln -sf "$SSH_AUTH_SOCK" "${HOME}/.ssh-agent-forwarded-sock"
    else
	echo "Warning: ${HOME}/.ssh-agent-forwarded-sock exists and is not a symlink!"
    fi
fi

# if ssh auth sock not exists and the symlink exists
# change $SSH_AUTH_SOCK to the symlink
if [ ! -e "$SSH_AUTH_SOCK" -a -e "${HOME}/.ssh-agent-forwarded-sock" ]; then
    SSH_AUTH_SOCK="${HOME}/.ssh-agent-forwarded-sock"
fi

export SSH_AUTH_SOCK