myshellconfig/bin/ssh-agent-start-or-restart

#!/bin/bash

[ -z "${SSH_IDENTITIES_DIR+x}" ] && { SSH_IDENTITIES_DIR="${SSH_IDENTITIES_DEFAULT_DIR-${HOME}/.ssh/identities}"; export SSH_IDENTITIES_DIR; }
[ -z "${SSH_AGENTS_DIR+x}" ] && { SSH_AGENTS_DIR=${SSH_AGENTS_DEFAULT_DIR-~/.ssh/agents}; export SSH_AGENTS_DIR; }
[ -z "${SSH_AGENT_SOCKETS_DIR+x}" ] && { SSH_AGENT_SOCKETS_DIR=${SSH_AGENT_SOCKETS_DEFAULT_DIR-~/.ssh/agents}; export SSH_AGENT_SOCKETS_DIR; }
echo SSH_AGENTS_DIR: $SSH_AGENTS_DIR >&2
echo SSH_AGENT_SOCKETS_DIR: $SSH_AGENT_SOCKETS_DIR >&2
echo SSH_IDENTITIES_DIR: $SSH_IDENTITIES_DIR >&2
agent-start-or-restart () {
    
    local ssh_identity
    local agentfile
    local agentsocket

    if [ -n "${1+x}" ]; then
        ssh_identity="$1"
        agentfile="${SSH_AGENTS_DIR}/agent-${ssh_identity}-$(hostname)"
        agentsocket="${SSH_AGENT_SOCKETS_DIR}/socket-${ssh_identity}-$(hostname)"
        echo "agentfile: $agentfile" >&2
        echo "agentsocket: $agentsocket" >&2
        echo ssh-identität: $ssh_identity >&2
        if [ -e $agentfile ]; then

            # look if agent is reachable
#            local sshsock sshpid
#            sshsock=$SSH_AUTH_SOCK
#            sshpid=$SSH_AGENT_PID
#            unset SSH_AUTH_SOCK SSH_AGENT_PID
            /bin/sh -c "unset SSH_AUTH_SOCK SSH_AGENT_PID; . $agentfile >/dev/null 2>&1; ssh-add -l >&2"
            case $? in
                0|1)
                    echo "agent is running" >&2
                    ;;
                2)
                    echo "agent is not running 1" >&2
                    [ -e $agentsocket ] && rm "$agentsocket"
                    ssh-agent -a $agentsocket $SSH_AGENT_OPTIONS > $agentfile 2>&2
                    echo "agent started" >&2
                    ;;
            esac
        else
            echo "agent is not running 2" >&2
            #rm "$agentsocket"
            echo ssh-agent -a $agentsocket \> $agentfile
            ssh-agent -a $agentsocket $SSH_AGENT_OPTIONS > $agentfile 2>&2
            echo "agent started" >&2
        fi

        echo -n "agent for $ssh_identity: " >&2
        echo $agentfile
        return 0

    else
        echo no identity given - exit >&2
        return 1
    fi


}

agent-load-identity-keys () {

    local ssh_identity
    local agentfile
    local agentsocket
    local fingerprints
    declare -a fingerprints
    local fingerprint
    local tokenfingerprint

    if [ -n "${1+x}" ]; then
        ssh_identity="$1"
        agentfile="${SSH_AGENTS_DIR}/agent-${ssh_identity}-$(hostname)"
        agentsocket="${SSH_AGENT_SOCKETS_DIR}/socket-${ssh_identity}-$(hostname)"
        identitydir=${SSH_IDENTITIES_DIR}/${ssh_identity}
        echo "agentfile: $agentfile" >&2
        echo "agentsocket: $agentsocket" >&2
        echo ssh-identität: $ssh_identity >&2

        fingerprints=( $(ssh-runinagent $agentfile "ssh-add -l|awk '{print \$2}'") )
        for key in $(ls ${SSH_IDENTITIES_DIR}/${ssh_identity}|grep -v "pub$\|so$"); do
            echo key: $key
            fingerprint=$(ssh-keygen -l -f ~/.ssh/identities/bmi/id_ed25519|awk '{print $2}')
            echo ${fingerprints[*]} and $fingerprint
            if [[ ${fingerprints[*]} =~ "$fingerprint" ]]; then
                echo "$key is loaded" >&2
            else
                echo "$key is not loaded" >&2
                ssh-runinagent $agentfile ssh-add ${SSH_ADD_OPTIONS} ${identitydir}/${key}
            fi
        done
        for token in $(ls ${SSH_IDENTITIES_DIR}/${ssh_identity}|grep  "so$"); do
            echo token: $token
            tokenfingerprint="$(ssh-keygen -l -D $token|tr -s ' '|awk '{print $2}')"
            if [[ ${fingerprints[*]} =~ "$tokenfingerprint" ]]; then
                echo "$token is loaded" >&2
            else
                echo "$token is not loaded" >&2
                ssh-runinagent $agentfile ssh-add ${SSH_ADD_OPTIONS} -s ${identitydir}/${token}
            fi
        done
    fi
}

ssh-runinagent () {

    local agentfile
    local command
    agentfile=${1}
    shift
    sshcommand=${@}

    echo "run command »$sshcommand« in agent $agentfile" >&2
    if [ -e "$agentfile" ]; then 
        /bin/sh -c "unset SSH_AUTH_SOCK SSH_AGENT_PID; . $agentfile >/dev/null 2>/dev/null; $sshcommand"
        return $?
    else
        echo "agentfile not existent" >&2
        return 1
    fi
}

agent-start-or-restart $1
agent-load-identity-keys $1
exit $?