sshrc

#!/usr/bin/env bash

sshrc_tar() {
    local sshhome="$1"
    shift
    tar cfz - -h -C "$sshhome" --absolute-names --transform='flags=r;s|^/.*/([^/]+)$|.sshrc.d/\1|x' "$@"
}

sshrc() {
    local SSHHOME=${SSHHOME:=~}
    if [[ -f "$SSHHOME/.sshrc" ]]; then
        local files=( .sshrc )
        if [[ -d "$SSHHOME/.sshrc.d" ]]; then
            files+=( .sshrc.d )
        fi
        if [[ -n "$SSHRC_FILES" ]]; then
            local -a additional_files
            IFS="|" read -a additional_files -r <<<"$SSHRC_FILES"
            files+=( "${additional_files[@]}" )
        fi
        SIZE=$(sshrc_tar "$SSHHOME" "${files[@]}" | wc -c)
        if (( SIZE > 65536 )); then
            echo >&2 $'.sshrc.d and .sshrc files must be less than 64kb\ncurrent size: '"$SIZE"' bytes'
            exit 1
        fi
        if [[ -z "$CMDARG" ]] && ! [[ -e ~/.sshrc.d/.hushlogin ]]; then
            WELCOME_MSG="
                if [ ! -e ~/.hushlogin ]; then
                    if [ -e /etc/motd ]; then cat /etc/motd; fi
                    if [ -e /etc/update-motd.d ]; then run-parts /etc/update-motd.d/ 2>/dev/null; fi
                    last -F \$USER 2>/dev/null | grep -v 'still logged in' | head -n1 | awk '{print \"Last login:\",\$4,\$5,\$6,\$7,\$8,\"from\",\$3;}'
                fi
                "
        else
            WELCOME_MSG=""
        fi
        ssh -t "$DOMAIN" "${SSHARGS[@]}" "
            (command -v base64 >/dev/null || command -v openssl >/dev/null) || { echo >&2 \"sshrc requires base64 or openssl to be installed on the server, but they're not. Aborting.\"; exit 1; }
            if ! command -v base64 >/dev/null; then
                base64() { openssl enc -base64 \"\$@\"; }
            fi
            $WELCOME_MSG
            export SSHHOME=\$(mktemp -d -t .$(whoami).sshrc.XXXXXX)
            export SSHRCCLEANUP=\$SSHHOME
            trap \"rm -rf \$SSHRCCLEANUP; exit\" 0
            echo $'$(base64 < "$0")' | tr -s ' ' $'\n' | base64 -d > \$SSHHOME/sshrc
            chmod +x \$SSHHOME/sshrc

            echo $'$( cat << 'EOF' | base64
                if [ -r /etc/profile ]; then source /etc/profile; fi
                if [ -r ~/.bash_profile ]; then source ~/.bash_profile
                elif [ -r ~/.bash_login ]; then source ~/.bash_login
                elif [ -r ~/.profile ]; then source ~/.profile
                fi
                export PATH=$PATH:$SSHHOME
                source $SSHHOME/.sshrc;
EOF
                )' | tr -s ' ' $'\n' | base64 -d > \$SSHHOME/sshrc.bashrc

            echo $'$( cat << 'EOF' | base64
#!/usr/bin/env bash
                if [ -z "${SSHHOME}" ]; then
                    export SSHHOME="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
                fi
                exec bash --rcfile <(echo '
                [ -r /etc/profile ] && source /etc/profile
                if [ -r ~/.bash_profile ]; then source ~/.bash_profile
                elif [ -r ~/.bash_login ]; then source ~/.bash_login
                elif [ -r ~/.profile ]; then source ~/.profile
                fi
                source '$SSHHOME'/.sshrc;
                export PATH=$PATH:'$SSHHOME'
                ') "$@"
EOF
                )' | tr -s ' ' $'\n' | base64 -d > \$SSHHOME/bashsshrc
            chmod +x \$SSHHOME/bashsshrc

            echo $'$(sshrc_tar "$SSHHOME" "${files[@]}" | base64)' | tr -s ' ' $'\n' | base64 -d | tar mxzf - -C \$SSHHOME
            export SSHHOME=\$SSHHOME
            echo \"$CMDARG\" >> \$SSHHOME/sshrc.bashrc
            bash --rcfile \$SSHHOME/sshrc.bashrc
            "
    else
        echo "No such file: $SSHHOME/.sshrc" >&2
        exit 1
    fi
}

sshrc_parse() {
    SSHARGS=()
    while [[ -n $1 ]]; do
        case $1 in
            -b | -c | -D | -E | -e | -F | -I | -i | -J | -L | -l | -m | -O | -o | -p | -Q | -R | -S | -W | -w )
                SSHARGS+=("$1" "$2"); shift ;;
            -* )
                SSHARGS+=("$1") ;;
            *)
                if [[ -z "$DOMAIN" ]]; then
                    DOMAIN="$1"
                else
                    local SEMICOLON
                    SEMICOLON=$([[ "$*" = *[![:space:]]* ]] && echo '; ')
                    CMDARG="$*$SEMICOLON exit"
                    return;
                fi
                ;;
        esac
        shift
    done
    if [[ -z "$DOMAIN" ]]; then
        ssh "${SSHARGS[@]}"; exit 1;
    fi
}

command -v base64 >/dev/null || { echo >&2 "sshrc requires base64 to be installed locally, but it's not. Aborting."; exit 1; }
sshrc_parse "$@"
sshrc