zsh: fixup env vars and update a comment

[dotfiles.git] / etc / zsh / .zprofile

# NOTE:
# our .zprofile can be expensive, so we keep track of what has been run
# already, and only set up what is necessary. this also allows us to re-source
# the file to reinitialize specific parts when desired.
#
# in order to ensure future interactive environments are set up as early as
# possible, we source this file from .zshenv for non-login shells, under some
# specific conditions outlined there.
#
# this file respects non-interactive sessions and will not intentionally emit
# output.

### fix path after system profile scripts have possibly mangled it
if [[ ! -v _sev_setup_path || -o login ]] {
    _sev_setpath
    export _sev_setup_path=
}

### dbus
if [[ ! -v DBUS_SESSION_BUS_ADDRESS && -v commands[dbus-launch] ]] {
    eval $(dbus-launch)
    export DBUS_SESSION_BUS_ADDRESS DBUS_SESSION_BUS_PID
}

### gpg agent + forwarding
# NOTE: while ssh manages its auth sock in-protocol when ForwardSsh is enabled,
#       GPG must be forwarded manually over Unix socket. to support this, we
#       forward the restricted gpg-agent extra socket to the remote host with a
#       RemoteForward rule in ~/.ssh/config that uses the _GNUPG_SOCK_* vars.
#
#       to avoid conflicts with other ssh sessions where the same user is
#       connecting to the same host from different machines, gpg should utilize
#       its own forwarded socket for each session. previously, you could
#       provide a path to the agent socket in GPG_AGENT_INFO, but that was
#       deprecated in GPG v2.1; instead, we must replace the socket in gpg's
#       socket dir.
#
#       gnupg commits fb88f37–aab8a0b moved sockets from GNUPGHOME by default
#       to directories under /run. aab8a0b in particular solidifies the
#       functionality shift to utilize systemd-logind's user runtime
#       directories. if the dir isn't found, gpg will fall back to the homedir.
#       since previous functionality allowed multiple homedirs with multiple
#       sockets, a provision was added where changing GNUPGHOME will also
#       change the socket dir to a hashed dir under the usual runtime dir.
#
#       utilizing this information, we can conclude:
#         - on systems with user runtime dirs, changing GNUPGHOME will also
#           give us a unique socket dir under the user runtime dir;
#         - on other systems, the socket dir follows GNUPGHOME.
#       therefore, the safest way to ensure unique sockets while not having to
#       write specific logic for both scenarios is to simply change GNUPGHOME.
#       the easiest way to do this is to create a new dir and link the contents
#       of GNUPGHOME to the new home. we can then replace all of the agent
#       sockets wherever they now are with the forwarded one. in either case we
#       will be overwriting the session-specific sockets.
#
# NOTE: since Unix sockets are not supported under Windows, this will not work
#       under msys, cygwin, mingw, etc., but may work under wsl2.
#
# HACK: without SendEnv, which is disabled by default in most sshd configs,
#       there is no foolproof way to prevent race conditions via socket
#       filename collisions or to pass the desired forward path to the remote
#       host environment. we just have to guess the path we choose is good on
#       the desination, and assume the newest matching socket is the correct
#       one after connecting. in theory, we could occlude the ssh binary on
#       PATH with an alias or script that would allow us to communicate with
#       the remote host before opening a shell, so that we can have the host
#       communicate back to the client where it wants a socket created or ask
#       the host if the path the client wants to use is writable. however, this
#       would open up too many edge cases where it wouldn't work or be too
#       clunky (e.g. asking for password twice) to make it worth it.
function _gpg_socketpath {
    # dirs are percent-encoded: https://stackoverflow.com/a/64312099
    echo ${1//(#b)%([[:xdigit:]](#c2))/${(#):-0x$match[1]}}
}
if [[ ! -v _sev_setup_gpg_forward && -v commands[gpg] ]] {
    # XXX: assuming /tmp exists and is writable on destination
    export _GNUPG_SOCK_DEST_BASE=/tmp/.gpg-agent-forward
    export _GNUPG_SOCK_DEST_EXT=$(date +%s).$RANDOM
    export _GNUPG_SOCK_DEST=$_GNUPG_SOCK_DEST_BASE.$_GNUPG_SOCK_DEST_EXT
    export _sev_gpg_forward_dir=$XDG_RUNTIME_DIR/gnupg/.ssh_forward
    _sev_zcleanup gpg-forward

    # find our forwarded socket
    s=($_GNUPG_SOCK_DEST_BASE*(N=oc[1]))
    if [[ -n $s && -v SSH_CLIENT ]] {
        # create new forward dir
        export _sev_setup_gpg_forward=
        h=$_sev_gpg_forward_dir/$$
        mkdir -pm700 $h
        for x (gpg{,-agent}.conf sshcontrol random_seed
               pubring.kbx{,~} trustdb.gpg private-keys-v1.d crls.d) {
            ln -s ${GNUPGHOME:-~/.gnupg}/$x $h
        }
        export GNUPGHOME=$h
        unset h
        for x in $(gpgconf --list-dirs | grep 'agent-.*-\?socket:'); do
            x=$(_gpg_socketpath ${x/#agent-*socket:})
            if [[ ! -v primary ]] {
                # move forwarded socket to first valid agent socket path
                # XXX: if tmp is on different filesystem this may not work
                mv $s $x
                primary=$x
            } else {
                # make links to forwarded socket for any others
                ln -s $primary $x
            }
        done
        unset x primary
    }
    unset s

    # what we will forward if we start a new ssh connection
    # NOTE: do this after setting up GNUPGHOME to pick up new socket path;
    #       if already connected over SSH, extra should be the remote one
    export _GNUPG_SOCK_SRC=$(_gpg_socketpath \
      $(gpgconf --list-dirs agent-extra-socket))
} elif [[ ! -v _sev_setup_gpg_forward ]] {
    # required for RemoteForward to not error out if the vars are unset
    [[ ! -v _GNUPG_SOCK_SRC ]] && export _GNUPG_SOCK_SRC=/nonexistent
    [[ ! -v _GNUPG_SOCK_DEST ]] && export _GNUPG_SOCK_DEST=/nonexistent
}

### gpg agent
if [[ -v commands[gpg-connect-agent] &&
        ( ! -v _sev_setup_gpgagent || -v _sev_refresh_gpgagent ) ]] {
    # avoid printing if we have already set up tty before
    [[ ! -v _sev_setup_gpgagent && -o interactive ]] && p=true || p=false
    if {$p} {
        print -nP '%F{blue}>>>%f GPG: '
        if [[ -v _sev_setup_gpg_forward ]] {
            print -nP '%F{yellow}Forwarded agent '
        } else {
            print -nP '%F{green}Agent '
        }
    }
    gpg-connect-agent /bye >/dev/null 2>&1
    if [[ $? -ne 0 ]] {
        $p && print -P '%F{red}communication error'
    } else {
        if [[ ! -v _sev_setup_gpg_forward ]] {
            if [[ ${+GPG_TTY} -eq 0 && -o interactive ]]
                export GPG_TTY=$(tty)
            if [[ ( -v DISPLAY || -v WAYLAND_DISPLAY ) &&
                  ${PINENTRY_USER_DATA/USE_TTY=0} == $PINENTRY_USER_DATA ]]
                export PINENTRY_USER_DATA=USE_TTY=$((
                  ${+DISPLAY} + ${+WAYLAND_DISPLAY} == 0))
            # XXX: don't know if gpg-agent supports comments after directives
            # XXX: path could have #
            # XXX: we are assuming this is our pinentry from .local/bin
            sed -Ei 's#^([[:space:]]*pinentry-program[[:space:]]).*$#\1'$HOME'/.local/bin/pinentry#' \
              ${GNUPGHOME:-~/.gnupg}/gpg-agent.conf 2>/dev/null
            # XXX: could check for changes before doing this to save perf
            gpg-connect-agent RELOADAGENT UPDATESTARTUPTTY /bye >/dev/null 2>&1
            if {$p} {
                gpg-connect-agent /subst /serverpid \
                  "/echo pid \${get serverpid} on $GPG_TTY" /bye 2>/dev/null
                print -nP '%f'
            }
        } elif {$p} {
            print -P '%f'
        }
        export _sev_setup_gpgagent=
    }
    unset p _sev_refresh_gpgagent
}

### ssh agent
if [[ ! -v _sev_setup_ssh ]] {
    # NOTE: preferred order of agents to check: okcagent, gnupg, openssh
    #       first block takes care of okcagent and openssh, second gnupg
    # XXX: doesn't actually check if ssh is enabled in gpg
    [[ -o interactive ]] && print -nP '%F{blue}>>>%f SSH: %F{green}'
    if [[ ! -v SSH_AUTH_SOCK && ( -v commands[okc-ssh-agent] ||
          ( -v commands[ssh-agent] && ! -v commands[gpg] ) ) ]] {
        okc=${commands[okc-ssh-agent]:+okc-}
        e=$_sev_tmp/${okc}ssh-agent-exports
        typeset sock=
        typeset -i pid=
        if [[ -f $e ]] {
            IFS=$'\0' read -r sock pid <$e
        }
        if [[ -S $sock && $pid > 0 ]] && kill -0 $pid >/dev/null 2>&1; then
            [[ -o interactive ]] && print -P "Reusing agent PID $pid%f"
            export SSH_AUTH_SOCK=$sock
            export SSH_AGENT_PID=$pid
        else
            # TODO: ensure ssh-agent path looks legit to avoid unsafe eval?
            # XXX: doesn't appear to be any other way to handle redirection.
            #      because eval needs to write to current scope environment
            #      subshells can't be used to capture output and print.
            c='TMPDIR=$_sev_tmp ${okc}ssh-agent'
            if [[ -o interactive ]] {
                eval $(eval $=c)
                print -nP '%f'
            } else {
                eval $(eval $=c) >/dev/null 2>&1
            }
            echo -n $SSH_AUTH_SOCK$'\0'$SSH_AGENT_PID >!$e
            unset c
        fi
        unset okc e sock pid
    } elif [[ ! -v SSH_AUTH_SOCK && -v commands[gpg] ]] {
        # since gpg should have been started above, just export and notify
        if [[ -o interactive ]] {
            if [[ -v _sev_setup_gpg_forward ]] {
                echo 'Forwarded GPG agent'
            } else {
                gpg-connect-agent /subst /serverpid \
                  '/echo GPG agent pid ${get serverpid}' /bye
            }
            print -nP '%f'
        }
        export SSH_AUTH_SOCK=$(_gpg_socketpath \
          $(gpgconf --list-dirs agent-ssh-socket))
    } elif [[ -v SSH_AUTH_SOCK ]] {
        [[ -o interactive ]] && print -P 'Preconfigured agent%f'
    } else {
        [[ -o interactive ]] && print -P '%F{red}No agent available%f'
    }

    export _sev_setup_ssh=
}
unfunction _gpg_socketpath

### load site-specific
load-site-dotfile zprofile