#!/bin/sh
#
# This file is part of steamos-devkit
# SPDX-License-Identifier: LGPL-2.1+
#
# Copyright © 2017-2018 Collabora Ltd
#
# This package is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This package is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this package.  If not, see
# <http://www.gnu.org/licenses/>.

# Sample script to install ssh keys that were approved by the
# approve-ssh-key script.
#
# A script or binary (written in any language) named install-ssh-key
# can be placed in the same directory as this sample, and it will be
# used preferentially.
#
# Execution environment:
# - Runs as root
# Input:
# - The public key is in a temporary file accessible via argv[1], in
#   OpenSSH format
# - argv[2], ... are the users to which we should grant access
# Output:
# - Exit 0 to accept the key, or nonzero to reject or on error
#
# This sample implementation should be suitable for any machine that
# has the specified users. A production implementation would be similar
# or even identical.

set -e

public_key="$1"
shift

echo "Installing public key '$public_key' for users: $*"

for user in "$@"
do
    if pwent="$(getent passwd "$user")"
    then
        home="$(echo "$pwent" | cut -d: -f6)"
        group="$(id -gn "$user")"
        install -d -m 0755 -o "$user" -g "$group" "$home/.ssh"
        if ! [ -e "$home/.ssh/authorized_keys" ]
        then
            install -m 0600 -o "$user" -g "$group" "$public_key" "$home/.ssh/authorized_keys"
        else
            if ! ( grep -v '^#' "$home/.ssh/authorized_keys" | grep -qF "$(cut -d " " -f2 "$public_key")" )
            then
                if [ -n "$(tail -1c "$home/.ssh/authorized_keys")" ]
                then
                    echo >> "$home/.ssh/authorized_keys"
                fi
                cat "$public_key" >> "$home/.ssh/authorized_keys"
            fi
        fi
    fi
done

echo "Public key installed"

exit 0