#!/bin/sh
## Allow remote users to "darcs push" to your server via SSH, without
## giving them full shell access, and without giving them access to
## one-another's repositories.  See git-shell2 and rrsync for similar
## examples for git(1) and rsync(1) respectively.
##
## Copyright (C) 2007  Miklós Vajna (git-shell2)
## Copyright (C) 2009  CSÉCSY László
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program 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 General Public License for more details.

## Ensure there is an account "darcs", for which key-based SSH logins
## are allowed.  In ~darcs/.ssh/authorized_keys, add lines of the form
##
##   command="/usr/local/bin/darcs-shell <user name>" <public key>
##
## Create and populate the access control list /usr/local/darcs/access
## with lines of the form
##
##   fred:/home/darcs/repos/foo/:r
##   fred:/home/darcs/repos/foo+john/:r
##   fred:/home/darcs/repos/foo+fred/:rw
##   john:/home/darcs/repos/foo/:r
##   john:/home/darcs/repos/foo+john/:rw
##   john:/home/darcs/repos/foo+fred/:r
##
## This gives two users "fred" and "john" access to three repos,
## "foo", "foo+fred" and "foo+john".  They both have read access to
## "foo" and each other's "foo+<name>", and write access to their own
## "foo+<name>".

access='/usr/local/darcs/access'
user=$1

if [ "x" = "x${user}" ]; then
    echo "No user supplied in authorized_keys" | logger -t darcs-shell
    exit 1
fi

if [ "x${SSH_ORIGINAL_COMMAND}" = "x" ]; then
    echo "SSH_ORIGINAL_COMMAND must be given" | logger -t darcs-shell
    exit 1
fi

if [ ! -f ${access} ]; then
    echo "Access control file ${access} does not exist!" | logger -t darcs-shell
    exit 1
fi

command=$(echo ${SSH_ORIGINAL_COMMAND} | cut -d' ' -f2)

acctype=''
if [ "x${command}" = "xtransfer-mode" ]; then
    acctype='r[^w]*'
    repo=$(echo ${SSH_ORIGINAL_COMMAND} | cut -d' ' -f4)
elif [ "x${command}" = "xapply" ]; then
    acctype='rw'
    repo=$(echo ${SSH_ORIGINAL_COMMAND} | cut -d' ' -f5 | cut -d\' -f2)/
    command="${command} --all"
else
    echo "Unknown command" | logger -t darcs-shell
    exit 1
fi

# Uncomment this to have extra debug info.
#echo "user: ${user} command: ${command} repo: ${repo} access: ${acctype}" | logger -t darcs-shell

if ! grep "${user}:${repo}:${acctype}" ${access} > /dev/null; then
    echo "No access granted for user ${user} to repository ${repo}" | logger -t darcs-shell
    exit 1
fi

if [ ! -d ${repo} ]; then
    echo "No such repository hosted" | logger -t darcs-shell
    exit 1
fi

darcs ${command} --repodir ${repo}