#!/usr/bin/env python
#
# Copyright 2008-2009 LShift Ltd
# Copyright 2005-2007 by Intevation GmbH <intevation@intevation.de>
# Authors:
# Paul Crowley <paul@lshift.net>
# Thomas Arendsen Hein <thomas@intevation.de>
# with ideas from  Mathieu PASQUET <kiorky@cryptelium.net>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

"""
hg-ssh - limit access to hg repositories reached via ssh.  Part of
mercurial-server.

This script is called by hg-ssh-wrapper with no arguments - everything
should be in enviroment variables:

HG_ACCESS_RULES_PATH identifies the paths to the rule files
REMOTE_USER the remote user (which is the key used by ssh)
SSH_ORIGINAL_COMMAND the command the user was trying to run

It uses SSH_ORIGINAL_COMMAND to determine what the user was trying to
do and to what repository, and then checks each rule in the rule file
in turn for a matching rule which decides what to do, defaulting to
disallowing the action.

"""

# enable importing on demand to reduce startup time
from mercurial import demandimport; demandimport.enable()

from mercurial import dispatch

import sys, os
from mercurialserver import ruleset

def fail(message):
    #logfile.write("Fail: %s\n" % message)
    sys.stderr.write(message + "\n")
    sys.exit(-1)

def getpath(path):
    if path.endswith("/"):
        path = path[:-1]
    if not ruleset.goodpath(path):
        fail("Disallowing path: %s" % path)
    return path

def try_cmd(rules, cmd):
    if cmd.startswith('hg -R ') and cmd.endswith(' serve --stdio'):
        repo = getpath(cmd[6:-14])
        if rules.allow("read", repo=repo):
            os.environ["HG_REPO_PATH"] = repo
            dispatch.dispatch(['-R', repo, 'serve', '--stdio'])
            return
    elif cmd.startswith('hg init '):
        repo = getpath(cmd[8:])
        if rules.allow("init", repo=repo):
            os.environ["HG_REPO_PATH"] = repo
            dispatch.dispatch(['init', repo])
            return
    fail("Illegal command %r" % cmd)

#logfile = open("/tmp/hg-ssh.%d.txt" % os.getpid(), "w")
#logfile.write("Started: %s\n" % sys.argv)

if len(sys.argv) != 2:
    fail("hg-ssh must have exactly one argument (%s)" 
        % sys.argv)

remote_user = sys.argv[1]
os.environ['REMOTE_USER'] = remote_user

rules = ruleset.rules_from_env()
rules.set(user = getpath(remote_user))
rules.set(branch = None, file = None)
try_cmd(rules, os.environ.get('SSH_ORIGINAL_COMMAND', '?'))