# acl.py - changeset access control for mercurial

#

# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

'''hooks for controlling repository access

This hook makes it possible to allow or deny write access to portions

The authorization is matched based on the local user name on the

system where the hook runs, and not the committer of the original

changeset (since the latter is merely informative).

The acl hook is best used along with a restricted shell like hgsh,

preventing authenticating users from doing anything other than

pushing or pulling. The hook is not safe to use if users have

interactive shell access, as they can then disable the hook.

Nor is it safe if remote users share an account, because then there

is no way to distinguish them.

  [extensions]

  acl =

  [hooks]

  pretxnchangegroup.acl = python:hgext.acl.hook

  [acl]

  # Check whether the source of incoming changes is in this list

  # ("serve" == ssh or http, "push", "pull", "bundle")

  sources = serve

  [acl.allow]

  docs/** = doc_writer

  .hgtags = release_engineer

'''

from mercurial.i18n import _

from mercurial import util, match

import getpass, urllib, grp

def _getusers(group):

    return grp.getgrnam(group).gr_mem

def _usermatch(user, usersorgroups):

    if usersorgroups == '*':

        return True

    for ug in usersorgroups.replace(',', ' ').split():

        if user == ug or ug.find('@') == 0 and user in _getusers(ug[1:]):

            return True

    return False

def buildmatch(ui, repo, user, key):

    '''return tuple of (match function, list enabled).'''

    if not ui.has_section(key):

        ui.debug('acl: %s not enabled\n' % key)

        return None

    pats = [pat for pat, users in ui.configitems(key)

            if _usermatch(user, users)]

    ui.debug('acl: %s enabled, %d entries for user %s\n' %

             (key, len(pats), user))

    if pats:

        return match.match(repo.root, '', pats)

    return match.exact(repo.root, '', [])

def hook(ui, repo, hooktype, node=None, source=None, **kwargs):

    if hooktype not in ['pretxnchangegroup', 'pretxncommit']:

        raise util.Abort(_('config error - hook type "%s" cannot stop '

                           'incoming changesets nor commits') % hooktype)

    if (hooktype == 'pretxnchangegroup' and

        source not in ui.config('acl', 'sources', 'serve').split()):

        ui.debug('acl: changes have source "%s" - skipping\n' % source)

        return

    user = None

    if source == 'serve' and 'url' in kwargs:

        url = kwargs['url'].split(':')

        if url[0] == 'remote' and url[1].startswith('http'):

            user = urllib.unquote(url[3])

    if user is None:

        user = getpass.getuser()

    cfg = ui.config('acl', 'config')

    if cfg:

        ui.readconfig(cfg, sections = ['acl.allow', 'acl.deny'])

    allow = buildmatch(ui, repo, user, 'acl.allow')

    deny = buildmatch(ui, repo, user, 'acl.deny')

    for rev in xrange(repo[node], len(repo)):

        ctx = repo[rev]

        for f in ctx.files():

            if deny and deny(f):

                ui.debug('acl: user %s denied on %s\n' % (user, f))

                raise util.Abort(_('acl: access denied for changeset %s') % ctx)

            if allow and not allow(f):

                ui.debug('acl: user %s not allowed on %s\n' % (user, f))

                raise util.Abort(_('acl: access denied for changeset %s') % ctx)

        ui.debug('acl: allowing changeset %s\n' % ctx)