# factotum.py - Plan 9 factotum integration for Mercurial

#

# Copyright (C) 2012 Steven Stallion <sstallion@gmail.com>

#

# 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.

#

# You should have received a copy of the GNU General Public License along

# with this program; if not, write to the Free Software Foundation, Inc.,

# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

'''http authentication with factotum

This extension allows the factotum(4) facility on Plan 9 from Bell Labs

platforms to provide authentication information for HTTP access. Configuration

entries specified in the auth section as well as authentication information

provided in the repository URL are fully supported. If no prefix is specified,

a value of "*" will be assumed.

By default, keys are specified as::

  proto=pass service=hg prefix=<prefix> user=<username> !password=<password>

If the factotum extension is unable to read the required key, one will be

requested interactively.

A configuration section is available to customize runtime behavior. By

default, these entries are::

  [factotum]

  executable = /bin/auth/factotum

  mountpoint = /mnt/factotum

  service = hg

The executable entry defines the full path to the factotum binary. The

mountpoint entry defines the path to the factotum file service. Lastly, the

service entry controls the service name used when reading keys.

'''

from __future__ import absolute_import

import os

from mercurial.i18n import _

from mercurial import (

    error,

    httpconnection,

    registrar,

    url,

    util,

)

urlreq = util.urlreq

passwordmgr = url.passwordmgr

ERRMAX = 128

_executable = _mountpoint = _service = None

configtable = {}

configitem = registrar.configitem(configtable)

configitem('factotum', 'executable',

    default='/bin/auth/factotum',

)

configitem('factotum', 'mountpoint',

    default='/mnt/factotum',

)

configitem('factotum', 'service',

    default='hg',

)

def auth_getkey(self, params):

    if not self.ui.interactive():

        raise error.Abort(_('factotum not interactive'))

    if 'user=' not in params:

        params = '%s user?' % params

    params = '%s !password?' % params

    os.system("%s -g '%s'" % (_executable, params))

def auth_getuserpasswd(self, getkey, params):

    params = 'proto=pass %s' % params

    while True:

        fd = os.open('%s/rpc' % _mountpoint, os.O_RDWR)

        try:

            os.write(fd, 'start %s' % params)

            l = os.read(fd, ERRMAX).split()

            if l[0] == 'ok':

                os.write(fd, 'read')

                status, user, passwd = os.read(fd, ERRMAX).split(None, 2)

                if status == 'ok':

                    if passwd.startswith("'"):

                        if passwd.endswith("'"):

                            passwd = passwd[1:-1].replace("''", "'")

                        else:

                            raise error.Abort(_('malformed password string'))

                    return (user, passwd)

        except (OSError, IOError):

            raise error.Abort(_('factotum not responding'))

        finally:

            os.close(fd)

        getkey(self, params)

def monkeypatch_method(cls):

    def decorator(func):

        setattr(cls, func.__name__, func)

        return func

    return decorator

@monkeypatch_method(passwordmgr)

def find_user_password(self, realm, authuri):

    user, passwd = self.passwddb.find_user_password(realm, authuri)

    if user and passwd:

        self._writedebug(user, passwd)

        return (user, passwd)

    prefix = ''

    res = httpconnection.readauthforuri(self.ui, authuri, user)

    if res:

        _, auth = res

        prefix = auth.get('prefix')

        user, passwd = auth.get('username'), auth.get('password')

    if not user or not passwd:

        if not prefix:

            prefix = realm.split(' ')[0].lower()

        params = 'service=%s prefix=%s' % (_service, prefix)

        if user:

            params = '%s user=%s' % (params, user)

        user, passwd = auth_getuserpasswd(self, auth_getkey, params)

    self.add_password(realm, authuri, user, passwd)

    self._writedebug(user, passwd)

    return (user, passwd)

def uisetup(ui):

    global _executable

    _executable = ui.config('factotum', 'executable')

    global _mountpoint

    _mountpoint = ui.config('factotum', 'mountpoint')

    global _service

    _service = ui.config('factotum', 'service')