#!/usr/bin/env python3

#

# Copyright 2005-2007 by Intevation GmbH <intevation@intevation.de>

#

# Author(s):

# Thomas Arendsen Hein <thomas@intevation.de>

#

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

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

"""

hg-ssh - a wrapper for ssh access to a limited set of mercurial repos

To be used in ~/.ssh/authorized_keys with the "command" option, see sshd(8):

command="hg-ssh path/to/repo1 /path/to/repo2 ~/repo3 ~user/repo4" ssh-dss ...

(probably together with these other useful options:

 no-port-forwarding,no-X11-forwarding,no-agent-forwarding)

This allows pull/push over ssh from/to the repositories given as arguments.

If all your repositories are subdirectories of a common directory, you can

allow shorter paths with:

command="cd path/to/my/repositories && hg-ssh repo1 subdir/repo2"

You can use pattern matching of your normal shell, e.g.:

command="cd repos && hg-ssh user/thomas/* projects/{mercurial,foo}"

You can also add a --read-only flag to allow read-only access to a key, e.g.:

command="hg-ssh --read-only repos/*"

"""

import os

import re

import shlex

import sys

# enable importing on demand to reduce startup time

import hgdemandimport

hgdemandimport.enable()

from mercurial import (

    dispatch,

    pycompat,

    ui as uimod,

)

def main():

    # Prevent insertion/deletion of CRs

    dispatch.initstdio()

    cwd = os.getcwd()

    if os.name == 'nt':

        # os.getcwd() is inconsistent on the capitalization of the drive

        # letter, so adjust it. see https://bugs.python.org/issue40368

        if re.match('^[a-z]:', cwd):

            cwd = cwd[0:1].upper() + cwd[1:]

    readonly = False

    args = sys.argv[1:]

    while len(args):

        if args[0] == '--read-only':

            readonly = True

            args.pop(0)

        else:

            break

    allowed_paths = [

        os.path.normpath(os.path.join(cwd, os.path.expanduser(path)))

        for path in args

    ]

    orig_cmd = os.getenv('SSH_ORIGINAL_COMMAND', '?')

    try:

        cmdargv = shlex.split(orig_cmd)

    except ValueError as e:

        sys.stderr.write('Illegal command "%s": %s\n' % (orig_cmd, e))

        sys.exit(255)

    if cmdargv[:2] == ['hg', '-R'] and cmdargv[3:] == ['serve', '--stdio']:

        path = cmdargv[2]

        repo = os.path.normpath(os.path.join(cwd, os.path.expanduser(path)))

        if repo in allowed_paths:

            cmd = [b'-R', pycompat.fsencode(repo), b'serve', b'--stdio']

            req = dispatch.request(cmd)

            if readonly:

                if not req.ui:

                    req.ui = uimod.ui.load()

                req.ui.setconfig(

                    b'hooks',

                    b'pretxnopen.hg-ssh',

                    b'python:__main__.rejectpush',

                    b'hg-ssh',

                )

                req.ui.setconfig(

                    b'hooks',

                    b'prepushkey.hg-ssh',

                    b'python:__main__.rejectpush',

                    b'hg-ssh',

                )

            dispatch.dispatch(req)

        else:

            sys.stderr.write('Illegal repository "%s"\n' % repo)

            sys.exit(255)

    else:

        sys.stderr.write('Illegal command "%s"\n' % orig_cmd)

        sys.exit(255)

def rejectpush(ui, **kwargs):

    ui.warn((b"Permission denied\n"))

    # mercurial hooks use unix process conventions for hook return values

    # so a truthy return means failure

    return True

if __name__ == '__main__':

    main()