contrib/hg-ssh

tests: update divergence test for `hg fix` to actually result in divergence

We have a test that checks that `hg fix` errors out if it might cause
divergence. However, the test simply prunes the commit it then tries
to fix, so fixing it wouldn't actually cause divergence. That works
because the implementation is simple enough that it doesn't notice the
difference. I'm about to make the implementation smarter, so let's fix
the test first.

Differential Revision: https://phab.mercurial-scm.org/D10267

#!/usr/bin/env python3
#
# Copyright 2005-2007 by Intevation GmbH <[e-mail]>
#
# Author(s):
# Thomas Arendsen Hein <[e-mail]>
#
# 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/*"
"""
from __future__ import absolute_import

import os
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()
    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()