view contrib/hg-ssh @ 37291:b0041036214e

wireproto: define frame to represent progress updates

Today, a long-running operation on a server may run without any sign
of progress on the client. This can lead to the conclusion that the
server has hung or the connection has dropped. In fact, connections
can and do time out due to inactivity. And a long-running server
operation can result in the connection dropping prematurely because
no data is being sent!

While we're inventing the new wire protocol, let's provide a mechanism
for communicating progress on potentially expensive server-side events.

We introduce a new frame type that conveys "progress" updates. This
frame type essentially holds the data required to formulate a
``ui.progress()`` call.

We only define the frame right now. Implementing it will be a bit of
work since there is no analog to progress frames in the existing
wire protocol. We'll need to teach the ui object to write to the
wire protocol, etc.

The use of a CBOR map may seem wasteful, as this will encode key
names in every frame. This *is* wasteful. However, maps are
extensible. And the intent is to always use compression via
streams. Compression will make the overhead negligible since repeated
strings will be mostly eliminated over the wire.

Differential Revision: https://phab.mercurial-scm.org/D2902

#!/usr/bin/env python
#
# 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,
    ui as uimod,
)

def main():
    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 = ['-R', repo, 'serve', '--stdio']
            req = dispatch.request(cmd)
            if readonly:
                if not req.ui:
                    req.ui = uimod.ui.load()
                req.ui.setconfig('hooks', 'pretxnopen.hg-ssh',
                                 'python:__main__.rejectpush', 'hg-ssh')
                req.ui.setconfig('hooks', 'prepushkey.hg-ssh',
                                 'python:__main__.rejectpush', '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(("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()