procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/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()