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sshpeer: initial definition and implementation of new SSH protocol...
sshpeer: initial definition and implementation of new SSH protocol The existing SSH protocol has several design flaws. Future commits will elaborate on these flaws as new features are introduced to combat these flaws. For now, hopefully you can take me for my word that a ground up rewrite of the SSH protocol is needed. This commit lays the foundation for a new SSH protocol by defining a mechanism to upgrade the SSH transport channel away from the default (version 1) protocol to something modern (which we'll call "version 2" for now). This upgrade process is detailed in the internals documentation for the wire protocol. The gist of it is the client sends a request line preceding the "hello" command/line which basically says "I'm requesting an upgrade: here's what I support." If the server recognizes that line, it processes the upgrade request and the transport channel is switched to use the new version of the protocol. If not, it sends an empty response, which is how all Mercurial SSH servers from the beginning of time reacted to unknown commands. The upgrade request is effectively ignored and the client continues to use the existing version of the protocol as if nothing happened. The new version of the SSH protocol is completely identical to version 1 aside from the upgrade dance and the bytes that follow. The immediate bytes that follow the protocol switch are defined to be a length framed "capabilities: " line containing the remote's advertised capabilities. In reality, this looks very similar to what the "hello" response would look like. But it will evolve quickly. The methodology by which the protocol will evolve is important. I'm not going to introduce the new protocol all at once. That would likely lead to endless bike shedding and forward progress would stall. Instead, I intend to tricle out new features and diversions from the existing protocol in small, incremental changes. To support the gradual evolution of the protocol, the on-the-wire advertised protocol name contains an "exp" to denote "experimental" and a 4 digit field to capture the sub-version of the protocol. Whenever we make a BC change to the wire protocol, we can increment this version and lock out all older clients because it will appear as a completely different protocol version. This means we can incur as many breaking changes as we want. We don't have to commit to supporting any one feature or idea for a long period of time. We can even evolve the handshake mechanism, because that is defined as being an implementation detail of the negotiated protocol version! Hopefully this lowers the barrier to accepting changes to the protocol and for experimenting with "radical" ideas during its development. In core, sshpeer received most of the attention. We haven't even implemented the server bits for the new protocol in core yet. Instead, we add very primitive support to our test server, mainly just to exercise the added code paths in sshpeer. Differential Revision: https://phab.mercurial-scm.org/D2061 # no-check-commit because of required foo_bar naming

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scmwindows.py
61 lines | 1.9 KiB | text/x-python | PythonLexer
Gregory Szorc
scmwindows: use absolute_import
r27481 from __future__ import absolute_import
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 import os
Gregory Szorc
scmwindows: use absolute_import
r27481
from . import (
Pulkit Goyal
py3: replace os.environ with encoding.environ (part 4 of 5)
r30637 encoding,
Pulkit Goyal
py3: replace os.pathsep with pycompat.ospathsep...
r30612 pycompat,
Gregory Szorc
scmwindows: use absolute_import
r27481 util,
Yuya Nishihara
scmutil: move util.termwidth()...
r30309 win32,
Gregory Szorc
scmwindows: use absolute_import
r27481 )
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690
Pulkit Goyal
py3: conditionalize _winreg import...
r29760 try:
import _winreg as winreg
winreg.CloseKey
except ImportError:
import winreg
Yuya Nishihara
pager: use less as a fallback on Unix...
r32078 # MS-DOS 'more' is the only pager available by default on Windows.
fallbackpager = 'more'
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 def systemrcpath():
'''return default os-specific hgrc search path'''
rcpath = []
filename = util.executablepath()
# Use mercurial.ini found in directory with hg.exe
progrc = os.path.join(os.path.dirname(filename), 'mercurial.ini')
Mads Kiilerich
windows: read all global config files, not just the first (issue4491) (BC)...
r26625 rcpath.append(progrc)
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 # Use hgrc.d found in directory with hg.exe
progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d')
if os.path.isdir(progrcd):
Yuya Nishihara
osutil: proxy through util (and platform) modules (API)...
r32203 for f, kind in util.listdir(progrcd):
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 if f.endswith('.rc'):
rcpath.append(os.path.join(progrcd, f))
# else look for a system rcpath in the registry
value = util.lookupreg('SOFTWARE\\Mercurial', None,
Pulkit Goyal
py3: conditionalize _winreg import...
r29760 winreg.HKEY_LOCAL_MACHINE)
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 if not isinstance(value, str) or not value:
return rcpath
value = util.localpath(value)
Pulkit Goyal
py3: replace os.pathsep with pycompat.ospathsep...
r30612 for p in value.split(pycompat.ospathsep):
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 if p.lower().endswith('mercurial.ini'):
rcpath.append(p)
elif os.path.isdir(p):
Yuya Nishihara
osutil: proxy through util (and platform) modules (API)...
r32203 for f, kind in util.listdir(p):
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 if f.endswith('.rc'):
rcpath.append(os.path.join(p, f))
return rcpath
def userrcpath():
'''return os-specific hgrc search path to the user dir'''
home = os.path.expanduser('~')
path = [os.path.join(home, 'mercurial.ini'),
os.path.join(home, '.hgrc')]
Pulkit Goyal
py3: replace os.environ with encoding.environ (part 4 of 5)
r30637 userprofile = encoding.environ.get('USERPROFILE')
Mads Kiilerich
config: don't read the same config file twice...
r22583 if userprofile and userprofile != home:
Kevin Bullock
scmutil: split platform-specific bits into their own modules...
r18690 path.append(os.path.join(userprofile, 'mercurial.ini'))
path.append(os.path.join(userprofile, '.hgrc'))
return path
Yuya Nishihara
scmutil: move util.termwidth()...
r30309
Yuya Nishihara
scmutil: extend termwidth() to return terminal height, renamed to termsize()...
r30314 def termsize(ui):
return win32.termsize()