Mercurial > hg
view tests/tinyproxy.py @ 46607:e9901d01d135
revlog: add a mechanism to verify expected file position before appending
If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.
The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)
When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.
For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.
This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.
Differential Revision: https://phab.mercurial-scm.org/D9952
author | Kyle Lippincott <spectral@google.com> |
---|---|
date | Wed, 03 Feb 2021 16:33:10 -0800 |
parents | c102b704edb5 |
children | 23f5ed6dbcb1 |
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#!/usr/bin/env python3 from __future__ import absolute_import, print_function __doc__ = """Tiny HTTP Proxy. This module implements GET, HEAD, POST, PUT and DELETE methods on BaseHTTPServer, and behaves as an HTTP proxy. The CONNECT method is also implemented experimentally, but has not been tested yet. Any help will be greatly appreciated. SUZUKI Hisao """ __version__ = "0.2.1" import optparse import os import select import socket import sys from mercurial import ( pycompat, util, ) httpserver = util.httpserver socketserver = util.socketserver urlreq = util.urlreq if os.environ.get('HGIPV6', '0') == '1': family = socket.AF_INET6 else: family = socket.AF_INET class ProxyHandler(httpserver.basehttprequesthandler): __base = httpserver.basehttprequesthandler __base_handle = __base.handle server_version = "TinyHTTPProxy/" + __version__ rbufsize = 0 # self.rfile Be unbuffered def handle(self): (ip, port) = self.client_address allowed = getattr(self, 'allowed_clients', None) if allowed is not None and ip not in allowed: self.raw_requestline = self.rfile.readline() if self.parse_request(): self.send_error(403) else: self.__base_handle() def log_request(self, code='-', size='-'): xheaders = [h for h in self.headers.items() if h[0].startswith('x-')] self.log_message( '"%s" %s %s%s', self.requestline, str(code), str(size), ''.join([' %s:%s' % h for h in sorted(xheaders)]), ) # Flush for Windows, so output isn't lost on TerminateProcess() sys.stdout.flush() sys.stderr.flush() def _connect_to(self, netloc, soc): i = netloc.find(':') if i >= 0: host_port = netloc[:i], int(netloc[i + 1 :]) else: host_port = netloc, 80 print("\t" "connect to %s:%d" % host_port) try: soc.connect(host_port) except socket.error as arg: try: msg = arg[1] except (IndexError, TypeError): msg = arg self.send_error(404, msg) return 0 return 1 def do_CONNECT(self): soc = socket.socket(family, socket.SOCK_STREAM) try: if self._connect_to(self.path, soc): self.log_request(200) self.wfile.write( pycompat.bytestr(self.protocol_version) + b" 200 Connection established\r\n" ) self.wfile.write( b"Proxy-agent: %s\r\n" % pycompat.bytestr(self.version_string()) ) self.wfile.write(b"\r\n") self._read_write(soc, 300) finally: print("\t" "bye") soc.close() self.connection.close() def do_GET(self): (scm, netloc, path, params, query, fragment) = urlreq.urlparse( self.path, 'http' ) if scm != 'http' or fragment or not netloc: self.send_error(400, "bad url %s" % self.path) return soc = socket.socket(family, socket.SOCK_STREAM) try: if self._connect_to(netloc, soc): self.log_request() url = urlreq.urlunparse(('', '', path, params, query, '')) soc.send( b"%s %s %s\r\n" % ( pycompat.bytestr(self.command), pycompat.bytestr(url), pycompat.bytestr(self.request_version), ) ) self.headers['Connection'] = 'close' del self.headers['Proxy-Connection'] for key, val in self.headers.items(): soc.send( b"%s: %s\r\n" % (pycompat.bytestr(key), pycompat.bytestr(val)) ) soc.send(b"\r\n") self._read_write(soc) finally: print("\t" "bye") soc.close() self.connection.close() def _read_write(self, soc, max_idling=20): iw = [self.connection, soc] ow = [] count = 0 while True: count += 1 (ins, _, exs) = select.select(iw, ow, iw, 3) if exs: break if ins: for i in ins: if i is soc: out = self.connection else: out = soc try: data = i.recv(8192) except socket.error: break if data: out.send(data) count = 0 else: print("\t" "idle", count) if count == max_idling: break do_HEAD = do_GET do_POST = do_GET do_PUT = do_GET do_DELETE = do_GET class ThreadingHTTPServer(socketserver.ThreadingMixIn, httpserver.httpserver): def __init__(self, *args, **kwargs): httpserver.httpserver.__init__(self, *args, **kwargs) a = open("proxy.pid", "w") a.write(str(os.getpid()) + "\n") a.close() def runserver(port=8000, bind=""): server_address = (bind, port) ProxyHandler.protocol_version = "HTTP/1.0" httpd = ThreadingHTTPServer(server_address, ProxyHandler) sa = httpd.socket.getsockname() print("Serving HTTP on", sa[0], "port", sa[1], "...") try: httpd.serve_forever() except KeyboardInterrupt: print("\nKeyboard interrupt received, exiting.") httpd.server_close() sys.exit(0) if __name__ == '__main__': argv = sys.argv if argv[1:] and argv[1] in ('-h', '--help'): print(argv[0], "[port [allowed_client_name ...]]") else: if argv[2:]: allowed = [] for name in argv[2:]: client = socket.gethostbyname(name) allowed.append(client) print("Accept: %s (%s)" % (client, name)) ProxyHandler.allowed_clients = allowed del argv[2:] else: print("Any clients will be served...") parser = optparse.OptionParser() parser.add_option( '-b', '--bind', metavar='ADDRESS', help='Specify alternate bind address ' '[default: all interfaces]', default='', ) (options, args) = parser.parse_args() port = 8000 if len(args) == 1: port = int(args[0]) runserver(port, options.bind)