Mercurial > hg
view mercurial/store.py @ 35884:197d10e157ce
httppeer: remove support for connecting to <0.9.1 servers (BC)
Previously, HTTP wire protocol clients would attempt a
"capabilities" wire protocol command. If that failed, they would
fall back to issuing a "between" command.
The "capabilities" command was added in Mercurial 0.9.1 (released
July 2006). The "between" command has been present for as long as
the wire protocol has existed. So if the "between" command failed,
it was safe to assume that the remote could not speak any version
of the Mercurial wire protocol.
The "between" fallback was added in 395a84f78736 in 2011. Before that
changeset, Mercurial would *always* issue the "between" command and
would issue "capabilities" if capabilities were requested. At that time,
many connections would issue "capabilities" eventually, so it was
decided to issue "capabilities" by default and fall back to "between"
if that failed. This saved a round trip when connecting to modern
servers while still preserving compatibility with legacy servers.
Fast forward ~7 years. Mercurial servers supporting "capabilities"
have been around for over a decade. If modern clients are
connecting to <0.9.1 servers, they are getting a bad experience.
They may even be getting bad data (an old server is vulnerable to
numerous security issues and could have been p0wned, leading to a
Mercurial repository serving backdoors or other badness).
In addition, the fallback can harm experience for modern servers.
If a client experiences an intermittent HTTP request failure (due to
bad network, etc) and falls back to a "between" that works, it would
assume an empty capability set and would attempt to communicate with
the repository using a very ancient wire protocol. Auditing HTTP logs
for hg.mozilla.org, I did find a handful of requests for the
null range of the "between" command. However, requests can be days
apart. And when I do see requests, they come in batches. Those
batches seem to correlate to spikes of HTTP 500 or other
server/network events. So I think these requests are fallbacks from
failed "capabilities" requests and not from old clients.
If you need even more evidence to discontinue support, apparently
we have no test coverage for communicating with servers not
supporting "capabilities." I know this because all tests pass
with the "between" fallback removed.
Finally, server-side support for <0.9.1 pushing (the "addchangegroup"
wire protocol command along with locking-related commands) was dropped
from the HTTP client in fda0867cfe03 in 2017 and the SSH client in
9f6e0e7ef828 in 2015.
I think this all adds up to enough justification for removing client
support for communicating with servers not supporting "capabilities."
So this commit removes that fallback.
Differential Revision: https://phab.mercurial-scm.org/D2001
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 02 Feb 2018 13:13:46 -0800 |
parents | 72b91f905065 |
children | 4c15bee42e9c |
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# store.py - repository store handling for Mercurial # # Copyright 2008 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import errno import hashlib import os import stat from .i18n import _ from . import ( error, node, policy, pycompat, util, vfs as vfsmod, ) parsers = policy.importmod(r'parsers') # This avoids a collision between a file named foo and a dir named # foo.i or foo.d def _encodedir(path): ''' >>> _encodedir(b'data/foo.i') 'data/foo.i' >>> _encodedir(b'data/foo.i/bla.i') 'data/foo.i.hg/bla.i' >>> _encodedir(b'data/foo.i.hg/bla.i') 'data/foo.i.hg.hg/bla.i' >>> _encodedir(b'data/foo.i\\ndata/foo.i/bla.i\\ndata/foo.i.hg/bla.i\\n') 'data/foo.i\\ndata/foo.i.hg/bla.i\\ndata/foo.i.hg.hg/bla.i\\n' ''' return (path .replace(".hg/", ".hg.hg/") .replace(".i/", ".i.hg/") .replace(".d/", ".d.hg/")) encodedir = getattr(parsers, 'encodedir', _encodedir) def decodedir(path): ''' >>> decodedir(b'data/foo.i') 'data/foo.i' >>> decodedir(b'data/foo.i.hg/bla.i') 'data/foo.i/bla.i' >>> decodedir(b'data/foo.i.hg.hg/bla.i') 'data/foo.i.hg/bla.i' ''' if ".hg/" not in path: return path return (path .replace(".d.hg/", ".d/") .replace(".i.hg/", ".i/") .replace(".hg.hg/", ".hg/")) def _reserved(): ''' characters that are problematic for filesystems * ascii escapes (0..31) * ascii hi (126..255) * windows specials these characters will be escaped by encodefunctions ''' winreserved = [ord(x) for x in u'\\:*?"<>|'] for x in range(32): yield x for x in range(126, 256): yield x for x in winreserved: yield x def _buildencodefun(): ''' >>> enc, dec = _buildencodefun() >>> enc(b'nothing/special.txt') 'nothing/special.txt' >>> dec(b'nothing/special.txt') 'nothing/special.txt' >>> enc(b'HELLO') '_h_e_l_l_o' >>> dec(b'_h_e_l_l_o') 'HELLO' >>> enc(b'hello:world?') 'hello~3aworld~3f' >>> dec(b'hello~3aworld~3f') 'hello:world?' >>> enc(b'the\\x07quick\\xADshot') 'the~07quick~adshot' >>> dec(b'the~07quick~adshot') 'the\\x07quick\\xadshot' ''' e = '_' xchr = pycompat.bytechr asciistr = list(map(xchr, range(127))) capitals = list(range(ord("A"), ord("Z") + 1)) cmap = dict((x, x) for x in asciistr) for x in _reserved(): cmap[xchr(x)] = "~%02x" % x for x in capitals + [ord(e)]: cmap[xchr(x)] = e + xchr(x).lower() dmap = {} for k, v in cmap.iteritems(): dmap[v] = k def decode(s): i = 0 while i < len(s): for l in xrange(1, 4): try: yield dmap[s[i:i + l]] i += l break except KeyError: pass else: raise KeyError return (lambda s: ''.join([cmap[s[c:c + 1]] for c in xrange(len(s))]), lambda s: ''.join(list(decode(s)))) _encodefname, _decodefname = _buildencodefun() def encodefilename(s): ''' >>> encodefilename(b'foo.i/bar.d/bla.hg/hi:world?/HELLO') 'foo.i.hg/bar.d.hg/bla.hg.hg/hi~3aworld~3f/_h_e_l_l_o' ''' return _encodefname(encodedir(s)) def decodefilename(s): ''' >>> decodefilename(b'foo.i.hg/bar.d.hg/bla.hg.hg/hi~3aworld~3f/_h_e_l_l_o') 'foo.i/bar.d/bla.hg/hi:world?/HELLO' ''' return decodedir(_decodefname(s)) def _buildlowerencodefun(): ''' >>> f = _buildlowerencodefun() >>> f(b'nothing/special.txt') 'nothing/special.txt' >>> f(b'HELLO') 'hello' >>> f(b'hello:world?') 'hello~3aworld~3f' >>> f(b'the\\x07quick\\xADshot') 'the~07quick~adshot' ''' xchr = pycompat.bytechr cmap = dict([(xchr(x), xchr(x)) for x in xrange(127)]) for x in _reserved(): cmap[xchr(x)] = "~%02x" % x for x in range(ord("A"), ord("Z") + 1): cmap[xchr(x)] = xchr(x).lower() def lowerencode(s): return "".join([cmap[c] for c in pycompat.iterbytestr(s)]) return lowerencode lowerencode = getattr(parsers, 'lowerencode', None) or _buildlowerencodefun() # Windows reserved names: con, prn, aux, nul, com1..com9, lpt1..lpt9 _winres3 = ('aux', 'con', 'prn', 'nul') # length 3 _winres4 = ('com', 'lpt') # length 4 (with trailing 1..9) def _auxencode(path, dotencode): ''' Encodes filenames containing names reserved by Windows or which end in period or space. Does not touch other single reserved characters c. Specifically, c in '\\:*?"<>|' or ord(c) <= 31 are *not* encoded here. Additionally encodes space or period at the beginning, if dotencode is True. Parameter path is assumed to be all lowercase. A segment only needs encoding if a reserved name appears as a basename (e.g. "aux", "aux.foo"). A directory or file named "foo.aux" doesn't need encoding. >>> s = b'.foo/aux.txt/txt.aux/con/prn/nul/foo.' >>> _auxencode(s.split(b'/'), True) ['~2efoo', 'au~78.txt', 'txt.aux', 'co~6e', 'pr~6e', 'nu~6c', 'foo~2e'] >>> s = b'.com1com2/lpt9.lpt4.lpt1/conprn/com0/lpt0/foo.' >>> _auxencode(s.split(b'/'), False) ['.com1com2', 'lp~749.lpt4.lpt1', 'conprn', 'com0', 'lpt0', 'foo~2e'] >>> _auxencode([b'foo. '], True) ['foo.~20'] >>> _auxencode([b' .foo'], True) ['~20.foo'] ''' for i, n in enumerate(path): if not n: continue if dotencode and n[0] in '. ': n = "~%02x" % ord(n[0:1]) + n[1:] path[i] = n else: l = n.find('.') if l == -1: l = len(n) if ((l == 3 and n[:3] in _winres3) or (l == 4 and n[3:4] <= '9' and n[3:4] >= '1' and n[:3] in _winres4)): # encode third letter ('aux' -> 'au~78') ec = "~%02x" % ord(n[2:3]) n = n[0:2] + ec + n[3:] path[i] = n if n[-1] in '. ': # encode last period or space ('foo...' -> 'foo..~2e') path[i] = n[:-1] + "~%02x" % ord(n[-1:]) return path _maxstorepathlen = 120 _dirprefixlen = 8 _maxshortdirslen = 8 * (_dirprefixlen + 1) - 4 def _hashencode(path, dotencode): digest = node.hex(hashlib.sha1(path).digest()) le = lowerencode(path[5:]).split('/') # skips prefix 'data/' or 'meta/' parts = _auxencode(le, dotencode) basename = parts[-1] _root, ext = os.path.splitext(basename) sdirs = [] sdirslen = 0 for p in parts[:-1]: d = p[:_dirprefixlen] if d[-1] in '. ': # Windows can't access dirs ending in period or space d = d[:-1] + '_' if sdirslen == 0: t = len(d) else: t = sdirslen + 1 + len(d) if t > _maxshortdirslen: break sdirs.append(d) sdirslen = t dirs = '/'.join(sdirs) if len(dirs) > 0: dirs += '/' res = 'dh/' + dirs + digest + ext spaceleft = _maxstorepathlen - len(res) if spaceleft > 0: filler = basename[:spaceleft] res = 'dh/' + dirs + filler + digest + ext return res def _hybridencode(path, dotencode): '''encodes path with a length limit Encodes all paths that begin with 'data/', according to the following. Default encoding (reversible): Encodes all uppercase letters 'X' as '_x'. All reserved or illegal characters are encoded as '~xx', where xx is the two digit hex code of the character (see encodefilename). Relevant path components consisting of Windows reserved filenames are masked by encoding the third character ('aux' -> 'au~78', see _auxencode). Hashed encoding (not reversible): If the default-encoded path is longer than _maxstorepathlen, a non-reversible hybrid hashing of the path is done instead. This encoding uses up to _dirprefixlen characters of all directory levels of the lowerencoded path, but not more levels than can fit into _maxshortdirslen. Then follows the filler followed by the sha digest of the full path. The filler is the beginning of the basename of the lowerencoded path (the basename is everything after the last path separator). The filler is as long as possible, filling in characters from the basename until the encoded path has _maxstorepathlen characters (or all chars of the basename have been taken). The extension (e.g. '.i' or '.d') is preserved. The string 'data/' at the beginning is replaced with 'dh/', if the hashed encoding was used. ''' path = encodedir(path) ef = _encodefname(path).split('/') res = '/'.join(_auxencode(ef, dotencode)) if len(res) > _maxstorepathlen: res = _hashencode(path, dotencode) return res def _pathencode(path): de = encodedir(path) if len(path) > _maxstorepathlen: return _hashencode(de, True) ef = _encodefname(de).split('/') res = '/'.join(_auxencode(ef, True)) if len(res) > _maxstorepathlen: return _hashencode(de, True) return res _pathencode = getattr(parsers, 'pathencode', _pathencode) def _plainhybridencode(f): return _hybridencode(f, False) def _calcmode(vfs): try: # files in .hg/ will be created using this mode mode = vfs.stat().st_mode # avoid some useless chmods if (0o777 & ~util.umask) == (0o777 & mode): mode = None except OSError: mode = None return mode _data = ('data meta 00manifest.d 00manifest.i 00changelog.d 00changelog.i' ' phaseroots obsstore') class basicstore(object): '''base class for local repository stores''' def __init__(self, path, vfstype): vfs = vfstype(path) self.path = vfs.base self.createmode = _calcmode(vfs) vfs.createmode = self.createmode self.rawvfs = vfs self.vfs = vfsmod.filtervfs(vfs, encodedir) self.opener = self.vfs def join(self, f): return self.path + '/' + encodedir(f) def _walk(self, relpath, recurse): '''yields (unencoded, encoded, size)''' path = self.path if relpath: path += '/' + relpath striplen = len(self.path) + 1 l = [] if self.rawvfs.isdir(path): visit = [path] readdir = self.rawvfs.readdir while visit: p = visit.pop() for f, kind, st in readdir(p, stat=True): fp = p + '/' + f if kind == stat.S_IFREG and f[-2:] in ('.d', '.i'): n = util.pconvert(fp[striplen:]) l.append((decodedir(n), n, st.st_size)) elif kind == stat.S_IFDIR and recurse: visit.append(fp) l.sort() return l def datafiles(self): return self._walk('data', True) + self._walk('meta', True) def topfiles(self): # yield manifest before changelog return reversed(self._walk('', False)) def walk(self): '''yields (unencoded, encoded, size)''' # yield data files first for x in self.datafiles(): yield x for x in self.topfiles(): yield x def copylist(self): return ['requires'] + _data.split() def write(self, tr): pass def invalidatecaches(self): pass def markremoved(self, fn): pass def __contains__(self, path): '''Checks if the store contains path''' path = "/".join(("data", path)) # file? if self.vfs.exists(path + ".i"): return True # dir? if not path.endswith("/"): path = path + "/" return self.vfs.exists(path) class encodedstore(basicstore): def __init__(self, path, vfstype): vfs = vfstype(path + '/store') self.path = vfs.base self.createmode = _calcmode(vfs) vfs.createmode = self.createmode self.rawvfs = vfs self.vfs = vfsmod.filtervfs(vfs, encodefilename) self.opener = self.vfs def datafiles(self): for a, b, size in super(encodedstore, self).datafiles(): try: a = decodefilename(a) except KeyError: a = None yield a, b, size def join(self, f): return self.path + '/' + encodefilename(f) def copylist(self): return (['requires', '00changelog.i'] + ['store/' + f for f in _data.split()]) class fncache(object): # the filename used to be partially encoded # hence the encodedir/decodedir dance def __init__(self, vfs): self.vfs = vfs self.entries = None self._dirty = False def _load(self): '''fill the entries from the fncache file''' self._dirty = False try: fp = self.vfs('fncache', mode='rb') except IOError: # skip nonexistent file self.entries = set() return self.entries = set(decodedir(fp.read()).splitlines()) if '' in self.entries: fp.seek(0) for n, line in enumerate(util.iterfile(fp)): if not line.rstrip('\n'): t = _('invalid entry in fncache, line %d') % (n + 1) raise error.Abort(t) fp.close() def write(self, tr): if self._dirty: tr.addbackup('fncache') fp = self.vfs('fncache', mode='wb', atomictemp=True) if self.entries: fp.write(encodedir('\n'.join(self.entries) + '\n')) fp.close() self._dirty = False def add(self, fn): if self.entries is None: self._load() if fn not in self.entries: self._dirty = True self.entries.add(fn) def remove(self, fn): if self.entries is None: self._load() try: self.entries.remove(fn) self._dirty = True except KeyError: pass def __contains__(self, fn): if self.entries is None: self._load() return fn in self.entries def __iter__(self): if self.entries is None: self._load() return iter(self.entries) class _fncachevfs(vfsmod.abstractvfs, vfsmod.proxyvfs): def __init__(self, vfs, fnc, encode): vfsmod.proxyvfs.__init__(self, vfs) self.fncache = fnc self.encode = encode def __call__(self, path, mode='r', *args, **kw): if mode not in ('r', 'rb') and (path.startswith('data/') or path.startswith('meta/')): self.fncache.add(path) return self.vfs(self.encode(path), mode, *args, **kw) def join(self, path): if path: return self.vfs.join(self.encode(path)) else: return self.vfs.join(path) class fncachestore(basicstore): def __init__(self, path, vfstype, dotencode): if dotencode: encode = _pathencode else: encode = _plainhybridencode self.encode = encode vfs = vfstype(path + '/store') self.path = vfs.base self.pathsep = self.path + '/' self.createmode = _calcmode(vfs) vfs.createmode = self.createmode self.rawvfs = vfs fnc = fncache(vfs) self.fncache = fnc self.vfs = _fncachevfs(vfs, fnc, encode) self.opener = self.vfs def join(self, f): return self.pathsep + self.encode(f) def getsize(self, path): return self.rawvfs.stat(path).st_size def datafiles(self): for f in sorted(self.fncache): ef = self.encode(f) try: yield f, ef, self.getsize(ef) except OSError as err: if err.errno != errno.ENOENT: raise def copylist(self): d = ('data meta dh fncache phaseroots obsstore' ' 00manifest.d 00manifest.i 00changelog.d 00changelog.i') return (['requires', '00changelog.i'] + ['store/' + f for f in d.split()]) def write(self, tr): self.fncache.write(tr) def invalidatecaches(self): self.fncache.entries = None def markremoved(self, fn): self.fncache.remove(fn) def _exists(self, f): ef = self.encode(f) try: self.getsize(ef) return True except OSError as err: if err.errno != errno.ENOENT: raise # nonexistent entry return False def __contains__(self, path): '''Checks if the store contains path''' path = "/".join(("data", path)) # check for files (exact match) e = path + '.i' if e in self.fncache and self._exists(e): return True # now check for directories (prefix match) if not path.endswith('/'): path += '/' for e in self.fncache: if e.startswith(path) and self._exists(e): return True return False def store(requirements, path, vfstype): if 'store' in requirements: if 'fncache' in requirements: return fncachestore(path, vfstype, 'dotencode' in requirements) return encodedstore(path, vfstype) return basicstore(path, vfstype)