Mercurial > hg
view mercurial/unionrepo.py @ 40626:87a872555e90
revlog: detect incomplete revlog reads
_readsegment() is supposed to return N bytes of revlog revision
data starting at a file offset. Surprisingly, its behavior before
this patch never verified that it actually read and returned N
bytes! Instead, it would perform the read(), then return whatever
data was available. And even more surprisingly, nothing in the
call chain appears to have been validating that it received all
the data it was expecting.
This behavior could lead to partial or incomplete revision chunks
being operated on. This could result in e.g. cached deltas being
applied against incomplete base revisions. The delta application
process would happily perform this operation. Only hash
verification would detect the corruption and save us.
This commit changes the behavior of raw revlog reading to validate
that we actually read() the number of bytes that were requested.
We will raise a more specific error faster, rather than possibly
have it go undetected or manifest later in the call stack, at
delta application or hash verification.
Differential Revision: https://phab.mercurial-scm.org/D5266
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 13 Nov 2018 12:30:59 -0800 |
parents | 55db747a21ad |
children | 3913223417ea |
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# unionrepo.py - repository class for viewing union of repository changesets # # Derived from bundlerepo.py # Copyright 2006, 2007 Benoit Boissinot <bboissin@gmail.com> # Copyright 2013 Unity Technologies, Mads Kiilerich <madski@unity3d.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """Repository class for "in-memory pull" of one local repository to another, allowing operations like diff and log with revsets. """ from __future__ import absolute_import from .i18n import _ from .node import nullid from . import ( changelog, cmdutil, encoding, error, filelog, localrepo, manifest, mdiff, pathutil, revlog, util, vfs as vfsmod, ) class unionrevlog(revlog.revlog): def __init__(self, opener, indexfile, revlog2, linkmapper): # How it works: # To retrieve a revision, we just need to know the node id so we can # look it up in revlog2. # # To differentiate a rev in the second revlog from a rev in the revlog, # we check revision against repotiprev. opener = vfsmod.readonlyvfs(opener) revlog.revlog.__init__(self, opener, indexfile) self.revlog2 = revlog2 n = len(self) self.repotiprev = n - 1 self.bundlerevs = set() # used by 'bundle()' revset expression for rev2 in self.revlog2: rev = self.revlog2.index[rev2] # rev numbers - in revlog2, very different from self.rev _start, _csize, rsize, base, linkrev, p1rev, p2rev, node = rev flags = _start & 0xFFFF if linkmapper is None: # link is to same revlog assert linkrev == rev2 # we never link back link = n else: # rev must be mapped from repo2 cl to unified cl by linkmapper link = linkmapper(linkrev) if linkmapper is not None: # link is to same revlog base = linkmapper(base) if node in self.nodemap: # this happens for the common revlog revisions self.bundlerevs.add(self.nodemap[node]) continue p1node = self.revlog2.node(p1rev) p2node = self.revlog2.node(p2rev) # TODO: it's probably wrong to set compressed length to None, but # I have no idea if csize is valid in the base revlog context. e = (flags, None, rsize, base, link, self.rev(p1node), self.rev(p2node), node) self.index.append(e) self.nodemap[node] = n self.bundlerevs.add(n) n += 1 def _chunk(self, rev): if rev <= self.repotiprev: return revlog.revlog._chunk(self, rev) return self.revlog2._chunk(self.node(rev)) def revdiff(self, rev1, rev2): """return or calculate a delta between two revisions""" if rev1 > self.repotiprev and rev2 > self.repotiprev: return self.revlog2.revdiff( self.revlog2.rev(self.node(rev1)), self.revlog2.rev(self.node(rev2))) elif rev1 <= self.repotiprev and rev2 <= self.repotiprev: return self.baserevdiff(rev1, rev2) return mdiff.textdiff(self.revision(rev1), self.revision(rev2)) def revision(self, nodeorrev, _df=None, raw=False): """return an uncompressed revision of a given node or revision number. """ if isinstance(nodeorrev, int): rev = nodeorrev node = self.node(rev) else: node = nodeorrev rev = self.rev(node) if node == nullid: return "" if rev > self.repotiprev: text = self.revlog2.revision(node) self._revisioncache = (node, rev, text) else: text = self.baserevision(rev) # already cached return text def baserevision(self, nodeorrev): # Revlog subclasses may override 'revision' method to modify format of # content retrieved from revlog. To use unionrevlog with such class one # needs to override 'baserevision' and make more specific call here. return revlog.revlog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): # Exists for the same purpose as baserevision. return revlog.revlog.revdiff(self, rev1, rev2) def addrevision(self, text, transaction, link, p1=None, p2=None, d=None): raise NotImplementedError def addgroup(self, deltas, transaction, addrevisioncb=None): raise NotImplementedError def strip(self, rev, minlink): raise NotImplementedError def checksize(self): raise NotImplementedError class unionchangelog(unionrevlog, changelog.changelog): def __init__(self, opener, opener2): changelog.changelog.__init__(self, opener) linkmapper = None changelog2 = changelog.changelog(opener2) unionrevlog.__init__(self, opener, self.indexfile, changelog2, linkmapper) def baserevision(self, nodeorrev): # Although changelog doesn't override 'revision' method, some extensions # may replace this class with another that does. Same story with # manifest and filelog classes. return changelog.changelog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): return changelog.changelog.revdiff(self, rev1, rev2) class unionmanifest(unionrevlog, manifest.manifestrevlog): def __init__(self, opener, opener2, linkmapper): manifest.manifestrevlog.__init__(self, opener) manifest2 = manifest.manifestrevlog(opener2) unionrevlog.__init__(self, opener, self.indexfile, manifest2, linkmapper) def baserevision(self, nodeorrev): return manifest.manifestrevlog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): return manifest.manifestrevlog.revdiff(self, rev1, rev2) class unionfilelog(filelog.filelog): def __init__(self, opener, path, opener2, linkmapper, repo): filelog.filelog.__init__(self, opener, path) filelog2 = filelog.filelog(opener2, path) self._revlog = unionrevlog(opener, self.indexfile, filelog2._revlog, linkmapper) self._repo = repo self.repotiprev = self._revlog.repotiprev self.revlog2 = self._revlog.revlog2 def baserevision(self, nodeorrev): return filelog.filelog.revision(self, nodeorrev) def baserevdiff(self, rev1, rev2): return filelog.filelog.revdiff(self, rev1, rev2) def iscensored(self, rev): """Check if a revision is censored.""" if rev <= self.repotiprev: return filelog.filelog.iscensored(self, rev) node = self.node(rev) return self.revlog2.iscensored(self.revlog2.rev(node)) class unionpeer(localrepo.localpeer): def canpush(self): return False class unionrepository(object): """Represents the union of data in 2 repositories. Instances are not usable if constructed directly. Use ``instance()`` or ``makeunionrepository()`` to create a usable instance. """ def __init__(self, repo2, url): self.repo2 = repo2 self._url = url self.ui.setconfig('phases', 'publish', False, 'unionrepo') @localrepo.unfilteredpropertycache def changelog(self): return unionchangelog(self.svfs, self.repo2.svfs) @localrepo.unfilteredpropertycache def manifestlog(self): rootstore = unionmanifest(self.svfs, self.repo2.svfs, self.unfiltered()._clrev) return manifest.manifestlog(self.svfs, self, rootstore) def _clrev(self, rev2): """map from repo2 changelog rev to temporary rev in self.changelog""" node = self.repo2.changelog.node(rev2) return self.changelog.rev(node) def url(self): return self._url def file(self, f): return unionfilelog(self.svfs, f, self.repo2.svfs, self.unfiltered()._clrev, self) def close(self): self.repo2.close() def cancopy(self): return False def peer(self): return unionpeer(self) def getcwd(self): return encoding.getcwd() # always outside the repo def instance(ui, path, create, intents=None, createopts=None): if create: raise error.Abort(_('cannot create new union repository')) parentpath = ui.config("bundle", "mainreporoot") if not parentpath: # try to find the correct path to the working directory repo parentpath = cmdutil.findrepo(encoding.getcwd()) if parentpath is None: parentpath = '' if parentpath: # Try to make the full path relative so we get a nice, short URL. # In particular, we don't want temp dir names in test outputs. cwd = encoding.getcwd() if parentpath == cwd: parentpath = '' else: cwd = pathutil.normasprefix(cwd) if parentpath.startswith(cwd): parentpath = parentpath[len(cwd):] if path.startswith('union:'): s = path.split(":", 1)[1].split("+", 1) if len(s) == 1: repopath, repopath2 = parentpath, s[0] else: repopath, repopath2 = s else: repopath, repopath2 = parentpath, path return makeunionrepository(ui, repopath, repopath2) def makeunionrepository(ui, repopath1, repopath2): """Make a union repository object from 2 local repo paths.""" repo1 = localrepo.instance(ui, repopath1, create=False) repo2 = localrepo.instance(ui, repopath2, create=False) url = 'union:%s+%s' % (util.expandpath(repopath1), util.expandpath(repopath2)) class derivedunionrepository(unionrepository, repo1.__class__): pass repo = repo1 repo.__class__ = derivedunionrepository unionrepository.__init__(repo1, repo2, url) return repo