view hgext/convert/darcs.py @ 26120:1a45e49a6bed stable 3.5.1

hgweb: fix trust of templates path (BC)

Long ago we disabled trust of the templates path with a comment
describing the (insecure) behavior before the change. At some later
refactor, the code was apparently changed back to match the comment,
unaware that the intent of the comment was to describe the behavior to
avoid.

This change disables the trust and updates the comment to explicitly
say not only what the old problem was, but also that it was in fact a
problem and the action taken to prevent it.

Impact: prior to this change, if you had a UNIX-based hgweb server
where users can write hgrc files, those users could potentially read
any file readable by the web server.

This is marked as a backwards compatibility issue because people may
have configured templates without proper trust settings. Issue spotted
by Greg Szorc.

# darcs.py - darcs support for the convert extension
#
#  Copyright 2007-2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from common import NoRepo, checktool, commandline, commit, converter_source
from mercurial.i18n import _
from mercurial import util
import os, shutil, tempfile, re, errno

# The naming drift of ElementTree is fun!

try:
    from xml.etree.cElementTree import ElementTree, XMLParser
except ImportError:
    try:
        from xml.etree.ElementTree import ElementTree, XMLParser
    except ImportError:
        try:
            from elementtree.cElementTree import ElementTree, XMLParser
        except ImportError:
            try:
                from elementtree.ElementTree import ElementTree, XMLParser
            except ImportError:
                pass

class darcs_source(converter_source, commandline):
    def __init__(self, ui, path, revs=None):
        converter_source.__init__(self, ui, path, revs=revs)
        commandline.__init__(self, ui, 'darcs')

        # check for _darcs, ElementTree so that we can easily skip
        # test-convert-darcs if ElementTree is not around
        if not os.path.exists(os.path.join(path, '_darcs')):
            raise NoRepo(_("%s does not look like a darcs repository") % path)

        checktool('darcs')
        version = self.run0('--version').splitlines()[0].strip()
        if version < '2.1':
            raise util.Abort(_('darcs version 2.1 or newer needed (found %r)') %
                             version)

        if "ElementTree" not in globals():
            raise util.Abort(_("Python ElementTree module is not available"))

        self.path = os.path.realpath(path)

        self.lastrev = None
        self.changes = {}
        self.parents = {}
        self.tags = {}

        # Check darcs repository format
        format = self.format()
        if format:
            if format in ('darcs-1.0', 'hashed'):
                raise NoRepo(_("%s repository format is unsupported, "
                               "please upgrade") % format)
        else:
            self.ui.warn(_('failed to detect repository format!'))

    def before(self):
        self.tmppath = tempfile.mkdtemp(
            prefix='convert-' + os.path.basename(self.path) + '-')
        output, status = self.run('init', repodir=self.tmppath)
        self.checkexit(status)

        tree = self.xml('changes', xml_output=True, summary=True,
                        repodir=self.path)
        tagname = None
        child = None
        for elt in tree.findall('patch'):
            node = elt.get('hash')
            name = elt.findtext('name', '')
            if name.startswith('TAG '):
                tagname = name[4:].strip()
            elif tagname is not None:
                self.tags[tagname] = node
                tagname = None
            self.changes[node] = elt
            self.parents[child] = [node]
            child = node
        self.parents[child] = []

    def after(self):
        self.ui.debug('cleaning up %s\n' % self.tmppath)
        shutil.rmtree(self.tmppath, ignore_errors=True)

    def recode(self, s, encoding=None):
        if isinstance(s, unicode):
            # XMLParser returns unicode objects for anything it can't
            # encode into ASCII. We convert them back to str to get
            # recode's normal conversion behavior.
            s = s.encode('latin-1')
        return super(darcs_source, self).recode(s, encoding)

    def xml(self, cmd, **kwargs):
        # NOTE: darcs is currently encoding agnostic and will print
        # patch metadata byte-for-byte, even in the XML changelog.
        etree = ElementTree()
        # While we are decoding the XML as latin-1 to be as liberal as
        # possible, etree will still raise an exception if any
        # non-printable characters are in the XML changelog.
        parser = XMLParser(encoding='latin-1')
        p = self._run(cmd, **kwargs)
        etree.parse(p.stdout, parser=parser)
        p.wait()
        self.checkexit(p.returncode)
        return etree.getroot()

    def format(self):
        output, status = self.run('show', 'repo', no_files=True,
                                  repodir=self.path)
        self.checkexit(status)
        m = re.search(r'^\s*Format:\s*(.*)$', output, re.MULTILINE)
        if not m:
            return None
        return ','.join(sorted(f.strip() for f in m.group(1).split(',')))

    def manifest(self):
        man = []
        output, status = self.run('show', 'files', no_directories=True,
                                  repodir=self.tmppath)
        self.checkexit(status)
        for line in output.split('\n'):
            path = line[2:]
            if path:
                man.append(path)
        return man

    def getheads(self):
        return self.parents[None]

    def getcommit(self, rev):
        elt = self.changes[rev]
        date = util.strdate(elt.get('local_date'), '%a %b %d %H:%M:%S %Z %Y')
        desc = elt.findtext('name') + '\n' + elt.findtext('comment', '')
        # etree can return unicode objects for name, comment, and author,
        # so recode() is used to ensure str objects are emitted.
        return commit(author=self.recode(elt.get('author')),
                      date=util.datestr(date, '%Y-%m-%d %H:%M:%S %1%2'),
                      desc=self.recode(desc).strip(),
                      parents=self.parents[rev])

    def pull(self, rev):
        output, status = self.run('pull', self.path, all=True,
                                  match='hash %s' % rev,
                                  no_test=True, no_posthook=True,
                                  external_merge='/bin/false',
                                  repodir=self.tmppath)
        if status:
            if output.find('We have conflicts in') == -1:
                self.checkexit(status, output)
            output, status = self.run('revert', all=True, repodir=self.tmppath)
            self.checkexit(status, output)

    def getchanges(self, rev, full):
        if full:
            raise util.Abort(_("convert from darcs do not support --full"))
        copies = {}
        changes = []
        man = None
        for elt in self.changes[rev].find('summary').getchildren():
            if elt.tag in ('add_directory', 'remove_directory'):
                continue
            if elt.tag == 'move':
                if man is None:
                    man = self.manifest()
                source, dest = elt.get('from'), elt.get('to')
                if source in man:
                    # File move
                    changes.append((source, rev))
                    changes.append((dest, rev))
                    copies[dest] = source
                else:
                    # Directory move, deduce file moves from manifest
                    source = source + '/'
                    for f in man:
                        if not f.startswith(source):
                            continue
                        fdest = dest + '/' + f[len(source):]
                        changes.append((f, rev))
                        changes.append((fdest, rev))
                        copies[fdest] = f
            else:
                changes.append((elt.text.strip(), rev))
        self.pull(rev)
        self.lastrev = rev
        return sorted(changes), copies, set()

    def getfile(self, name, rev):
        if rev != self.lastrev:
            raise util.Abort(_('internal calling inconsistency'))
        path = os.path.join(self.tmppath, name)
        try:
            data = util.readfile(path)
            mode = os.lstat(path).st_mode
        except IOError as inst:
            if inst.errno == errno.ENOENT:
                return None, None
            raise
        mode = (mode & 0o111) and 'x' or ''
        return data, mode

    def gettags(self):
        return self.tags