mercurial/match.py

sslutil: abort when unable to verify peer connection (BC)

Previously, when we connected to a server and were unable to verify
its certificate against a trusted certificate authority we would
issue a warning and continue to connect. This is obviously not
great behavior because the x509 certificate model is based upon
trust of specific CAs. Failure to enforce that trust erodes security.
This behavior was defined several years ago when Python did not
support loading the system trusted CA store (Python 2.7.9's
backports of Python 3's improvements to the "ssl" module enabled
this).

This commit changes behavior when connecting to abort if the peer
certificate can't be validated. With an empty/default Mercurial
configuration, the peer certificate can be validated if Python is
able to load the system trusted CA store. Environments able to load
the system trusted CA store include:

* Python 2.7.9+ on most platforms and installations
* Python 2.7 distributions with a modern ssl module (e.g. RHEL7's
  patched 2.7.5 package)
* Python shipped on OS X

Environments unable to load the system trusted CA store include:

* Python 2.6
* Python 2.7 on many existing Linux installs (because they don't
  ship 2.7.9+ or haven't backported modern ssl module)
* Python 2.7.9+ on some installs where Python is unable to locate
  the system CA store (this is hopefully rare)

Users of these Pythongs will need to configure Mercurial to load the
system CA store using web.cacerts. This should ideally be performed
by packagers (by setting web.cacerts in the global/system hgrc file).
Where Mercurial packagers aren't setting this, the linked URL in the
new abort message can contain instructions for users.

In the future, we may want to add more code for finding the system
CA store. For example, many Linux distributions have the CA store
at well-known locations (such as /etc/ssl/certs/ca-certificates.crt
in the case of Ubuntu). This will enable CA loading to "just work"
on more Python configurations and will be best for our users since
they won't have to change anything after upgrading to a Mercurial
with this patch.

We may also want to consider distributing a trusted CA store with
Mercurial. Although we should think long and hard about that because
most systems have a global CA store and Mercurial should almost
certainly use the same store used by everything else on the system.

# match.py - filename matching
#
#  Copyright 2008, 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 __future__ import absolute_import

import copy
import os
import re

from .i18n import _
from . import (
    error,
    pathutil,
    util,
)

propertycache = util.propertycache

def _rematcher(regex):
    '''compile the regexp with the best available regexp engine and return a
    matcher function'''
    m = util.re.compile(regex)
    try:
        # slightly faster, provided by facebook's re2 bindings
        return m.test_match
    except AttributeError:
        return m.match

def _expandsets(kindpats, ctx, listsubrepos):
    '''Returns the kindpats list with the 'set' patterns expanded.'''
    fset = set()
    other = []

    for kind, pat, source in kindpats:
        if kind == 'set':
            if not ctx:
                raise error.Abort(_("fileset expression with no context"))
            s = ctx.getfileset(pat)
            fset.update(s)

            if listsubrepos:
                for subpath in ctx.substate:
                    s = ctx.sub(subpath).getfileset(pat)
                    fset.update(subpath + '/' + f for f in s)

            continue
        other.append((kind, pat, source))
    return fset, other

def _expandsubinclude(kindpats, root):
    '''Returns the list of subinclude matchers and the kindpats without the
    subincludes in it.'''
    relmatchers = []
    other = []

    for kind, pat, source in kindpats:
        if kind == 'subinclude':
            sourceroot = pathutil.dirname(util.normpath(source))
            pat = util.pconvert(pat)
            path = pathutil.join(sourceroot, pat)

            newroot = pathutil.dirname(path)
            relmatcher = match(newroot, '', [], ['include:%s' % path])

            prefix = pathutil.canonpath(root, root, newroot)
            if prefix:
                prefix += '/'
            relmatchers.append((prefix, relmatcher))
        else:
            other.append((kind, pat, source))

    return relmatchers, other

def _kindpatsalwaysmatch(kindpats):
    """"Checks whether the kindspats match everything, as e.g.
    'relpath:.' does.
    """
    for kind, pat, source in kindpats:
        if pat != '' or kind not in ['relpath', 'glob']:
            return False
    return True

class match(object):
    def __init__(self, root, cwd, patterns, include=[], exclude=[],
                 default='glob', exact=False, auditor=None, ctx=None,
                 listsubrepos=False, warn=None, badfn=None):
        """build an object to match a set of file patterns

        arguments:
        root - the canonical root of the tree you're matching against
        cwd - the current working directory, if relevant
        patterns - patterns to find
        include - patterns to include (unless they are excluded)
        exclude - patterns to exclude (even if they are included)
        default - if a pattern in patterns has no explicit type, assume this one
        exact - patterns are actually filenames (include/exclude still apply)
        warn - optional function used for printing warnings
        badfn - optional bad() callback for this matcher instead of the default

        a pattern is one of:
        'glob:<glob>' - a glob relative to cwd
        're:<regexp>' - a regular expression
        'path:<path>' - a path relative to repository root
        'relglob:<glob>' - an unrooted glob (*.c matches C files in all dirs)
        'relpath:<path>' - a path relative to cwd
        'relre:<regexp>' - a regexp that needn't match the start of a name
        'set:<fileset>' - a fileset expression
        'include:<path>' - a file of patterns to read and include
        'subinclude:<path>' - a file of patterns to match against files under
                              the same directory
        '<something>' - a pattern of the specified default type
        """

        self._root = root
        self._cwd = cwd
        self._files = [] # exact files and roots of patterns
        self._anypats = bool(include or exclude)
        self._always = False
        self._pathrestricted = bool(include or exclude or patterns)
        self._warn = warn
        self._includeroots = set()
        self._includedirs = set(['.'])
        self._excluderoots = set()

        if badfn is not None:
            self.bad = badfn

        matchfns = []
        if include:
            kindpats = self._normalize(include, 'glob', root, cwd, auditor)
            self.includepat, im = _buildmatch(ctx, kindpats, '(?:/|$)',
                                              listsubrepos, root)
            self._includeroots.update(_roots(kindpats))
            self._includedirs.update(util.dirs(self._includeroots))
            matchfns.append(im)
        if exclude:
            kindpats = self._normalize(exclude, 'glob', root, cwd, auditor)
            self.excludepat, em = _buildmatch(ctx, kindpats, '(?:/|$)',
                                              listsubrepos, root)
            if not _anypats(kindpats):
                self._excluderoots.update(_roots(kindpats))
            matchfns.append(lambda f: not em(f))
        if exact:
            if isinstance(patterns, list):
                self._files = patterns
            else:
                self._files = list(patterns)
            matchfns.append(self.exact)
        elif patterns:
            kindpats = self._normalize(patterns, default, root, cwd, auditor)
            if not _kindpatsalwaysmatch(kindpats):
                self._files = _roots(kindpats)
                self._anypats = self._anypats or _anypats(kindpats)
                self.patternspat, pm = _buildmatch(ctx, kindpats, '$',
                                                   listsubrepos, root)
                matchfns.append(pm)

        if not matchfns:
            m = util.always
            self._always = True
        elif len(matchfns) == 1:
            m = matchfns[0]
        else:
            def m(f):
                for matchfn in matchfns:
                    if not matchfn(f):
                        return False
                return True

        self.matchfn = m
        self._fileroots = set(self._files)

    def __call__(self, fn):
        return self.matchfn(fn)
    def __iter__(self):
        for f in self._files:
            yield f

    # Callbacks related to how the matcher is used by dirstate.walk.
    # Subscribers to these events must monkeypatch the matcher object.
    def bad(self, f, msg):
        '''Callback from dirstate.walk for each explicit file that can't be
        found/accessed, with an error message.'''
        pass

    # If an explicitdir is set, it will be called when an explicitly listed
    # directory is visited.
    explicitdir = None

    # If an traversedir is set, it will be called when a directory discovered
    # by recursive traversal is visited.
    traversedir = None

    def abs(self, f):
        '''Convert a repo path back to path that is relative to the root of the
        matcher.'''
        return f

    def rel(self, f):
        '''Convert repo path back to path that is relative to cwd of matcher.'''
        return util.pathto(self._root, self._cwd, f)

    def uipath(self, f):
        '''Convert repo path to a display path.  If patterns or -I/-X were used
        to create this matcher, the display path will be relative to cwd.
        Otherwise it is relative to the root of the repo.'''
        return (self._pathrestricted and self.rel(f)) or self.abs(f)

    def files(self):
        '''Explicitly listed files or patterns or roots:
        if no patterns or .always(): empty list,
        if exact: list exact files,
        if not .anypats(): list all files and dirs,
        else: optimal roots'''
        return self._files

    @propertycache
    def _dirs(self):
        return set(util.dirs(self._fileroots)) | set(['.'])

    def visitdir(self, dir):
        '''Decides whether a directory should be visited based on whether it
        has potential matches in it or one of its subdirectories. This is
        based on the match's primary, included, and excluded patterns.

        Returns the string 'all' if the given directory and all subdirectories
        should be visited. Otherwise returns True or False indicating whether
        the given directory should be visited.

        This function's behavior is undefined if it has returned False for
        one of the dir's parent directories.
        '''
        if self.prefix() and dir in self._fileroots:
            return 'all'
        if dir in self._excluderoots:
            return False
        if (self._includeroots and
            '.' not in self._includeroots and
            dir not in self._includeroots and
            dir not in self._includedirs and
            not any(parent in self._includeroots
                    for parent in util.finddirs(dir))):
            return False
        return (not self._fileroots or
                '.' in self._fileroots or
                dir in self._fileroots or
                dir in self._dirs or
                any(parentdir in self._fileroots
                    for parentdir in util.finddirs(dir)))

    def exact(self, f):
        '''Returns True if f is in .files().'''
        return f in self._fileroots

    def anypats(self):
        '''Matcher uses patterns or include/exclude.'''
        return self._anypats

    def always(self):
        '''Matcher will match everything and .files() will be empty
        - optimization might be possible and necessary.'''
        return self._always

    def ispartial(self):
        '''True if the matcher won't always match.

        Although it's just the inverse of _always in this implementation,
        an extension such as narrowhg might make it return something
        slightly different.'''
        return not self._always

    def isexact(self):
        return self.matchfn == self.exact

    def prefix(self):
        return not self.always() and not self.isexact() and not self.anypats()

    def _normalize(self, patterns, default, root, cwd, auditor):
        '''Convert 'kind:pat' from the patterns list to tuples with kind and
        normalized and rooted patterns and with listfiles expanded.'''
        kindpats = []
        for kind, pat in [_patsplit(p, default) for p in patterns]:
            if kind in ('glob', 'relpath'):
                pat = pathutil.canonpath(root, cwd, pat, auditor)
            elif kind in ('relglob', 'path'):
                pat = util.normpath(pat)
            elif kind in ('listfile', 'listfile0'):
                try:
                    files = util.readfile(pat)
                    if kind == 'listfile0':
                        files = files.split('\0')
                    else:
                        files = files.splitlines()
                    files = [f for f in files if f]
                except EnvironmentError:
                    raise error.Abort(_("unable to read file list (%s)") % pat)
                for k, p, source in self._normalize(files, default, root, cwd,
                                                    auditor):
                    kindpats.append((k, p, pat))
                continue
            elif kind == 'include':
                try:
                    fullpath = os.path.join(root, util.localpath(pat))
                    includepats = readpatternfile(fullpath, self._warn)
                    for k, p, source in self._normalize(includepats, default,
                                                        root, cwd, auditor):
                        kindpats.append((k, p, source or pat))
                except error.Abort as inst:
                    raise error.Abort('%s: %s' % (pat, inst[0]))
                except IOError as inst:
                    if self._warn:
                        self._warn(_("skipping unreadable pattern file "
                                     "'%s': %s\n") % (pat, inst.strerror))
                continue
            # else: re or relre - which cannot be normalized
            kindpats.append((kind, pat, ''))
        return kindpats

def exact(root, cwd, files, badfn=None):
    return match(root, cwd, files, exact=True, badfn=badfn)

def always(root, cwd):
    return match(root, cwd, [])

def badmatch(match, badfn):
    """Make a copy of the given matcher, replacing its bad method with the given
    one.
    """
    m = copy.copy(match)
    m.bad = badfn
    return m

class subdirmatcher(match):
    """Adapt a matcher to work on a subdirectory only.

    The paths are remapped to remove/insert the path as needed:

    >>> m1 = match('root', '', ['a.txt', 'sub/b.txt'])
    >>> m2 = subdirmatcher('sub', m1)
    >>> bool(m2('a.txt'))
    False
    >>> bool(m2('b.txt'))
    True
    >>> bool(m2.matchfn('a.txt'))
    False
    >>> bool(m2.matchfn('b.txt'))
    True
    >>> m2.files()
    ['b.txt']
    >>> m2.exact('b.txt')
    True
    >>> util.pconvert(m2.rel('b.txt'))
    'sub/b.txt'
    >>> def bad(f, msg):
    ...     print "%s: %s" % (f, msg)
    >>> m1.bad = bad
    >>> m2.bad('x.txt', 'No such file')
    sub/x.txt: No such file
    >>> m2.abs('c.txt')
    'sub/c.txt'
    """

    def __init__(self, path, matcher):
        self._root = matcher._root
        self._cwd = matcher._cwd
        self._path = path
        self._matcher = matcher
        self._always = matcher._always
        self._pathrestricted = matcher._pathrestricted

        self._files = [f[len(path) + 1:] for f in matcher._files
                       if f.startswith(path + "/")]

        # If the parent repo had a path to this subrepo and no patterns are
        # specified, this submatcher always matches.
        if not self._always and not matcher._anypats:
            self._always = any(f == path for f in matcher._files)

        self._anypats = matcher._anypats
        # Some information is lost in the superclass's constructor, so we
        # can not accurately create the matching function for the subdirectory
        # from the inputs. Instead, we override matchfn() and visitdir() to
        # call the original matcher with the subdirectory path prepended.
        self.matchfn = lambda fn: matcher.matchfn(self._path + "/" + fn)
        def visitdir(dir):
            if dir == '.':
                return matcher.visitdir(self._path)
            return matcher.visitdir(self._path + "/" + dir)
        self.visitdir = visitdir
        self._fileroots = set(self._files)

    def abs(self, f):
        return self._matcher.abs(self._path + "/" + f)

    def bad(self, f, msg):
        self._matcher.bad(self._path + "/" + f, msg)

    def rel(self, f):
        return self._matcher.rel(self._path + "/" + f)

class icasefsmatcher(match):
    """A matcher for wdir on case insensitive filesystems, which normalizes the
    given patterns to the case in the filesystem.
    """

    def __init__(self, root, cwd, patterns, include, exclude, default, auditor,
                 ctx, listsubrepos=False, badfn=None):
        init = super(icasefsmatcher, self).__init__
        self._dirstate = ctx.repo().dirstate
        self._dsnormalize = self._dirstate.normalize

        init(root, cwd, patterns, include, exclude, default, auditor=auditor,
             ctx=ctx, listsubrepos=listsubrepos, badfn=badfn)

        # m.exact(file) must be based off of the actual user input, otherwise
        # inexact case matches are treated as exact, and not noted without -v.
        if self._files:
            self._fileroots = set(_roots(self._kp))

    def _normalize(self, patterns, default, root, cwd, auditor):
        self._kp = super(icasefsmatcher, self)._normalize(patterns, default,
                                                          root, cwd, auditor)
        kindpats = []
        for kind, pats, source in self._kp:
            if kind not in ('re', 'relre'):  # regex can't be normalized
                p = pats
                pats = self._dsnormalize(pats)

                # Preserve the original to handle a case only rename.
                if p != pats and p in self._dirstate:
                    kindpats.append((kind, p, source))

            kindpats.append((kind, pats, source))
        return kindpats

def patkind(pattern, default=None):
    '''If pattern is 'kind:pat' with a known kind, return kind.'''
    return _patsplit(pattern, default)[0]

def _patsplit(pattern, default):
    """Split a string into the optional pattern kind prefix and the actual
    pattern."""
    if ':' in pattern:
        kind, pat = pattern.split(':', 1)
        if kind in ('re', 'glob', 'path', 'relglob', 'relpath', 'relre',
                    'listfile', 'listfile0', 'set', 'include', 'subinclude'):
            return kind, pat
    return default, pattern

def _globre(pat):
    r'''Convert an extended glob string to a regexp string.

    >>> print _globre(r'?')
    .
    >>> print _globre(r'*')
    [^/]*
    >>> print _globre(r'**')
    .*
    >>> print _globre(r'**/a')
    (?:.*/)?a
    >>> print _globre(r'a/**/b')
    a\/(?:.*/)?b
    >>> print _globre(r'[a*?!^][^b][!c]')
    [a*?!^][\^b][^c]
    >>> print _globre(r'{a,b}')
    (?:a|b)
    >>> print _globre(r'.\*\?')
    \.\*\?
    '''
    i, n = 0, len(pat)
    res = ''
    group = 0
    escape = util.re.escape
    def peek():
        return i < n and pat[i]
    while i < n:
        c = pat[i]
        i += 1
        if c not in '*?[{},\\':
            res += escape(c)
        elif c == '*':
            if peek() == '*':
                i += 1
                if peek() == '/':
                    i += 1
                    res += '(?:.*/)?'
                else:
                    res += '.*'
            else:
                res += '[^/]*'
        elif c == '?':
            res += '.'
        elif c == '[':
            j = i
            if j < n and pat[j] in '!]':
                j += 1
            while j < n and pat[j] != ']':
                j += 1
            if j >= n:
                res += '\\['
            else:
                stuff = pat[i:j].replace('\\','\\\\')
                i = j + 1
                if stuff[0] == '!':
                    stuff = '^' + stuff[1:]
                elif stuff[0] == '^':
                    stuff = '\\' + stuff
                res = '%s[%s]' % (res, stuff)
        elif c == '{':
            group += 1
            res += '(?:'
        elif c == '}' and group:
            res += ')'
            group -= 1
        elif c == ',' and group:
            res += '|'
        elif c == '\\':
            p = peek()
            if p:
                i += 1
                res += escape(p)
            else:
                res += escape(c)
        else:
            res += escape(c)
    return res

def _regex(kind, pat, globsuffix):
    '''Convert a (normalized) pattern of any kind into a regular expression.
    globsuffix is appended to the regexp of globs.'''
    if not pat:
        return ''
    if kind == 're':
        return pat
    if kind == 'path':
        if pat == '.':
            return ''
        return '^' + util.re.escape(pat) + '(?:/|$)'
    if kind == 'relglob':
        return '(?:|.*/)' + _globre(pat) + globsuffix
    if kind == 'relpath':
        return util.re.escape(pat) + '(?:/|$)'
    if kind == 'relre':
        if pat.startswith('^'):
            return pat
        return '.*' + pat
    return _globre(pat) + globsuffix

def _buildmatch(ctx, kindpats, globsuffix, listsubrepos, root):
    '''Return regexp string and a matcher function for kindpats.
    globsuffix is appended to the regexp of globs.'''
    matchfuncs = []

    subincludes, kindpats = _expandsubinclude(kindpats, root)
    if subincludes:
        def matchsubinclude(f):
            for prefix, mf in subincludes:
                if f.startswith(prefix) and mf(f[len(prefix):]):
                    return True
            return False
        matchfuncs.append(matchsubinclude)

    fset, kindpats = _expandsets(kindpats, ctx, listsubrepos)
    if fset:
        matchfuncs.append(fset.__contains__)

    regex = ''
    if kindpats:
        regex, mf = _buildregexmatch(kindpats, globsuffix)
        matchfuncs.append(mf)

    if len(matchfuncs) == 1:
        return regex, matchfuncs[0]
    else:
        return regex, lambda f: any(mf(f) for mf in matchfuncs)

def _buildregexmatch(kindpats, globsuffix):
    """Build a match function from a list of kinds and kindpats,
    return regexp string and a matcher function."""
    try:
        regex = '(?:%s)' % '|'.join([_regex(k, p, globsuffix)
                                     for (k, p, s) in kindpats])
        if len(regex) > 20000:
            raise OverflowError
        return regex, _rematcher(regex)
    except OverflowError:
        # We're using a Python with a tiny regex engine and we
        # made it explode, so we'll divide the pattern list in two
        # until it works
        l = len(kindpats)
        if l < 2:
            raise
        regexa, a = _buildregexmatch(kindpats[:l//2], globsuffix)
        regexb, b = _buildregexmatch(kindpats[l//2:], globsuffix)
        return regex, lambda s: a(s) or b(s)
    except re.error:
        for k, p, s in kindpats:
            try:
                _rematcher('(?:%s)' % _regex(k, p, globsuffix))
            except re.error:
                if s:
                    raise error.Abort(_("%s: invalid pattern (%s): %s") %
                                     (s, k, p))
                else:
                    raise error.Abort(_("invalid pattern (%s): %s") % (k, p))
        raise error.Abort(_("invalid pattern"))

def _roots(kindpats):
    '''return roots and exact explicitly listed files from patterns

    >>> _roots([('glob', 'g/*', ''), ('glob', 'g', ''), ('glob', 'g*', '')])
    ['g', 'g', '.']
    >>> _roots([('relpath', 'r', ''), ('path', 'p/p', ''), ('path', '', '')])
    ['r', 'p/p', '.']
    >>> _roots([('relglob', 'rg*', ''), ('re', 're/', ''), ('relre', 'rr', '')])
    ['.', '.', '.']
    '''
    r = []
    for kind, pat, source in kindpats:
        if kind == 'glob': # find the non-glob prefix
            root = []
            for p in pat.split('/'):
                if '[' in p or '{' in p or '*' in p or '?' in p:
                    break
                root.append(p)
            r.append('/'.join(root) or '.')
        elif kind in ('relpath', 'path'):
            r.append(pat or '.')
        else: # relglob, re, relre
            r.append('.')
    return r

def _anypats(kindpats):
    for kind, pat, source in kindpats:
        if kind in ('glob', 're', 'relglob', 'relre', 'set'):
            return True

_commentre = None

def readpatternfile(filepath, warn, sourceinfo=False):
    '''parse a pattern file, returning a list of
    patterns. These patterns should be given to compile()
    to be validated and converted into a match function.

    trailing white space is dropped.
    the escape character is backslash.
    comments start with #.
    empty lines are skipped.

    lines can be of the following formats:

    syntax: regexp # defaults following lines to non-rooted regexps
    syntax: glob   # defaults following lines to non-rooted globs
    re:pattern     # non-rooted regular expression
    glob:pattern   # non-rooted glob
    pattern        # pattern of the current default type

    if sourceinfo is set, returns a list of tuples:
    (pattern, lineno, originalline). This is useful to debug ignore patterns.
    '''

    syntaxes = {'re': 'relre:', 'regexp': 'relre:', 'glob': 'relglob:',
                'include': 'include', 'subinclude': 'subinclude'}
    syntax = 'relre:'
    patterns = []

    fp = open(filepath)
    for lineno, line in enumerate(fp, start=1):
        if "#" in line:
            global _commentre
            if not _commentre:
                _commentre = util.re.compile(r'((?:^|[^\\])(?:\\\\)*)#.*')
            # remove comments prefixed by an even number of escapes
            m = _commentre.search(line)
            if m:
                line = line[:m.end(1)]
            # fixup properly escaped comments that survived the above
            line = line.replace("\\#", "#")
        line = line.rstrip()
        if not line:
            continue

        if line.startswith('syntax:'):
            s = line[7:].strip()
            try:
                syntax = syntaxes[s]
            except KeyError:
                if warn:
                    warn(_("%s: ignoring invalid syntax '%s'\n") %
                         (filepath, s))
            continue

        linesyntax = syntax
        for s, rels in syntaxes.iteritems():
            if line.startswith(rels):
                linesyntax = rels
                line = line[len(rels):]
                break
            elif line.startswith(s+':'):
                linesyntax = rels
                line = line[len(s) + 1:]
                break
        if sourceinfo:
            patterns.append((linesyntax + line, lineno, line))
        else:
            patterns.append(linesyntax + line)
    fp.close()
    return patterns