hgext/gpg.py

blackbox: defer opening a log file until needed (issue3869)

Previously, we opened the log file when creating a repo object. This
was inefficient (not all repo creation is going to result in a need to
log something), but more importantly it broke subrepo updates when used
on NFS.

* perform an update in the master repo that triggers a subrepo clone

* empty subrepo already exists, and has an open, empty blackbox.log file
  due to it being opened eagerly/prematurely

* hg decides to blow away the skeletal subrepo (see use of shutil.rmtree
  in subrepo._get)

* we crash, due to NFS treating a delete of an open file as really a
  rename to a hidden ".nfs" file

Now that we open the blackbox log file on demand, no file exists at the
time the empty subrepo is deleted, so the above problem does not occur.

# Copyright 2005, 2006 Benoit Boissinot <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''commands to sign and verify changesets'''

import os, tempfile, binascii
from mercurial import util, commands, match, cmdutil
from mercurial import node as hgnode
from mercurial.i18n import _

cmdtable = {}
command = cmdutil.command(cmdtable)
testedwith = 'internal'

class gpg(object):
    def __init__(self, path, key=None):
        self.path = path
        self.key = (key and " --local-user \"%s\"" % key) or ""

    def sign(self, data):
        gpgcmd = "%s --sign --detach-sign%s" % (self.path, self.key)
        return util.filter(data, gpgcmd)

    def verify(self, data, sig):
        """ returns of the good and bad signatures"""
        sigfile = datafile = None
        try:
            # create temporary files
            fd, sigfile = tempfile.mkstemp(prefix="hg-gpg-", suffix=".sig")
            fp = os.fdopen(fd, 'wb')
            fp.write(sig)
            fp.close()
            fd, datafile = tempfile.mkstemp(prefix="hg-gpg-", suffix=".txt")
            fp = os.fdopen(fd, 'wb')
            fp.write(data)
            fp.close()
            gpgcmd = ("%s --logger-fd 1 --status-fd 1 --verify "
                      "\"%s\" \"%s\"" % (self.path, sigfile, datafile))
            ret = util.filter("", gpgcmd)
        finally:
            for f in (sigfile, datafile):
                try:
                    if f:
                        os.unlink(f)
                except OSError:
                    pass
        keys = []
        key, fingerprint = None, None
        err = ""
        for l in ret.splitlines():
            # see DETAILS in the gnupg documentation
            # filter the logger output
            if not l.startswith("[GNUPG:]"):
                continue
            l = l[9:]
            if l.startswith("ERRSIG"):
                err = _("error while verifying signature")
                break
            elif l.startswith("VALIDSIG"):
                # fingerprint of the primary key
                fingerprint = l.split()[10]
            elif (l.startswith("GOODSIG") or
                  l.startswith("EXPSIG") or
                  l.startswith("EXPKEYSIG") or
                  l.startswith("BADSIG")):
                if key is not None:
                    keys.append(key + [fingerprint])
                key = l.split(" ", 2)
                fingerprint = None
        if err:
            return err, []
        if key is not None:
            keys.append(key + [fingerprint])
        return err, keys

def newgpg(ui, **opts):
    """create a new gpg instance"""
    gpgpath = ui.config("gpg", "cmd", "gpg")
    gpgkey = opts.get('key')
    if not gpgkey:
        gpgkey = ui.config("gpg", "key", None)
    return gpg(gpgpath, gpgkey)

def sigwalk(repo):
    """
    walk over every sigs, yields a couple
    ((node, version, sig), (filename, linenumber))
    """
    def parsefile(fileiter, context):
        ln = 1
        for l in fileiter:
            if not l:
                continue
            yield (l.split(" ", 2), (context, ln))
            ln += 1

    # read the heads
    fl = repo.file(".hgsigs")
    for r in reversed(fl.heads()):
        fn = ".hgsigs|%s" % hgnode.short(r)
        for item in parsefile(fl.read(r).splitlines(), fn):
            yield item
    try:
        # read local signatures
        fn = "localsigs"
        for item in parsefile(repo.opener(fn), fn):
            yield item
    except IOError:
        pass

def getkeys(ui, repo, mygpg, sigdata, context):
    """get the keys who signed a data"""
    fn, ln = context
    node, version, sig = sigdata
    prefix = "%s:%d" % (fn, ln)
    node = hgnode.bin(node)

    data = node2txt(repo, node, version)
    sig = binascii.a2b_base64(sig)
    err, keys = mygpg.verify(data, sig)
    if err:
        ui.warn("%s:%d %s\n" % (fn, ln , err))
        return None

    validkeys = []
    # warn for expired key and/or sigs
    for key in keys:
        if key[0] == "BADSIG":
            ui.write(_("%s Bad signature from \"%s\"\n") % (prefix, key[2]))
            continue
        if key[0] == "EXPSIG":
            ui.write(_("%s Note: Signature has expired"
                       " (signed by: \"%s\")\n") % (prefix, key[2]))
        elif key[0] == "EXPKEYSIG":
            ui.write(_("%s Note: This key has expired"
                       " (signed by: \"%s\")\n") % (prefix, key[2]))
        validkeys.append((key[1], key[2], key[3]))
    return validkeys

@command("sigs", [], _('hg sigs'))
def sigs(ui, repo):
    """list signed changesets"""
    mygpg = newgpg(ui)
    revs = {}

    for data, context in sigwalk(repo):
        node, version, sig = data
        fn, ln = context
        try:
            n = repo.lookup(node)
        except KeyError:
            ui.warn(_("%s:%d node does not exist\n") % (fn, ln))
            continue
        r = repo.changelog.rev(n)
        keys = getkeys(ui, repo, mygpg, data, context)
        if not keys:
            continue
        revs.setdefault(r, [])
        revs[r].extend(keys)
    for rev in sorted(revs, reverse=True):
        for k in revs[rev]:
            r = "%5d:%s" % (rev, hgnode.hex(repo.changelog.node(rev)))
            ui.write("%-30s %s\n" % (keystr(ui, k), r))

@command("sigcheck", [], _('hg sigcheck REV'))
def check(ui, repo, rev):
    """verify all the signatures there may be for a particular revision"""
    mygpg = newgpg(ui)
    rev = repo.lookup(rev)
    hexrev = hgnode.hex(rev)
    keys = []

    for data, context in sigwalk(repo):
        node, version, sig = data
        if node == hexrev:
            k = getkeys(ui, repo, mygpg, data, context)
            if k:
                keys.extend(k)

    if not keys:
        ui.write(_("no valid signature for %s\n") % hgnode.short(rev))
        return

    # print summary
    ui.write("%s is signed by:\n" % hgnode.short(rev))
    for key in keys:
        ui.write(" %s\n" % keystr(ui, key))

def keystr(ui, key):
    """associate a string to a key (username, comment)"""
    keyid, user, fingerprint = key
    comment = ui.config("gpg", fingerprint, None)
    if comment:
        return "%s (%s)" % (user, comment)
    else:
        return user

@command("sign",
         [('l', 'local', None, _('make the signature local')),
          ('f', 'force', None, _('sign even if the sigfile is modified')),
          ('', 'no-commit', None, _('do not commit the sigfile after signing')),
          ('k', 'key', '',
           _('the key id to sign with'), _('ID')),
          ('m', 'message', '',
           _('commit message'), _('TEXT')),
         ] + commands.commitopts2,
         _('hg sign [OPTION]... [REV]...'))
def sign(ui, repo, *revs, **opts):
    """add a signature for the current or given revision

    If no revision is given, the parent of the working directory is used,
    or tip if no revision is checked out.

    See :hg:`help dates` for a list of formats valid for -d/--date.
    """

    mygpg = newgpg(ui, **opts)
    sigver = "0"
    sigmessage = ""

    date = opts.get('date')
    if date:
        opts['date'] = util.parsedate(date)

    if revs:
        nodes = [repo.lookup(n) for n in revs]
    else:
        nodes = [node for node in repo.dirstate.parents()
                 if node != hgnode.nullid]
        if len(nodes) > 1:
            raise util.Abort(_('uncommitted merge - please provide a '
                               'specific revision'))
        if not nodes:
            nodes = [repo.changelog.tip()]

    for n in nodes:
        hexnode = hgnode.hex(n)
        ui.write(_("signing %d:%s\n") % (repo.changelog.rev(n),
                                         hgnode.short(n)))
        # build data
        data = node2txt(repo, n, sigver)
        sig = mygpg.sign(data)
        if not sig:
            raise util.Abort(_("error while signing"))
        sig = binascii.b2a_base64(sig)
        sig = sig.replace("\n", "")
        sigmessage += "%s %s %s\n" % (hexnode, sigver, sig)

    # write it
    if opts['local']:
        repo.opener.append("localsigs", sigmessage)
        return

    msigs = match.exact(repo.root, '', ['.hgsigs'])
    s = repo.status(match=msigs, unknown=True, ignored=True)[:6]
    if util.any(s) and not opts["force"]:
        raise util.Abort(_("working copy of .hgsigs is changed "
                           "(please commit .hgsigs manually "
                           "or use --force)"))

    sigsfile = repo.wfile(".hgsigs", "ab")
    sigsfile.write(sigmessage)
    sigsfile.close()

    if '.hgsigs' not in repo.dirstate:
        repo[None].add([".hgsigs"])

    if opts["no_commit"]:
        return

    message = opts['message']
    if not message:
        # we don't translate commit messages
        message = "\n".join(["Added signature for changeset %s"
                             % hgnode.short(n)
                             for n in nodes])
    try:
        repo.commit(message, opts['user'], opts['date'], match=msigs)
    except ValueError, inst:
        raise util.Abort(str(inst))

def node2txt(repo, node, ver):
    """map a manifest into some text"""
    if ver == "0":
        return "%s\n" % hgnode.hex(node)
    else:
        raise util.Abort(_("unknown signature version"))