hgext/gpg.py

copy/rename to a removed destination file

When the destination of a copy or rename operation has been
marked for removal, we need to restore it before we overwrite
it with the new content. This also handles the case of
idempotent renames, i.e.

    hg rename "a" "b"
    hg rename "b" "a"

# GnuPG signing extension for Mercurial
#
# Copyright 2005, 2006 Benoit Boissinot <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import os, tempfile, binascii
from mercurial import util
from mercurial import node as hgnode
from mercurial.i18n import gettext as _

class gpg:
    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"""
        try:
            # create temporary files
            fd, sigfile = tempfile.mkstemp(prefix="hggpgsig")
            fp = os.fdopen(fd, 'wb')
            fp.write(sig)
            fp.close()
            fd, datafile = tempfile.mkstemp(prefix="hggpgdata")
            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)
        except:
            for f in (sigfile, datafile):
                try:
                    if f: os.unlink(f)
                except: pass
            raise
        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

    fl = repo.file(".hgsigs")
    h = fl.heads()
    h.reverse()
    # read the heads
    for r in h:
        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

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)
    nodes = list(revs)
    nodes.reverse()
    for rev in nodes:
        for k in revs[rev]:
            r = "%5d:%s" % (rev, hgnode.hex(repo.changelog.node(rev)))
            ui.write("%-30s %s\n" % (keystr(ui, k), r))

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

def sign(ui, repo, *revs, **opts):
    """add a signature for the current tip or a given revision"""
    mygpg = newgpg(ui, **opts)
    sigver = "0"
    sigmessage = ""
    if revs:
        nodes = [repo.lookup(n) for n in revs]
    else:
        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("localsigs", "ab").write(sigmessage)
        return

    for x in repo.changes():
        if ".hgsigs" in x and not opts["force"]:
            raise util.Abort(_("working copy of .hgsigs is changed "
                               "(please commit .hgsigs manually "
                               "or use --force)"))

    repo.wfile(".hgsigs", "ab").write(sigmessage)

    if repo.dirstate.state(".hgsigs") == '?':
        repo.add([".hgsigs"])

    if opts["no_commit"]:
        return

    message = opts['message']
    if not message:
        message = "\n".join([_("Added signature for changeset %s")
                             % hgnode.hex(n)
                             for n in nodes])
    try:
        repo.commit([".hgsigs"], message, opts['user'], opts['date'])
    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"))

cmdtable = {
    "sign":
        (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")),
          ('m', 'message', "", _("commit message")),
          ('d', 'date', "", _("date code")),
          ('u', 'user', "", _("user")),
          ('k', 'key', "", _("the key id to sign with"))],
         _("hg sign [OPTION]... [REVISION]...")),
    "sigcheck": (check, [], _('hg sigcheck REVISION')),
    "sigs": (sigs, [], _('hg sigs')),
}