view mercurial/mail.py @ 29847:9a9629b9416c stable

bundle2: fail faster when interrupted

Before this patch, bundle2 application attempted to consume remaining
bundle2 part data when the process is interrupted (SIGINT) or when
sys.exit is called (translated into a SystemExit exception). This
meant that if one of these occurred when applying a say 1 GB
changegroup bundle2 part being downloaded over a network, it may take
Mercurial *several minutes* to terminate after a SIGINT because the
process is waiting on the network to stream megabytes of data. This is
not a great user experience and a regression from bundle1. Furthermore,
many process supervisors tend to only give processes a finite amount of
time to exit after delivering SIGINT: if processes take too long to
self-terminate, a SIGKILL is issued and Mercurial has no opportunity to
clean up. This would mean orphaned locks and transactions. Not good.

This patch changes the bundle2 application behavior to fail faster
when an interrupt or system exit is requested. It does so by not
catching BaseException (which includes KeyboardInterrupt and
SystemExit) and by explicitly checking for these conditions in
yet another handler which would also seek to the end of the current
bundle2 part on failure.

The end result of this patch is that SIGINT is now reacted to
significantly faster: the active transaction is rolled back
immediately without waiting for incoming bundle2 data to be consumed.
This restores the pre-bundle2 behavior and makes Mercurial treat
signals with the urgency they deserve.

# mail.py - mail sending bits for mercurial
#
# Copyright 2006 Matt Mackall <[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.

from __future__ import absolute_import, print_function

import email
import os
import quopri
import smtplib
import socket
import sys
import time

from .i18n import _
from . import (
    encoding,
    error,
    sslutil,
    util,
)

_oldheaderinit = email.Header.Header.__init__
def _unifiedheaderinit(self, *args, **kw):
    """
    Python 2.7 introduces a backwards incompatible change
    (Python issue1974, r70772) in email.Generator.Generator code:
    pre-2.7 code passed "continuation_ws='\t'" to the Header
    constructor, and 2.7 removed this parameter.

    Default argument is continuation_ws=' ', which means that the
    behavior is different in <2.7 and 2.7

    We consider the 2.7 behavior to be preferable, but need
    to have an unified behavior for versions 2.4 to 2.7
    """
    # override continuation_ws
    kw['continuation_ws'] = ' '
    _oldheaderinit(self, *args, **kw)

setattr(email.header.Header, '__init__', _unifiedheaderinit)

class STARTTLS(smtplib.SMTP):
    '''Derived class to verify the peer certificate for STARTTLS.

    This class allows to pass any keyword arguments to SSL socket creation.
    '''
    def __init__(self, ui, host=None, **kwargs):
        smtplib.SMTP.__init__(self, **kwargs)
        self._ui = ui
        self._host = host

    def starttls(self, keyfile=None, certfile=None):
        if not self.has_extn("starttls"):
            msg = "STARTTLS extension not supported by server"
            raise smtplib.SMTPException(msg)
        (resp, reply) = self.docmd("STARTTLS")
        if resp == 220:
            self.sock = sslutil.wrapsocket(self.sock, keyfile, certfile,
                                           ui=self._ui,
                                           serverhostname=self._host)
            self.file = smtplib.SSLFakeFile(self.sock)
            self.helo_resp = None
            self.ehlo_resp = None
            self.esmtp_features = {}
            self.does_esmtp = 0
        return (resp, reply)

class SMTPS(smtplib.SMTP):
    '''Derived class to verify the peer certificate for SMTPS.

    This class allows to pass any keyword arguments to SSL socket creation.
    '''
    def __init__(self, ui, keyfile=None, certfile=None, host=None,
                 **kwargs):
        self.keyfile = keyfile
        self.certfile = certfile
        smtplib.SMTP.__init__(self, **kwargs)
        self._host = host
        self.default_port = smtplib.SMTP_SSL_PORT
        self._ui = ui

    def _get_socket(self, host, port, timeout):
        if self.debuglevel > 0:
            print('connect:', (host, port), file=sys.stderr)
        new_socket = socket.create_connection((host, port), timeout)
        new_socket = sslutil.wrapsocket(new_socket,
                                        self.keyfile, self.certfile,
                                        ui=self._ui,
                                        serverhostname=self._host)
        self.file = smtplib.SSLFakeFile(new_socket)
        return new_socket

def _smtp(ui):
    '''build an smtp connection and return a function to send mail'''
    local_hostname = ui.config('smtp', 'local_hostname')
    tls = ui.config('smtp', 'tls', 'none')
    # backward compatible: when tls = true, we use starttls.
    starttls = tls == 'starttls' or util.parsebool(tls)
    smtps = tls == 'smtps'
    if (starttls or smtps) and not util.safehasattr(socket, 'ssl'):
        raise error.Abort(_("can't use TLS: Python SSL support not installed"))
    mailhost = ui.config('smtp', 'host')
    if not mailhost:
        raise error.Abort(_('smtp.host not configured - cannot send mail'))
    if smtps:
        ui.note(_('(using smtps)\n'))
        s = SMTPS(ui, local_hostname=local_hostname, host=mailhost)
    elif starttls:
        s = STARTTLS(ui, local_hostname=local_hostname, host=mailhost)
    else:
        s = smtplib.SMTP(local_hostname=local_hostname)
    if smtps:
        defaultport = 465
    else:
        defaultport = 25
    mailport = util.getport(ui.config('smtp', 'port', defaultport))
    ui.note(_('sending mail: smtp host %s, port %d\n') %
            (mailhost, mailport))
    s.connect(host=mailhost, port=mailport)
    if starttls:
        ui.note(_('(using starttls)\n'))
        s.ehlo()
        s.starttls()
        s.ehlo()
    if starttls or smtps:
        ui.note(_('(verifying remote certificate)\n'))
        sslutil.validatesocket(s.sock)
    username = ui.config('smtp', 'username')
    password = ui.config('smtp', 'password')
    if username and not password:
        password = ui.getpass()
    if username and password:
        ui.note(_('(authenticating to mail server as %s)\n') %
                  (username))
        try:
            s.login(username, password)
        except smtplib.SMTPException as inst:
            raise error.Abort(inst)

    def send(sender, recipients, msg):
        try:
            return s.sendmail(sender, recipients, msg)
        except smtplib.SMTPRecipientsRefused as inst:
            recipients = [r[1] for r in inst.recipients.values()]
            raise error.Abort('\n' + '\n'.join(recipients))
        except smtplib.SMTPException as inst:
            raise error.Abort(inst)

    return send

def _sendmail(ui, sender, recipients, msg):
    '''send mail using sendmail.'''
    program = ui.config('email', 'method', 'smtp')
    cmdline = '%s -f %s %s' % (program, util.email(sender),
                               ' '.join(map(util.email, recipients)))
    ui.note(_('sending mail: %s\n') % cmdline)
    fp = util.popen(cmdline, 'w')
    fp.write(msg)
    ret = fp.close()
    if ret:
        raise error.Abort('%s %s' % (
            os.path.basename(program.split(None, 1)[0]),
            util.explainexit(ret)[0]))

def _mbox(mbox, sender, recipients, msg):
    '''write mails to mbox'''
    fp = open(mbox, 'ab+')
    # Should be time.asctime(), but Windows prints 2-characters day
    # of month instead of one. Make them print the same thing.
    date = time.strftime('%a %b %d %H:%M:%S %Y', time.localtime())
    fp.write('From %s %s\n' % (sender, date))
    fp.write(msg)
    fp.write('\n\n')
    fp.close()

def connect(ui, mbox=None):
    '''make a mail connection. return a function to send mail.
    call as sendmail(sender, list-of-recipients, msg).'''
    if mbox:
        open(mbox, 'wb').close()
        return lambda s, r, m: _mbox(mbox, s, r, m)
    if ui.config('email', 'method', 'smtp') == 'smtp':
        return _smtp(ui)
    return lambda s, r, m: _sendmail(ui, s, r, m)

def sendmail(ui, sender, recipients, msg, mbox=None):
    send = connect(ui, mbox=mbox)
    return send(sender, recipients, msg)

def validateconfig(ui):
    '''determine if we have enough config data to try sending email.'''
    method = ui.config('email', 'method', 'smtp')
    if method == 'smtp':
        if not ui.config('smtp', 'host'):
            raise error.Abort(_('smtp specified as email transport, '
                               'but no smtp host configured'))
    else:
        if not util.findexe(method):
            raise error.Abort(_('%r specified as email transport, '
                               'but not in PATH') % method)

def mimetextpatch(s, subtype='plain', display=False):
    '''Return MIME message suitable for a patch.
    Charset will be detected as utf-8 or (possibly fake) us-ascii.
    Transfer encodings will be used if necessary.'''

    cs = 'us-ascii'
    if not display:
        try:
            s.decode('us-ascii')
        except UnicodeDecodeError:
            try:
                s.decode('utf-8')
                cs = 'utf-8'
            except UnicodeDecodeError:
                # We'll go with us-ascii as a fallback.
                pass

    return mimetextqp(s, subtype, cs)

def mimetextqp(body, subtype, charset):
    '''Return MIME message.
    Quoted-printable transfer encoding will be used if necessary.
    '''
    enc = None
    for line in body.splitlines():
        if len(line) > 950:
            body = quopri.encodestring(body)
            enc = "quoted-printable"
            break

    msg = email.MIMEText.MIMEText(body, subtype, charset)
    if enc:
        del msg['Content-Transfer-Encoding']
        msg['Content-Transfer-Encoding'] = enc
    return msg

def _charsets(ui):
    '''Obtains charsets to send mail parts not containing patches.'''
    charsets = [cs.lower() for cs in ui.configlist('email', 'charsets')]
    fallbacks = [encoding.fallbackencoding.lower(),
                 encoding.encoding.lower(), 'utf-8']
    for cs in fallbacks: # find unique charsets while keeping order
        if cs not in charsets:
            charsets.append(cs)
    return [cs for cs in charsets if not cs.endswith('ascii')]

def _encode(ui, s, charsets):
    '''Returns (converted) string, charset tuple.
    Finds out best charset by cycling through sendcharsets in descending
    order. Tries both encoding and fallbackencoding for input. Only as
    last resort send as is in fake ascii.
    Caveat: Do not use for mail parts containing patches!'''
    try:
        s.decode('ascii')
    except UnicodeDecodeError:
        sendcharsets = charsets or _charsets(ui)
        for ics in (encoding.encoding, encoding.fallbackencoding):
            try:
                u = s.decode(ics)
            except UnicodeDecodeError:
                continue
            for ocs in sendcharsets:
                try:
                    return u.encode(ocs), ocs
                except UnicodeEncodeError:
                    pass
                except LookupError:
                    ui.warn(_('ignoring invalid sendcharset: %s\n') % ocs)
    # if ascii, or all conversion attempts fail, send (broken) ascii
    return s, 'us-ascii'

def headencode(ui, s, charsets=None, display=False):
    '''Returns RFC-2047 compliant header from given string.'''
    if not display:
        # split into words?
        s, cs = _encode(ui, s, charsets)
        return str(email.Header.Header(s, cs))
    return s

def _addressencode(ui, name, addr, charsets=None):
    name = headencode(ui, name, charsets)
    try:
        acc, dom = addr.split('@')
        acc = acc.encode('ascii')
        dom = dom.decode(encoding.encoding).encode('idna')
        addr = '%s@%s' % (acc, dom)
    except UnicodeDecodeError:
        raise error.Abort(_('invalid email address: %s') % addr)
    except ValueError:
        try:
            # too strict?
            addr = addr.encode('ascii')
        except UnicodeDecodeError:
            raise error.Abort(_('invalid local address: %s') % addr)
    return email.Utils.formataddr((name, addr))

def addressencode(ui, address, charsets=None, display=False):
    '''Turns address into RFC-2047 compliant header.'''
    if display or not address:
        return address or ''
    name, addr = email.Utils.parseaddr(address)
    return _addressencode(ui, name, addr, charsets)

def addrlistencode(ui, addrs, charsets=None, display=False):
    '''Turns a list of addresses into a list of RFC-2047 compliant headers.
    A single element of input list may contain multiple addresses, but output
    always has one address per item'''
    if display:
        return [a.strip() for a in addrs if a.strip()]

    result = []
    for name, addr in email.Utils.getaddresses(addrs):
        if name or addr:
            result.append(_addressencode(ui, name, addr, charsets))
    return result

def mimeencode(ui, s, charsets=None, display=False):
    '''creates mime text object, encodes it if needed, and sets
    charset and transfer-encoding accordingly.'''
    cs = 'us-ascii'
    if not display:
        s, cs = _encode(ui, s, charsets)
    return mimetextqp(s, 'plain', cs)

def headdecode(s):
    '''Decodes RFC-2047 header'''
    uparts = []
    for part, charset in email.Header.decode_header(s):
        if charset is not None:
            try:
                uparts.append(part.decode(charset))
                continue
            except UnicodeDecodeError:
                pass
        try:
            uparts.append(part.decode('UTF-8'))
            continue
        except UnicodeDecodeError:
            pass
        uparts.append(part.decode('ISO-8859-1'))
    return encoding.tolocal(u' '.join(uparts).encode('UTF-8'))