lock: block signal interrupt while making a lock file
On Windows where symlink isn't supported, util.makelock() could leave an empty
file if interrupted immediately after os.open(). This empty lock never dies
as it has no process id recorded.
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
# an interrupt may occur here
os.write(ld, info)
os.close(ld)
This was a long-standing bug of TortoiseHg which runs a command-server and
kills it by CTRL_C_EVENT, reported by random Windows users.
https://bitbucket.org/tortoisehg/thg/issues/4873/#comment-
43591129
At first, I tried to fix makelock() to clean up a stale lock file, which
turned out to be hard because any instructions may be interrupted by a
signal.
ld = None
try:
# CALL_FUNCTION # os.open(...)
# an interrupt may occur here
# STORE_FAST # ld = ...
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
os.write(ld, info)
...
return True
except:
if ld:
...
os.unlink(pathname)
return False
So I decided to block signals by temporarily replacing the signal handlers
so makelcok() and held = 1 will never be interrupted.
Many thanks to Fernando Najera for investigating the issue.
# zeroconf.py - zeroconf support for Mercurial
#
# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''discover and advertise repositories on the local network
Zeroconf-enabled repositories will be announced in a network without
the need to configure a server or a service. They can be discovered
without knowing their actual IP address.
To allow other people to discover your repository using run
:hg:`serve` in your repository::
$ cd test
$ hg serve
You can discover Zeroconf-enabled repositories by running
:hg:`paths`::
$ hg paths
zc-test = http://example.com:8000/test
'''
from __future__ import absolute_import
import os
import socket
import time
from . import Zeroconf
from mercurial import (
dispatch,
encoding,
extensions,
hg,
ui as uimod,
)
from mercurial.hgweb import (
server as servermod
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
# publish
server = None
localip = None
def getip():
# finds external-facing interface without sending any packets (Linux)
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.connect(('1.0.0.1', 0))
ip = s.getsockname()[0]
return ip
except socket.error:
pass
# Generic method, sometimes gives useless results
try:
dumbip = socket.gethostbyaddr(socket.gethostname())[2][0]
if ':' in dumbip:
dumbip = '127.0.0.1'
if not dumbip.startswith('127.'):
return dumbip
except (socket.gaierror, socket.herror):
dumbip = '127.0.0.1'
# works elsewhere, but actually sends a packet
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.connect(('1.0.0.1', 1))
ip = s.getsockname()[0]
return ip
except socket.error:
pass
return dumbip
def publish(name, desc, path, port):
global server, localip
if not server:
ip = getip()
if ip.startswith('127.'):
# if we have no internet connection, this can happen.
return
localip = socket.inet_aton(ip)
server = Zeroconf.Zeroconf(ip)
hostname = socket.gethostname().split('.')[0]
host = hostname + ".local"
name = "%s-%s" % (hostname, name)
# advertise to browsers
svc = Zeroconf.ServiceInfo('_http._tcp.local.',
name + '._http._tcp.local.',
server = host,
port = port,
properties = {'description': desc,
'path': "/" + path},
address = localip, weight = 0, priority = 0)
server.registerService(svc)
# advertise to Mercurial clients
svc = Zeroconf.ServiceInfo('_hg._tcp.local.',
name + '._hg._tcp.local.',
server = host,
port = port,
properties = {'description': desc,
'path': "/" + path},
address = localip, weight = 0, priority = 0)
server.registerService(svc)
def zc_create_server(create_server, ui, app):
httpd = create_server(ui, app)
port = httpd.port
try:
repos = app.repos
except AttributeError:
# single repo
with app._obtainrepo() as repo:
name = app.reponame or os.path.basename(repo.root)
path = repo.ui.config("web", "prefix", "").strip('/')
desc = repo.ui.config("web", "description")
if not desc:
desc = name
publish(name, desc, path, port)
else:
# webdir
prefix = app.ui.config("web", "prefix", "").strip('/') + '/'
for repo, path in repos:
u = app.ui.copy()
u.readconfig(os.path.join(path, '.hg', 'hgrc'))
name = os.path.basename(repo)
path = (prefix + repo).strip('/')
desc = u.config('web', 'description')
if not desc:
desc = name
publish(name, desc, path, port)
return httpd
# listen
class listener(object):
def __init__(self):
self.found = {}
def removeService(self, server, type, name):
if repr(name) in self.found:
del self.found[repr(name)]
def addService(self, server, type, name):
self.found[repr(name)] = server.getServiceInfo(type, name)
def getzcpaths():
ip = getip()
if ip.startswith('127.'):
return
server = Zeroconf.Zeroconf(ip)
l = listener()
Zeroconf.ServiceBrowser(server, "_hg._tcp.local.", l)
time.sleep(1)
server.close()
for value in l.found.values():
name = value.name[:value.name.index('.')]
url = "http://%s:%s%s" % (socket.inet_ntoa(value.address), value.port,
value.properties.get("path", "/"))
yield "zc-" + name, url
def config(orig, self, section, key, *args, **kwargs):
if section == "paths" and key.startswith("zc-"):
for name, path in getzcpaths():
if name == key:
return path
return orig(self, section, key, *args, **kwargs)
def configitems(orig, self, section, *args, **kwargs):
repos = orig(self, section, *args, **kwargs)
if section == "paths":
repos += getzcpaths()
return repos
def configsuboptions(orig, self, section, name, *args, **kwargs):
opt, sub = orig(self, section, name, *args, **kwargs)
if section == "paths" and name.startswith("zc-"):
# We have to find the URL in the zeroconf paths. We can't cons up any
# suboptions, so we use any that we found in the original config.
for zcname, zcurl in getzcpaths():
if zcname == name:
return zcurl, sub
return opt, sub
def defaultdest(orig, source):
for name, path in getzcpaths():
if path == source:
return name.encode(encoding.encoding)
return orig(source)
def cleanupafterdispatch(orig, ui, options, cmd, cmdfunc):
try:
return orig(ui, options, cmd, cmdfunc)
finally:
# we need to call close() on the server to notify() the various
# threading Conditions and allow the background threads to exit
global server
if server:
server.close()
extensions.wrapfunction(dispatch, '_runcommand', cleanupafterdispatch)
extensions.wrapfunction(uimod.ui, 'config', config)
extensions.wrapfunction(uimod.ui, 'configitems', configitems)
extensions.wrapfunction(uimod.ui, 'configsuboptions', configsuboptions)
extensions.wrapfunction(hg, 'defaultdest', defaultdest)
extensions.wrapfunction(servermod, 'create_server', zc_create_server)