Merge pull request #6099 from takluyver/check-nbservers-pid

Check process existence when listing nbserver processes

IPython/html/notebookapp.py

@@ -1,924 +1,935 b''
 # coding: utf-8
 """A tornado based IPython notebook server."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import print_function
 
 import base64
 import errno
 import io
 import json
 import logging
 import os
 import random
 import re
 import select
 import signal
 import socket
 import sys
 import threading
 import time
 import webbrowser
 
 
 # check for pyzmq 2.1.11
 from IPython.utils.zmqrelated import check_for_zmq
 check_for_zmq('2.1.11', 'IPython.html')
 
 from jinja2 import Environment, FileSystemLoader
 
 # Install the pyzmq ioloop. This has to be done before anything else from
 # tornado is imported.
 from zmq.eventloop import ioloop
 ioloop.install()
 
 # check for tornado 3.1.0
 msg = "The IPython Notebook requires tornado >= 3.1.0"
 try:
     import tornado
 except ImportError:
     raise ImportError(msg)
 try:
     version_info = tornado.version_info
 except AttributeError:
     raise ImportError(msg + ", but you have < 1.1.0")
 if version_info < (3,1,0):
     raise ImportError(msg + ", but you have %s" % tornado.version)
 
 from tornado import httpserver
 from tornado import web
 from tornado.log import LogFormatter
 
 from IPython.html import DEFAULT_STATIC_FILES_PATH
 from .base.handlers import Template404
 from .log import log_request
 from .services.kernels.kernelmanager import MappingKernelManager
 from .services.notebooks.nbmanager import NotebookManager
 from .services.notebooks.filenbmanager import FileNotebookManager
 from .services.clusters.clustermanager import ClusterManager
 from .services.sessions.sessionmanager import SessionManager
 
 from .base.handlers import AuthenticatedFileHandler, FileFindHandler
 
 from IPython.config import Config
 from IPython.config.application import catch_config_error, boolean_flag
 from IPython.core.application import (
     BaseIPythonApplication, base_flags, base_aliases,
 )
 from IPython.core.profiledir import ProfileDir
 from IPython.kernel import KernelManager
 from IPython.kernel.kernelspec import KernelSpecManager
 from IPython.kernel.zmq.session import default_secure, Session
 from IPython.nbformat.sign import NotebookNotary
 from IPython.utils.importstring import import_item
 from IPython.utils import submodule
+from IPython.utils.process import check_pid
 from IPython.utils.traitlets import (
     Dict, Unicode, Integer, List, Bool, Bytes, Instance,
     DottedObjectName, TraitError,
 )
 from IPython.utils import py3compat
 from IPython.utils.path import filefind, get_ipython_dir
 
 from .utils import url_path_join
 
 #-----------------------------------------------------------------------------
 # Module globals
 #-----------------------------------------------------------------------------
 
 _examples = """
 ipython notebook                       # start the notebook
 ipython notebook --profile=sympy       # use the sympy profile
 ipython notebook --certfile=mycert.pem # use SSL/TLS certificate
 """
 
 #-----------------------------------------------------------------------------
 # Helper functions
 #-----------------------------------------------------------------------------
 
 def random_ports(port, n):
     """Generate a list of n random ports near the given port.
 
     The first 5 ports will be sequential, and the remaining n-5 will be
     randomly selected in the range [port-2*n, port+2*n].
     """
     for i in range(min(5, n)):
         yield port + i
     for i in range(n-5):
         yield max(1, port + random.randint(-2*n, 2*n))
 
 def load_handlers(name):
     """Load the (URL pattern, handler) tuples for each component."""
     name = 'IPython.html.' + name
     mod = __import__(name, fromlist=['default_handlers'])
     return mod.default_handlers
 
 #-----------------------------------------------------------------------------
 # The Tornado web application
 #-----------------------------------------------------------------------------
 
 class NotebookWebApplication(web.Application):
 
     def __init__(self, ipython_app, kernel_manager, notebook_manager,
                  cluster_manager, session_manager, kernel_spec_manager, log,
                  base_url, settings_overrides, jinja_env_options):
 
         settings = self.init_settings(
             ipython_app, kernel_manager, notebook_manager, cluster_manager,
             session_manager, kernel_spec_manager, log, base_url,
             settings_overrides, jinja_env_options)
         handlers = self.init_handlers(settings)
 
         super(NotebookWebApplication, self).__init__(handlers, **settings)
 
     def init_settings(self, ipython_app, kernel_manager, notebook_manager,
                       cluster_manager, session_manager, kernel_spec_manager,
                       log, base_url, settings_overrides,
                       jinja_env_options=None):
         # Python < 2.6.5 doesn't accept unicode keys in f(**kwargs), and
         # base_url will always be unicode, which will in turn
         # make the patterns unicode, and ultimately result in unicode
         # keys in kwargs to handler._execute(**kwargs) in tornado.
         # This enforces that base_url be ascii in that situation.
         # 
         # Note that the URLs these patterns check against are escaped,
         # and thus guaranteed to be ASCII: 'héllo' is really 'h%C3%A9llo'.
         base_url = py3compat.unicode_to_str(base_url, 'ascii')
         template_path = settings_overrides.get("template_path", os.path.join(os.path.dirname(__file__), "templates"))
         jenv_opt = jinja_env_options if jinja_env_options else {}
         env = Environment(loader=FileSystemLoader(template_path),**jenv_opt )
         settings = dict(
             # basics
             log_function=log_request,
             base_url=base_url,
             template_path=template_path,
             static_path=ipython_app.static_file_path,
             static_handler_class = FileFindHandler,
             static_url_prefix = url_path_join(base_url,'/static/'),
             
             # authentication
             cookie_secret=ipython_app.cookie_secret,
             login_url=url_path_join(base_url,'/login'),
             password=ipython_app.password,
             
             # managers
             kernel_manager=kernel_manager,
             notebook_manager=notebook_manager,
             cluster_manager=cluster_manager,
             session_manager=session_manager,
             kernel_spec_manager=kernel_spec_manager,
 
             # IPython stuff
             nbextensions_path = ipython_app.nbextensions_path,
             mathjax_url=ipython_app.mathjax_url,
             config=ipython_app.config,
             jinja2_env=env,
         )
 
         # allow custom overrides for the tornado web app.
         settings.update(settings_overrides)
         return settings
 
     def init_handlers(self, settings):
         # Load the (URL pattern, handler) tuples for each component.
         handlers = []
         handlers.extend(load_handlers('base.handlers'))
         handlers.extend(load_handlers('tree.handlers'))
         handlers.extend(load_handlers('auth.login'))
         handlers.extend(load_handlers('auth.logout'))
         handlers.extend(load_handlers('notebook.handlers'))
         handlers.extend(load_handlers('nbconvert.handlers'))
         handlers.extend(load_handlers('kernelspecs.handlers'))
         handlers.extend(load_handlers('services.kernels.handlers'))
         handlers.extend(load_handlers('services.notebooks.handlers'))
         handlers.extend(load_handlers('services.clusters.handlers'))
         handlers.extend(load_handlers('services.sessions.handlers'))
         handlers.extend(load_handlers('services.nbconvert.handlers'))
         handlers.extend(load_handlers('services.kernelspecs.handlers'))
         # FIXME: /files/ should be handled by the Contents service when it exists
         nbm = settings['notebook_manager']
         if hasattr(nbm, 'notebook_dir'):
             handlers.extend([
             (r"/files/(.*)", AuthenticatedFileHandler, {'path' : nbm.notebook_dir}),
             (r"/nbextensions/(.*)", FileFindHandler, {'path' : settings['nbextensions_path']}),
         ])
         # prepend base_url onto the patterns that we match
         new_handlers = []
         for handler in handlers:
             pattern = url_path_join(settings['base_url'], handler[0])
             new_handler = tuple([pattern] + list(handler[1:]))
             new_handlers.append(new_handler)
         # add 404 on the end, which will catch everything that falls through
         new_handlers.append((r'(.*)', Template404))
         return new_handlers
 
 
 class NbserverListApp(BaseIPythonApplication):
     
     description="List currently running notebook servers in this profile."
     
     flags = dict(
         json=({'NbserverListApp': {'json': True}},
               "Produce machine-readable JSON output."),
     )
     
     json = Bool(False, config=True,
           help="If True, each line of output will be a JSON object with the "
                   "details from the server info file.")
 
     def start(self):
         if not self.json:
             print("Currently running servers:")
         for serverinfo in list_running_servers(self.profile):
             if self.json:
                 print(json.dumps(serverinfo))
             else:
                 print(serverinfo['url'], "::", serverinfo['notebook_dir'])
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 flags = dict(base_flags)
 flags['no-browser']=(
     {'NotebookApp' : {'open_browser' : False}},
     "Don't open the notebook in a browser after startup."
 )
 flags['pylab']=(
     {'NotebookApp' : {'pylab' : 'warn'}},
     "DISABLED: use %pylab or %matplotlib in the notebook to enable matplotlib."
 )
 flags['no-mathjax']=(
     {'NotebookApp' : {'enable_mathjax' : False}},
     """Disable MathJax
     
     MathJax is the javascript library IPython uses to render math/LaTeX. It is
     very large, so you may want to disable it if you have a slow internet
     connection, or for offline use of the notebook.
     
     When disabled, equations etc. will appear as their untransformed TeX source.
     """
 )
 
 # Add notebook manager flags
 flags.update(boolean_flag('script', 'FileNotebookManager.save_script',
                'Auto-save a .py script everytime the .ipynb notebook is saved',
                'Do not auto-save .py scripts for every notebook'))
 
 aliases = dict(base_aliases)
 
 aliases.update({
     'ip': 'NotebookApp.ip',
     'port': 'NotebookApp.port',
     'port-retries': 'NotebookApp.port_retries',
     'transport': 'KernelManager.transport',
     'keyfile': 'NotebookApp.keyfile',
     'certfile': 'NotebookApp.certfile',
     'notebook-dir': 'NotebookApp.notebook_dir',
     'browser': 'NotebookApp.browser',
     'pylab': 'NotebookApp.pylab',
 })
 
 #-----------------------------------------------------------------------------
 # NotebookApp
 #-----------------------------------------------------------------------------
 
 class NotebookApp(BaseIPythonApplication):
 
     name = 'ipython-notebook'
     
     description = """
         The IPython HTML Notebook.
         
         This launches a Tornado based HTML Notebook Server that serves up an
         HTML5/Javascript Notebook client.
     """
     examples = _examples
     aliases = aliases
     flags = flags
     
     classes = [
         KernelManager, ProfileDir, Session, MappingKernelManager,
         NotebookManager, FileNotebookManager, NotebookNotary,
     ]
     flags = Dict(flags)
     aliases = Dict(aliases)
     
     subcommands = dict(
         list=(NbserverListApp, NbserverListApp.description.splitlines()[0]),
     )
 
     kernel_argv = List(Unicode)
     
     _log_formatter_cls = LogFormatter
 
     def _log_level_default(self):
         return logging.INFO
 
     def _log_datefmt_default(self):
         """Exclude date from default date format"""
         return "%H:%M:%S"
     
     def _log_format_default(self):
         """override default log format to include time"""
         return u"%(color)s[%(levelname)1.1s %(asctime)s.%(msecs).03d %(name)s]%(end_color)s %(message)s"
 
     # create requested profiles by default, if they don't exist:
     auto_create = Bool(True)
 
     # file to be opened in the notebook server
     file_to_run = Unicode('', config=True)
     def _file_to_run_changed(self, name, old, new):
         path, base = os.path.split(new)
         if path:
             self.file_to_run = base
             self.notebook_dir = path
 
     # Network related information
     
     allow_origin = Unicode('', config=True,
         help="""Set the Access-Control-Allow-Origin header
         
         Use '*' to allow any origin to access your server.
         
         Takes precedence over allow_origin_pat.
         """
     )
     
     allow_origin_pat = Unicode('', config=True,
         help="""Use a regular expression for the Access-Control-Allow-Origin header
         
         Requests from an origin matching the expression will get replies with:
         
             Access-Control-Allow-Origin: origin
         
         where `origin` is the origin of the request.
         
         Ignored if allow_origin is set.
         """
     )
     
     allow_credentials = Bool(False, config=True,
         help="Set the Access-Control-Allow-Credentials: true header"
     )
     
     ip = Unicode('localhost', config=True,
         help="The IP address the notebook server will listen on."
     )
 
     def _ip_changed(self, name, old, new):
         if new == u'*': self.ip = u''
 
     port = Integer(8888, config=True,
         help="The port the notebook server will listen on."
     )
     port_retries = Integer(50, config=True,
         help="The number of additional ports to try if the specified port is not available."
     )
 
     certfile = Unicode(u'', config=True, 
         help="""The full path to an SSL/TLS certificate file."""
     )
     
     keyfile = Unicode(u'', config=True, 
         help="""The full path to a private key file for usage with SSL/TLS."""
     )
     
     cookie_secret_file = Unicode(config=True,
         help="""The file where the cookie secret is stored."""
     )
     def _cookie_secret_file_default(self):
         if self.profile_dir is None:
             return ''
         return os.path.join(self.profile_dir.security_dir, 'notebook_cookie_secret')
     
     cookie_secret = Bytes(b'', config=True,
         help="""The random bytes used to secure cookies.
         By default this is a new random number every time you start the Notebook.
         Set it to a value in a config file to enable logins to persist across server sessions.
         
         Note: Cookie secrets should be kept private, do not share config files with
         cookie_secret stored in plaintext (you can read the value from a file).
         """
     )
     def _cookie_secret_default(self):
         if os.path.exists(self.cookie_secret_file):
             with io.open(self.cookie_secret_file, 'rb') as f:
                 return f.read()
         else:
             secret = base64.encodestring(os.urandom(1024))
             self._write_cookie_secret_file(secret)
             return secret
     
     def _write_cookie_secret_file(self, secret):
         """write my secret to my secret_file"""
         self.log.info("Writing notebook server cookie secret to %s", self.cookie_secret_file)
         with io.open(self.cookie_secret_file, 'wb') as f:
             f.write(secret)
         try:
             os.chmod(self.cookie_secret_file, 0o600)
         except OSError:
             self.log.warn(
                 "Could not set permissions on %s",
                 self.cookie_secret_file
             )
 
     password = Unicode(u'', config=True,
                       help="""Hashed password to use for web authentication.
 
                       To generate, type in a python/IPython shell:
 
                         from IPython.lib import passwd; passwd()
 
                       The string should be of the form type:salt:hashed-password.
                       """
     )
 
     open_browser = Bool(True, config=True,
                         help="""Whether to open in a browser after starting.
                         The specific browser used is platform dependent and
                         determined by the python standard library `webbrowser`
                         module, unless it is overridden using the --browser
                         (NotebookApp.browser) configuration option.
                         """)
 
     browser = Unicode(u'', config=True,
                       help="""Specify what command to use to invoke a web
                       browser when opening the notebook. If not specified, the
                       default browser will be determined by the `webbrowser`
                       standard library module, which allows setting of the
                       BROWSER environment variable to override it.
                       """)
     
     webapp_settings = Dict(config=True,
             help="Supply overrides for the tornado.web.Application that the "
                  "IPython notebook uses.")
 
     jinja_environment_options = Dict(config=True, 
             help="Supply extra arguments that will be passed to Jinja environment.")
 
     
     enable_mathjax = Bool(True, config=True,
         help="""Whether to enable MathJax for typesetting math/TeX
 
         MathJax is the javascript library IPython uses to render math/LaTeX. It is
         very large, so you may want to disable it if you have a slow internet
         connection, or for offline use of the notebook.
 
         When disabled, equations etc. will appear as their untransformed TeX source.
         """
     )
     def _enable_mathjax_changed(self, name, old, new):
         """set mathjax url to empty if mathjax is disabled"""
         if not new:
             self.mathjax_url = u''
 
     base_url = Unicode('/', config=True,
                                help='''The base URL for the notebook server.
 
                                Leading and trailing slashes can be omitted,
                                and will automatically be added.
                                ''')
     def _base_url_changed(self, name, old, new):
         if not new.startswith('/'):
             self.base_url = '/'+new
         elif not new.endswith('/'):
             self.base_url = new+'/'
     
     base_project_url = Unicode('/', config=True, help="""DEPRECATED use base_url""")
     def _base_project_url_changed(self, name, old, new):
         self.log.warn("base_project_url is deprecated, use base_url")
         self.base_url = new
 
     extra_static_paths = List(Unicode, config=True,
         help="""Extra paths to search for serving static files.
         
         This allows adding javascript/css to be available from the notebook server machine,
         or overriding individual files in the IPython"""
     )
     def _extra_static_paths_default(self):
         return [os.path.join(self.profile_dir.location, 'static')]
     
     @property
     def static_file_path(self):
         """return extra paths + the default location"""
         return self.extra_static_paths + [DEFAULT_STATIC_FILES_PATH]
     
     nbextensions_path = List(Unicode, config=True,
         help="""paths for Javascript extensions. By default, this is just IPYTHONDIR/nbextensions"""
     )
     def _nbextensions_path_default(self):
         return [os.path.join(get_ipython_dir(), 'nbextensions')]
 
     mathjax_url = Unicode("", config=True,
         help="""The url for MathJax.js."""
     )
     def _mathjax_url_default(self):
         if not self.enable_mathjax:
             return u''
         static_url_prefix = self.webapp_settings.get("static_url_prefix",
                          url_path_join(self.base_url, "static")
         )
         
         # try local mathjax, either in nbextensions/mathjax or static/mathjax
         for (url_prefix, search_path) in [
             (url_path_join(self.base_url, "nbextensions"), self.nbextensions_path),
             (static_url_prefix, self.static_file_path),
         ]:
             self.log.debug("searching for local mathjax in %s", search_path)
             try:
                 mathjax = filefind(os.path.join('mathjax', 'MathJax.js'), search_path)
             except IOError:
                 continue
             else:
                 url = url_path_join(url_prefix, u"mathjax/MathJax.js")
                 self.log.info("Serving local MathJax from %s at %s", mathjax, url)
                 return url
         
         # no local mathjax, serve from CDN
         url = u"//cdn.mathjax.org/mathjax/latest/MathJax.js"
         self.log.info("Using MathJax from CDN: %s", url)
         return url
     
     def _mathjax_url_changed(self, name, old, new):
         if new and not self.enable_mathjax:
             # enable_mathjax=False overrides mathjax_url
             self.mathjax_url = u''
         else:
             self.log.info("Using MathJax: %s", new)
 
     notebook_manager_class = DottedObjectName('IPython.html.services.notebooks.filenbmanager.FileNotebookManager',
         config=True,
         help='The notebook manager class to use.'
     )
     kernel_manager_class = DottedObjectName('IPython.html.services.kernels.kernelmanager.MappingKernelManager',
         config=True,
         help='The kernel manager class to use.'
     )
     session_manager_class = DottedObjectName('IPython.html.services.sessions.sessionmanager.SessionManager',
         config=True,
         help='The session manager class to use.'
     )
     cluster_manager_class = DottedObjectName('IPython.html.services.clusters.clustermanager.ClusterManager',
         config=True,
         help='The cluster manager class to use.'
     )
 
     kernel_spec_manager = Instance(KernelSpecManager)
 
     def _kernel_spec_manager_default(self):
         return KernelSpecManager(ipython_dir=self.ipython_dir)
 
     trust_xheaders = Bool(False, config=True,
         help=("Whether to trust or not X-Scheme/X-Forwarded-Proto and X-Real-Ip/X-Forwarded-For headers"
               "sent by the upstream reverse proxy. Necessary if the proxy handles SSL")
     )
     
     info_file = Unicode()
 
     def _info_file_default(self):
         info_file = "nbserver-%s.json"%os.getpid()
         return os.path.join(self.profile_dir.security_dir, info_file)
     
     notebook_dir = Unicode(py3compat.getcwd(), config=True,
         help="The directory to use for notebooks and kernels."
     )
     
     pylab = Unicode('disabled', config=True,
         help="""
         DISABLED: use %pylab or %matplotlib in the notebook to enable matplotlib.
         """
     )
     def _pylab_changed(self, name, old, new):
         """when --pylab is specified, display a warning and exit"""
         if new != 'warn':
             backend = ' %s' % new
         else:
             backend = ''
         self.log.error("Support for specifying --pylab on the command line has been removed.")
         self.log.error(
             "Please use `%pylab{0}` or `%matplotlib{0}` in the notebook itself.".format(backend)
         )
         self.exit(1)
 
     def _notebook_dir_changed(self, name, old, new):
         """Do a bit of validation of the notebook dir."""
         if not os.path.isabs(new):
             # If we receive a non-absolute path, make it absolute.
             self.notebook_dir = os.path.abspath(new)
             return
         if not os.path.isdir(new):
             raise TraitError("No such notebook dir: %r" % new)
         
         # setting App.notebook_dir implies setting notebook and kernel dirs as well
         self.config.FileNotebookManager.notebook_dir = new
         self.config.MappingKernelManager.root_dir = new
         
 
     def parse_command_line(self, argv=None):
         super(NotebookApp, self).parse_command_line(argv)
         
         if self.extra_args:
             arg0 = self.extra_args[0]
             f = os.path.abspath(arg0)
             self.argv.remove(arg0)
             if not os.path.exists(f):
                 self.log.critical("No such file or directory: %s", f)
                 self.exit(1)
             
             # Use config here, to ensure that it takes higher priority than
             # anything that comes from the profile.
             c = Config()
             if os.path.isdir(f):
                 c.NotebookApp.notebook_dir = f
             elif os.path.isfile(f):
                 c.NotebookApp.file_to_run = f
             self.update_config(c)
 
     def init_kernel_argv(self):
         """construct the kernel arguments"""
         # Kernel should get *absolute* path to profile directory
         self.kernel_argv = ["--profile-dir", self.profile_dir.location]
 
     def init_configurables(self):
         # force Session default to be secure
         default_secure(self.config)
         kls = import_item(self.kernel_manager_class)
         self.kernel_manager = kls(
             parent=self, log=self.log, kernel_argv=self.kernel_argv,
             connection_dir = self.profile_dir.security_dir,
         )
         kls = import_item(self.notebook_manager_class)
         self.notebook_manager = kls(parent=self, log=self.log)
         kls = import_item(self.session_manager_class)
         self.session_manager = kls(parent=self, log=self.log,
                                    kernel_manager=self.kernel_manager,
                                    notebook_manager=self.notebook_manager)
         kls = import_item(self.cluster_manager_class)
         self.cluster_manager = kls(parent=self, log=self.log)
         self.cluster_manager.update_profiles()
 
     def init_logging(self):
         # This prevents double log messages because tornado use a root logger that
         # self.log is a child of. The logging module dipatches log messages to a log
         # and all of its ancenstors until propagate is set to False.
         self.log.propagate = False
         
         # hook up tornado 3's loggers to our app handlers
         logger = logging.getLogger('tornado')
         logger.propagate = True
         logger.parent = self.log
         logger.setLevel(self.log.level)
     
     def init_webapp(self):
         """initialize tornado webapp and httpserver"""
         self.webapp_settings['allow_origin'] = self.allow_origin
         if self.allow_origin_pat:
             self.webapp_settings['allow_origin_pat'] = re.compile(self.allow_origin_pat)
         self.webapp_settings['allow_credentials'] = self.allow_credentials
         
         self.web_app = NotebookWebApplication(
             self, self.kernel_manager, self.notebook_manager, 
             self.cluster_manager, self.session_manager, self.kernel_spec_manager,
             self.log, self.base_url, self.webapp_settings,
             self.jinja_environment_options
         )
         if self.certfile:
             ssl_options = dict(certfile=self.certfile)
             if self.keyfile:
                 ssl_options['keyfile'] = self.keyfile
         else:
             ssl_options = None
         self.web_app.password = self.password
         self.http_server = httpserver.HTTPServer(self.web_app, ssl_options=ssl_options,
                                                  xheaders=self.trust_xheaders)
         if not self.ip:
             warning = "WARNING: The notebook server is listening on all IP addresses"
             if ssl_options is None:
                 self.log.critical(warning + " and not using encryption. This "
                     "is not recommended.")
             if not self.password:
                 self.log.critical(warning + " and not using authentication. "
                     "This is highly insecure and not recommended.")
         success = None
         for port in random_ports(self.port, self.port_retries+1):
             try:
                 self.http_server.listen(port, self.ip)
             except socket.error as e:
                 if e.errno == errno.EADDRINUSE:
                     self.log.info('The port %i is already in use, trying another random port.' % port)
                     continue
                 elif e.errno in (errno.EACCES, getattr(errno, 'WSAEACCES', errno.EACCES)):
                     self.log.warn("Permission to listen on port %i denied" % port)
                     continue
                 else:
                     raise
             else:
                 self.port = port
                 success = True
                 break
         if not success:
             self.log.critical('ERROR: the notebook server could not be started because '
                               'no available port could be found.')
             self.exit(1)
     
     @property
     def display_url(self):
         ip = self.ip if self.ip else '[all ip addresses on your system]'
         return self._url(ip)
 
     @property
     def connection_url(self):
         ip = self.ip if self.ip else 'localhost'
         return self._url(ip)
 
     def _url(self, ip):
         proto = 'https' if self.certfile else 'http'
         return "%s://%s:%i%s" % (proto, ip, self.port, self.base_url)
 
     def init_signal(self):
         if not sys.platform.startswith('win'):
             signal.signal(signal.SIGINT, self._handle_sigint)
         signal.signal(signal.SIGTERM, self._signal_stop)
         if hasattr(signal, 'SIGUSR1'):
             # Windows doesn't support SIGUSR1
             signal.signal(signal.SIGUSR1, self._signal_info)
         if hasattr(signal, 'SIGINFO'):
             # only on BSD-based systems
             signal.signal(signal.SIGINFO, self._signal_info)
     
     def _handle_sigint(self, sig, frame):
         """SIGINT handler spawns confirmation dialog"""
         # register more forceful signal handler for ^C^C case
         signal.signal(signal.SIGINT, self._signal_stop)
         # request confirmation dialog in bg thread, to avoid
         # blocking the App
         thread = threading.Thread(target=self._confirm_exit)
         thread.daemon = True
         thread.start()
     
     def _restore_sigint_handler(self):
         """callback for restoring original SIGINT handler"""
         signal.signal(signal.SIGINT, self._handle_sigint)
     
     def _confirm_exit(self):
         """confirm shutdown on ^C
         
         A second ^C, or answering 'y' within 5s will cause shutdown,
         otherwise original SIGINT handler will be restored.
         
         This doesn't work on Windows.
         """
         info = self.log.info
         info('interrupted')
         print(self.notebook_info())
         sys.stdout.write("Shutdown this notebook server (y/[n])? ")
         sys.stdout.flush()
         r,w,x = select.select([sys.stdin], [], [], 5)
         if r:
             line = sys.stdin.readline()
             if line.lower().startswith('y') and 'n' not in line.lower():
                 self.log.critical("Shutdown confirmed")
                 ioloop.IOLoop.instance().stop()
                 return
         else:
             print("No answer for 5s:", end=' ')
         print("resuming operation...")
         # no answer, or answer is no:
         # set it back to original SIGINT handler
         # use IOLoop.add_callback because signal.signal must be called
         # from main thread
         ioloop.IOLoop.instance().add_callback(self._restore_sigint_handler)
     
     def _signal_stop(self, sig, frame):
         self.log.critical("received signal %s, stopping", sig)
         ioloop.IOLoop.instance().stop()
 
     def _signal_info(self, sig, frame):
         print(self.notebook_info())
     
     def init_components(self):
         """Check the components submodule, and warn if it's unclean"""
         status = submodule.check_submodule_status()
         if status == 'missing':
             self.log.warn("components submodule missing, running `git submodule update`")
             submodule.update_submodules(submodule.ipython_parent())
         elif status == 'unclean':
             self.log.warn("components submodule unclean, you may see 404s on static/components")
             self.log.warn("run `setup.py submodule` or `git submodule update` to update")
     
     @catch_config_error
     def initialize(self, argv=None):
         super(NotebookApp, self).initialize(argv)
         self.init_logging()
         self.init_kernel_argv()
         self.init_configurables()
         self.init_components()
         self.init_webapp()
         self.init_signal()
 
     def cleanup_kernels(self):
         """Shutdown all kernels.
         
         The kernels will shutdown themselves when this process no longer exists,
         but explicit shutdown allows the KernelManagers to cleanup the connection files.
         """
         self.log.info('Shutting down kernels')
         self.kernel_manager.shutdown_all()
 
     def notebook_info(self):
         "Return the current working directory and the server url information"
         info = self.notebook_manager.info_string() + "\n"
         info += "%d active kernels \n" % len(self.kernel_manager._kernels)
         return info + "The IPython Notebook is running at: %s" % self.display_url
 
     def server_info(self):
         """Return a JSONable dict of information about this server."""
         return {'url': self.connection_url,
                 'hostname': self.ip if self.ip else 'localhost',
                 'port': self.port,
                 'secure': bool(self.certfile),
                 'base_url': self.base_url,
                 'notebook_dir': os.path.abspath(self.notebook_dir),
+                'pid': os.getpid()
                }
 
     def write_server_info_file(self):
         """Write the result of server_info() to the JSON file info_file."""
         with open(self.info_file, 'w') as f:
             json.dump(self.server_info(), f, indent=2)
 
     def remove_server_info_file(self):
         """Remove the nbserver-<pid>.json file created for this server.
         
         Ignores the error raised when the file has already been removed.
         """
         try:
             os.unlink(self.info_file)
         except OSError as e:
             if e.errno != errno.ENOENT:
                 raise
 
     def start(self):
         """ Start the IPython Notebook server app, after initialization
         
         This method takes no arguments so all configuration and initialization
         must be done prior to calling this method."""
         if self.subapp is not None:
             return self.subapp.start()
 
         info = self.log.info
         for line in self.notebook_info().split("\n"):
             info(line)
         info("Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).")
 
         self.write_server_info_file()
 
         if self.open_browser or self.file_to_run:
             try:
                 browser = webbrowser.get(self.browser or None)
             except webbrowser.Error as e:
                 self.log.warn('No web browser found: %s.' % e)
                 browser = None
             
             if self.file_to_run:
                 fullpath = os.path.join(self.notebook_dir, self.file_to_run)
                 if not os.path.exists(fullpath):
                     self.log.critical("%s does not exist" % fullpath)
                     self.exit(1)
                 
                 uri = url_path_join('notebooks', self.file_to_run)
             else:
                 uri = 'tree'
             if browser:
                 b = lambda : browser.open(url_path_join(self.connection_url, uri),
                                           new=2)
                 threading.Thread(target=b).start()
         try:
             ioloop.IOLoop.instance().start()
         except KeyboardInterrupt:
             info("Interrupted...")
         finally:
             self.cleanup_kernels()
             self.remove_server_info_file()
 
 
 def list_running_servers(profile='default'):
     """Iterate over the server info files of running notebook servers.
     
     Given a profile name, find nbserver-* files in the security directory of
     that profile, and yield dicts of their information, each one pertaining to
     a currently running notebook server instance.
     """
     pd = ProfileDir.find_profile_dir_by_name(get_ipython_dir(), name=profile)
     for file in os.listdir(pd.security_dir):
         if file.startswith('nbserver-'):
             with io.open(os.path.join(pd.security_dir, file), encoding='utf-8') as f:
-                yield json.load(f)
+                info = json.load(f)
 
+            # Simple check whether that process is really still running
+            if check_pid(info['pid']):
+                yield info
+            else:
+                # If the process has died, try to delete its info file
+                try:
+                    os.unlink(file)
+                except OSError:
+                    pass  # TODO: This should warn or log or something
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 launch_new_instance = NotebookApp.launch_instance
 

IPython/parallel/apps/baseapp.py

@@ -1,276 +1,260 b''
 # encoding: utf-8
 """
 The Base Application class for IPython.parallel apps
 
 Authors:
 
 * Brian Granger
 * Min RK
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import logging
 import re
 import sys
 
 from subprocess import Popen, PIPE
 
 from IPython.config.application import catch_config_error, LevelFormatter
 from IPython.core import release
 from IPython.core.crashhandler import CrashHandler
 from IPython.core.application import (
     BaseIPythonApplication,
     base_aliases as base_ip_aliases,
     base_flags as base_ip_flags
 )
 from IPython.utils.path import expand_path
+from IPython.utils.process import check_pid
 from IPython.utils import py3compat
 from IPython.utils.py3compat import unicode_type
 
 from IPython.utils.traitlets import Unicode, Bool, Instance, Dict
 
 #-----------------------------------------------------------------------------
 # Module errors
 #-----------------------------------------------------------------------------
 
 class PIDFileError(Exception):
     pass
 
 
 #-----------------------------------------------------------------------------
 # Crash handler for this application
 #-----------------------------------------------------------------------------
 
 class ParallelCrashHandler(CrashHandler):
     """sys.excepthook for IPython itself, leaves a detailed report on disk."""
 
     def __init__(self, app):
         contact_name = release.authors['Min'][0]
         contact_email = release.author_email
         bug_tracker = 'https://github.com/ipython/ipython/issues'
         super(ParallelCrashHandler,self).__init__(
             app, contact_name, contact_email, bug_tracker
         )
 
 
 #-----------------------------------------------------------------------------
 # Main application
 #-----------------------------------------------------------------------------
 base_aliases = {}
 base_aliases.update(base_ip_aliases)
 base_aliases.update({
     'work-dir' : 'BaseParallelApplication.work_dir',
     'log-to-file' : 'BaseParallelApplication.log_to_file',
     'clean-logs' : 'BaseParallelApplication.clean_logs',
     'log-url' : 'BaseParallelApplication.log_url',
     'cluster-id' : 'BaseParallelApplication.cluster_id',
 })
 
 base_flags = {
     'log-to-file' : (
         {'BaseParallelApplication' : {'log_to_file' : True}},
         "send log output to a file"
     )
 }
 base_flags.update(base_ip_flags)
 
 class BaseParallelApplication(BaseIPythonApplication):
     """The base Application for IPython.parallel apps
     
     Principle extensions to BaseIPyythonApplication:
     
     * work_dir
     * remote logging via pyzmq
     * IOLoop instance
     """
 
     crash_handler_class = ParallelCrashHandler
     
     def _log_level_default(self):
         # temporarily override default_log_level to INFO
         return logging.INFO
     
     def _log_format_default(self):
         """override default log format to include time"""
         return u"%(asctime)s.%(msecs).03d [%(name)s]%(highlevel)s %(message)s"
 
     work_dir = Unicode(py3compat.getcwd(), config=True,
         help='Set the working dir for the process.'
     )
     def _work_dir_changed(self, name, old, new):
         self.work_dir = unicode_type(expand_path(new))
 
     log_to_file = Bool(config=True,
         help="whether to log to a file")
 
     clean_logs = Bool(False, config=True,
         help="whether to cleanup old logfiles before starting")
 
     log_url = Unicode('', config=True,
         help="The ZMQ URL of the iplogger to aggregate logging.")
 
     cluster_id = Unicode('', config=True,
         help="""String id to add to runtime files, to prevent name collisions when
         using multiple clusters with a single profile simultaneously.
         
         When set, files will be named like: 'ipcontroller-<cluster_id>-engine.json'
         
         Since this is text inserted into filenames, typical recommendations apply:
         Simple character strings are ideal, and spaces are not recommended (but should
         generally work).
         """
     )
     def _cluster_id_changed(self, name, old, new):
         self.name = self.__class__.name
         if new:
             self.name += '-%s'%new
     
     def _config_files_default(self):
         return ['ipcontroller_config.py', 'ipengine_config.py', 'ipcluster_config.py']
     
     loop = Instance('zmq.eventloop.ioloop.IOLoop')
     def _loop_default(self):
         from zmq.eventloop.ioloop import IOLoop
         return IOLoop.instance()
 
     aliases = Dict(base_aliases)
     flags = Dict(base_flags)
     
     @catch_config_error
     def initialize(self, argv=None):
         """initialize the app"""
         super(BaseParallelApplication, self).initialize(argv)
         self.to_work_dir()
         self.reinit_logging()
         
     def to_work_dir(self):
         wd = self.work_dir
         if unicode_type(wd) != py3compat.getcwd():
             os.chdir(wd)
             self.log.info("Changing to working dir: %s" % wd)
         # This is the working dir by now.
         sys.path.insert(0, '')
 
     def reinit_logging(self):
         # Remove old log files
         log_dir = self.profile_dir.log_dir
         if self.clean_logs:
             for f in os.listdir(log_dir):
                 if re.match(r'%s-\d+\.(log|err|out)' % self.name, f):
                     try:
                         os.remove(os.path.join(log_dir, f))
                     except (OSError, IOError):
                         # probably just conflict from sibling process
                         # already removing it
                         pass
         if self.log_to_file:
             # Start logging to the new log file
             log_filename = self.name + u'-' + str(os.getpid()) + u'.log'
             logfile = os.path.join(log_dir, log_filename)
             open_log_file = open(logfile, 'w')
         else:
             open_log_file = None
         if open_log_file is not None:
             while self.log.handlers:
                 self.log.removeHandler(self.log.handlers[0])
             self._log_handler = logging.StreamHandler(open_log_file)
             self.log.addHandler(self._log_handler)
         else:
             self._log_handler = self.log.handlers[0]
         # Add timestamps to log format:
         self._log_formatter = LevelFormatter(self.log_format,
                                                 datefmt=self.log_datefmt)
         self._log_handler.setFormatter(self._log_formatter)
         # do not propagate log messages to root logger
         # ipcluster app will sometimes print duplicate messages during shutdown
         # if this is 1 (default):
         self.log.propagate = False
 
     def write_pid_file(self, overwrite=False):
         """Create a .pid file in the pid_dir with my pid.
 
         This must be called after pre_construct, which sets `self.pid_dir`.
         This raises :exc:`PIDFileError` if the pid file exists already.
         """
         pid_file = os.path.join(self.profile_dir.pid_dir, self.name + u'.pid')
         if os.path.isfile(pid_file):
             pid = self.get_pid_from_file()
             if not overwrite:
                 raise PIDFileError(
                     'The pid file [%s] already exists. \nThis could mean that this '
                     'server is already running with [pid=%s].' % (pid_file, pid)
                 )
         with open(pid_file, 'w') as f:
             self.log.info("Creating pid file: %s" % pid_file)
             f.write(repr(os.getpid())+'\n')
 
     def remove_pid_file(self):
         """Remove the pid file.
 
         This should be called at shutdown by registering a callback with
         :func:`reactor.addSystemEventTrigger`. This needs to return
         ``None``.
         """
         pid_file = os.path.join(self.profile_dir.pid_dir, self.name + u'.pid')
         if os.path.isfile(pid_file):
             try:
                 self.log.info("Removing pid file: %s" % pid_file)
                 os.remove(pid_file)
             except:
                 self.log.warn("Error removing the pid file: %s" % pid_file)
 
     def get_pid_from_file(self):
         """Get the pid from the pid file.
 
         If the  pid file doesn't exist a :exc:`PIDFileError` is raised.
         """
         pid_file = os.path.join(self.profile_dir.pid_dir, self.name + u'.pid')
         if os.path.isfile(pid_file):
             with open(pid_file, 'r') as f:
                 s = f.read().strip()
                 try:
                     pid = int(s)
                 except:
                     raise PIDFileError("invalid pid file: %s (contents: %r)"%(pid_file, s))
                 return pid
         else:
             raise PIDFileError('pid file not found: %s' % pid_file)
     
     def check_pid(self, pid):
-        if os.name == 'nt':
-            try:
-                import ctypes
-                # returns 0 if no such process (of ours) exists
-                # positive int otherwise
-                p = ctypes.windll.kernel32.OpenProcess(1,0,pid)
-            except Exception:
-                self.log.warn(
-                    "Could not determine whether pid %i is running via `OpenProcess`. "
-                    " Making the likely assumption that it is."%pid
-                )
-                return True
-            return bool(p)
-        else:
-            try:
-                p = Popen(['ps','x'], stdout=PIPE, stderr=PIPE)
-                output,_ = p.communicate()
-            except OSError:
-                self.log.warn(
-                    "Could not determine whether pid %i is running via `ps x`. "
-                    " Making the likely assumption that it is."%pid
-                )
-                return True
-            pids = list(map(int, re.findall(br'^\W*\d+', output, re.MULTILINE)))
-            return pid in pids
+        try:
+            return check_pid(pid)
+        except Exception:
+            self.log.warn(
+                "Could not determine whether pid %i is running. "
+                " Making the likely assumption that it is."%pid
+            )
+            return True

IPython/utils/_process_posix.py

@@ -1,213 +1,225 b''
 """Posix-specific implementation of process utilities.
 
 This file is only meant to be imported by process.py, not by end-users.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Stdlib
+import errno
+import os
 import subprocess as sp
 import sys
 
 from IPython.external import pexpect
 
 # Our own
 from ._process_common import getoutput, arg_split
 from IPython.utils import py3compat
 from IPython.utils.encoding import DEFAULT_ENCODING
 
 #-----------------------------------------------------------------------------
 # Function definitions
 #-----------------------------------------------------------------------------
 
 def _find_cmd(cmd):
     """Find the full path to a command using which."""
 
     path = sp.Popen(['/usr/bin/env', 'which', cmd],
                     stdout=sp.PIPE, stderr=sp.PIPE).communicate()[0]
     return py3compat.bytes_to_str(path)
 
 
 class ProcessHandler(object):
     """Execute subprocesses under the control of pexpect.
     """
     # Timeout in seconds to wait on each reading of the subprocess' output.
     # This should not be set too low to avoid cpu overusage from our side,
     # since we read in a loop whose period is controlled by this timeout.
     read_timeout = 0.05
 
     # Timeout to give a process if we receive SIGINT, between sending the
     # SIGINT to the process and forcefully terminating it.
     terminate_timeout = 0.2
 
     # File object where stdout and stderr of the subprocess will be written
     logfile = None
 
     # Shell to call for subprocesses to execute
     _sh = None
 
     @property
     def sh(self):
         if self._sh is None:        
             self._sh = pexpect.which('sh')
             if self._sh is None:
                 raise OSError('"sh" shell not found')
         
         return self._sh
 
     def __init__(self, logfile=None, read_timeout=None, terminate_timeout=None):
         """Arguments are used for pexpect calls."""
         self.read_timeout = (ProcessHandler.read_timeout if read_timeout is
                              None else read_timeout)
         self.terminate_timeout = (ProcessHandler.terminate_timeout if
                                   terminate_timeout is None else
                                   terminate_timeout)
         self.logfile = sys.stdout if logfile is None else logfile
 
     def getoutput(self, cmd):
         """Run a command and return its stdout/stderr as a string.
 
         Parameters
         ----------
         cmd : str
           A command to be executed in the system shell.
 
         Returns
         -------
         output : str
           A string containing the combination of stdout and stderr from the
         subprocess, in whatever order the subprocess originally wrote to its
         file descriptors (so the order of the information in this string is the
         correct order as would be seen if running the command in a terminal).
         """
         try:
             return pexpect.run(self.sh, args=['-c', cmd]).replace('\r\n', '\n')
         except KeyboardInterrupt:
             print('^C', file=sys.stderr, end='')
 
     def getoutput_pexpect(self, cmd):
         """Run a command and return its stdout/stderr as a string.
 
         Parameters
         ----------
         cmd : str
           A command to be executed in the system shell.
 
         Returns
         -------
         output : str
           A string containing the combination of stdout and stderr from the
         subprocess, in whatever order the subprocess originally wrote to its
         file descriptors (so the order of the information in this string is the
         correct order as would be seen if running the command in a terminal).
         """
         try:
             return pexpect.run(self.sh, args=['-c', cmd]).replace('\r\n', '\n')
         except KeyboardInterrupt:
             print('^C', file=sys.stderr, end='')
 
     def system(self, cmd):
         """Execute a command in a subshell.
 
         Parameters
         ----------
         cmd : str
           A command to be executed in the system shell.
 
         Returns
         -------
         int : child's exitstatus
         """
         # Get likely encoding for the output.
         enc = DEFAULT_ENCODING
         
         # Patterns to match on the output, for pexpect.  We read input and
         # allow either a short timeout or EOF
         patterns = [pexpect.TIMEOUT, pexpect.EOF]
         # the index of the EOF pattern in the list.
         # even though we know it's 1, this call means we don't have to worry if
         # we change the above list, and forget to change this value:
         EOF_index = patterns.index(pexpect.EOF)
         # The size of the output stored so far in the process output buffer.
         # Since pexpect only appends to this buffer, each time we print we
         # record how far we've printed, so that next time we only print *new*
         # content from the buffer.
         out_size = 0
         try:
             # Since we're not really searching the buffer for text patterns, we
             # can set pexpect's search window to be tiny and it won't matter.
             # We only search for the 'patterns' timeout or EOF, which aren't in
             # the text itself.
             #child = pexpect.spawn(pcmd, searchwindowsize=1)
             if hasattr(pexpect, 'spawnb'):
                 child = pexpect.spawnb(self.sh, args=['-c', cmd]) # Pexpect-U
             else:
                 child = pexpect.spawn(self.sh, args=['-c', cmd])  # Vanilla Pexpect
             flush = sys.stdout.flush
             while True:
                 # res is the index of the pattern that caused the match, so we
                 # know whether we've finished (if we matched EOF) or not
                 res_idx = child.expect_list(patterns, self.read_timeout)
                 print(child.before[out_size:].decode(enc, 'replace'), end='')
                 flush()
                 if res_idx==EOF_index:
                     break
                 # Update the pointer to what we've already printed
                 out_size = len(child.before)
         except KeyboardInterrupt:
             # We need to send ^C to the process.  The ascii code for '^C' is 3
             # (the character is known as ETX for 'End of Text', see
             # curses.ascii.ETX).
             child.sendline(chr(3))
             # Read and print any more output the program might produce on its
             # way out.
             try:
                 out_size = len(child.before)
                 child.expect_list(patterns, self.terminate_timeout)
                 print(child.before[out_size:].decode(enc, 'replace'), end='')
                 sys.stdout.flush()
             except KeyboardInterrupt:
                 # Impatient users tend to type it multiple times
                 pass
             finally:
                 # Ensure the subprocess really is terminated
                 child.terminate(force=True)
         # add isalive check, to ensure exitstatus is set:
         child.isalive()
 
         # We follow the subprocess pattern, returning either the exit status
         # as a positive number, or the terminating signal as a negative
         # number.
         # on Linux, sh returns 128+n for signals terminating child processes on Linux
         # on BSD (OS X), the signal code is set instead
         if child.exitstatus is None:
             # on WIFSIGNALED, pexpect sets signalstatus, leaving exitstatus=None
             if child.signalstatus is None:
                 # this condition may never occur,
                 # but let's be certain we always return an integer.
                 return 0
             return -child.signalstatus
         if child.exitstatus > 128:
             return -(child.exitstatus - 128)
         return child.exitstatus
 
 
 # Make system() with a functional interface for outside use.  Note that we use
 # getoutput() from the _common utils, which is built on top of popen(). Using
 # pexpect to get subprocess output produces difficult to parse output, since
 # programs think they are talking to a tty and produce highly formatted output
 # (ls is a good example) that makes them hard.
 system = ProcessHandler().system
 
-
-
+def check_pid(pid):
+    try:
+        os.kill(pid, 0)
+    except OSError as err:
+        if err.errno == errno.ESRCH:
+            return False
+        elif err.errno == errno.EPERM:
+            # Don't have permission to signal the process - probably means it exists
+            return True
+        raise
+    else:
+        return True

IPython/utils/_process_win32.py

@@ -1,187 +1,192 b''
 """Windows-specific implementation of process utilities.
 
 This file is only meant to be imported by process.py, not by end-users.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # stdlib
 import os
 import sys
 import ctypes
 
 from ctypes import c_int, POINTER
 from ctypes.wintypes import LPCWSTR, HLOCAL
 from subprocess import STDOUT
 
 # our own imports
 from ._process_common import read_no_interrupt, process_handler, arg_split as py_arg_split
 from . import py3compat
 from .encoding import DEFAULT_ENCODING
 
 #-----------------------------------------------------------------------------
 # Function definitions
 #-----------------------------------------------------------------------------
 
 class AvoidUNCPath(object):
     """A context manager to protect command execution from UNC paths.
 
     In the Win32 API, commands can't be invoked with the cwd being a UNC path.
     This context manager temporarily changes directory to the 'C:' drive on
     entering, and restores the original working directory on exit.
 
     The context manager returns the starting working directory *if* it made a
     change and None otherwise, so that users can apply the necessary adjustment
     to their system calls in the event of a change.
 
     Examples
     --------
     ::
         cmd = 'dir'
         with AvoidUNCPath() as path:
             if path is not None:
                 cmd = '"pushd %s &&"%s' % (path, cmd)
             os.system(cmd)
     """
     def __enter__(self):
         self.path = py3compat.getcwd()
         self.is_unc_path = self.path.startswith(r"\\")
         if self.is_unc_path:
             # change to c drive (as cmd.exe cannot handle UNC addresses)
             os.chdir("C:")
             return self.path
         else:
             # We return None to signal that there was no change in the working
             # directory
             return None
 
     def __exit__(self, exc_type, exc_value, traceback):
         if self.is_unc_path:
             os.chdir(self.path)
 
 
 def _find_cmd(cmd):
     """Find the full path to a .bat or .exe using the win32api module."""
     try:
         from win32api import SearchPath
     except ImportError:
         raise ImportError('you need to have pywin32 installed for this to work')
     else:
         PATH = os.environ['PATH']
         extensions = ['.exe', '.com', '.bat', '.py']
         path = None
         for ext in extensions:
             try:
                 path = SearchPath(PATH, cmd, ext)[0]
             except:
                 pass
         if path is None:
             raise OSError("command %r not found" % cmd)
         else:
             return path
 
 
 def _system_body(p):
     """Callback for _system."""
     enc = DEFAULT_ENCODING
     for line in read_no_interrupt(p.stdout).splitlines():
         line = line.decode(enc, 'replace')
         print(line, file=sys.stdout)
     for line in read_no_interrupt(p.stderr).splitlines():
         line = line.decode(enc, 'replace')
         print(line, file=sys.stderr)
 
     # Wait to finish for returncode
     return p.wait()
 
 
 def system(cmd):
     """Win32 version of os.system() that works with network shares.
 
     Note that this implementation returns None, as meant for use in IPython.
 
     Parameters
     ----------
     cmd : str or list
       A command to be executed in the system shell.
 
     Returns
     -------
     None : we explicitly do NOT return the subprocess status code, as this
     utility is meant to be used extensively in IPython, where any return value
     would trigger :func:`sys.displayhook` calls.
     """
     # The controller provides interactivity with both
     # stdin and stdout
     #import _process_win32_controller
     #_process_win32_controller.system(cmd)
 
     with AvoidUNCPath() as path:
         if path is not None:
             cmd = '"pushd %s &&"%s' % (path, cmd)
         return process_handler(cmd, _system_body)
 
 def getoutput(cmd):
     """Return standard output of executing cmd in a shell.
 
     Accepts the same arguments as os.system().
 
     Parameters
     ----------
     cmd : str or list
       A command to be executed in the system shell.
 
     Returns
     -------
     stdout : str
     """
 
     with AvoidUNCPath() as path:
         if path is not None:
             cmd = '"pushd %s &&"%s' % (path, cmd)
         out = process_handler(cmd, lambda p: p.communicate()[0], STDOUT)
 
     if out is None:
         out = b''
     return py3compat.bytes_to_str(out)
 
 try:
     CommandLineToArgvW = ctypes.windll.shell32.CommandLineToArgvW
     CommandLineToArgvW.arg_types = [LPCWSTR, POINTER(c_int)]
     CommandLineToArgvW.restype = POINTER(LPCWSTR)
     LocalFree = ctypes.windll.kernel32.LocalFree
     LocalFree.res_type = HLOCAL
     LocalFree.arg_types = [HLOCAL]
     
     def arg_split(commandline, posix=False, strict=True):
         """Split a command line's arguments in a shell-like manner.
 
         This is a special version for windows that use a ctypes call to CommandLineToArgvW
         to do the argv splitting. The posix paramter is ignored.
         
         If strict=False, process_common.arg_split(...strict=False) is used instead.
         """
         #CommandLineToArgvW returns path to executable if called with empty string.
         if commandline.strip() == "":
             return []
         if not strict:
             # not really a cl-arg, fallback on _process_common
             return py_arg_split(commandline, posix=posix, strict=strict)
         argvn = c_int()
         result_pointer = CommandLineToArgvW(py3compat.cast_unicode(commandline.lstrip()), ctypes.byref(argvn))
         result_array_type = LPCWSTR * argvn.value
         result = [arg for arg in result_array_type.from_address(ctypes.addressof(result_pointer.contents))]
         retval = LocalFree(result_pointer)
         return result
 except AttributeError:
     arg_split = py_arg_split
+
+def check_pid(pid):
+    # OpenProcess returns 0 if no such process (of ours) exists
+    # positive int otherwise
+    return bool(ctypes.windll.kernel32.OpenProcess(1,0,pid))

IPython/utils/process.py

@@ -1,123 +1,123 b''
 # encoding: utf-8
 """
 Utilities for working with external processes.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Stdlib
 import os
 import sys
 
 # Our own
 if sys.platform == 'win32':
-    from ._process_win32 import _find_cmd, system, getoutput, arg_split
+    from ._process_win32 import _find_cmd, system, getoutput, arg_split, check_pid
 elif sys.platform == 'cli':
     from ._process_cli import _find_cmd, system, getoutput, arg_split
 else:
-    from ._process_posix import _find_cmd, system, getoutput, arg_split
+    from ._process_posix import _find_cmd, system, getoutput, arg_split, check_pid
 
 from ._process_common import getoutputerror, get_output_error_code, process_handler
 from . import py3compat
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 
 class FindCmdError(Exception):
     pass
 
 
 def find_cmd(cmd):
     """Find absolute path to executable cmd in a cross platform manner.
 
     This function tries to determine the full path to a command line program
     using `which` on Unix/Linux/OS X and `win32api` on Windows.  Most of the
     time it will use the version that is first on the users `PATH`.
 
     Warning, don't use this to find IPython command line programs as there
     is a risk you will find the wrong one.  Instead find those using the
     following code and looking for the application itself::
 
         from IPython.utils.path import get_ipython_module_path
         from IPython.utils.process import pycmd2argv
         argv = pycmd2argv(get_ipython_module_path('IPython.terminal.ipapp'))
 
     Parameters
     ----------
     cmd : str
         The command line program to look for.
     """
     try:
         path = _find_cmd(cmd).rstrip()
     except OSError:
         raise FindCmdError('command could not be found: %s' % cmd)
     # which returns empty if not found
     if path == '':
         raise FindCmdError('command could not be found: %s' % cmd)
     return os.path.abspath(path)
 
 
 def is_cmd_found(cmd):
     """Check whether executable `cmd` exists or not and return a bool."""
     try:
         find_cmd(cmd)
         return True
     except FindCmdError:
         return False
 
 
 def pycmd2argv(cmd):
     r"""Take the path of a python command and return a list (argv-style).
 
     This only works on Python based command line programs and will find the
     location of the ``python`` executable using ``sys.executable`` to make
     sure the right version is used.
 
     For a given path ``cmd``, this returns [cmd] if cmd's extension is .exe,
     .com or .bat, and [, cmd] otherwise.
 
     Parameters
     ----------
     cmd : string
       The path of the command.
 
     Returns
     -------
     argv-style list.
     """
     ext = os.path.splitext(cmd)[1]
     if ext in ['.exe', '.com', '.bat']:
         return [cmd]
     else:
         return [sys.executable, cmd]
 
 
 def abbrev_cwd():
     """ Return abbreviated version of cwd, e.g. d:mydir """
     cwd = py3compat.getcwd().replace('\\','/')
     drivepart = ''
     tail = cwd
     if sys.platform == 'win32':
         if len(cwd) < 4:
             return cwd
         drivepart,tail = os.path.splitdrive(cwd)
 
 
     parts = tail.split('/')
     if len(parts) > 2:
         tail = '/'.join(parts[-2:])
 
     return (drivepart + (
         cwd == '/' and '/' or tail))