python类setpgid()的实例源码

def _setPgid(pid, pgid):
    """set pgid of a process, ignored exception caused by race condition
    that occurs if already set by parent or child has already existed"""
    # Should just ignore on EACCES, as to handle race condition with parent
    # and child.  However some Linux kernels (seen in 2.6.18-53) report ESRCH
    # or EPERM.  To handle this is a straight-forward way, just check that the
    # change has been made.  However, in some cases the change didn't take,
    # retrying seems to make the problem go away.
    for i in xrange(0,5):
        try:
            os.setpgid(pid, pgid)
            return
        except OSError:
            if os.getpgid(pid) == pgid:
                return
            time.sleep(0.25) # sleep for retry
    # last try, let it return an error
    os.setpgid(pid, pgid)

# FIXME: why not use pipes.quote?

def execute(self,dt):
        if self.finished: return "finished"
        if not self.running:
            self.process = Process(target = executeInProcessGroup, args = (self,))
            self.process.start()
            print "timeshare child PID:",self.process.pid
            os.setpgid(self.process.pid,self.process.pid)
            print "timeshare process group",os.getpgid(self.process.pid)
            assert os.getpgid(self.process.pid) == self.process.pid
            print "my process group",os.getpgrp(),"which should be",os.getpgid(0)
            assert os.getpgid(self.process.pid) != os.getpgid(0)
            self.running = True
        else:
            os.killpg(self.process.pid, signal.SIGCONT)

        self.process.join(dt)
        if self.process.is_alive():
            os.killpg(self.process.pid, signal.SIGSTOP)
            return "still running"
        else:
            self.finished = True
            return self.q.get()

def start(self):
        """
        Start the process.
        """
        preexec = None
        if hasattr(self, '_process_group_leader'):
            # This probably needs some kind of syncronization...
            if self._process_group_leader is ...:
                preexec = os.setpgrp
            else:
                pgid = self._process_group_leader.pid

                def preexec():
                    os.setpgid(0, pgid)

        self._proc = subprocess.Popen(
            # What to execute
            self.cmd,
            preexec_fn=preexec,
            # What IO it has
            stdin=self.stdin, stdout=self.stdout, stderr=self.stderr,
            # Environment it executes in
            cwd=self.cwd, env=self.environ,
        )

def __init__(self, name, conf, threads=1000):
        os.umask(0o27)  # ensure files are created with the correct privileges
        self._logger = logging.getLogger("eventlet.wsgi.server")
        self._wsgi_logger = WritableLogger(self._logger)
        self.name = name
        self.threads = threads
        self.children = set()
        self.stale_children = set()
        self.running = True
        self.pgid = os.getpid()
        self.conf = conf
        try:
            os.setpgid(self.pgid, self.pgid)
        except OSError:
            self.pgid = 0

def setpgid_preexec_fn():
    os.setpgid(0, 0)

def executeInProcessGroup(task):
    os.setpgid(0,0)
    task.q.put(task.command(*task.arguments))

def __init__(self, *args, **kwargs):
            if len(args) >= 7:
                raise Exception("Arguments preexec_fn and after must be passed by keyword.")

            real_preexec_fn = kwargs.pop("preexec_fn", None)
            def setpgid_preexec_fn():
                os.setpgid(0, 0)
                if real_preexec_fn:
                    apply(real_preexec_fn)

            kwargs['preexec_fn'] = setpgid_preexec_fn

            subprocess.Popen.__init__(self, *args, **kwargs)

def __init__(self, threads=1000, initialize_glance_store=False):
        os.umask(0o27)  # ensure files are created with the correct privileges
        self._logger = logging.getLogger("eventlet.wsgi.server")
        self.threads = threads
        self.children = set()
        self.stale_children = set()
        self.running = True
        self.initialize_glance_store = initialize_glance_store
        self.pgid = os.getpid()
        try:
            os.setpgid(self.pgid, self.pgid)
        except OSError:
            self.pgid = 0

def add(self, proc):
        super().add(proc)
        if self.started and proc.started and not isinstance(proc, base.VirtualProcess):
            os.setpgid(proc.pid, self.pgid)

def _spawnChild(self, sock):
        """
        Spawn a single child. Returns True if successful, False otherwise.
        """
        # This socket pair is used for very simple communication between
        # the parent and its children.
        parent, child = socket.socketpair()
        parent.setblocking(0)
        setCloseOnExec(parent)
        child.setblocking(0)
        setCloseOnExec(child)
        try:
            pid = os.fork()
        except OSError, e:
            if e[0] in (errno.EAGAIN, errno.ENOMEM):
                return False # Can't fork anymore.
            raise
        if not pid:
            # Child
            child.close()
            # Put child into its own process group.
            pid = os.getpid()
            os.setpgid(pid, pid)
            # Restore signal handlers.
            self._restoreSignalHandlers()
            # Close copies of child sockets.
            for f in [x['file'] for x in self._children.values()
                      if x['file'] is not None]:
                f.close()
            self._children = {}
            try:
                # Enter main loop.
                self._child(sock, parent)
            except KeyboardInterrupt:
                pass
            sys.exit(0)
        else:
            # Parent
            parent.close()
            d = self._children[pid] = {}
            d['file'] = child
            d['avail'] = True
            return True

def _spawnChild(self, sock):
        """
        Spawn a single child. Returns True if successful, False otherwise.
        """
        # This socket pair is used for very simple communication between
        # the parent and its children.
        parent, child = socket.socketpair()
        parent.setblocking(0)
        setCloseOnExec(parent)
        child.setblocking(0)
        setCloseOnExec(child)
        try:
            pid = os.fork()
        except OSError, e:
            if e[0] in (errno.EAGAIN, errno.ENOMEM):
                return False # Can't fork anymore.
            raise
        if not pid:
            # Child
            child.close()
            # Put child into its own process group.
            pid = os.getpid()
            os.setpgid(pid, pid)
            # Restore signal handlers.
            self._restoreSignalHandlers()
            # Close copies of child sockets.
            for f in [x['file'] for x in self._children.values()
                      if x['file'] is not None]:
                f.close()
            self._children = {}
            try:
                # Enter main loop.
                self._child(sock, parent)
            except KeyboardInterrupt:
                pass
            sys.exit(0)
        else:
            # Parent
            parent.close()
            d = self._children[pid] = {}
            d['file'] = child
            d['avail'] = True
            return True