Python os.waitpid() Examples

def _internal_poll(self, _deadstate=None, _waitpid=os.waitpid,
                _WNOHANG=os.WNOHANG, _os_error=os.error, _ECHILD=errno.ECHILD):
            """Check if child process has terminated.  Returns returncode
            attribute.

            This method is called by __del__, so it cannot reference anything
            outside of the local scope (nor can any methods it calls).

            """
            if self.returncode is None:
                try:
                    pid, sts = _waitpid(self.pid, _WNOHANG)
                    if pid == self.pid:
                        self._handle_exitstatus(sts)
                except _os_error as e:
                    if _deadstate is not None:
                        self.returncode = _deadstate
                    elif e.errno == _ECHILD:
                        # This happens if SIGCLD is set to be ignored or
                        # waiting for child processes has otherwise been
                        # disabled for our process.  This child is dead, we
                        # can't get the status.
                        # http://bugs.python.org/issue15756
                        self.returncode = 0
            return self.returncode 

def _zombie_reaper(self):
        while True:
            try:
                res = os.waitpid(-1, os.WNOHANG)
                # don't sleep or stop if a zombie process was found
                # as there could be more
                if res != (0, 0):
                    continue
            except ChildProcessError:
                # There are no child processes yet (or they have been killed)
                pass
            except os.error:
                LOG.exception("Got OS error while reaping zombie processes")
            if self._terminate_called.isSet():
                break
            time.sleep(1) 

def test_reinit_tls_after_fork(self):
        # Issue #13817: fork() would deadlock in a multithreaded program with
        # the ad-hoc TLS implementation.

        def do_fork_and_wait():
            # just fork a child process and wait it
            pid = os.fork()
            if pid > 0:
                os.waitpid(pid, 0)
            else:
                os._exit(0)

        # start a bunch of threads that will fork() child processes
        threads = []
        for i in range(16):
            t = threading.Thread(target=do_fork_and_wait)
            threads.append(t)
            t.start()

        for t in threads:
            t.join() 

def _internal_poll(self, _deadstate=None, _waitpid=os.waitpid,
                _WNOHANG=os.WNOHANG, _os_error=os.error):
            """Check if child process has terminated.  Returns returncode
            attribute.

            This method is called by __del__, so it cannot reference anything
            outside of the local scope (nor can any methods it calls).

            """
            if self.returncode is None:
                try:
                    pid, sts = _waitpid(self.pid, _WNOHANG)
                    if pid == self.pid:
                        self._handle_exitstatus(sts)
                except _os_error:
                    if _deadstate is not None:
                        self.returncode = _deadstate
            return self.returncode 

def reap_children():
    """Use this function at the end of test_main() whenever sub-processes
    are started.  This will help ensure that no extra children (zombies)
    stick around to hog resources and create problems when looking
    for refleaks.
    """

    # Reap all our dead child processes so we don't leave zombies around.
    # These hog resources and might be causing some of the buildbots to die.
    if hasattr(os, 'waitpid'):
        any_process = -1
        while True:
            try:
                # This will raise an exception on Windows.  That's ok.
                pid, status = os.waitpid(any_process, os.WNOHANG)
                if pid == 0:
                    break
            except:
                break 

def work(self):
        """
        Wait for message from running child process
        """
        succ, msg = self.msg.read_msg()
        if isinstance(msg, CmdFinish):
            try:
                pid, _ = os.waitpid(msg.pid, 0)
            except OSError:
                pid = msg.pid
            if (succ is False or pid == msg.pid):
                self.basecmd._finished = True
                return True
            else:
                return False
        else:
            self.basecmd.results = msg 

def reap_children():
    """Use this function at the end of test_main() whenever sub-processes
    are started.  This will help ensure that no extra children (zombies)
    stick around to hog resources and create problems when looking
    for refleaks.
    """

    # Reap all our dead child processes so we don't leave zombies around.
    # These hog resources and might be causing some of the buildbots to die.
    if hasattr(os, 'waitpid'):
        any_process = -1
        while True:
            try:
                # This will raise an exception on Windows.  That's ok.
                pid, status = os.waitpid(any_process, os.WNOHANG)
                if pid == 0:
                    break
            except:
                break 

def cleanup_defunct_processes():
  """Cleans up defunct processes."""
  # Defunct processes happen only on unix platforms.
  if environment.platform() != 'WINDOWS':
    while True:
      try:
        # Matches any defunct child process.
        p, _ = os.waitpid(-1, os.WNOHANG)
        if not p:
          break

        logs.log('Clearing defunct process %s.' % str(p))
      except:
        break


# Note: changes to this function may require changes to untrusted_runner.proto.
# This should only be used for running target black box applications which
# return text output. 

def poll(self, flag=os.WNOHANG):
            if self.returncode is None:
                while True:
                    try:
                        pid, sts = os.waitpid(self.pid, flag)
                    except os.error as e:
                        if e.errno == errno.EINTR:
                            continue
                        # Child process not yet created. See #1731717
                        # e.errno == errno.ECHILD == 10
                        return None
                    else:
                        break
                if pid == self.pid:
                    if os.WIFSIGNALED(sts):
                        self.returncode = -os.WTERMSIG(sts)
                    else:
                        assert os.WIFEXITED(sts)
                        self.returncode = os.WEXITSTATUS(sts)
            return self.returncode 

def test_mac_ver_with_fork(self):
        # Issue7895: platform.mac_ver() crashes when using fork without exec
        #
        # This test checks that the fix for that issue works.
        #
        pid = os.fork()
        if pid == 0:
            # child
            info = platform.mac_ver()
            os._exit(0)

        else:
            # parent
            cpid, sts = os.waitpid(pid, 0)
            self.assertEqual(cpid, pid)
            self.assertEqual(sts, 0) 

def waitfinish(self, waiter=os.waitpid):
        pid, systemstatus = waiter(self.pid, 0)
        if systemstatus:
            if os.WIFSIGNALED(systemstatus):
                exitstatus = os.WTERMSIG(systemstatus) + 128
            else:
                exitstatus = os.WEXITSTATUS(systemstatus)
        else:
            exitstatus = 0
        signal = systemstatus & 0x7f
        if not exitstatus and not signal:
            retval = self.RETVAL.open('rb')
            try:
                retval_data = retval.read()
            finally:
                retval.close()
            retval = marshal.loads(retval_data)
        else:
            retval = None
        stdout = self.STDOUT.read()
        stderr = self.STDERR.read()
        self._removetemp()
        return Result(exitstatus, signal, retval, stdout, stderr) 

def reap_children():
    """Use this function at the end of test_main() whenever sub-processes
    are started.  This will help ensure that no extra children (zombies)
    stick around to hog resources and create problems when looking
    for refleaks.
    """

    # Reap all our dead child processes so we don't leave zombies around.
    # These hog resources and might be causing some of the buildbots to die.
    if hasattr(os, 'waitpid'):
        any_process = -1
        while True:
            try:
                # This will raise an exception on Windows.  That's ok.
                pid, status = os.waitpid(any_process, os.WNOHANG)
                if pid == 0:
                    break
            except:
                break 

def maybe_start_cleaner_thread(self):
        if not self.over_limit():
            return
        # exit immediately if another cleaner is active
        cleaner_lock = os.path.join(self.pcache_dir, ".clean")
        if self.lock_file(cleaner_lock, blocking=False):
            self.log(INFO, "cleanup not starting:  %s locked", cleaner_lock)
            return
        # see http://www.faqs.org/faqs/unix-faq/faq/part3/section-13.html
        # for explanation of double-fork
        pid = os.fork()
        if pid:  # parent
            os.waitpid(pid, 0)
            return
        else:  # child
            self.daemonize()
            pid = os.fork()
            if pid:
                os._exit(0)
            # grandchild
            self.clean_cache()
            self.unlock_file(cleaner_lock)
            os._exit(0) 

def test_stopped(self):
        """Test wait() behavior when waitpid returns WIFSTOPPED; issue29335."""
        args = [sys.executable, '-c', 'pass']
        proc = subprocess.Popen(args)

        # Wait until the real process completes to avoid zombie process
        pid = proc.pid
        pid, status = os.waitpid(pid, 0)
        self.assertEqual(status, 0)

        status = _testcapi.W_STOPCODE(3)

        def mock_waitpid(pid, flags):
            return (pid, status)

        with test_support.swap_attr(os, 'waitpid', mock_waitpid):
            returncode = proc.wait()

        self.assertEqual(returncode, -3) 

def waitfinish(self, waiter=os.waitpid):
        pid, systemstatus = waiter(self.pid, 0)
        if systemstatus:
            if os.WIFSIGNALED(systemstatus):
                exitstatus = os.WTERMSIG(systemstatus) + 128
            else:
                exitstatus = os.WEXITSTATUS(systemstatus)
        else:
            exitstatus = 0
        signal = systemstatus & 0x7f
        if not exitstatus and not signal:
            retval = self.RETVAL.open('rb')
            try:
                retval_data = retval.read()
            finally:
                retval.close()
            retval = marshal.loads(retval_data)
        else:
            retval = None
        stdout = self.STDOUT.read()
        stderr = self.STDERR.read()
        self._removetemp()
        return Result(exitstatus, signal, retval, stdout, stderr) 

def waitfinish(self, waiter=os.waitpid):
        pid, systemstatus = waiter(self.pid, 0)
        if systemstatus:
            if os.WIFSIGNALED(systemstatus):
                exitstatus = os.WTERMSIG(systemstatus) + 128
            else:
                exitstatus = os.WEXITSTATUS(systemstatus)
        else:
            exitstatus = 0
        signal = systemstatus & 0x7f
        if not exitstatus and not signal:
            retval = self.RETVAL.open('rb')
            try:
                retval_data = retval.read()
            finally:
                retval.close()
            retval = marshal.loads(retval_data)
        else:
            retval = None
        stdout = self.STDOUT.read()
        stderr = self.STDERR.read()
        self._removetemp()
        return Result(exitstatus, signal, retval, stdout, stderr) 

def prompt(default=None):
    editor = 'nano'
    with tempfile.NamedTemporaryFile(mode='r+') as tmpfile:
        if default:
            tmpfile.write(default)
            tmpfile.flush()

        child_pid = os.fork()
        is_child = child_pid == 0

        if is_child:
            os.execvp(editor, [editor, tmpfile.name])
        else:
            os.waitpid(child_pid, 0)
            tmpfile.seek(0)
            return tmpfile.read().strip() 

def _internal_poll(self, _deadstate=None, _waitpid=os.waitpid,
                _WNOHANG=os.WNOHANG, _os_error=os.error, _ECHILD=errno.ECHILD):
            """Check if child process has terminated.  Returns returncode
            attribute.

            This method is called by __del__, so it cannot reference anything
            outside of the local scope (nor can any methods it calls).

            """
            if self.returncode is None:
                try:
                    pid, sts = _waitpid(self.pid, _WNOHANG)
                    if pid == self.pid:
                        self._handle_exitstatus(sts)
                except _os_error as e:
                    if _deadstate is not None:
                        self.returncode = _deadstate
                    if e.errno == _ECHILD:
                        # This happens if SIGCLD is set to be ignored or
                        # waiting for child processes has otherwise been
                        # disabled for our process.  This child is dead, we
                        # can't get the status.
                        # http://bugs.python.org/issue15756
                        self.returncode = 0
            return self.returncode 

def wait(self):
            """Wait for child process to terminate.  Returns returncode
            attribute."""
            while self.returncode is None:
                try:
                    pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
                except OSError as e:
                    if e.errno != errno.ECHILD:
                        raise
                    # This happens if SIGCLD is set to be ignored or waiting
                    # for child processes has otherwise been disabled for our
                    # process.  This child is dead, we can't get the status.
                    pid = self.pid
                    sts = 0
                # Check the pid and loop as waitpid has been known to return
                # 0 even without WNOHANG in odd situations.  issue14396.
                if pid == self.pid:
                    self._handle_exitstatus(sts)
            return self.returncode 

def test_is_alive_after_fork(self):
        # Try hard to trigger #18418: is_alive() could sometimes be True on
        # threads that vanished after a fork.
        old_interval = sys.getcheckinterval()

        # Make the bug more likely to manifest.
        sys.setcheckinterval(10)

        try:
            for i in range(20):
                t = threading.Thread(target=lambda: None)
                t.start()
                pid = os.fork()
                if pid == 0:
                    os._exit(1 if t.is_alive() else 0)
                else:
                    t.join()
                    pid, status = os.waitpid(pid, 0)
                    self.assertEqual(0, status)
        finally:
            sys.setcheckinterval(old_interval) 

def test_3_join_in_forked_from_thread(self):
        # Like the test above, but fork() was called from a worker thread
        # In the forked process, the main Thread object must be marked as stopped.
        script = """if 1:
            main_thread = threading.current_thread()
            def worker():
                childpid = os.fork()
                if childpid != 0:
                    os.waitpid(childpid, 0)
                    sys.exit(0)

                t = threading.Thread(target=joiningfunc,
                                     args=(main_thread,))
                print 'end of main'
                t.start()
                t.join() # Should not block: main_thread is already stopped

            w = threading.Thread(target=worker)
            w.start()
            """
        self._run_and_join(script) 

def test_os_waitpid_eintr(self):
        # os.waitpid() is supposed to "retry" on EINTR.
        with mock.patch("psutil._psposix.os.waitpid",
                        side_effect=OSError(errno.EINTR, "")) as m:
            self.assertRaises(
                psutil._psposix.TimeoutExpired,
                psutil._psposix.wait_pid, os.getpid(), timeout=0.01)
            assert m.called 

def spawnve(mode, file, args, env):
        spawn_lock.acquire()
        try:
            if mode == os.P_WAIT:
                ret = os.spawnve(os.P_NOWAIT, file, args, env)
            else:
                ret = os.spawnve(mode, file, args, env)
        finally:
            spawn_lock.release()
        if mode == os.P_WAIT:
            pid, status = os.waitpid(ret, 0)
            ret = status >> 8
        return ret 

def collect_children(self):
        """Internal routine to wait for children that have exited."""
        if self.active_children is None:
            return

        # If we're above the max number of children, wait and reap them until
        # we go back below threshold. Note that we use waitpid(-1) below to be
        # able to collect children in size(<defunct children>) syscalls instead
        # of size(<children>): the downside is that this might reap children
        # which we didn't spawn, which is why we only resort to this when we're
        # above max_children.
        while len(self.active_children) >= self.max_children:
            try:
                pid, _ = os.waitpid(-1, 0)
                self.active_children.discard(pid)
            except OSError as e:
                if e.errno == errno.ECHILD:
                    # we don't have any children, we're done
                    self.active_children.clear()
                elif e.errno != errno.EINTR:
                    break

        # Now reap all defunct children.
        for pid in self.active_children.copy():
            try:
                pid, _ = os.waitpid(pid, os.WNOHANG)
                # if the child hasn't exited yet, pid will be 0 and ignored by
                # discard() below
                self.active_children.discard(pid)
            except OSError as e:
                if e.errno == errno.ECHILD:
                    # someone else reaped it
                    self.active_children.discard(pid) 

def wait(self):
        """Wait for and return the exit status of the child process."""
        if self.sts < 0:
            pid, sts = os.waitpid(self.pid, 0)
            # This used to be a test, but it is believed to be
            # always true, so I changed it to an assertion - mvl
            assert pid == self.pid
            self.sts = sts
        return self.sts 

def test_os_waitpid_let_raise(self):
        # os.waitpid() is supposed to catch EINTR and ECHILD only.
        # Test that any other errno results in an exception.
        with mock.patch("psutil._psposix.os.waitpid",
                        side_effect=OSError(errno.EBADF, "")) as m:
            self.assertRaises(OSError, psutil._psposix.wait_pid, os.getpid())
            assert m.called 

def spawnve(mode, file, args, env):
        spawn_lock.acquire()
        try:
            if mode == os.P_WAIT:
                ret = os.spawnve(os.P_NOWAIT, file, args, env)
            else:
                ret = os.spawnve(mode, file, args, env)
        finally:
            spawn_lock.release()
        if mode == os.P_WAIT:
            pid, status = os.waitpid(ret, 0)
            ret = status >> 8
        return ret 

def wait_impl(self, cpid):
        for i in range(10):
            # waitpid() shouldn't hang, but some of the buildbots seem to hang
            # in the forking tests.  This is an attempt to fix the problem.
            spid, status = os.waitpid(cpid, os.WNOHANG)
            if spid == cpid:
                break
            time.sleep(1.0)

        self.assertEqual(spid, cpid)
        self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8)) 

def stop(self):
		"""
		Send a stop request to the child process and wait for it to exit.
		"""
		if not os.path.exists("/proc/{0}".format(self.child_pid)):
			return
		request = {'action': 'stop'}
		with self._lock:
			self.send(request)
			os.waitpid(self.child_pid, 0)
		self.rfile.close()
		self.wfile.close() 

def poll(self, _deadstate=None):
            """Check if child process has terminated.  Returns returncode
            attribute."""
            if self.returncode is None:
                try:
                    pid, sts = os.waitpid(self.pid, os.WNOHANG)
                    if pid == self.pid:
                        self._handle_exitstatus(sts)
                except os.error:
                    if _deadstate is not None:
                        self.returncode = _deadstate
            return self.returncode