pass code check

pmonitor() is hard to get right, but this seems like
a reasonable improvement:

1. non-blocking I/O so we can drain buffer with impunity
2. drain buffer after poll
3. unregister fd on POLLHUP

Note we may have a unicode splitting problem since we're
decoding chunks of bytes, but that is a problem for another
day I think.

.travis.yml

@@ -1,35 +1,35 @@
 language: python
 sudo: required
 
-python:
- - "2.7
- - "3.6"
-
 matrix:
   include:
     - dist: trusty
+      python: 2.7
+      env: dist="14.04 LTS trusty"
+    - dist: trusty
+      python: 3.6
       env: dist="14.04 LTS trusty"
-#    - dist: xenial
-#      env: dist="16.04 LTS xenial"
-# Travis-CI only proposes 14.04 LTS Trusty and there is no plan to update to 16.04 xenial
-# (c.f. https://github.com/travis-ci/travis-ci/issues/5821)
-# It is useless to add a second job because it will run in the same Ubuntu version (14.04)
 
 before_install:
 - sudo apt-get update -qq
 - sudo apt-get install -qq vlan
-- sudo util/install.sh -n
+- PYTHON=`which python` util/install.sh -n
 
 install:
 - bash -c "if [ `lsb_release -rs` == '14.04' ]; then make codecheck; fi"
-- sudo util/install.sh -fnvw
+- pip install pexpect || pip3 install pexpect
+- util/install.sh -nfvw
 
 script:
-- sudo mn --test pingall
-- sudo python mininet/test/runner.py -v -quick
-- sudo python examples/test/runner.py -v -quick
+- alias sudo="sudo env PATH=$PATH"
+- export PYTHON=`which python`
+- echo 'px import sys; print(sys.version_info)' | sudo $PYTHON bin/mn -v output
+- sudo $PYTHON bin/mn --test pingall
+- sudo $PYTHON mininet/test/runner.py -v -quick
+- sudo $PYTHON examples/test/runner.py -v -quick
 
 notifications:
   email:
     on_success: never
-# More details: https://docs.travis-ci.com/user/notifications#Configuring-email-notifications
+
+# More details: https://docs.travis-ci.com/user/notifications

INSTALL

@@ -2,7 +2,7 @@
 Mininet Installation/Configuration Notes
 ----------------------------------------
 
-Mininet 2.3.0d1
+Mininet 2.3.0d4
 ---
 
 The supported installation methods for Mininet are 1) using a

LICENSE

@@ -1,4 +1,4 @@
-Mininet 2.3.0d1 License
+Mininet 2.3.0d4 License
 
 Copyright (c) 2013-2018 Open Networking Laboratory
 Copyright (c) 2009-2012 Bob Lantz and The Board of Trustees of

README.md

@@ -2,7 +2,7 @@ Mininet: Rapid Prototyping for Software Defined Networks
 ========================================================
 *The best way to emulate almost any network on your laptop!*
 
-Mininet 2.3.0d1
+Mininet 2.3.0d4
 
 [![Build Status][1]](https://travis-ci.org/mininet/mininet)
 
@@ -126,7 +126,7 @@ hard work that Mininet continues to grow and improve.
 Best wishes, and we look forward to seeing what you can do with
 Mininet to change the networking world!
 
-Bob Lantz  
+Bob Lantz
 Mininet Core Team
 
 [1]: https://travis-ci.org/mininet/mininet.svg?branch=master

examples/miniedit.py

@@ -24,6 +24,7 @@ import sys
 from optparse import OptionParser
 from subprocess import call
 
+# pylint: disable=import-error
 if sys.version_info[0] == 2:
     from Tkinter import ( Frame, Label, LabelFrame, Entry, OptionMenu,
                           Checkbutton, Menu, Toplevel, Button, BitmapImage,
@@ -32,11 +33,9 @@ if sys.version_info[0] == 2:
                           CENTER, RIGHT, LEFT, BOTH, TRUE, FALSE )
     from ttk import Notebook
     from tkMessageBox import showerror
-    from subprocess import call
     import tkFont
     import tkFileDialog
     import tkSimpleDialog
-    import tkFileDialog
 else:
     from tkinter import ( Frame, Label, LabelFrame, Entry, OptionMenu,
                           Checkbutton, Menu, Toplevel, Button, BitmapImage,
@@ -48,6 +47,7 @@ else:
     from tkinter import font as tkFont
     from tkinter import simpledialog as tkSimpleDialog
     from tkinter import filedialog as tkFileDialog
+# pylint: enable=import-error
 
 import re
 import json

mininet/net.py

@@ -108,7 +108,7 @@ from mininet.util import ( quietRun, fixLimits, numCores, ensureRoot,
 from mininet.term import cleanUpScreens, makeTerms
 
 # Mininet version: should be consistent with README and LICENSE
-VERSION = "2.3.0d1"
+VERSION = "2.3.0d4"
 
 class Mininet( object ):
     "Network emulation with hosts spawned in network namespaces."

mininet/node.py

@@ -89,7 +89,7 @@ class Node( object ):
         self.inNamespace = params.get( 'inNamespace', inNamespace )
 
         # Python 3 complains if we don't wait for shell exit
-        self.waitExited = params.get( 'waitExited', Python3 == True )
+        self.waitExited = params.get( 'waitExited', Python3 )
 
         # Stash configuration parameters for future reference
         self.params = params
@@ -107,6 +107,7 @@ class Node( object ):
         self.readbuf = ''
 
         # Start command interpreter shell
+        self.master, self.slave = None, None  # pylint
         self.startShell()
         self.mountPrivateDirs()
 
@@ -145,12 +146,12 @@ class Node( object ):
         # Spawn a shell subprocess in a pseudo-tty, to disable buffering
         # in the subprocess and insulate it from signals (e.g. SIGINT)
         # received by the parent
-        master, slave = pty.openpty()
-        self.shell = self._popen( cmd, stdin=slave, stdout=slave, stderr=slave,
-                                  close_fds=False )
+        self.master, self.slave = pty.openpty()
+        self.shell = self._popen( cmd, stdin=self.slave, stdout=self.slave,
+                                  stderr=self.slave, close_fds=False )
         # XXX BL: This doesn't seem right, and we should also probably
         # close our files when we exit...
-        self.stdin = os.fdopen( master, 'r' )
+        self.stdin = os.fdopen( self.master, 'r' )
         self.stdout = self.stdin
         self.pid = self.shell.pid
         self.pollOut = select.poll()
@@ -217,9 +218,13 @@ class Node( object ):
         # for intfName in self.intfNames():
         # if self.name in intfName:
         # quietRun( 'ip link del ' + intfName )
-        if self.waitExited and self.shell:
-            debug( 'waiting for', self.pid, 'to terminate\n' )
-            self.shell.wait()
+        if self.shell:
+            # Close ptys
+            self.stdin.close()
+            os.close(self.slave)
+            if self.waitExited:
+                debug( 'waiting for', self.pid, 'to terminate\n' )
+                self.shell.wait()
         self.shell = None
 
     # Subshell I/O, commands and control
@@ -383,23 +388,23 @@ class Node( object ):
                      'mncmd':
                      [ 'mnexec', '-da', str( self.pid ) ] }
         defaults.update( kwargs )
+        shell = defaults.pop( 'shell', False )
         if len( args ) == 1:
             if isinstance( args[ 0 ], list ):
                 # popen([cmd, arg1, arg2...])
                 cmd = args[ 0 ]
             elif isinstance( args[ 0 ], BaseString ):
                 # popen("cmd arg1 arg2...")
-                cmd = args[ 0 ].split()
+                cmd = [ args[ 0 ] ] if shell else args[ 0 ].split()
             else:
                 raise Exception( 'popen() requires a string or list' )
         elif len( args ) > 0:
             # popen( cmd, arg1, arg2... )
             cmd = list( args )
+        if shell:
+            cmd = [ os.environ[ 'SHELL' ], '-c' ] + [ ' '.join( cmd ) ]
         # Attach to our namespace  using mnexec -a
         cmd = defaults.pop( 'mncmd' ) + cmd
-        # Shell requires a string, not a list!
-        if defaults.get( 'shell', False ):
-            cmd = ' '.join( cmd )
         popen = self._popen( cmd, **defaults )
         return popen
 

mininet/test/test_walkthrough.py

@@ -228,7 +228,7 @@ class testWalkthrough( unittest.TestCase ):
                   r'([\d\.]+)/([\d\.]+)/([\d\.]+)/([\d\.]+) ms' )
         delay = float( p.match.group( 2 ) )
         self.assertTrue( delay >= 40, 'Delay < 40ms' )
-        self.assertTrue( delay <= 50, 'Delay > 50s' )
+        self.assertTrue( delay <= 50, 'Delay > 50ms' )
         p.expect( self.prompt )
         p.sendline( 'exit' )
         p.wait()

mininet/util.py

@@ -25,7 +25,10 @@ def encode( s ):
     "Encode a byte string if needed for Python 3"
     return s.encode( Encoding ) if Python3 else s
 try:
+    # pylint: disable=import-error
+    oldpexpect = None
     import pexpect as oldpexpect
+    # pylint: enable=import-error
 
     class Pexpect( object ):
         "Custom pexpect that is compatible with str"
@@ -413,34 +416,27 @@ def pmonitor(popens, timeoutms=500, readline=True,
     for host, popen in popens.items():
         fd = popen.stdout.fileno()
         fdToHost[ fd ] = host
-        poller.register( fd, POLLIN )
-        if not readline:
-            # Use non-blocking reads
-            flags = fcntl( fd, F_GETFL )
-            fcntl( fd, F_SETFL, flags | O_NONBLOCK )
-
-    def readit( f ):
-        "Helper function - read line or data"
-        # Note this will block if readline is True
-        line = f.readline() if readline else f.read( readmax )
-        return decode( line )
-
+        poller.register( fd, POLLIN | POLLHUP )
+        flags = fcntl( fd, F_GETFL )
+        fcntl( fd, F_SETFL, flags | O_NONBLOCK )
     while popens:
         fds = poller.poll( timeoutms )
         if fds:
             for fd, event in fds:
                 host = fdToHost[ fd ]
                 popen = popens[ host ]
-                if event & POLLIN:
-                    line = readit( popen.stdout )
-                    yield host, line
-                if event & POLLHUP:
+                if event & POLLIN or event & POLLHUP:
                     while True:
-                        # Drain buffer
-                        line = readit( popen.stdout )
-                        yield host, line
+                        try:
+                            f = popen.stdout
+                            line = decode( f.readline() if readline
+                                           else f.read( readmax ) )
+                        except IOError:
+                            line = ''
                         if line == '':
                             break
+                        yield host, line
+                if event & POLLHUP:
                     poller.unregister( fd )
                     del popens[ host ]
         else: