Handle VMX domains correctly across xend restarts

This patch remembers the device model pid across xend restarts and
avoids creating duplicate device model processes.

Also, device models don't inherit socket fds from xend (which are closed
on exec now), which used to prevent xend restarting.

Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Xiaohui Xin <xiaohui.xin@intel.com>
Signed-off-by: Arun Sharma <arun.sharma@intel.com>

tools/python/xen/web/connection.py

@@ -20,6 +20,7 @@ import sys
 import threading
 import select
 import socket
+import fcntl
 
 from errno import EAGAIN, EINTR, EWOULDBLOCK
 
@@ -152,6 +153,9 @@ class SocketListener:
     def createSocket(self):
         raise NotImplementedError()
 
+    def setCloExec(self):
+        fcntl.fcntl(self.sock.fileno(), fcntl.F_SETFD, fcntl.FD_CLOEXEC)
+
     def acceptConnection(self, sock, protocol, addr):
         return SocketServerConnection(sock, protocol, addr, self)
 

tools/python/xen/web/reactor.py

@@ -16,4 +16,4 @@
 #============================================================================
 
 from unix import listenUNIX, connectUNIX
-from tcp import listenTCP, connectTCP
+from tcp import listenTCP, connectTCP, SetCloExec

tools/python/xen/web/tcp.py

@@ -85,6 +85,9 @@ def listenTCP(port, factory, interface='', backlog=None):
     l.startListening()
     return l
 
+def SetCloExec(SocketListener):
+    SocketListener.SetCloExec()
+
 def connectTCP(host, port, factory, timeout=None, bindAddress=None):
     c = TCPConnector(host, port, factory, timeout=timeout, bindAddress=bindAddress)
     c.connect()

tools/python/xen/xend/XendDomainInfo.py

@@ -231,6 +231,7 @@ class XendDomainInfo:
         DBVar('restart_time',  ty='float'),
         DBVar('restart_count', ty='int'),
         DBVar('target',        ty='long', path="memory/target"),
+        DBVar('device_model_pid', ty='int'),
         ]
     
     def __init__(self, db):
@@ -275,6 +276,7 @@ class XendDomainInfo:
         self.vcpus = 1
         self.vcpusdb = {}
         self.bootloader = None
+        self.device_model_pid = 0
 
     def setDB(self, db):
         self.db = db
@@ -457,6 +459,8 @@ class XendDomainInfo:
             sxpr.append(devs)
         if self.config:
             sxpr.append(['config', self.config])
+        if self.device_model_pid:
+            sxpr.append(['device_model_pid',self.device_model_pid])
         return sxpr
 
     def sxpr_devices(self):
@@ -739,7 +743,8 @@ class XendDomainInfo:
                 ctrl.initController(reboot=True)
         else:
             self.create_configured_devices()
-        self.image.createDeviceModel()
+        if not self.device_model_pid:
+            self.device_model_pid = self.image.createDeviceModel()
 
     def device_create(self, dev_config):
         """Create a new device.

tools/python/xen/xend/image.py

@@ -262,7 +262,7 @@ class VmxImageHandler(ImageHandler):
     memmap = None
     memmap_value = []
     device_channel = None
-
+    pid = 0
     def createImage(self):
         """Create a VM for the VMX environment.
         """
@@ -369,6 +369,7 @@ class VmxImageHandler(ImageHandler):
         log.info("spawning device models: %s %s", device_model, args)
         self.pid = os.spawnve(os.P_NOWAIT, device_model, args, env)
         log.info("device model pid: %d", self.pid)
+        return self.pid
 
     def vncParams(self):
         # see if a vncviewer was specified
@@ -388,8 +389,11 @@ class VmxImageHandler(ImageHandler):
     def destroy(self):
         channel.eventChannelClose(self.device_channel)
         import signal
+        if not self.pid:
+            self.pid = self.vm.device_model_pid
         os.kill(self.pid, signal.SIGKILL)
         (pid, status) = os.waitpid(self.pid, 0)
+        self.pid = 0
 
     def getDomainMemory(self, mem_mb):
         return (mem_mb * 1024) + self.getPageTableSize(mem_mb)

tools/python/xen/xend/server/relocate.py

@@ -140,7 +140,8 @@ def listenRelocation():
     if xroot.get_xend_relocation_server():
         port = xroot.get_xend_relocation_port()
         interface = xroot.get_xend_relocation_address()
-        reactor.listenTCP(port, factory, interface=interface)
+        l = reactor.listenTCP(port, factory, interface=interface)
+        l.setCloExec()
 
 def setupRelocation(dst, port):
     try: