qemurunner: more cleanups for output blocking

If we are only tracking stdout and are not using self.readsock we end
up throwing an exception blocking further action from the thread. Fix
this by checking self.readsock is not None first.

While we are at it split even into fd, event to make things clearer
and handle the fail path of stringify_event by echoing the hex value
of the unknown flag.

(From OE-Core rev: 5e58737c66090fe009ec49296f3e7d687eb05766)

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Mikko Rapeli <mikko.rapeli@linaro.org>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/utils/qemurunner.py

@@ -785,19 +785,20 @@ def eventloop(self):
         self.logger.debug("Starting thread event loop")
         while not breakout:
             events = poll.poll(2)
-            for event in events:
+            for fd, event in events:
+
                 # An error occurred, bail out
-                if event[1] & self.errorevents:
-                    raise Exception(self.stringify_event(event[1]))
+                if event & self.errorevents:
+                    raise Exception(self.stringify_event(event))
 
                 # Event to stop the thread
-                if self.readpipe == event[0]:
+                if self.readpipe == fd:
                     self.logger.debug("Stop event received")
                     breakout = True
                     break
 
                 # A connection request was received
-                elif self.serversock and self.serversock.fileno() == event[0]:
+                elif self.serversock and self.serversock.fileno() == fd:
                     self.logger.debug("Connection request received")
                     self.readsock, _ = self.serversock.accept()
                     self.readsock.setblocking(0)
@@ -808,14 +809,14 @@ def eventloop(self):
                     self.connection_established.set()
 
                 # Actual data to be logged
-                elif self.readsock.fileno() == event[0]:
+                elif self.readsock and self.readsock.fileno() == fd:
                     data = self.recv(1024, self.readsock)
                     self.logfunc(data)
-                elif self.qemuoutput.fileno() == event[0]:
+                elif self.qemuoutput.fileno() == fd:
                     data = self.qemuoutput.read()
                     self.logger.debug("Data received on qemu stdout %s" % data)
                     self.logfunc(data, ".stdout")
-                elif self.serialsock and self.serialsock.fileno() == event[0]:
+                elif self.serialsock and self.serialsock.fileno() == fd:
                     if self.serial_lock.acquire(blocking=False):
                         data = self.recv(1024, self.serialsock)
                         self.logger.debug("Data received serial thread %s" % data.decode('utf-8', 'replace'))
@@ -864,6 +865,9 @@ def stringify_event(self, event):
             val = 'POLLHUP'
         elif select.POLLNVAL == event:
             val = 'POLLNVAL'
+        else:
+            val = "0x%x" % (event)
+
         return val
 
     def close_socket(self, sock):