add argument for reliably checking the started X server is our own

pyvirtualdisplay/abstractdisplay.py

@@ -5,6 +5,8 @@
 import time
 import tempfile
 from threading import Lock
+import select
+import fcntl
 
 from pyvirtualdisplay import xauth
 
@@ -22,7 +24,7 @@
 MIN_DISPLAY_NR = 1000
 USED_DISPLAY_NR_LIST=[]
 
-X_START_TIMEOUT = 1
+X_START_TIMEOUT = 10
 X_START_TIME_STEP = 0.1
 X_START_WAIT = 0.1
 
@@ -34,7 +36,7 @@ class AbstractDisplay(EasyProcess):
     Common parent for Xvfb and Xephyr
     '''
 
-    def __init__(self, use_xauth=False):
+    def __init__(self, use_xauth=False, check_startup=False):
         mutex.acquire()
         try:
             self.display = self.search_for_display()
@@ -48,6 +50,15 @@ def __init__(self, use_xauth=False):
         self.use_xauth = use_xauth
         self._old_xauth = None
         self._xauth_filename = None
+        self.check_startup = check_startup
+        if self.check_startup:
+            rp, wp = os.pipe()
+            fcntl.fcntl(rp, fcntl.F_SETFD, fcntl.FD_CLOEXEC)
+            #to properly allow to inherit fds to subprocess on
+            #python 3.2+ the easyprocess needs small fix..
+            fcntl.fcntl(wp, fcntl.F_SETFD, 0)
+            self.check_startup_fd = wp
+            self._check_startup_fd = rp
         EasyProcess.__init__(self, self._cmd)
 
     @property
@@ -115,9 +126,25 @@ def start(self):
 
         # wait until X server is active
         start_time = time.time()
-        ok = False
+        if self.check_startup:
+            rp = self._check_startup_fd
+            display_check = None
+            rlist, wlist, xlist = select.select((rp,), (), (), X_START_TIMEOUT)
+            if rlist:
+                display_check = os.read(rp, 10).rstrip()
+            else:
+                msg = 'No display number returned by X server'
+                raise XStartTimeoutError(msg)
+            dnbs = str(self.display)
+            if bytes != str:
+                dnbs = bytes(dnbs, 'ascii')
+            if display_check != dnbs:
+                msg = 'Display number "%s" not returned by X server' + str(display_check)
+                raise XStartTimeoutError(msg % self.display)
+
         d = self.new_display_var
-        while time.time() - start_time < X_START_TIMEOUT:
+        ok = False
+        while True:
             try:
                 exit_code = EasyProcess('xdpyinfo').call().return_code
             except EasyProcessError:
@@ -133,6 +160,8 @@ def start(self):
                 ok = True
                 break
 
+            if time.time() - start_time >= X_START_TIMEOUT:
+                break
             time.sleep(X_START_TIME_STEP)
         if not ok:
             msg = 'Failed to start X on display "%s" (xdpyinfo check failed).'

pyvirtualdisplay/display.py

@@ -15,7 +15,7 @@ class Display(AbstractDisplay):
     :param backend: 'xvfb', 'xvnc' or 'xephyr', ignores ``visible``
     :param xauth: If a Xauthority file should be created.
     '''
-    def __init__(self, backend=None, visible=False, size=(1024, 768), color_depth=24, bgcolor='black', use_xauth=False, **kwargs):
+    def __init__(self, backend=None, visible=False, size=(1024, 768), color_depth=24, bgcolor='black', use_xauth=False, check_startup=False, **kwargs):
         self.color_depth = color_depth
         self.size = size
         self.bgcolor = bgcolor
@@ -36,7 +36,7 @@ def __init__(self, backend=None, visible=False, size=(1024, 768), color_depth=24
             color_depth=color_depth,
             bgcolor=bgcolor,
             **kwargs)
-        AbstractDisplay.__init__(self, use_xauth=use_xauth)
+        AbstractDisplay.__init__(self, use_xauth=use_xauth, check_startup=check_startup)
 
     @property
     def display_class(self):
@@ -56,4 +56,7 @@ def display_class(self):
     @property
     def _cmd(self):
         self._obj.display = self.display
+        self._obj.check_startup = self.check_startup
+        if self.check_startup:
+            self._obj.check_startup_fd = self.check_startup_fd
         return self._obj._cmd

pyvirtualdisplay/xephyr.py

@@ -38,4 +38,6 @@ def _cmd(self):
                '-resizeable',
                self.new_display_var,
                ]
+        if self.check_startup:
+            cmd += ['-displayfd', str(self.check_startup_fd)]
         return cmd

pyvirtualdisplay/xvfb.py

@@ -50,4 +50,6 @@ def _cmd(self):
                ]
         if self.fbdir:
             cmd += ['-fbdir', self.fbdir]
+        if self.check_startup:
+            cmd += ['-displayfd', str(self.check_startup_fd)]
         return [PROGRAM] + cmd

pyvirtualdisplay/xvnc.py

@@ -40,4 +40,6 @@ def _cmd(self):
                '-rfbport', str(self.rfbport),
                self.new_display_var,
                ]
+        if self.check_startup:
+            cmd += ['-displayfd', str(self.check_startup_fd)]
         return cmd