webkitpy: Override TEMPDIR for Xvfb.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/linux.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 139 matching lines @@
         assert dummy_home != self._original_home
         self._filesystem.rmtree(dummy_home)
         self.host.environ['HOME'] = self._original_home
 
     def _start_xvfb(self):
         display = self._find_display()
         if not display:
             _log.warn('Failed to find a free display to start Xvfb.')
             return
 
-        _log.info('Starting Xvfb with display "%s".', display)
+        # Parts of Xvfb use a hard-coded "/tmp" for its temporary directory.
+        # This can cause a failure when those parts expect to hardlink against
+        # files that were created in "TEMPDIR" / "TMPDIR".
+        #
+        # See: https://crbug.com/715848
+        env = self.host.environ.copy()
+        if env.get('TMPDIR') and env['TMPDIR'] != '/tmp':
+            _log.info('Overriding TMPDIR to "/tmp" for Xvfb, was: %s', env['TMPDIR'])
+            env['TMPDIR'] = '/tmp'
+
+        _log.debug('Starting Xvfb with display "%s".', display)
         self._xvfb_stdout = tempfile.NamedTemporaryFile(delete=False)
         self._xvfb_stderr = tempfile.NamedTemporaryFile(delete=False)
         self._xvfb_process = self.host.executive.popen(
             ['Xvfb', display, '-screen', '0', '1280x800x24', '-ac', '-dpi', '96'],
-            stdout=self._xvfb_stdout, stderr=self._xvfb_stderr)
+            stdout=self._xvfb_stdout, stderr=self._xvfb_stderr, env=env)
 
         # By setting DISPLAY here, the individual worker processes will
         # get the right DISPLAY. Note, if this environment could be passed
         # when creating workers, then we wouldn't need to modify DISPLAY here.
         self._original_display = self.host.environ.get('DISPLAY')
         self.host.environ['DISPLAY'] = display
 
         # The poll() method will return None if the process has not terminated:
         # https://docs.python.org/2/library/subprocess.html#subprocess.Popen.poll
         if self._xvfb_process.poll() is not None:
@@ skipping 42 matching lines @@
             self.host.filesystem.remove(self._xvfb_stdout.name)
         if self._xvfb_stderr and self.host.filesystem.exists(self._xvfb_stderr.name):
             for line in self.host.filesystem.read_text_file(self._xvfb_stderr.name).splitlines():
                 _log.warn('Xvfb stderr:  %s', line)
             self.host.filesystem.remove(self._xvfb_stderr.name)
         self._xvfb_stdout = self._xvfb_stderr = self._xvfb_process = None
 
     def _path_to_driver(self, target=None):
         binary_name = self.driver_name()
         return self._build_path_with_target(target, binary_name)