1 files changed, 71 insertions, 0 deletions
diff --git a/lib/python2.7/test/test_fork1.py b/lib/python2.7/test/test_fork1.py
new file mode 100644
index 0000000..3930667
--- /dev/null
+++ b/lib/python2.7/test/test_fork1.py
@@ -0,0 +1,71 @@
+"""This test checks for correct fork() behavior.
+"""
+
+import imp
+import os
+import signal
+import sys
+import time
+
+from test.fork_wait import ForkWait
+from test.test_support import run_unittest, reap_children, get_attribute, import_module
+threading = import_module('threading')
+
+#Skip test if fork does not exist.
+get_attribute(os, 'fork')
+
+
+class ForkTest(ForkWait):
+    def wait_impl(self, cpid):
+        for i in range(10):
+            # waitpid() shouldn't hang, but some of the buildbots seem to hang
+            # in the forking tests.  This is an attempt to fix the problem.
+            spid, status = os.waitpid(cpid, os.WNOHANG)
+            if spid == cpid:
+                break
+            time.sleep(1.0)
+
+        self.assertEqual(spid, cpid)
+        self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
+
+    def test_import_lock_fork(self):
+        import_started = threading.Event()
+        fake_module_name = "fake test module"
+        partial_module = "partial"
+        complete_module = "complete"
+        def importer():
+            imp.acquire_lock()
+            sys.modules[fake_module_name] = partial_module
+            import_started.set()
+            time.sleep(0.01) # Give the other thread time to try and acquire.
+            sys.modules[fake_module_name] = complete_module
+            imp.release_lock()
+        t = threading.Thread(target=importer)
+        t.start()
+        import_started.wait()
+        pid = os.fork()
+        try:
+            if not pid:
+                m = __import__(fake_module_name)
+                if m == complete_module:
+                    os._exit(0)
+                else:
+                    os._exit(1)
+            else:
+                t.join()
+                # Exitcode 1 means the child got a partial module (bad.) No
+                # exitcode (but a hang, which manifests as 'got pid 0')
+                # means the child deadlocked (also bad.)
+                self.wait_impl(pid)
+        finally:
+            try:
+                os.kill(pid, signal.SIGKILL)
+            except OSError:
+                pass
+
+def test_main():
+    run_unittest(ForkTest)
+    reap_children()
+
+if __name__ == "__main__":
+    test_main()