# HG changeset patch
# Parent  96c88daac37a43a51dce51da14686265ffc1c904
Issue #25868: Block SIGUSR1 in attempt to fix test_eintr hang

Posix says that sigwait(), and therefore sigwaitinfo(), is undefined unless
the signal in question is blocked. Blocking the signal should avoid a few
race conditions that may have been triggering an occasional hang on Free BSD.

Also added a counter to the SIGALRM handler to verify that it is being called
by Python's sigwaitinfo() implementation, and removed the previous pipe
workaround.

diff -r 96c88daac37a Lib/test/eintrdata/eintr_tester.py
--- a/Lib/test/eintrdata/eintr_tester.py	Wed Jan 27 11:52:13 2016 -0500
+++ b/Lib/test/eintrdata/eintr_tester.py	Fri Jan 29 03:25:45 2016 +0000
@@ -47,7 +47,8 @@
 
     @classmethod
     def setUpClass(cls):
-        cls.orig_handler = signal.signal(signal.SIGALRM, lambda *args: None)
+        cls.count = 0
+        cls.orig_handler = signal.signal(signal.SIGALRM, cls.handler)
         signal.setitimer(signal.ITIMER_REAL, cls.signal_delay,
                          cls.signal_period)
 
@@ -56,6 +57,10 @@
             faulthandler.dump_traceback_later(10 * 60, exit=True)
 
     @classmethod
+    def handler(cls, *args):
+        cls.count += 1
+
+    @classmethod
     def stop_alarm(cls):
         signal.setitimer(signal.ITIMER_REAL, 0, 0)
 
@@ -379,45 +384,37 @@
     @unittest.skipUnless(hasattr(signal, 'sigwaitinfo'),
                          'need signal.sigwaitinfo()')
     def test_sigwaitinfo(self):
-        # Issue #25277, #25868: give a few miliseconds to the parent process
-        # between os.write() and signal.sigwaitinfo() to works around a race
-        # condition
-        self.sleep_time = 0.100
-
         signum = signal.SIGUSR1
         pid = os.getpid()
 
         old_handler = signal.signal(signum, lambda *args: None)
         self.addCleanup(signal.signal, signum, old_handler)
 
-        rpipe, wpipe = os.pipe()
-
         code = '\n'.join((
             'import os, time',
             'pid = %s' % os.getpid(),
             'signum = %s' % int(signum),
             'sleep_time = %r' % self.sleep_time,
-            'rpipe = %r' % rpipe,
-            'os.read(rpipe, 1)',
-            'os.close(rpipe)',
             'time.sleep(sleep_time)',
             'os.kill(pid, signum)',
         ))
 
-        t0 = time.monotonic()
-        proc = self.subprocess(code, pass_fds=(rpipe,))
-        os.close(rpipe)
-        with kill_on_error(proc):
-            # sync child-parent
-            os.write(wpipe, b'x')
-            os.close(wpipe)
-
-            # parent
-            signal.sigwaitinfo([signum])
-            dt = time.monotonic() - t0
-            self.assertEqual(proc.wait(), 0)
+        old_mask = signal.pthread_sigmask(signal.SIG_BLOCK, {signum})
+        try:
+            t0 = time.monotonic()
+            proc = self.subprocess(code)
+            with kill_on_error(proc):
+                # parent
+                type(self).count = 0
+                signal.sigwaitinfo([signum])
+                dt = time.monotonic() - t0
+                interrupts = self.count
+                self.assertEqual(proc.wait(), 0)
+        finally:
+            signal.pthread_sigmask(signal.SIG_SETMASK, old_mask)
 
         self.assertGreaterEqual(dt, self.sleep_time)
+        self.assertGreaterEqual(interrupts, 1)
 
 
 @unittest.skipUnless(hasattr(signal, "setitimer"), "requires setitimer()")