bpo-33332: Add signal.valid_signals() (GH-6581)

6 files changed, 54 insertions, 6 deletions

diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py
index 6cac137..f64037a 100644
--- a/Lib/asyncio/unix_events.py
+++ b/Lib/asyncio/unix_events.py
@@ -167,8 +167,8 @@ class _UnixSelectorEventLoop(selector_events.BaseSelectorEventLoop):
         if not isinstance(sig, int):
             raise TypeError(f'sig must be an int, not {sig!r}')
 
-        if not (1 <= sig < signal.NSIG):
-            raise ValueError(f'sig {sig} out of range(1, {signal.NSIG})')
+        if sig not in signal.valid_signals():
+            raise ValueError(f'invalid signal number {sig}')
 
     def _make_read_pipe_transport(self, pipe, protocol, waiter=None,
                                   extra=None):
diff --git a/Lib/multiprocessing/resource_sharer.py b/Lib/multiprocessing/resource_sharer.py
index 6d99da1..730b2aa 100644
--- a/Lib/multiprocessing/resource_sharer.py
+++ b/Lib/multiprocessing/resource_sharer.py
@@ -136,7 +136,7 @@ class _ResourceSharer(object):
 
     def _serve(self):
         if hasattr(signal, 'pthread_sigmask'):
-            signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
+            signal.pthread_sigmask(signal.SIG_BLOCK, signal.valid_signals())
         while 1:
             try:
                 with self._listener.accept() as conn:
diff --git a/Lib/signal.py b/Lib/signal.py
index 9f05c91..826b62c 100644
--- a/Lib/signal.py
+++ b/Lib/signal.py
@@ -65,8 +65,7 @@ if 'pthread_sigmask' in _globals:
 if 'sigpending' in _globals:
     @_wraps(_signal.sigpending)
     def sigpending():
-        sigs = _signal.sigpending()
-        return set(_int_to_enum(x, Signals) for x in sigs)
+        return {_int_to_enum(x, Signals) for x in _signal.sigpending()}
 
 
 if 'sigwait' in _globals:
@@ -76,4 +75,11 @@ if 'sigwait' in _globals:
         return _int_to_enum(retsig, Signals)
     sigwait.__doc__ = _signal.sigwait
 
+
+if 'valid_signals' in _globals:
+    @_wraps(_signal.valid_signals)
+    def valid_signals():
+        return {_int_to_enum(x, Signals) for x in _signal.valid_signals()}
+
+
 del _globals, _wraps
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index a5f86d4..f1c4c95 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2810,7 +2810,7 @@ class SaveSignals:
     def __init__(self):
         import signal
         self.signal = signal
-        self.signals = list(range(1, signal.NSIG))
+        self.signals = signal.valid_signals()
         # SIGKILL and SIGSTOP signals cannot be ignored nor caught
         for signame in ('SIGKILL', 'SIGSTOP'):
             try:
diff --git a/Lib/test/test_asyncio/test_unix_events.py b/Lib/test/test_asyncio/test_unix_events.py
index 104f995..a01efed 100644
--- a/Lib/test/test_asyncio/test_unix_events.py
+++ b/Lib/test/test_asyncio/test_unix_events.py
@@ -69,6 +69,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_add_signal_handler_setup_error(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
         m_signal.set_wakeup_fd.side_effect = ValueError
 
         self.assertRaises(
@@ -96,6 +97,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_add_signal_handler(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
 
         cb = lambda: True
         self.loop.add_signal_handler(signal.SIGHUP, cb)
@@ -106,6 +108,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_add_signal_handler_install_error(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
 
         def set_wakeup_fd(fd):
             if fd == -1:
@@ -125,6 +128,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.base_events.logger')
     def test_add_signal_handler_install_error2(self, m_logging, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
 
         class Err(OSError):
             errno = errno.EINVAL
@@ -145,6 +149,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
             errno = errno.EINVAL
         m_signal.signal.side_effect = Err
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
 
         self.assertRaises(
             RuntimeError,
@@ -156,6 +161,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_remove_signal_handler(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
 
         self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
 
@@ -170,6 +176,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     def test_remove_signal_handler_2(self, m_signal):
         m_signal.NSIG = signal.NSIG
         m_signal.SIGINT = signal.SIGINT
+        m_signal.valid_signals = signal.valid_signals
 
         self.loop.add_signal_handler(signal.SIGINT, lambda: True)
         self.loop._signal_handlers[signal.SIGHUP] = object()
@@ -187,6 +194,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.base_events.logger')
     def test_remove_signal_handler_cleanup_error(self, m_logging, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
         self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
 
         m_signal.set_wakeup_fd.side_effect = ValueError
@@ -197,6 +205,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_remove_signal_handler_error(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
         self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
 
         m_signal.signal.side_effect = OSError
@@ -207,6 +216,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_remove_signal_handler_error2(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
         self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
 
         class Err(OSError):
@@ -219,6 +229,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_close(self, m_signal):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
 
         self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
         self.loop.add_signal_handler(signal.SIGCHLD, lambda: True)
@@ -236,6 +247,7 @@ class SelectorEventLoopSignalTests(test_utils.TestCase):
     @mock.patch('asyncio.unix_events.signal')
     def test_close_on_finalizing(self, m_signal, m_sys):
         m_signal.NSIG = signal.NSIG
+        m_signal.valid_signals = signal.valid_signals
         self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
 
         self.assertEqual(len(self.loop._signal_handlers), 1)
diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py
index 7635eec..7ce89f6 100644
--- a/Lib/test/test_signal.py
+++ b/Lib/test/test_signal.py
@@ -67,9 +67,28 @@ class PosixTests(unittest.TestCase):
         script = os.path.join(dirname, 'signalinterproctester.py')
         assert_python_ok(script)
 
+    def test_valid_signals(self):
+        s = signal.valid_signals()
+        self.assertIsInstance(s, set)
+        self.assertIn(signal.Signals.SIGINT, s)
+        self.assertIn(signal.Signals.SIGALRM, s)
+        self.assertNotIn(0, s)
+        self.assertNotIn(signal.NSIG, s)
+        self.assertLess(len(s), signal.NSIG)
+
 
 @unittest.skipUnless(sys.platform == "win32", "Windows specific")
 class WindowsSignalTests(unittest.TestCase):
+
+    def test_valid_signals(self):
+        s = signal.valid_signals()
+        self.assertIsInstance(s, set)
+        self.assertGreaterEqual(len(s), 6)
+        self.assertIn(signal.Signals.SIGINT, s)
+        self.assertNotIn(0, s)
+        self.assertNotIn(signal.NSIG, s)
+        self.assertLess(len(s), signal.NSIG)
+
     def test_issue9324(self):
         # Updated for issue #10003, adding SIGBREAK
         handler = lambda x, y: None
@@ -922,6 +941,17 @@ class PendingSignalsTests(unittest.TestCase):
         self.assertRaises(TypeError, signal.pthread_sigmask, 1)
         self.assertRaises(TypeError, signal.pthread_sigmask, 1, 2, 3)
         self.assertRaises(OSError, signal.pthread_sigmask, 1700, [])
+        with self.assertRaises(ValueError):
+            signal.pthread_sigmask(signal.SIG_BLOCK, [signal.NSIG])
+
+    @unittest.skipUnless(hasattr(signal, 'pthread_sigmask'),
+                         'need signal.pthread_sigmask()')
+    def test_pthread_sigmask_valid_signals(self):
+        s = signal.pthread_sigmask(signal.SIG_BLOCK, signal.valid_signals())
+        self.addCleanup(signal.pthread_sigmask, signal.SIG_SETMASK, s)
+        # Get current blocked set
+        s = signal.pthread_sigmask(signal.SIG_UNBLOCK, signal.valid_signals())
+        self.assertLessEqual(s, signal.valid_signals())
 
     @unittest.skipUnless(hasattr(signal, 'pthread_sigmask'),
                          'need signal.pthread_sigmask()')