Fix allow_threads and EINTR handling (#7457)

* Fix allow_threads and EINTR handling

- Wrap Windows SemLock acquire wait with allow_threads
- Retry nanosleep on EINTR with remaining time instead of
  returning early
- Remove expectedFailure for test_sleep in _test_eintr.py

* Remove expectedFailureIfWindows for testHashComparisonOfMethods

Lib/test/_test_eintr.py

@@ -392,7 +392,6 @@ class SocketEINTRTest(EINTRBaseTest):
 class TimeEINTRTest(EINTRBaseTest):
     """ EINTR tests for the time module. """
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_sleep(self):
         t0 = time.monotonic()
         time.sleep(self.sleep_time)

Lib/test/test_class.py

@@ -614,7 +614,6 @@ class ClassTests(unittest.TestCase):
         with self.assertRaises(TypeError):
             a >= b
 
-    @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON; AssertionError: 1543448294720 != 1543448295392")
     def testHashComparisonOfMethods(self):
         # Test comparison and hash of methods
         class A:

crates/stdlib/src/multiprocessing.rs

@@ -193,7 +193,8 @@ mod _multiprocessing {
                     remaining.min(poll_ms)
                 };
 
-                let res = unsafe { WaitForSingleObjectEx(self.handle.as_raw(), wait_ms, 0) };
+                let handle = self.handle.as_raw();
+                let res = vm.allow_threads(|| unsafe { WaitForSingleObjectEx(handle, wait_ms, 0) });
 
                 match res {
                     WAIT_OBJECT_0 => {

crates/vm/src/stdlib/time.rs

@@ -115,17 +115,30 @@ mod decl {
 
         #[cfg(unix)]
         {
-            // this is basically std::thread::sleep, but that catches interrupts and we don't want to;
-            let ts = nix::sys::time::TimeSpec::from(dur);
-            // Capture errno inside the closure: attach_thread (called by
-            // allow_threads on return) can clobber errno via syscalls.
-            let (res, err) = vm.allow_threads(|| {
-                let r = unsafe { libc::nanosleep(ts.as_ref(), core::ptr::null_mut()) };
-                (r, nix::Error::last_raw())
-            });
-            let interrupted = res == -1 && err == libc::EINTR;
-
-            if interrupted {
+            // Loop on nanosleep, recomputing the
+            // remaining timeout after each EINTR so that signals don't
+            // shorten the requested sleep duration.
+            use std::time::Instant;
+            let deadline = Instant::now() + dur;
+            loop {
+                let remaining = deadline.saturating_duration_since(Instant::now());
+                if remaining.is_zero() {
+                    break;
+                }
+                let ts = nix::sys::time::TimeSpec::from(remaining);
+                let (res, err) = vm.allow_threads(|| {
+                    let r = unsafe { libc::nanosleep(ts.as_ref(), core::ptr::null_mut()) };
+                    (r, nix::Error::last_raw())
+                });
+                if res == 0 {
+                    break;
+                }
+                if err != libc::EINTR {
+                    return Err(
+                        vm.new_os_error(format!("nanosleep: {}", nix::Error::from_raw(err)))
+                    );
+                }
+                // EINTR: run signal handlers, then retry with remaining time
                 vm.check_signals()?;
             }
         }