gh-84570: Send-Wait Fixes for _xxinterpchannels (gh-111006)

There were a few things I did in gh-110565 that need to be fixed. I also forgot to add tests in that PR.

(Note that this PR exposes a refleak introduced by gh-110246. I'll take care of that separately.)

1 files changed, 50 insertions, 0 deletions

diff --git a/Python/thread.c b/Python/thread.c
index bf207ce..7185dd4 100644
--- a/Python/thread.c
+++ b/Python/thread.c
@@ -6,6 +6,7 @@
    Stuff shared by all thread_*.h files is collected here. */
 
 #include "Python.h"
+#include "pycore_ceval.h"         // _PyEval_MakePendingCalls()
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_structseq.h"     // _PyStructSequence_FiniBuiltin()
 #include "pycore_pythread.h"      // _POSIX_THREADS
@@ -92,6 +93,55 @@ PyThread_set_stacksize(size_t size)
 }
 
 
+PyLockStatus
+PyThread_acquire_lock_timed_with_retries(PyThread_type_lock lock,
+                                         PY_TIMEOUT_T timeout)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    _PyTime_t endtime = 0;
+    if (timeout > 0) {
+        endtime = _PyDeadline_Init(timeout);
+    }
+
+    PyLockStatus r;
+    do {
+        _PyTime_t microseconds;
+        microseconds = _PyTime_AsMicroseconds(timeout, _PyTime_ROUND_CEILING);
+
+        /* first a simple non-blocking try without releasing the GIL */
+        r = PyThread_acquire_lock_timed(lock, 0, 0);
+        if (r == PY_LOCK_FAILURE && microseconds != 0) {
+            Py_BEGIN_ALLOW_THREADS
+            r = PyThread_acquire_lock_timed(lock, microseconds, 1);
+            Py_END_ALLOW_THREADS
+        }
+
+        if (r == PY_LOCK_INTR) {
+            /* Run signal handlers if we were interrupted.  Propagate
+             * exceptions from signal handlers, such as KeyboardInterrupt, by
+             * passing up PY_LOCK_INTR.  */
+            if (_PyEval_MakePendingCalls(tstate) < 0) {
+                return PY_LOCK_INTR;
+            }
+
+            /* If we're using a timeout, recompute the timeout after processing
+             * signals, since those can take time.  */
+            if (timeout > 0) {
+                timeout = _PyDeadline_Get(endtime);
+
+                /* Check for negative values, since those mean block forever.
+                 */
+                if (timeout < 0) {
+                    r = PY_LOCK_FAILURE;
+                }
+            }
+        }
+    } while (r == PY_LOCK_INTR);  /* Retry if we were interrupted. */
+
+    return r;
+}
+
+
 /* Thread Specific Storage (TSS) API
 
    Cross-platform components of TSS API implementation.