From 4ee52924a61bdb2fd8ce7b64d111cf7df4d19fe3 Mon Sep 17 00:00:00 2001
From: Christopher Faylor <me@cgf.cx>
Date: Thu, 23 Dec 2004 14:57:08 +0000
Subject: * cygthread.cc (cygthread::stub): Detect if thread function wants to
 release itself here, to avoid a race. (cygthread::release): Clear more stuff.
  Add a diagnostic for an internal error. * cygthread.h (auto_release): New
 function. * pinfo.h (pinfo::remember): Add an argument to denote whether
 child is detached. * fork.cc (fork_parent): Reflect change in arguments to
 pinfo::remember. * pinfo.cc (_pinfo::exit): Signal exit more forcibly.
 (proc_waiter): Use cygthread::auto_release to signify that cygthread::stub
 should release the thread.  This should avoid a race. (pinfo::alert_parent):
 Don't signify an error when wr_proc_pipe == NULL. * sigproc.cc
 (proc_subproc): Add support for PROC_DETACHED_CHILD. * sigproc.h: Ditto. *
 spawn.cc (spawn_guts): Specify whether child is detached or not when calling
 pinfo::remember.

---
 winsup/cygwin/cygthread.cc | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

(limited to 'winsup/cygwin/cygthread.cc')

diff --git a/winsup/cygwin/cygthread.cc b/winsup/cygwin/cygthread.cc
index 949f4716c..bca2b28f8 100644
--- a/winsup/cygwin/cygthread.cc
+++ b/winsup/cygwin/cygthread.cc
@@ -69,13 +69,21 @@ cygthread::stub (VOID *arg)
 	  info->func (info->arg == cygself ? info : info->arg);
 	  /* ...so the above should always return */
 
+	  /* If stack_ptr is NULL, the above function has set that to indicate
+	     that it doesn't want to alert anyone with a SetEvent and should
+	     just be marked as no longer inuse.  Hopefully the function knows
+	     that it is doing.  */
+	  if (!info->func)
+	    info->release (false);
+	  else
+	    {
 #ifdef DEBUGGING
-	  info->func = NULL;	// catch erroneous activation
-	  info->__oldname = info->__name;
+	      info->func = NULL;	// catch erroneous activation
+	      info->__oldname = info->__name;
 #endif
-	  info->__name = NULL;
-	  if (info->inuse)
-	    SetEvent (info->ev);
+	      info->__name = NULL;
+	      SetEvent (info->ev);
+	    }
 	}
       switch (WaitForSingleObject (info->thread_sync, INFINITE))
 	{
@@ -231,7 +239,13 @@ cygthread::release (bool nuke_h)
   __oldname = __name;
   __name = NULL;
   stack_ptr = NULL;
-  (void) InterlockedExchange (&inuse, 0); /* No longer in use */
+  func = NULL;
+  if (!InterlockedExchange (&inuse, 0))
+#ifdef DEBUGGING
+    api_fatal ("released a thread that was not inuse");
+#else
+    system_printf ("released a thread that was not inuse");
+#endif
 }
 
 /* Forcibly terminate a thread. */
-- 
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