Cygwin: FIFO: fix the use of the read_ready event

Make read_ready a manual reset event.  It should always be set shortly
after startup of the listen_client thread and remain set until the
thread terminates.  (We don't want writers to connect without being
recorded in the client handler list.)

Remove the unnecessary code that checks for read_ready when a reader
is opening.

1 files changed, 16 insertions, 35 deletions

diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc
index f9796f300..479021e8e 100644
--- a/winsup/cygwin/fhandler_fifo.cc
+++ b/winsup/cygwin/fhandler_fifo.cc
@@ -344,6 +344,8 @@ fhandler_fifo::listen_client ()
 DWORD
 fhandler_fifo::listen_client_thread ()
 {
+  DWORD ret = -1;
+
   while (1)
     {
       bool found;
@@ -360,7 +362,7 @@ fhandler_fifo::listen_client_thread ()
 	    if (disconnect_and_reconnect (i) < 0)
 	      {
 		fifo_client_unlock ();
-		goto errout;
+		goto out;
 	      }
 	    else
 	      /* Recheck fc_handler[i].state. */
@@ -383,23 +385,27 @@ fhandler_fifo::listen_client_thread ()
 	res = add_client_handler ();
       fifo_client_unlock ();
       if (res < 0)
-	goto errout;
+	goto out;
       else if (!found)
 	continue;
 
+      /* Allow a writer to open. */
       if (!arm (read_ready))
 	{
 	  __seterrno ();
-	  goto errout;
+	  goto out;
 	}
 
       /* Wait for a client to connect. */
       wait_ret = WaitForMultipleObjects (nhandlers + 1, w, false, INFINITE);
       i = wait_ret - WAIT_OBJECT_0;
       if (i < 0 || i > nhandlers)
-	goto errout;
-      else if (i == nhandlers)	/* Reader is closing. */
-	return 0;
+	goto out;
+      else if (i == nhandlers)	/* Thread termination requested. */
+	{
+	  ret = 0;
+	  goto out;
+	}
       else
 	{
 	  fifo_client_lock ();
@@ -410,9 +416,9 @@ fhandler_fifo::listen_client_thread ()
 	  yield ();
 	}
     }
-errout:
+out:
   ResetEvent (read_ready);
-  return -1;
+  return ret;
 }
 
 int
@@ -457,7 +463,7 @@ fhandler_fifo::open (int flags, mode_t)
 
   char npbuf[MAX_PATH];
   __small_sprintf (npbuf, "r-event.%08x.%016X", get_dev (), get_ino ());
-  if (!(read_ready = CreateEvent (sa_buf, duplexer, false, npbuf)))
+  if (!(read_ready = CreateEvent (sa_buf, true, false, npbuf)))
     {
       debug_printf ("CreateEvent for %s failed, %E", npbuf);
       res = error_set_errno;
@@ -523,32 +529,7 @@ fhandler_fifo::open (int flags, mode_t)
 	  res = error_errno_set;
 	  goto out;
 	}
-      /* Wait for the listen_client thread to signal read_ready.  This
-	 should be quick.  */
-      HANDLE w[2] = { listen_client_thr, read_ready };
-      switch (WaitForMultipleObjects (2, w, FALSE, INFINITE))
-	{
-	case WAIT_OBJECT_0:
-	  debug_printf ("listen_client_thread exited unexpectedly");
-	  DWORD err;
-	  GetExitCodeThread (listen_client_thr, &err);
-	  __seterrno_from_win_error (err);
-	  res = error_errno_set;
-	  goto out;
-	  break;
-	case WAIT_OBJECT_0 + 1:
-	  if (!arm (read_ready))
-	    {
-	      res = error_set_errno;
-	      goto out;
-	    }
-	  break;
-	default:
-	  res = error_set_errno;
-	  goto out;
-	  break;
-	}
-      if (!duplexer && !wait (write_ready))
+      else if (!duplexer && !wait (write_ready))
 	{
 	  res = error_errno_set;
 	  goto out;