[newlib-cygwin] Cygwin: FIFO: hit_eof: add a call to fifo_client_lock

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=528169992668a7e292b8c1c5a39e2c1e24ff6683

commit 528169992668a7e292b8c1c5a39e2c1e24ff6683
Author: Ken Brown <kbrown@cornell.edu>
Date:   Sun Apr 14 19:15:56 2019 +0000

    Cygwin: FIFO: hit_eof: add a call to fifo_client_lock
    
    The second check of nconnected needs to be protected by a lock as well
    as the first.

Diff:
---
 winsup/cygwin/fhandler_fifo.cc | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc
index 9016964..70551eb 100644
--- a/winsup/cygwin/fhandler_fifo.cc
+++ b/winsup/cygwin/fhandler_fifo.cc
@@ -705,15 +705,20 @@ fhandler_fifo::raw_write (const void *ptr, size_t len)
 bool
 fhandler_fifo::hit_eof ()
 {
-  fifo_client_lock ();
-  bool eof = (nconnected == 0);
-  fifo_client_unlock ();
-  if (eof)
-    {
-      /* Give the listen_client thread time to catch up, then recheck. */
-      Sleep (1);
+  bool eof;
+  bool retry = true;
+
+retry:
+      fifo_client_lock ();
       eof = (nconnected == 0);
-    }
+      fifo_client_unlock ();
+      if (eof && retry)
+	{
+	  retry = false;
+	  /* Give the listen_client thread time to catch up. */
+	  Sleep (1);
+	  goto retry;
+	}
   return eof;
 }