[PATCH] Cygwin: FIFO: avoid hang after exec

[Ken Brown <kbrown at cornell dot edu>]

Define fhandler:fifo::fixup_after_exec, which sets listen_client_thr
and lct_termination_evt to NULL.  This forces the listen_client thread
to restart on the first attempt to read after an exec.  Previously the
exec'd process could hang in fhandler_fifo::raw_read.
---
 winsup/cygwin/fhandler.h       | 1 +
 winsup/cygwin/fhandler_fifo.cc | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index 8fb176b24..da007ee45 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -1301,6 +1301,7 @@ public:
   ssize_t __reg3 raw_write (const void *ptr, size_t ulen);
   bool arm (HANDLE h);
   void fixup_after_fork (HANDLE);
+  void fixup_after_exec ();
   int __reg2 fstatvfs (struct statvfs *buf);
   void clear_readahead ()
   {
diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc
index 1d02adbaa..bc9c23998 100644
--- a/winsup/cygwin/fhandler_fifo.cc
+++ b/winsup/cygwin/fhandler_fifo.cc
@@ -942,6 +942,15 @@ fhandler_fifo::fixup_after_fork (HANDLE parent)
   fifo_client_unlock ();
 }
 
+void
+fhandler_fifo::fixup_after_exec ()
+{
+  fhandler_base::fixup_after_exec ();
+  listen_client_thr = NULL;
+  lct_termination_evt = NULL;
+  fifo_client_unlock ();
+}
+
 void
 fhandler_fifo::set_close_on_exec (bool val)
 {
-- 
2.17.0