From 781822a646eb87f01ce47b98dea8fbc7dfc4d177 Mon Sep 17 00:00:00 2001
From: Corinna Vinschen <corinna@vinschen.de>
Date: Tue, 3 May 2011 15:58:52 +0000
Subject: [PATCH] 	* select.cc (cygwin_select): Make degenerate case
 cancelable. 	(select_stuff::destroy): New inline method to delete memory
 taken 	by select_stuff. 	(select_stuff::~select_stuff): Call destroy. 
 (select_stuff::wait): Add case to allow canceling select. 	* select.h
 (select_stuff::destroy): Declare. 	* thread.cc: Mark poll, pselect and
 poll as cancelable.

---
 winsup/cygwin/ChangeLog | 10 ++++++++++
 winsup/cygwin/select.cc | 44 ++++++++++++++++++++++++++++++++++-------
 winsup/cygwin/select.h  |  1 +
 winsup/cygwin/thread.cc |  6 +++---
 4 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 330bd8131..b348b12c8 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,13 @@
+2011-05-03  Corinna Vinschen  <corinna@vinschen.de>
+
+	* select.cc (cygwin_select): Make degenerate case cancelable.
+	(select_stuff::destroy): New inline method to delete memory taken
+	by select_stuff.
+	(select_stuff::~select_stuff): Call destroy.
+	(select_stuff::wait): Add case to allow canceling select.
+	* select.h (select_stuff::destroy): Declare.
+	* thread.cc: Mark poll, pselect and poll as cancelable.
+
 2011-05-03  Corinna Vinschen  <corinna@vinschen.de>
 
 	* fhandler.cc (fhandler_base_overlapped::wait_overlapped): Make
diff --git a/winsup/cygwin/select.cc b/winsup/cygwin/select.cc
index 6c093a06d..fd0281f50 100644
--- a/winsup/cygwin/select.cc
+++ b/winsup/cygwin/select.cc
@@ -133,11 +133,21 @@ cygwin_select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
   /* Degenerate case.  No fds to wait for.  Just wait. */
   if (sel.start.next == NULL)
     {
-      if (WaitForSingleObject (signal_arrived, ms) == WAIT_OBJECT_0)
+      HANDLE w4[2] = { signal_arrived, pthread::get_cancel_event () };
+      DWORD cnt = w4[1] ? 2 : 1;
+
+      switch (WaitForMultipleObjects (cnt, w4, FALSE, ms))
 	{
+	case WAIT_OBJECT_0:
 	  select_printf ("signal received");
 	  set_sig_errno (EINTR);
 	  return -1;
+	case WAIT_OBJECT_0 + 1:
+	  sel.destroy ();
+	  pthread::static_cancel_self ();
+	  /*NOTREACHED*/
+	default:
+	  break;
 	}
       timeout = 1;
     }
@@ -193,9 +203,9 @@ select_stuff::cleanup ()
 }
 
 /* Destroy all storage associated with select stuff. */
-select_stuff::~select_stuff ()
+inline void
+select_stuff::destroy ()
 {
-  cleanup ();
   select_record *s = &start;
   select_record *snext = start.next;
 
@@ -207,6 +217,12 @@ select_stuff::~select_stuff ()
     }
 }
 
+select_stuff::~select_stuff ()
+{
+  cleanup ();
+  destroy ();
+}
+
 /* Add a record to the select chain */
 bool
 select_stuff::test_and_set (int i, fd_set *readfds, fd_set *writefds,
@@ -254,8 +270,15 @@ select_stuff::wait (fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
   select_record *s = &start;
   int m = 0;
   int res = 0;
+  bool is_cancelable = false;
 
   w4[m++] = signal_arrived;  /* Always wait for the arrival of a signal. */
+  if ((w4[m] = pthread::get_cancel_event ()) != NULL)
+    {
+      ++m;
+      is_cancelable = true;
+    }
+
   /* Loop through the select chain, starting up anything appropriate and
      counting the number of active fds. */
   while ((s = s->next))
@@ -292,10 +315,9 @@ select_stuff::wait (fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 	   the problem that the call to PeekMessage disarms the queue state
 	   so that a subsequent MWFMO hangs, even if there are still messages
 	   in the queue. */
-	wait_ret =
-	  MsgWaitForMultipleObjectsEx (m, w4, ms,
-				       QS_ALLINPUT | QS_ALLPOSTMESSAGE,
-				       MWMO_INPUTAVAILABLE);
+	wait_ret = MsgWaitForMultipleObjectsEx (m, w4, ms,
+						QS_ALLINPUT | QS_ALLPOSTMESSAGE,
+						MWMO_INPUTAVAILABLE);
 
       switch (wait_ret)
       {
@@ -304,6 +326,14 @@ select_stuff::wait (fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 	  select_printf ("signal received");
 	  set_sig_errno (EINTR);
 	  return -1;
+	case WAIT_OBJECT_0 + 1:
+	  if (is_cancelable)
+	    {
+	      cleanup ();
+	      destroy ();
+	      pthread::static_cancel_self ();
+	    }
+	  break;
 	case WAIT_FAILED:
 	  cleanup ();
 	  system_printf ("WaitForMultipleObjects failed");
diff --git a/winsup/cygwin/select.h b/winsup/cygwin/select.h
index 8734b1e04..2f5434bc8 100644
--- a/winsup/cygwin/select.h
+++ b/winsup/cygwin/select.h
@@ -83,6 +83,7 @@ public:
   int poll (fd_set *readfds, fd_set *writefds, fd_set *exceptfds);
   int wait (fd_set *readfds, fd_set *writefds, fd_set *exceptfds, DWORD ms);
   void cleanup ();
+  void destroy ();
   select_stuff (): always_ready (0), windows_used (0), start (0),
 		   device_specific_pipe (0),
 		   device_specific_socket (0),
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index 0085320ad..a521773d8 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -597,9 +597,9 @@ pthread::cancel ()
     * open ()
     * openat ()
     * pause ()
-      poll ()
+    * poll ()
     * pread ()
-      pselect ()
+    * pselect ()
     * pthread_cond_timedwait ()
     * pthread_cond_wait ()
     * pthread_join ()
@@ -612,7 +612,7 @@ pthread::cancel ()
     * recv ()
     * recvfrom ()
     * recvmsg ()
-      select ()
+    * select ()
     * sem_timedwait ()
     * sem_wait ()
     * send ()