libpthread/nptl: core of the "Native Posix Threading Library" for uClibc

targetting arm,sh,i386,mips,sparc for now

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/libpthread/nptl/pthread_setcancelstate.c b/libpthread/nptl/pthread_setcancelstate.c
new file mode 100644
index 000000000..a452c2ec4
--- /dev/null
+++ b/libpthread/nptl/pthread_setcancelstate.c
@@ -0,0 +1,73 @@
+/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include "pthreadP.h"
+#include <atomic.h>
+
+
+int
+__pthread_setcancelstate (state, oldstate)
+     int state;
+     int *oldstate;
+{
+  volatile struct pthread *self;
+
+  if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE)
+    return EINVAL;
+
+  self = THREAD_SELF;
+
+  int oldval = THREAD_GETMEM (self, cancelhandling);
+  while (1)
+    {
+      int newval = (state == PTHREAD_CANCEL_DISABLE
+		    ? oldval | CANCELSTATE_BITMASK
+		    : oldval & ~CANCELSTATE_BITMASK);
+
+      /* Store the old value.  */
+      if (oldstate != NULL)
+	*oldstate = ((oldval & CANCELSTATE_BITMASK)
+		     ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
+
+      /* Avoid doing unnecessary work.  The atomic operation can
+	 potentially be expensive if the memory has to be locked and
+	 remote cache lines have to be invalidated.  */
+      if (oldval == newval)
+	break;
+
+      /* Update the cancel handling word.  This has to be done
+	 atomically since other bits could be modified as well.  */
+      int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
+					      oldval);
+      if (__builtin_expect (curval == oldval, 1))
+	{
+	  if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
+	    __do_cancel ();
+
+	  break;
+	}
+
+      /* Prepare for the next round.  */
+      oldval = curval;
+    }
+
+  return 0;
+}
+strong_alias (__pthread_setcancelstate, pthread_setcancelstate)