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-rw-r--r--nptl/pthread_cancel.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c
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+/* Copyright (C) 2002 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 <signal.h>
+#include "pthreadP.h"
+#include "atomic.h"
+
+
+int
+pthread_cancel (th)
+ pthread_t th;
+{
+ volatile struct pthread *pd = (volatile struct pthread *) th;
+
+ while (1)
+ {
+ int oldval = pd->cancelhandling;
+ int newval = oldval | CANCELED_BITMASK;
+
+ /* Avoid doing unnecessary work. The atomic operation can
+ potentially be expensive if the bug has to be locked and
+ remote cache lines have to be invalidated. */
+ if (oldval == newval)
+ break;
+
+ /* If the cancellation is handled asynchronously just send a
+ signal. We avoid this if possible since it's more
+ expensive. */
+ if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
+ {
+ /* The cancellation handler will take care of marking the
+ thread as canceled. */
+ pthread_kill (th, SIGCANCEL);
+
+ break;
+ }
+
+ /* Mark the thread as canceled. This has to be done
+ atomically since other bits could be modified as well. */
+ if (atomic_compare_and_exchange_acq (&pd->cancelhandling, newval,
+ oldval) == 0)
+ break;
+ }
+
+ return 0;
+}