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-rw-r--r--libpthread/nptl/libc-cancellation.c116
1 files changed, 116 insertions, 0 deletions
diff --git a/libpthread/nptl/libc-cancellation.c b/libpthread/nptl/libc-cancellation.c
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+++ b/libpthread/nptl/libc-cancellation.c
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+/* 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 <setjmp.h>
+#include <stdlib.h>
+#include "pthreadP.h"
+#include "atomic.h"
+#include <bits/libc-lock.h>
+
+
+#ifndef NOT_IN_libc
+
+/* The next two functions are similar to pthread_setcanceltype() but
+ more specialized for the use in the cancelable functions like write().
+ They do not need to check parameters etc. */
+int
+attribute_hidden
+__libc_enable_asynccancel (void)
+{
+ struct pthread *self = THREAD_SELF;
+ int oldval = THREAD_GETMEM (self, cancelhandling);
+
+ while (1)
+ {
+ int newval = oldval | CANCELTYPE_BITMASK;
+
+ if (__builtin_expect ((oldval & CANCELED_BITMASK) != 0, 0))
+ {
+ /* If we are already exiting or if PTHREAD_CANCEL_DISABLED,
+ stop right here. */
+ if ((oldval & (EXITING_BITMASK | CANCELSTATE_BITMASK)) != 0)
+ break;
+
+ int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
+ newval, oldval);
+ if (__builtin_expect (curval != oldval, 0))
+ {
+ /* Somebody else modified the word, try again. */
+ oldval = curval;
+ continue;
+ }
+
+ THREAD_SETMEM (self, result, PTHREAD_CANCELED);
+
+ __do_cancel ();
+
+ /* NOTREACHED */
+ }
+
+ int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
+ oldval);
+ if (__builtin_expect (curval == oldval, 1))
+ break;
+
+ /* Prepare the next round. */
+ oldval = curval;
+ }
+
+ return oldval;
+}
+
+
+void
+internal_function attribute_hidden
+__libc_disable_asynccancel (int oldtype)
+{
+ /* If asynchronous cancellation was enabled before we do not have
+ anything to do. */
+ if (oldtype & CANCELTYPE_BITMASK)
+ return;
+
+ struct pthread *self = THREAD_SELF;
+ int oldval = THREAD_GETMEM (self, cancelhandling);
+
+ while (1)
+ {
+ int newval = oldval & ~CANCELTYPE_BITMASK;
+
+ if (newval == oldval)
+ break;
+
+ int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
+ oldval);
+ if (__builtin_expect (curval == oldval, 1))
+ break;
+
+ /* Prepare the next round. */
+ oldval = curval;
+ }
+}
+
+
+void
+__libc_cleanup_routine (struct __pthread_cleanup_frame *f)
+{
+ if (f->__do_it)
+ f->__cancel_routine (f->__cancel_arg);
+}
+
+#endif