summaryrefslogtreecommitdiff
path: root/libpthread/nptl/pthread_setcancelstate.c
diff options
context:
space:
mode:
Diffstat (limited to 'libpthread/nptl/pthread_setcancelstate.c')
-rw-r--r--libpthread/nptl/pthread_setcancelstate.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/libpthread/nptl/pthread_setcancelstate.c b/libpthread/nptl/pthread_setcancelstate.c
new file mode 100644
index 000000000..0da9a74f9
--- /dev/null
+++ b/libpthread/nptl/pthread_setcancelstate.c
@@ -0,0 +1,74 @@
+/* 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
+attribute_hidden
+__pthread_setcancelstate (
+ 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)