diff options
author | Austin Foxley <austinf@cetoncorp.com> | 2009-10-17 12:26:24 -0700 |
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committer | Austin Foxley <austinf@cetoncorp.com> | 2009-10-17 12:26:24 -0700 |
commit | c68d0fa2d88fc2134a38d99e7e944828384a7671 (patch) | |
tree | 6596943bd1c77f18d6e49d4153ddd3f3d67b49f5 /libpthread/nptl/pthread_setcancelstate.c | |
parent | 9a03e98a3b418f33c347a6023e9320f3a42cb9e4 (diff) |
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>
Diffstat (limited to 'libpthread/nptl/pthread_setcancelstate.c')
-rw-r--r-- | libpthread/nptl/pthread_setcancelstate.c | 73 |
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) |