From 0b3366f6a93ac0f7e2028745ea557c0acd8722c6 Mon Sep 17 00:00:00 2001 From: "\"Steven J. Hill\"" Date: Sat, 7 May 2005 02:04:55 +0000 Subject: Import in NPTL code from glibc. For further information please consult the 'README.NPTL' file. --- libpthread/nptl/pthread_cancel.c | 104 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 libpthread/nptl/pthread_cancel.c (limited to 'libpthread/nptl/pthread_cancel.c') diff --git a/libpthread/nptl/pthread_cancel.c b/libpthread/nptl/pthread_cancel.c new file mode 100644 index 000000000..a13af56b3 --- /dev/null +++ b/libpthread/nptl/pthread_cancel.c @@ -0,0 +1,104 @@ +/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 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 +#include +#include "pthreadP.h" +#include "atomic.h" +#include +#include + + +int +pthread_cancel (th) + pthread_t th; +{ + volatile struct pthread *pd = (volatile struct pthread *) th; + + /* Make sure the descriptor is valid. */ + if (INVALID_TD_P (pd)) + /* Not a valid thread handle. */ + return ESRCH; + +#ifdef SHARED + pthread_cancel_init (); +#endif + int result = 0; + int oldval; + int newval; + do + { + oldval = pd->cancelhandling; + newval = oldval | CANCELING_BITMASK | 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)) + { + /* Mark the cancellation as "in progress". */ + atomic_bit_set (&pd->cancelhandling, CANCELING_BIT); + + /* The cancellation handler will take care of marking the + thread as canceled. */ + INTERNAL_SYSCALL_DECL (err); + + /* One comment: The PID field in the TCB can temporarily be + changed (in fork). But this must not affect this code + here. Since this function would have to be called while + the thread is executing fork, it would have to happen in + a signal handler. But this is no allowed, pthread_cancel + is not guaranteed to be async-safe. */ + int val; +#if __ASSUME_TGKILL + val = INTERNAL_SYSCALL (tgkill, err, 3, + THREAD_GETMEM (THREAD_SELF, pid), pd->tid, + SIGCANCEL); +#else +# ifdef __NR_tgkill + val = INTERNAL_SYSCALL (tgkill, err, 3, + THREAD_GETMEM (THREAD_SELF, pid), pd->tid, + SIGCANCEL); + if (INTERNAL_SYSCALL_ERROR_P (val, err) + && INTERNAL_SYSCALL_ERRNO (val, err) == ENOSYS) +# endif + val = INTERNAL_SYSCALL (tkill, err, 2, pd->tid, SIGCANCEL); +#endif + + if (INTERNAL_SYSCALL_ERROR_P (val, err)) + result = INTERNAL_SYSCALL_ERRNO (val, err); + + break; + } + } + /* Mark the thread as canceled. This has to be done + atomically since other bits could be modified as well. */ + while (atomic_compare_and_exchange_bool_acq (&pd->cancelhandling, newval, + oldval)); + + return result; +} + +PTHREAD_STATIC_FN_REQUIRE (pthread_create) -- cgit v1.2.3