mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-17 10:30:20 +00:00
105 lines
3.3 KiB
C
105 lines
3.3 KiB
C
/* Copyright (C) 2002, 2003, 2004 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 <signal.h>
|
|
#include "pthreadP.h"
|
|
#include "atomic.h"
|
|
#include <sysdep.h>
|
|
#include <kernel-features.h>
|
|
|
|
|
|
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)
|