92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
/* Copyright (C) 2002-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <setjmp.h>
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#include <stdlib.h>
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#include "pthreadP.h"
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#include <futex-internal.h>
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/* The next two functions are similar to pthread_setcanceltype() but
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more specialized for the use in the cancelable functions like write().
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They do not need to check parameters etc. These functions must be
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AS-safe, with the exception of the actual cancellation, because they
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are called by wrappers around AS-safe functions like write().*/
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int
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__pthread_enable_asynccancel (void)
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{
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struct pthread *self = THREAD_SELF;
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int oldval = atomic_load_relaxed (&self->cancelhandling);
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while (1)
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{
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int newval = oldval | CANCELTYPE_BITMASK;
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if (newval == oldval)
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break;
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if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
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&oldval, newval))
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{
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if (cancel_enabled_and_canceled_and_async (newval))
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{
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self->result = PTHREAD_CANCELED;
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__do_cancel ();
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}
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break;
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}
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}
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return oldval;
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}
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libc_hidden_def (__pthread_enable_asynccancel)
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/* See the comment for __pthread_enable_asynccancel regarding
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the AS-safety of this function. */
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void
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__pthread_disable_asynccancel (int oldtype)
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{
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/* If asynchronous cancellation was enabled before we do not have
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anything to do. */
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if (oldtype & CANCELTYPE_BITMASK)
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return;
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struct pthread *self = THREAD_SELF;
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int newval;
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int oldval = atomic_load_relaxed (&self->cancelhandling);
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do
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{
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newval = oldval & ~CANCELTYPE_BITMASK;
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}
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while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
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&oldval, newval));
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/* We cannot return when we are being canceled. Upon return the
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thread might be things which would have to be undone. The
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following loop should loop until the cancellation signal is
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delivered. */
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while (__glibc_unlikely ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
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== CANCELING_BITMASK))
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{
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futex_wait_simple ((unsigned int *) &self->cancelhandling, newval,
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FUTEX_PRIVATE);
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newval = atomic_load_relaxed (&self->cancelhandling);
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}
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}
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libc_hidden_def (__pthread_disable_asynccancel)
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