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ce0b7961ae
Previously, the source file nptl/cancellation.c was compiled multiple times, for libc, libpthread, librt. This commit switches to a single implementation, with new __pthread_enable_asynccancel@@GLIBC_PRIVATE, __pthread_disable_asynccancel@@GLIBC_PRIVATE exports. The almost-unused CANCEL_ASYNC and CANCEL_RESET macros are replaced by LIBC_CANCEL_ASYNC and LIBC_CANCEL_ASYNC macros. They call the __pthread_* functions unconditionally now. The macros are still needed because shared code uses them; Hurd has different definitions. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
105 lines
3.1 KiB
C
105 lines
3.1 KiB
C
/* Copyright (C) 2002-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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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 = THREAD_GETMEM (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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int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
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oldval);
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if (__glibc_likely (curval == oldval))
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{
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if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
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{
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THREAD_SETMEM (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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/* Prepare the next round. */
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oldval = curval;
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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 = THREAD_GETMEM (self, cancelhandling);
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while (1)
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{
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newval = oldval & ~CANCELTYPE_BITMASK;
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int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
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oldval);
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if (__glibc_likely (curval == oldval))
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break;
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/* Prepare the next round. */
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oldval = curval;
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}
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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 (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
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== CANCELING_BITMASK, 0))
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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 = THREAD_GETMEM (self, cancelhandling);
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}
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}
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libc_hidden_def (__pthread_disable_asynccancel)
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