145 lines
4.4 KiB
C
145 lines
4.4 KiB
C
/* Copyright (C) 2002-2014 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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<http://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <errno.h>
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#include <string.h>
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#include <kernel-features.h>
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#include "pthreadP.h"
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#include <stap-probe.h>
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static const struct pthread_mutexattr default_mutexattr =
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{
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/* Default is a normal mutex, not shared between processes. */
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.mutexkind = PTHREAD_MUTEX_NORMAL
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};
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#ifndef __ASSUME_FUTEX_LOCK_PI
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static int tpi_supported;
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#endif
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int
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__pthread_mutex_init (mutex, mutexattr)
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pthread_mutex_t *mutex;
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const pthread_mutexattr_t *mutexattr;
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{
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const struct pthread_mutexattr *imutexattr;
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assert (sizeof (pthread_mutex_t) <= __SIZEOF_PTHREAD_MUTEX_T);
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imutexattr = ((const struct pthread_mutexattr *) mutexattr
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?: &default_mutexattr);
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/* Sanity checks. */
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switch (__builtin_expect (imutexattr->mutexkind
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& PTHREAD_MUTEXATTR_PROTOCOL_MASK,
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PTHREAD_PRIO_NONE
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<< PTHREAD_MUTEXATTR_PROTOCOL_SHIFT))
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{
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case PTHREAD_PRIO_NONE << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
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break;
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case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
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#ifndef __ASSUME_FUTEX_LOCK_PI
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if (__glibc_unlikely (tpi_supported == 0))
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{
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int lock = 0;
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INTERNAL_SYSCALL_DECL (err);
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int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI,
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0, 0);
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assert (INTERNAL_SYSCALL_ERROR_P (ret, err));
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tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1;
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}
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if (__glibc_unlikely (tpi_supported < 0))
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return ENOTSUP;
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#endif
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break;
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default:
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/* XXX: For now we don't support robust priority protected mutexes. */
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if (imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST)
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return ENOTSUP;
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break;
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}
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/* Clear the whole variable. */
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memset (mutex, '\0', __SIZEOF_PTHREAD_MUTEX_T);
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/* Copy the values from the attribute. */
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mutex->__data.__kind = imutexattr->mutexkind & ~PTHREAD_MUTEXATTR_FLAG_BITS;
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if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) != 0)
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{
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#ifndef __ASSUME_SET_ROBUST_LIST
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if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_PSHARED) != 0
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&& __set_robust_list_avail < 0)
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return ENOTSUP;
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#endif
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mutex->__data.__kind |= PTHREAD_MUTEX_ROBUST_NORMAL_NP;
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}
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switch (imutexattr->mutexkind & PTHREAD_MUTEXATTR_PROTOCOL_MASK)
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{
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case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
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mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_INHERIT_NP;
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break;
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case PTHREAD_PRIO_PROTECT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
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mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_PROTECT_NP;
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int ceiling = (imutexattr->mutexkind
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& PTHREAD_MUTEXATTR_PRIO_CEILING_MASK)
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>> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT;
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if (! ceiling)
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{
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if (__sched_fifo_min_prio == -1)
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__init_sched_fifo_prio ();
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if (ceiling < __sched_fifo_min_prio)
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ceiling = __sched_fifo_min_prio;
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}
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mutex->__data.__lock = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
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break;
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default:
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break;
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}
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/* The kernel when waking robust mutexes on exit never uses
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FUTEX_PRIVATE_FLAG FUTEX_WAKE. */
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if ((imutexattr->mutexkind & (PTHREAD_MUTEXATTR_FLAG_PSHARED
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| PTHREAD_MUTEXATTR_FLAG_ROBUST)) != 0)
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mutex->__data.__kind |= PTHREAD_MUTEX_PSHARED_BIT;
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/* Default values: mutex not used yet. */
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// mutex->__count = 0; already done by memset
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// mutex->__owner = 0; already done by memset
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// mutex->__nusers = 0; already done by memset
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// mutex->__spins = 0; already done by memset
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// mutex->__next = NULL; already done by memset
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LIBC_PROBE (mutex_init, 1, mutex);
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return 0;
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}
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strong_alias (__pthread_mutex_init, pthread_mutex_init)
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hidden_def (__pthread_mutex_init)
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