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glibc/nptl/sem_init.c
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/* Copyright (C) 2002-2015 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, see | |
<http://www.gnu.org/licenses/>. */ | |
#include <errno.h> | |
#include <semaphore.h> | |
#include <shlib-compat.h> | |
#include "semaphoreP.h" | |
#include <kernel-features.h> | |
/* Returns FUTEX_PRIVATE if pshared is zero and private futexes are supported; | |
returns FUTEX_SHARED otherwise. | |
TODO Remove when cleaning up the futex API throughout glibc. */ | |
static __always_inline int | |
futex_private_if_supported (int pshared) | |
{ | |
if (pshared != 0) | |
return LLL_SHARED; | |
#ifdef __ASSUME_PRIVATE_FUTEX | |
return LLL_PRIVATE; | |
#else | |
return THREAD_GETMEM (THREAD_SELF, header.private_futex) | |
^ FUTEX_PRIVATE_FLAG; | |
#endif | |
} | |
int | |
__new_sem_init (sem_t *sem, int pshared, unsigned int value) | |
{ | |
/* Parameter sanity check. */ | |
if (__glibc_unlikely (value > SEM_VALUE_MAX)) | |
{ | |
__set_errno (EINVAL); | |
return -1; | |
} | |
/* Map to the internal type. */ | |
struct new_sem *isem = (struct new_sem *) sem; | |
/* Use the values the caller provided. */ | |
#if __HAVE_64B_ATOMICS | |
isem->data = value; | |
#else | |
isem->value = value << SEM_VALUE_SHIFT; | |
isem->nwaiters = 0; | |
#endif | |
isem->private = futex_private_if_supported (pshared); | |
return 0; | |
} | |
versioned_symbol (libpthread, __new_sem_init, sem_init, GLIBC_2_1); | |
#if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1) | |
int | |
attribute_compat_text_section | |
__old_sem_init (sem, pshared, value) | |
sem_t *sem; | |
int pshared; | |
unsigned int value; | |
{ | |
/* Parameter sanity check. */ | |
if (__glibc_unlikely (value > SEM_VALUE_MAX)) | |
{ | |
__set_errno (EINVAL); | |
return -1; | |
} | |
/* Map to the internal type. */ | |
struct old_sem *isem = (struct old_sem *) sem; | |
/* Use the value the user provided. */ | |
isem->value = value; | |
/* We cannot store the PSHARED attribute. So we always use the | |
operations needed for shared semaphores. */ | |
return 0; | |
} | |
compat_symbol (libpthread, __old_sem_init, sem_init, GLIBC_2_0); | |
#endif |