mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-11 22:00:08 +00:00
ab355d9aa5
* sysdeps/unix/sysv/linux/structsem.sym: Add SEM_VALUE_MAX. * sysdeps/unix/sysv/linux/sem_post.c: Don't overflow value field. * sysdeps/unix/sysv/linux/i386/i486/sem_post.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/sem_post.S: Likewise.
81 lines
2.2 KiB
C
81 lines
2.2 KiB
C
/* sem_post -- post to a POSIX semaphore. Generic futex-using version.
|
|
Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
|
|
|
|
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 <sysdep.h>
|
|
#include <lowlevellock.h>
|
|
#include <internaltypes.h>
|
|
#include <semaphore.h>
|
|
|
|
#include <shlib-compat.h>
|
|
|
|
int
|
|
__new_sem_post (sem_t *sem)
|
|
{
|
|
struct new_sem *isem = (struct new_sem *) sem;
|
|
|
|
__typeof (isem->value) cur;
|
|
do
|
|
{
|
|
cur = isem->value;
|
|
if (isem->value == SEM_VALUE_MAX)
|
|
{
|
|
__set_errno (EOVERFLOW);
|
|
return -1;
|
|
}
|
|
}
|
|
while (atomic_compare_and_exchange_bool_acq (&isem->value, cur + 1, cur));
|
|
|
|
atomic_full_barrier ();
|
|
if (isem->nwaiters > 0)
|
|
{
|
|
int err = lll_futex_wake (&isem->value, 1,
|
|
isem->private ^ FUTEX_PRIVATE_FLAG);
|
|
if (__builtin_expect (err, 0) < 0)
|
|
{
|
|
__set_errno (-err);
|
|
return -1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
versioned_symbol (libpthread, __new_sem_post, sem_post, GLIBC_2_1);
|
|
|
|
|
|
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
|
|
int
|
|
attribute_compat_text_section
|
|
__old_sem_post (sem_t *sem)
|
|
{
|
|
int *futex = (int *) sem;
|
|
|
|
int nr = atomic_increment_val (futex);
|
|
/* We always have to assume it is a shared semaphore. */
|
|
int err = lll_futex_wake (futex, 1, LLL_SHARED);
|
|
if (__builtin_expect (err, 0) < 0)
|
|
{
|
|
__set_errno (-err);
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
compat_symbol (libpthread, __old_sem_post, sem_post, GLIBC_2_0);
|
|
#endif
|