Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/nptl/sem_wait.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
93 lines (78 sloc)
2.62 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* sem_wait -- wait on a semaphore. Generic futex-using version. | |
Copyright (C) 2003-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Paul Mackerras <paulus@au.ibm.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, see | |
<http://www.gnu.org/licenses/>. */ | |
#include <lowlevellock.h> /* lll_futex* used by the old code. */ | |
#include "sem_waitcommon.c" | |
int | |
__new_sem_wait (sem_t *sem) | |
{ | |
if (__new_sem_wait_fast ((struct new_sem *) sem, 0) == 0) | |
return 0; | |
else | |
return __new_sem_wait_slow((struct new_sem *) sem, NULL); | |
} | |
versioned_symbol (libpthread, __new_sem_wait, sem_wait, GLIBC_2_1); | |
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1) | |
int | |
attribute_compat_text_section | |
__old_sem_wait (sem_t *sem) | |
{ | |
int *futex = (int *) sem; | |
int err; | |
do | |
{ | |
if (atomic_decrement_if_positive (futex) > 0) | |
return 0; | |
/* Enable asynchronous cancellation. Required by the standard. */ | |
int oldtype = __pthread_enable_asynccancel (); | |
/* Always assume the semaphore is shared. */ | |
err = lll_futex_wait (futex, 0, LLL_SHARED); | |
/* Disable asynchronous cancellation. */ | |
__pthread_disable_asynccancel (oldtype); | |
} | |
while (err == 0 || err == -EWOULDBLOCK); | |
__set_errno (-err); | |
return -1; | |
} | |
compat_symbol (libpthread, __old_sem_wait, sem_wait, GLIBC_2_0); | |
#endif | |
int | |
__new_sem_trywait (sem_t *sem) | |
{ | |
/* We must not fail spuriously, so require a definitive result even if this | |
may lead to a long execution time. */ | |
if (__new_sem_wait_fast ((struct new_sem *) sem, 1) == 0) | |
return 0; | |
__set_errno (EAGAIN); | |
return -1; | |
} | |
versioned_symbol (libpthread, __new_sem_trywait, sem_trywait, GLIBC_2_1); | |
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1) | |
int | |
__old_sem_trywait (sem_t *sem) | |
{ | |
int *futex = (int *) sem; | |
int val; | |
if (*futex > 0) | |
{ | |
val = atomic_decrement_if_positive (futex); | |
if (val > 0) | |
return 0; | |
} | |
__set_errno (EAGAIN); | |
return -1; | |
} | |
compat_symbol (libpthread, __old_sem_trywait, sem_trywait, GLIBC_2_0); | |
#endif |