mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-26 12:41:05 +00:00
b8d3e8fbaa
The sem_clockwait and sem_timedwait have been converted to support 64 bit time.
This change reuses futex_abstimed_wait_cancelable64 function introduced earlier.
The sem_{clock|timed}wait only accepts absolute time. Moreover, there is no
need to check for NULL passed as *abstime pointer to the syscalls as both calls
have exported symbols marked with __nonull attribute for abstime.
For systems with __TIMESIZE != 64 && __WORDSIZE == 32:
- Conversion from 32 bit time to 64 bit struct __timespec64 was necessary
- Redirection to __sem_{clock|timed}wait64 will provide support for 64 bit
time
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Run-time tests:
- Run specific tests on ARM/x86 32bit systems (qemu):
https://github.com/lmajewski/meta-y2038 and run tests:
https://github.com/lmajewski/y2038-tests/commits/master
Above tests were performed with Y2038 redirection applied as well as without
to test the proper usage of both __sem_{clock|timed}wait64 and
__sem_{clock|timed}wait.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
/* sem_wait -- wait on a semaphore. Generic futex-using version.
|
|
Copyright (C) 2003-2020 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <lowlevellock.h> /* lll_futex* used by the old code. */
|
|
#include "semaphoreP.h"
|
|
#include "sem_waitcommon.c"
|
|
|
|
int
|
|
__new_sem_wait (sem_t *sem)
|
|
{
|
|
/* We need to check whether we need to act upon a cancellation request here
|
|
because POSIX specifies that cancellation points "shall occur" in
|
|
sem_wait and sem_timedwait, which also means that they need to check
|
|
this regardless whether they block or not (unlike "may occur"
|
|
functions). See the POSIX Rationale for this requirement: Section
|
|
"Thread Cancellation Overview" [1] and austin group issue #1076 [2]
|
|
for thoughs on why this may be a suboptimal design.
|
|
|
|
[1] http://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xsh_chap02.html
|
|
[2] http://austingroupbugs.net/view.php?id=1076 for thoughts on why this
|
|
*/
|
|
__pthread_testcancel ();
|
|
|
|
if (__new_sem_wait_fast ((struct new_sem *) sem, 0) == 0)
|
|
return 0;
|
|
else
|
|
return __new_sem_wait_slow64 ((struct new_sem *) sem,
|
|
CLOCK_REALTIME, 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;
|
|
|
|
/* Always assume the semaphore is shared. */
|
|
err = lll_futex_wait_cancel (futex, 0, LLL_SHARED);
|
|
}
|
|
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
|