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linux: Only use 64-bit syscall if required for sigtimedwait

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For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
This commit is contained in:
Adhemerval Zanella 2021-06-16 09:58:29 -03:00
parent 1faff27011
commit dafab287b4
3 changed files with 36 additions and 9 deletions
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2
sysdeps/unix/sysv/linux/Makefile
View File

@ -145,6 +145,8 @@ endif
$(objpfx)tst-ppoll: $(librt)
$(objpfx)tst-ppoll-time64: $(librt)
$(objpfx)tst-sigtimedwait: $(librt)
$(objpfx)tst-sigtimedwait-time64: $(librt)
$(objpfx)tst-timerfd: $(librt)
$(objpfx)tst-timerfd-time64: $(librt)

25
sysdeps/unix/sysv/linux/sigtimedwait.c
View File

@ -25,20 +25,27 @@ __sigtimedwait64 (const sigset_t *set, siginfo_t *info,
#ifndef __NR_rt_sigtimedwait_time64
# define __NR_rt_sigtimedwait_time64 __NR_rt_sigtimedwait
#endif
int result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
__NSIG_BYTES);
#ifndef __ASSUME_TIME64_SYSCALLS
if (result != 0 && errno == ENOSYS)
int result;
#ifdef __ASSUME_TIME64_SYSCALLS
result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
__NSIG_BYTES);
#else
bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
if (need_time64)
{
result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
__NSIG_BYTES);
if (result == 0 || errno != ENOSYS)
return result;
__set_errno (EOVERFLOW);
return -1;
}
else
{
struct timespec ts32, *pts32 = NULL;
if (timeout != NULL)
{
if (! in_time_t_range (timeout->tv_sec))
{
__set_errno (EINVAL);
return -1;
}
ts32 = valid_timespec64_to_timespec (*timeout);
pts32 = &ts32;
}

18
sysdeps/unix/sysv/linux/tst-sigtimedwait.c
View File

@ -17,11 +17,13 @@
<https://www.gnu.org/licenses/>. */
#include <time.h>
#include <intprops.h>
#include <errno.h>
#include <signal.h>
#include <support/check.h>
#include <support/xtime.h>
#include <support/timespec.h>
#include <support/support.h>
#include <stdbool.h>
static int
@ -47,6 +49,20 @@ test_sigtimedwait_timeout (bool zero_tmo)
return 0;
}
static void
test_sigtimedwait_large_timeout (void)
{
support_create_timer (0, 100000000, false, NULL);
struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };
sigset_t ss_usr1;
sigemptyset (&ss_usr1);
sigaddset (&ss_usr1, SIGUSR1);
TEST_COMPARE (sigtimedwait (&ss_usr1, NULL, &ts), -1);
TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
}
static int
do_test (void)
{
@ -56,6 +72,8 @@ do_test (void)
/* Check if sigtimedwait exits after specified timeout. */
test_sigtimedwait_timeout (false);
test_sigtimedwait_large_timeout ();
return 0;
}