[15/18] linux: Only use 64-bit syscall if required for sigtimedwait
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| dj/TryBot-apply_patch |
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Patch applied to master at the time it was sent
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Commit Message
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.
---
sysdeps/unix/sysv/linux/Makefile | 2 ++
sysdeps/unix/sysv/linux/sigtimedwait.c | 26 ++++++++++++++--------
sysdeps/unix/sysv/linux/tst-sigtimedwait.c | 18 +++++++++++++++
3 files changed, 37 insertions(+), 9 deletions(-)
Comments
On Jun 17 2021, Adhemerval Zanella via Libc-alpha wrote:
> + bool is32bit = timeout != NULL
> + ? in_time_t_range (timeout->tv_sec) : true;
bool is32bit = timeout == NULL || in_time_t_range (timeout->tv_sec);
or
bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
Andreas.
On 17/06/2021 09:25, Andreas Schwab wrote:
>
> bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
This is indeed better, I adjusted all the patches to follow this.
@@ -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)
@@ -25,20 +25,28 @@ __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 is32bit = timeout != NULL
+ ? in_time_t_range (timeout->tv_sec) : true;
+ if (!is32bit)
+ {
+ 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;
}
@@ -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;
}