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* [glibc] linux: Only use 64-bit syscall if required for sigtimedwait
@ 2021-06-22 15:12 Adhemerval Zanella
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From: Adhemerval Zanella @ 2021-06-22 15:12 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=dafab287b4d5dea1918f6471dc8bf74bff029133
commit dafab287b4d5dea1918f6471dc8bf74bff029133
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed Jun 16 09:58:29 2021 -0300
linux: Only use 64-bit syscall if required for sigtimedwait
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>
Diff:
---
sysdeps/unix/sysv/linux/Makefile | 2 ++
sysdeps/unix/sysv/linux/sigtimedwait.c | 25 ++++++++++++++++---------
sysdeps/unix/sysv/linux/tst-sigtimedwait.c | 18 ++++++++++++++++++
3 files changed, 36 insertions(+), 9 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index bda01878c3..88d7cd7c1b 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -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)
diff --git a/sysdeps/unix/sysv/linux/sigtimedwait.c b/sysdeps/unix/sysv/linux/sigtimedwait.c
index 25ed0adb0d..607381a0a7 100644
--- a/sysdeps/unix/sysv/linux/sigtimedwait.c
+++ b/sysdeps/unix/sysv/linux/sigtimedwait.c
@@ -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;
}
diff --git a/sysdeps/unix/sysv/linux/tst-sigtimedwait.c b/sysdeps/unix/sysv/linux/tst-sigtimedwait.c
index 973fb5d301..a8b9893c61 100644
--- a/sysdeps/unix/sysv/linux/tst-sigtimedwait.c
+++ b/sysdeps/unix/sysv/linux/tst-sigtimedwait.c
@@ -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;
}
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