[06/18] linux: Only use 64-bit syscall if required for select

Message ID 20210617115104.1359598-7-adhemerval.zanella@linaro.org
State New
Headers show
Series
  • More y2038 fixes
Related show

Commit Message

H.J. Lu via Libc-alpha June 17, 2021, 11:50 a.m.
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.  This also avoids the need
to use supports_time64() (which breaks the usage case of live migration
like CRIU or similar).

It also fixes an issue on 32-bit select call for !__ASSUME_PSELECT
(microblase with older kernels only) where the expected timeout
is a 'struct timeval' instead of 'struct timespec'.

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.
---
 include/sys/select.h               |  5 +++
 misc/Makefile                      |  2 +
 misc/tst-select.c                  | 39 +++++++++++--------
 sysdeps/unix/sysv/linux/Makefile   |  2 +-
 sysdeps/unix/sysv/linux/select.c   | 60 ++++++++++--------------------
 sysdeps/unix/sysv/linux/select32.c | 58 +++++++++++++++++++++++++++++
 6 files changed, 109 insertions(+), 57 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/select32.c

-- 
2.30.2

Comments

Lukasz Majewski June 21, 2021, 7:43 a.m. | #1
On Thu, 17 Jun 2021 08:50:52 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:

> 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.  This also

> avoids the need to use supports_time64() (which breaks the usage case

> of live migration like CRIU or similar).

> 

> It also fixes an issue on 32-bit select call for !__ASSUME_PSELECT

> (microblase with older kernels only) where the expected timeout

> is a 'struct timeval' instead of 'struct timespec'.

> 

> 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.

> ---

>  include/sys/select.h               |  5 +++

>  misc/Makefile                      |  2 +

>  misc/tst-select.c                  | 39 +++++++++++--------

>  sysdeps/unix/sysv/linux/Makefile   |  2 +-

>  sysdeps/unix/sysv/linux/select.c   | 60

> ++++++++++-------------------- sysdeps/unix/sysv/linux/select32.c |

> 58 +++++++++++++++++++++++++++++ 6 files changed, 109 insertions(+),

> 57 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/select32.c

> 

> diff --git a/include/sys/select.h b/include/sys/select.h

> index ec073deeba..a8961afbed 100644

> --- a/include/sys/select.h

> +++ b/include/sys/select.h

> @@ -21,6 +21,11 @@ extern int __pselect32 (int __nfds, fd_set

> *__readfds, const struct __timespec64 *__timeout,

>  			const __sigset_t *__sigmask)

>    attribute_hidden;

> +extern int __select32 (int __nfds, fd_set *__readfds,

> +		       fd_set *__writefds, fd_set *__exceptfds,

> +		       const struct __timespec64 *ts64,

> +		       struct __timeval64 *timeout)

> +  attribute_hidden;

>  

>  extern int __select64 (int __nfds, fd_set *__readfds,

>  		       fd_set *__writefds, fd_set *__exceptfds,

> diff --git a/misc/Makefile b/misc/Makefile

> index fa40bf0e11..66586bcc7e 100644

> --- a/misc/Makefile

> +++ b/misc/Makefile

> @@ -169,5 +169,7 @@ $(objpfx)tst-allocate_once-mem.out:

> $(objpfx)tst-allocate_once.out $(common-objpfx)malloc/mtrace

> $(objpfx)tst-allocate_once.mtrace > $@; \ $(evaluate-test)

>  

> +$(objpfx)tst-select: $(librt)

> +$(objpfx)tst-select-time64: $(librt)

>  $(objpfx)tst-pselect: $(librt)

>  $(objpfx)tst-pselect-time64: $(librt)

> diff --git a/misc/tst-select.c b/misc/tst-select.c

> index 52aa26651f..134eed99be 100644

> --- a/misc/tst-select.c

> +++ b/misc/tst-select.c

> @@ -17,6 +17,7 @@

>     <https://www.gnu.org/licenses/>.  */

>  

>  #include <errno.h>

> +#include <intprops.h>

>  #include <support/capture_subprocess.h>

>  #include <support/check.h>

>  #include <support/support.h>

> @@ -31,12 +32,6 @@ struct child_args

>    struct timeval tmo;

>  };

>  

> -static void

> -alarm_handler (int signum)

> -{

> -  /* Do nothing.  */

> -}

> -

>  static void

>  do_test_child (void *clousure)

>  {

> @@ -69,17 +64,20 @@ do_test_child (void *clousure)

>  static void

>  do_test_child_alarm (void *clousure)

>  {

> -  struct sigaction act = { .sa_handler = alarm_handler };

> -  xsigaction (SIGALRM, &act, NULL);

> -  alarm (1);

> +  struct child_args *args = (struct child_args *) clousure;

>  

> -  struct timeval tv = { .tv_sec = 10, .tv_usec = 0 };

> +  support_create_timer (0, 100000000, false, NULL);

> +  struct timeval tv = { .tv_sec = args->tmo.tv_sec, .tv_usec = 0 };

>    int r = select (0, NULL, NULL, NULL, &tv);

>    TEST_COMPARE (r, -1);

> -  TEST_COMPARE (errno, EINTR);

> -

> -  if (support_select_modifies_timeout ())

> -    TEST_VERIFY (tv.tv_sec < 10);

> +  if (args->tmo.tv_sec > INT_MAX)

> +    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);

> +  else

> +    {

> +      TEST_COMPARE (errno, EINTR);

> +      if (support_select_modifies_timeout ())

> +       TEST_VERIFY (tv.tv_sec < args->tmo.tv_sec);

> +    }

>  }

>  

>  static int

> @@ -121,13 +119,24 @@ do_test (void)

>    xclose (args.fds[0][0]);

>    xclose (args.fds[1][1]);

>  

> +  args.tmo = (struct timeval) { .tv_sec = 10, .tv_usec = 0 };

> +  {

> +    struct support_capture_subprocess result;

> +    result = support_capture_subprocess (do_test_child_alarm, &args);

> +    support_capture_subprocess_check (&result, "tst-select-child", 0,

> +				      sc_allow_none);

> +  }

> +

> +  args.tmo = (struct timeval) { .tv_sec = TYPE_MAXIMUM (time_t),

> +				.tv_usec = 0 };

>    {

>      struct support_capture_subprocess result;

> -    result = support_capture_subprocess (do_test_child_alarm, NULL);

> +    result = support_capture_subprocess (do_test_child_alarm, &args);

>      support_capture_subprocess_check (&result, "tst-select-child", 0,

>  				      sc_allow_none);

>    }

>  

> +  args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 0 };

>    {

>      fd_set rfds;

>      FD_ZERO (&rfds);

> diff --git a/sysdeps/unix/sysv/linux/Makefile

> b/sysdeps/unix/sysv/linux/Makefile index c36ea0e494..710169a454 100644

> --- a/sysdeps/unix/sysv/linux/Makefile

> +++ b/sysdeps/unix/sysv/linux/Makefile

> @@ -61,7 +61,7 @@ sysdep_routines += adjtimex clone umount umount2

> readahead sysctl \ open_by_handle_at mlock2 pkey_mprotect pkey_set

> pkey_get \ timerfd_gettime timerfd_settime prctl \

>  		   process_vm_readv process_vm_writev clock_adjtime \

> -		   time64-support pselect32 \

> +		   time64-support pselect32 select32 \

>  		   xstat fxstat lxstat xstat64 fxstat64 lxstat64 \

>  		   fxstatat fxstatat64 \

>  		   xmknod xmknodat convert_scm_timestamps

> diff --git a/sysdeps/unix/sysv/linux/select.c

> b/sysdeps/unix/sysv/linux/select.c index dc16a816ed..2d2a7fa720 100644

> --- a/sysdeps/unix/sysv/linux/select.c

> +++ b/sysdeps/unix/sysv/linux/select.c

> @@ -21,7 +21,6 @@

>  #include <sys/select.h>

>  #include <errno.h>

>  #include <sysdep-cancel.h>

> -#include <time64-support.h>

>  

>  /* Check the first NFDS descriptors each in READFDS (if not NULL)

> for read readiness, in WRITEFDS (if not NULL) for write readiness,

> and in EXCEPTFDS @@ -65,53 +64,32 @@ __select64 (int nfds, fd_set

> *readfds, fd_set *writefds, fd_set *exceptfds, #ifndef

> __NR_pselect6_time64 # define __NR_pselect6_time64 __NR_pselect6

>  #endif

> +

> +#ifdef __ASSUME_TIME64_SYSCALLS

> +  int r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds,

> exceptfds,

> +			  pts64, NULL);

> +  if (timeout != NULL)

> +    TIMESPEC_TO_TIMEVAL (timeout, pts64);

> +  return r;

> +#else

> +  bool is32bit = timeout != NULL

> +		 ? in_time_t_range (timeout->tv_sec) : true;

>    int r;

> -  if (supports_time64 ())

> +  if (!is32bit)

>      {

> -      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds,

> exceptfds,

> -			  pts64, NULL);

> -      /* Linux by default will update the timeout after a pselect6

> syscall

> -         (though the pselect() glibc call suppresses this behavior).

> -         Since select() on Linux has the same behavior as the

> pselect6

> -         syscall, we update the timeout here.  */

> -      if (r >= 0 || errno != ENOSYS)

> +      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds,

> +			      exceptfds, pts64, NULL);

> +      if ((r >= 0 || errno != ENOSYS) && timeout != NULL)

>  	{

> -	  if (timeout != NULL)

> -	    TIMESPEC_TO_TIMEVAL (timeout, &ts64);

> -	  return r;

> +	  TIMESPEC_TO_TIMEVAL (timeout, &ts64);

>  	}

> -

> -      mark_time64_unsupported ();

> +      else

> +	__set_errno (EOVERFLOW);

> +      return r;

>      }

>  

> -#ifndef __ASSUME_TIME64_SYSCALLS

> -  struct timespec ts32, *pts32 = NULL;

> -  if (pts64 != NULL)

> -    {

> -      if (! in_time_t_range (pts64->tv_sec))

> -	{

> -	  __set_errno (EINVAL);

> -	  return -1;

> -	}

> -      ts32.tv_sec = s;

> -      ts32.tv_nsec = ns;

> -      pts32 = &ts32;

> -    }

> -# ifndef __ASSUME_PSELECT

> -#  ifdef __NR__newselect

> -#   undef __NR_select

> -#   define __NR_select __NR__newselect

> -#  endif

> -  r = SYSCALL_CANCEL (select, nfds, readfds, writefds, exceptfds,

> pts32); -# else

> -  r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds,

> pts32,

> -		      NULL);

> -# endif

> -  if (timeout != NULL)

> -    *timeout = valid_timespec_to_timeval64 (ts32);

> +  return __select32 (nfds, readfds, writefds, exceptfds, pts64,

> timeout); #endif

> -

> -  return r;

>  }

>  

>  #if __TIMESIZE != 64

> diff --git a/sysdeps/unix/sysv/linux/select32.c

> b/sysdeps/unix/sysv/linux/select32.c new file mode 100644

> index 0000000000..b7e122fe2c

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/select32.c

> @@ -0,0 +1,58 @@

> +/* Synchronous I/O multiplexing.  Linux 32-bit time fallback.

> +   Copyright (C) 2020-2021 Free Software Foundation, Inc.

> +   This file is part of the GNU C Library.

> +

> +   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 <sys/select.h>

> +#include <sysdep-cancel.h>

> +

> +#ifndef __ASSUME_TIME64_SYSCALLS

> +

> +int

> +__select32 (int nfds, fd_set *readfds, fd_set *writefds,

> +	    fd_set *exceptfds, const struct __timespec64 *ts64,

> +	    struct __timeval64 *timeout)

> +{

> +#ifdef __ASSUME_PSELECT

> +  struct timespec ts32, *pts32 = NULL;

> +  if (ts64 != NULL)

> +    {

> +      ts32.tv_sec = ts64->tv_sec;

> +      ts32.tv_nsec = ts64->tv_nsec;

> +      pts32 = &ts32;

> +    }

> +

> +  int r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds,

> exceptfds, pts32,

> +			  NULL);

> +  if (timeout != NULL)

> +    TIMESPEC_TO_TIMEVAL (timeout, pts32);

> +  return r;

> +#else

> +  struct timeval tv32, *ptv32 = NULL;

> +  if (ts64 != NULL)

> +    {

> +      tv32 = valid_timespec64_to_timeval (*ts64);

> +      ptv32 = &tv32;

> +    }

> +

> +  int r = SYSCALL_CANCEL (select, nfds, readfds, writefds,

> exceptfds, ptv32);

> +  if (timeout != NULL)

> +    *timeout = valid_timeval_to_timeval64 (tv32);

> +  return r;

> +#endif /* __ASSUME_PSELECT  */

> +}

> +

> +#endif


Reviewed-by: Lukasz Majewski <lukma@denx.de>



Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Patch

diff --git a/include/sys/select.h b/include/sys/select.h
index ec073deeba..a8961afbed 100644
--- a/include/sys/select.h
+++ b/include/sys/select.h
@@ -21,6 +21,11 @@  extern int __pselect32 (int __nfds, fd_set *__readfds,
 			const struct __timespec64 *__timeout,
 			const __sigset_t *__sigmask)
   attribute_hidden;
+extern int __select32 (int __nfds, fd_set *__readfds,
+		       fd_set *__writefds, fd_set *__exceptfds,
+		       const struct __timespec64 *ts64,
+		       struct __timeval64 *timeout)
+  attribute_hidden;
 
 extern int __select64 (int __nfds, fd_set *__readfds,
 		       fd_set *__writefds, fd_set *__exceptfds,
diff --git a/misc/Makefile b/misc/Makefile
index fa40bf0e11..66586bcc7e 100644
--- a/misc/Makefile
+++ b/misc/Makefile
@@ -169,5 +169,7 @@  $(objpfx)tst-allocate_once-mem.out: $(objpfx)tst-allocate_once.out
 	$(common-objpfx)malloc/mtrace $(objpfx)tst-allocate_once.mtrace > $@; \
 	$(evaluate-test)
 
+$(objpfx)tst-select: $(librt)
+$(objpfx)tst-select-time64: $(librt)
 $(objpfx)tst-pselect: $(librt)
 $(objpfx)tst-pselect-time64: $(librt)
diff --git a/misc/tst-select.c b/misc/tst-select.c
index 52aa26651f..134eed99be 100644
--- a/misc/tst-select.c
+++ b/misc/tst-select.c
@@ -17,6 +17,7 @@ 
    <https://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
+#include <intprops.h>
 #include <support/capture_subprocess.h>
 #include <support/check.h>
 #include <support/support.h>
@@ -31,12 +32,6 @@  struct child_args
   struct timeval tmo;
 };
 
-static void
-alarm_handler (int signum)
-{
-  /* Do nothing.  */
-}
-
 static void
 do_test_child (void *clousure)
 {
@@ -69,17 +64,20 @@  do_test_child (void *clousure)
 static void
 do_test_child_alarm (void *clousure)
 {
-  struct sigaction act = { .sa_handler = alarm_handler };
-  xsigaction (SIGALRM, &act, NULL);
-  alarm (1);
+  struct child_args *args = (struct child_args *) clousure;
 
-  struct timeval tv = { .tv_sec = 10, .tv_usec = 0 };
+  support_create_timer (0, 100000000, false, NULL);
+  struct timeval tv = { .tv_sec = args->tmo.tv_sec, .tv_usec = 0 };
   int r = select (0, NULL, NULL, NULL, &tv);
   TEST_COMPARE (r, -1);
-  TEST_COMPARE (errno, EINTR);
-
-  if (support_select_modifies_timeout ())
-    TEST_VERIFY (tv.tv_sec < 10);
+  if (args->tmo.tv_sec > INT_MAX)
+    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
+  else
+    {
+      TEST_COMPARE (errno, EINTR);
+      if (support_select_modifies_timeout ())
+       TEST_VERIFY (tv.tv_sec < args->tmo.tv_sec);
+    }
 }
 
 static int
@@ -121,13 +119,24 @@  do_test (void)
   xclose (args.fds[0][0]);
   xclose (args.fds[1][1]);
 
+  args.tmo = (struct timeval) { .tv_sec = 10, .tv_usec = 0 };
+  {
+    struct support_capture_subprocess result;
+    result = support_capture_subprocess (do_test_child_alarm, &args);
+    support_capture_subprocess_check (&result, "tst-select-child", 0,
+				      sc_allow_none);
+  }
+
+  args.tmo = (struct timeval) { .tv_sec = TYPE_MAXIMUM (time_t),
+				.tv_usec = 0 };
   {
     struct support_capture_subprocess result;
-    result = support_capture_subprocess (do_test_child_alarm, NULL);
+    result = support_capture_subprocess (do_test_child_alarm, &args);
     support_capture_subprocess_check (&result, "tst-select-child", 0,
 				      sc_allow_none);
   }
 
+  args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 0 };
   {
     fd_set rfds;
     FD_ZERO (&rfds);
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index c36ea0e494..710169a454 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -61,7 +61,7 @@  sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
 		   open_by_handle_at mlock2 pkey_mprotect pkey_set pkey_get \
 		   timerfd_gettime timerfd_settime prctl \
 		   process_vm_readv process_vm_writev clock_adjtime \
-		   time64-support pselect32 \
+		   time64-support pselect32 select32 \
 		   xstat fxstat lxstat xstat64 fxstat64 lxstat64 \
 		   fxstatat fxstatat64 \
 		   xmknod xmknodat convert_scm_timestamps
diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
index dc16a816ed..2d2a7fa720 100644
--- a/sysdeps/unix/sysv/linux/select.c
+++ b/sysdeps/unix/sysv/linux/select.c
@@ -21,7 +21,6 @@ 
 #include <sys/select.h>
 #include <errno.h>
 #include <sysdep-cancel.h>
-#include <time64-support.h>
 
 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
    readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
@@ -65,53 +64,32 @@  __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 #ifndef __NR_pselect6_time64
 # define __NR_pselect6_time64 __NR_pselect6
 #endif
+
+#ifdef __ASSUME_TIME64_SYSCALLS
+  int r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds, exceptfds,
+			  pts64, NULL);
+  if (timeout != NULL)
+    TIMESPEC_TO_TIMEVAL (timeout, pts64);
+  return r;
+#else
+  bool is32bit = timeout != NULL
+		 ? in_time_t_range (timeout->tv_sec) : true;
   int r;
-  if (supports_time64 ())
+  if (!is32bit)
     {
-      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds, exceptfds,
-			  pts64, NULL);
-      /* Linux by default will update the timeout after a pselect6 syscall
-         (though the pselect() glibc call suppresses this behavior).
-         Since select() on Linux has the same behavior as the pselect6
-         syscall, we update the timeout here.  */
-      if (r >= 0 || errno != ENOSYS)
+      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds,
+			      exceptfds, pts64, NULL);
+      if ((r >= 0 || errno != ENOSYS) && timeout != NULL)
 	{
-	  if (timeout != NULL)
-	    TIMESPEC_TO_TIMEVAL (timeout, &ts64);
-	  return r;
+	  TIMESPEC_TO_TIMEVAL (timeout, &ts64);
 	}
-
-      mark_time64_unsupported ();
+      else
+	__set_errno (EOVERFLOW);
+      return r;
     }
 
-#ifndef __ASSUME_TIME64_SYSCALLS
-  struct timespec ts32, *pts32 = NULL;
-  if (pts64 != NULL)
-    {
-      if (! in_time_t_range (pts64->tv_sec))
-	{
-	  __set_errno (EINVAL);
-	  return -1;
-	}
-      ts32.tv_sec = s;
-      ts32.tv_nsec = ns;
-      pts32 = &ts32;
-    }
-# ifndef __ASSUME_PSELECT
-#  ifdef __NR__newselect
-#   undef __NR_select
-#   define __NR_select __NR__newselect
-#  endif
-  r = SYSCALL_CANCEL (select, nfds, readfds, writefds, exceptfds, pts32);
-# else
-  r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, pts32,
-		      NULL);
-# endif
-  if (timeout != NULL)
-    *timeout = valid_timespec_to_timeval64 (ts32);
+  return __select32 (nfds, readfds, writefds, exceptfds, pts64, timeout);
 #endif
-
-  return r;
 }
 
 #if __TIMESIZE != 64
diff --git a/sysdeps/unix/sysv/linux/select32.c b/sysdeps/unix/sysv/linux/select32.c
new file mode 100644
index 0000000000..b7e122fe2c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/select32.c
@@ -0,0 +1,58 @@ 
+/* Synchronous I/O multiplexing.  Linux 32-bit time fallback.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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 <sys/select.h>
+#include <sysdep-cancel.h>
+
+#ifndef __ASSUME_TIME64_SYSCALLS
+
+int
+__select32 (int nfds, fd_set *readfds, fd_set *writefds,
+	    fd_set *exceptfds, const struct __timespec64 *ts64,
+	    struct __timeval64 *timeout)
+{
+#ifdef __ASSUME_PSELECT
+  struct timespec ts32, *pts32 = NULL;
+  if (ts64 != NULL)
+    {
+      ts32.tv_sec = ts64->tv_sec;
+      ts32.tv_nsec = ts64->tv_nsec;
+      pts32 = &ts32;
+    }
+
+  int r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, pts32,
+			  NULL);
+  if (timeout != NULL)
+    TIMESPEC_TO_TIMEVAL (timeout, pts32);
+  return r;
+#else
+  struct timeval tv32, *ptv32 = NULL;
+  if (ts64 != NULL)
+    {
+      tv32 = valid_timespec64_to_timeval (*ts64);
+      ptv32 = &tv32;
+    }
+
+  int r = SYSCALL_CANCEL (select, nfds, readfds, writefds, exceptfds, ptv32);
+  if (timeout != NULL)
+    *timeout = valid_timeval_to_timeval64 (tv32);
+  return r;
+#endif /* __ASSUME_PSELECT  */
+}
+
+#endif