y2038: linux: Provide __settimeofday64 implementation

This patch provides new __settimeofday64 explicit 64 bit function for setting
64 bit time in the kernel (by internally calling __clock_settime64).
Moreover, a 32 bit version - __settimeofday has been refactored to internally
use __settimeofday64.

The __settimeofday is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary conversion of struct
timeval to 64 bit struct __timespec64.

Internally the settimeofday uses __settimeofday64. This patch is necessary
for having architectures with __WORDSIZE == 32 Y2038 safe.

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 proper usage of both __settimeofday64 and __settimeofday.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

include/time.h

@@ -8,6 +8,7 @@
 # include <time/mktime-internal.h>
 # include <endian.h>
 # include <time-clockid.h>
+# include <sys/time.h>
 
 extern __typeof (strftime_l) __strftime_l;
 libc_hidden_proto (__strftime_l)
@@ -224,6 +225,14 @@ extern int __sched_rr_get_interval64 (pid_t pid, struct __timespec64 *tp);
 libc_hidden_proto (__sched_rr_get_interval64);
 #endif
 
+#if __TIMESIZE == 64
+# define __settimeofday64 __settimeofday
+#else
+extern int __settimeofday64 (const struct __timeval64 *tv,
+                             const struct timezone *tz);
+libc_hidden_proto (__settimeofday64)
+#endif
+
 /* Compute the `struct tm' representation of T,
    offset OFFSET seconds east of UTC,
    and store year, yday, mon, mday, wday, hour, min, sec into *TP.

sysdeps/unix/sysv/linux/settimeofday.c

@@ -0,0 +1,53 @@
+/* settimeofday -- set system time - Linux version supporting 64 bit time.
+   Copyright (C) 2020 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 <errno.h>
+#include <time.h>
+#include <sys/time.h>
+
+/* Set the current time of day and timezone information.
+   This call is restricted to the super-user.  */
+int
+__settimeofday64 (const struct __timeval64 *tv, const struct timezone *tz)
+{
+  if (__glibc_unlikely (tz != 0))
+    {
+      if (tv != 0)
+	{
+	  __set_errno (EINVAL);
+	  return -1;
+	}
+      return __settimezone (tz);
+    }
+
+  struct __timespec64 ts = timeval64_to_timespec64 (*tv);
+  return __clock_settime64 (CLOCK_REALTIME, &ts);
+}
+
+#if __TIMESIZE != 64
+libc_hidden_def (__settimeofday64)
+
+int
+__settimeofday (const struct timeval *tv, const struct timezone *tz)
+{
+  struct __timeval64 tv64 = valid_timeval_to_timeval64 (*tv);
+
+  return __settimeofday64 (&tv64, tz);
+}
+#endif
+weak_alias (__settimeofday, settimeofday);