[PATCH v2 3/7] y2038: linux: Provide __adjtime64 implementation

[Lukasz Majewski]

This patch provides new __adjtime64 explicit 64 bit function for adjusting
Linux kernel clock.

Internally, the __clock_adjtime64 syscall is used instead of __adjtimex. This
patch is necessary for having architectures with __WORDSIZE == 32 Y2038 safe.

Moreover, a 32 bit version - __adjtime has been refactored to internally use
__adjtime64.

The __adjtime is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary conversions between struct
timeval and 64 bit struct __timeval64.

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 the proper usage of both __adjtime64 and __adjtime.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
---
 include/sys/time.h                |  9 +++++++++
 sysdeps/unix/sysv/linux/adjtime.c | 26 ++++++++++++++++++++++----
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/include/sys/time.h b/include/sys/time.h
index 8153d75033..567e4b7562 100644
--- a/include/sys/time.h
+++ b/include/sys/time.h
@@ -26,6 +26,15 @@ extern int __settimezone (const struct timezone *__tz)
 	attribute_hidden;
 extern int __adjtime (const struct timeval *__delta,
 		      struct timeval *__olddelta);
+
+#  include <struct___timeval64.h>
+#  if __TIMESIZE == 64
+#   define __adjtime64 __adjtime
+#  else
+extern int __adjtime64 (const struct __timeval64 *itv,
+                        struct __timeval64 *otv);
+libc_hidden_proto (__adjtime64)
+#  endif
 extern int __getitimer (enum __itimer_which __which,
 			struct itimerval *__value);
 extern int __setitimer (enum __itimer_which __which,
diff --git a/sysdeps/unix/sysv/linux/adjtime.c b/sysdeps/unix/sysv/linux/adjtime.c
index c142f4f6ea..3f9a4ea2eb 100644
--- a/sysdeps/unix/sysv/linux/adjtime.c
+++ b/sysdeps/unix/sysv/linux/adjtime.c
@@ -24,13 +24,13 @@
 #define MIN_SEC	(INT_MIN / 1000000L + 2)
 
 int
-__adjtime (const struct timeval *itv, struct timeval *otv)
+__adjtime64 (const struct __timeval64 *itv, struct __timeval64 *otv)
 {
-  struct timex tntx;
+  struct __timex64 tntx;
 
   if (itv)
     {
-      struct timeval tmp;
+      struct __timeval64 tmp;
 
       /* We will do some check here. */
       tmp.tv_sec = itv->tv_sec + itv->tv_usec / 1000000L;
@@ -43,7 +43,7 @@ __adjtime (const struct timeval *itv, struct timeval *otv)
   else
     tntx.modes = ADJ_OFFSET_SS_READ;
 
-  if (__glibc_unlikely (__adjtimex (&tntx) < 0))
+  if (__glibc_unlikely (__clock_adjtime64 (CLOCK_REALTIME, &tntx) < 0))
     return -1;
 
   if (otv)
@@ -62,6 +62,24 @@ __adjtime (const struct timeval *itv, struct timeval *otv)
   return 0;
 }
 
+#if __TIMESIZE != 64
+libc_hidden_def (__adjtime64)
+
+int
+__adjtime (const struct timeval *itv, struct timeval *otv)
+{
+  struct __timeval64 itv64, otv64;
+  int retval;
+
+  itv64 = valid_timeval_to_timeval64 (*itv);
+  retval = __adjtime64 (&itv64, otv != NULL ? &otv64 : NULL);
+  if (otv != NULL)
+    *otv = valid_timeval64_to_timeval (otv64);
+
+  return retval;
+}
+#endif
+
 #ifdef VERSION_adjtime
 weak_alias (__adjtime, __wadjtime);
 default_symbol_version (__wadjtime, adjtime, VERSION_adjtime);
-- 
2.20.1