[PATCH 3/3] y2038: linux: Provide __utime64 implementation

[Lukasz Majewski <lukma at denx dot de>]

This patch replaces auto generated wrapper (as described in
sysdeps/unix/sysv/linux/syscalls.list) for utime with one which adds extra
support for setting file's access and modification 64 bit time on machines
with __TIMESIZE != 64.

Internally, the __utimensat_time64 helper function is used. This patch is
necessary for having architectures with __WORDSIZE == 32 && __TIMESIZE != 64
Y2038 safe.

Moreover, a 32 bit version - __utime has been refactored to internally use
__utime64.
The __utime is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary conversion between struct
utimbuf and struct __utimbuf64.

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 __utime64 and __utime.
---
 include/time.h                        |  3 ++
 sysdeps/unix/sysv/linux/syscalls.list |  1 -
 sysdeps/unix/sysv/linux/utime.c       | 56 +++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/unix/sysv/linux/utime.c

diff --git a/include/time.h b/include/time.h
index b04747889a..c0d1ea3315 100644
--- a/include/time.h
+++ b/include/time.h
@@ -211,9 +211,12 @@ libc_hidden_proto (__clock_getres64);
 #endif
 
 #if __TIMESIZE == 64
+# define __utime64 __utime
 # define __utimes64 __utimes
 # define __utimensat64 __utimensat
 #else
+extern int __utime64 (const char *file, const struct __utimbuf64 *times);
+libc_hidden_proto (__utime64)
 extern int __utimes64 (const char *file, const struct __timeval64 tvp[2]);
 libc_hidden_proto (__utimes64)
 extern int __utimensat64 (int fd, const char *file,
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index 5d65ed23e0..e40f993495 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -65,7 +65,6 @@ swapon		-	swapon		i:si	__swapon	swapon
 swapoff		-	swapoff		i:s	__swapoff	swapoff
 unshare		EXTRA	unshare		i:i	unshare
 uselib		EXTRA	uselib		i:s	__compat_uselib	uselib@GLIBC_2.0:GLIBC_2.23
-utime		-	utime		i:sP	utime
 
 chown		-	chown		i:sii	__libc_chown	__chown chown
 
diff --git a/sysdeps/unix/sysv/linux/utime.c b/sysdeps/unix/sysv/linux/utime.c
new file mode 100644
index 0000000000..75ee0745ec
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/utime.c
@@ -0,0 +1,56 @@
+/* utime -- Change access and modification times of file.  Linux version.
+   Copyright (C) 1991-2020 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 <utime.h>
+#include <time.h>
+
+int
+__utime64 (const char *file, const struct __utimbuf64 *times)
+{
+  struct __timespec64 ts64[2];
+
+  if (times)
+    {
+      ts64[0].tv_sec = times->actime;
+      ts64[0].tv_nsec = 0LL;
+      ts64[1].tv_sec = times->modtime;
+      ts64[1].tv_nsec = 0LL;
+    }
+
+  return __utimensat64_helper (0, file, times ? ts64 : NULL, 0);
+}
+
+#if __TIMESIZE != 64
+libc_hidden_def (__utime64)
+
+int
+__utime (const char *file, const struct utimbuf *times)
+{
+  struct __utimbuf64 utb64;
+
+  if (times)
+    {
+      utb64.actime = (__time64_t) times->actime;
+      utb64.modtime = (__time64_t) times->modtime;
+    }
+
+  return __utime64 (file, times ? &utb64 : NULL);
+}
+#endif
+strong_alias (__utime, utime)
+libc_hidden_def (utime)
-- 
2.20.1