linux: Add {f}stat{at} y2038 support

A new struct __stat{64}_t64 type is added with the required
__timespec64 time definition.  Only LFS is added, 64-bit time with
32-bit offsets is not supposed to be supported (no existing glibc
configuration supports such a combination).  It is done with an extra
__NR_statx call plus a conversion to the new __stat{64}_t64 type.
The statx call is done only for 32-bit time_t ABIs.

Internally some extra routines to copy from/to struct stat{64}
to struct __stat{64} used on multiple implementations (stat, fstat,
lstat, and fstatat) are added on a extra implementation
(stat_t64_cp.c).  Alse some extra routines to copy from statx to
__stat{64} is added on statx_cp.c.

Checked with a build for all affected ABIs. I also checked on x86_64,
i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x.

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

1 files changed, 56 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/stat_t64_cp.c b/sysdeps/unix/sysv/linux/stat_t64_cp.c
new file mode 100644
index 0000000000..a7de35761f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/stat_t64_cp.c
@@ -0,0 +1,56 @@
+/* Struct stat/stat64 to stat/stat64 conversion for Linux.
+   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 <stat_t64_cp.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+
+#if __TIMESIZE != 64
+int
+__cp_stat64_t64_stat64 (const struct __stat64_t64 *st64_t64,
+			struct stat64 *st64)
+{
+  if (! in_time_t_range (st64_t64->st_atim.tv_sec)
+      || ! in_time_t_range (st64_t64->st_mtim.tv_sec)
+      || ! in_time_t_range (st64_t64->st_ctim.tv_sec))
+    {
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
+
+  /* Clear both pad and reserved fields.  */
+  memset (st64, 0, sizeof (*st64));
+
+  st64->st_dev = st64_t64->st_dev,
+  st64->st_ino = st64_t64->st_ino;
+  st64->st_mode = st64_t64->st_mode;
+  st64->st_nlink = st64_t64->st_nlink;
+  st64->st_uid = st64_t64->st_uid;
+  st64->st_gid = st64_t64->st_gid;
+  st64->st_rdev = st64_t64->st_rdev;
+  st64->st_size = st64_t64->st_size;
+  st64->st_blksize = st64_t64->st_blksize;
+  st64->st_blocks  = st64_t64->st_blocks;
+  st64->st_atim = valid_timespec64_to_timespec (st64_t64->st_atim);
+  st64->st_mtim = valid_timespec64_to_timespec (st64_t64->st_mtim);
+  st64->st_ctim = valid_timespec64_to_timespec (st64_t64->st_ctim);
+
+  return 0;
+}
+#endif