y2038: Use a common definition for stat

Instead of replicate the same definitions from struct_stat_time64.h
on the multiple struct_stat.h, use a common header which is included
when required (struct_stat_time64_helper.h).  The 64-bit time support
is added only for LFS support.

The __USE_TIME_BITS64 is not defined internally yet, although the
internal header is used when building the 64-bit stat implementations.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

2 files changed, 95 insertions, 21 deletions

diff --git a/sysdeps/unix/sysv/linux/bits/struct_stat.h b/sysdeps/unix/sysv/linux/bits/struct_stat.h
index b852ee256e..298418966f 100644
--- a/sysdeps/unix/sysv/linux/bits/struct_stat.h
+++ b/sysdeps/unix/sysv/linux/bits/struct_stat.h
@@ -28,32 +28,35 @@
 
 struct stat
   {
+#ifdef __USE_TIME_BITS64
+# include <bits/struct_stat_time64_helper.h>
+#else
     __dev_t st_dev;			/* Device.  */
     unsigned short int __pad1;
-#ifndef __USE_FILE_OFFSET64
+# ifndef __USE_FILE_OFFSET64
     __ino_t st_ino;			/* File serial number.	*/
-#else
+# else
     __ino_t __st_ino;			/* 32bit file serial number.	*/
-#endif
+# endif
     __mode_t st_mode;			/* File mode.  */
     __nlink_t st_nlink;			/* Link count.  */
     __uid_t st_uid;			/* User ID of the file's owner.	*/
     __gid_t st_gid;			/* Group ID of the file's group.*/
     __dev_t st_rdev;			/* Device number, if device.  */
     unsigned short int __pad2;
-#ifndef __USE_FILE_OFFSET64
+# ifndef __USE_FILE_OFFSET64
     __off_t st_size;			/* Size of file, in bytes.  */
-#else
+# else
     __off64_t st_size;			/* Size of file, in bytes.  */
-#endif
+# endif
     __blksize_t st_blksize;		/* Optimal block size for I/O.  */
 
-#ifndef __USE_FILE_OFFSET64
+# ifndef __USE_FILE_OFFSET64
     __blkcnt_t st_blocks;		/* Number 512-byte blocks allocated. */
-#else
+# else
     __blkcnt64_t st_blocks;		/* Number 512-byte blocks allocated. */
-#endif
-#ifdef __USE_XOPEN2K8
+# endif
+# ifdef __USE_XOPEN2K8
     /* Nanosecond resolution timestamps are stored in a format
        equivalent to 'struct timespec'.  This is the type used
        whenever possible but the Unix namespace rules do not allow the
@@ -63,28 +66,32 @@ struct stat
     struct timespec st_atim;		/* Time of last access.  */
     struct timespec st_mtim;		/* Time of last modification.  */
     struct timespec st_ctim;		/* Time of last status change.  */
-# define st_atime st_atim.tv_sec	/* Backward compatibility.  */
-# define st_mtime st_mtim.tv_sec
-# define st_ctime st_ctim.tv_sec
-#else
+#  define st_atime st_atim.tv_sec	/* Backward compatibility.  */
+#  define st_mtime st_mtim.tv_sec
+#  define st_ctime st_ctim.tv_sec
+# else
     __time_t st_atime;			/* Time of last access.  */
     unsigned long int st_atimensec;	/* Nscecs of last access.  */
     __time_t st_mtime;			/* Time of last modification.  */
     unsigned long int st_mtimensec;	/* Nsecs of last modification.  */
     __time_t st_ctime;			/* Time of last status change.  */
     unsigned long int st_ctimensec;	/* Nsecs of last status change.  */
-#endif
-#ifndef __USE_FILE_OFFSET64
+# endif
+# ifndef __USE_FILE_OFFSET64
     unsigned long int __glibc_reserved4;
     unsigned long int __glibc_reserved5;
-#else
+# else
     __ino64_t st_ino;			/* File serial number.	*/
-#endif
+# endif
+#endif /* __USE_TIME_BITS64  */
   };
 
 #ifdef __USE_LARGEFILE64
 struct stat64
   {
+# ifdef __USE_TIME_BITS64
+#  include <bits/struct_stat_time64_helper.h>
+# else
     __dev_t st_dev;			/* Device.  */
     unsigned int __pad1;
 
@@ -99,7 +106,7 @@ struct stat64
     __blksize_t st_blksize;		/* Optimal block size for I/O.  */
 
     __blkcnt64_t st_blocks;		/* Number 512-byte blocks allocated. */
-# ifdef __USE_XOPEN2K8
+#  ifdef __USE_XOPEN2K8
     /* Nanosecond resolution timestamps are stored in a format
        equivalent to 'struct timespec'.  This is the type used
        whenever possible but the Unix namespace rules do not allow the
@@ -109,15 +116,16 @@ struct stat64
     struct timespec st_atim;		/* Time of last access.  */
     struct timespec st_mtim;		/* Time of last modification.  */
     struct timespec st_ctim;		/* Time of last status change.  */
-# else
+#  else
     __time_t st_atime;			/* Time of last access.  */
     unsigned long int st_atimensec;	/* Nscecs of last access.  */
     __time_t st_mtime;			/* Time of last modification.  */
     unsigned long int st_mtimensec;	/* Nsecs of last modification.  */
     __time_t st_ctime;			/* Time of last status change.  */
     unsigned long int st_ctimensec;	/* Nsecs of last status change.  */
-# endif
+#  endif
     __ino64_t st_ino;			/* File serial number.		*/
+# endif /* __USE_TIME_BITS64  */
   };
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/bits/struct_stat_time64_helper.h b/sysdeps/unix/sysv/linux/bits/struct_stat_time64_helper.h
new file mode 100644
index 0000000000..04e0ca7386
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/struct_stat_time64_helper.h
@@ -0,0 +1,66 @@
+/* Definition for helper to define struct stat with 64-bit time.
+   Copyright (C) 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/>.  */
+
+  /* Content of internal __stat64_t64 struct.  */
+  __dev_t st_dev;		/* Device.  */
+  __ino64_t st_ino;		/* file serial number.	*/
+  __mode_t st_mode;		/* File mode.  */
+  __nlink_t st_nlink;		/* Link count.  */
+  __uid_t st_uid;		/* User ID of the file's owner.  */
+  __gid_t st_gid;		/* Group ID of the file's group.  */
+  __dev_t st_rdev;		/* Device number, if device.  */
+  __off64_t st_size;		/* Size of file, in bytes.  */
+  __blksize_t st_blksize;	/* Optimal block size for I/O.  */
+  __blkcnt64_t st_blocks;	/* Number 512-byte blocks allocated. */
+#ifdef __USE_XOPEN2K8
+# ifndef __struct_timespec
+#  define __struct_timespec struct timespec
+# endif
+  /* Nanosecond resolution timestamps are stored in a format
+     equivalent to 'struct timespec'.  This is the type used
+     whenever possible but the Unix namespace rules do not allow the
+     identifier 'timespec' to appear in the <sys/stat.h> header.
+     Therefore we have to handle the use of this header in strictly
+     standard-compliant sources special.  */
+  __struct_timespec st_atim;
+  __struct_timespec st_mtim;
+  __struct_timespec st_ctim;
+# define st_atime st_atim.tv_sec
+# define st_mtime st_mtim.tv_sec
+# define st_ctime st_ctim.tv_sec
+# undef __struct_timespec
+#else
+/* The definition should be equal to the 'struct __timespec64' internal
+   layout.  */
+# if __BYTE_ORDER == __BIG_ENDIAN
+#  define __fieldts64(name)					\
+   __time64_t name; __int32_t :32; __int32_t name ## nsec
+# else
+#  define __fieldts64(name)					\
+   __time64_t name; __int32_t name ## nsec; __int32_t :32
+# endif
+
+  __fieldts64 (st_atime);
+  __fieldts64 (st_mtime);
+  __fieldts64 (st_ctime);
+
+  unsigned long int __glibc_reserved4;
+  unsigned long int __glibc_reserved5;
+
+# undef __fieldts64
+#endif