<sys/stat.h>: Use Linux UAPI header for statx if available and useful

This will automatically import new STATX_* constants.  It also avoids
a conflict between <sys/stat.h> and <linux/stat.h>.

ChangeLog

@@ -1,3 +1,20 @@
+2019-06-12  Florian Weimer  <fweimer@redhat.com>
+
+	Linux: Use kernel headers for statx definitions if available.
+	* include/bits/statx-generic.h: New file.
+	* include/bits/types/struct_statx.h: Likewise.
+	* include/bits/types/struct_statx_timestamp.h: Likewise.
+	* io/Makefile (headers): Add bits/statx-generic.h.
+	* io/bits/statx-generic.h: New file.  Partly copied from
+	io/bits/statx.h.
+	* io/statx_generic.c: Include <bits/types/struct_statx.h> to
+	define original_statx.
+	* io/bits/types/struct_statx.h: Likewise.
+	* io/bits/types/struct_statx_timestamp.h: Likewise.
+	(statx_generic): Use original_statx.
+	* io/bits/statx.h: Rewrite to include <bits/statx-generic.h>.
+	* sysdeps/unix/sysv/linux/bits/statx.h: New file.
+
 2019-06-12  Florian Weimer  <fweimer@redhat.com>
 
 	* misc/sys/cdefs.h (__glibc_has_include): Define.

include/bits/statx-generic.h

@@ -0,0 +1 @@
+#include <io/bits/statx-generic.h>

include/bits/types/struct_statx.h

@@ -0,0 +1 @@
+#include <io/bits/types/struct_statx.h>

include/bits/types/struct_statx_timestamp.h

@@ -0,0 +1 @@
+#include <io/bits/types/struct_statx_timestamp.h>

io/Makefile

@@ -25,7 +25,9 @@ include ../Makeconfig
 headers := sys/stat.h bits/stat.h sys/statfs.h bits/statfs.h sys/vfs.h \
 	   sys/statvfs.h bits/statvfs.h fcntl.h sys/fcntl.h bits/fcntl.h \
 	   poll.h sys/poll.h bits/poll.h bits/fcntl2.h bits/poll2.h \
-	   bits/statx.h utime.h ftw.h fts.h sys/sendfile.h
+	   bits/statx.h bits/statx-generic.h bits/types/struct_statx.h \
+	   bits/types/struct_statx_timestamp.h \
+	   utime.h ftw.h fts.h sys/sendfile.h
 
 routines :=								\
 	utime								\

io/bits/statx-generic.h

@@ -0,0 +1,60 @@
+/* Generic statx-related definitions and declarations.
+   Copyright (C) 2018-2019 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* This interface is based on <linux/stat.h> in Linux.  */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/statx-generic.h> directly, include <sys/stat.h> instead.
+#endif
+
+#include <bits/types/struct_statx_timestamp.h>
+#include <bits/types/struct_statx.h>
+
+#ifndef STATX_TYPE
+# define STATX_TYPE 0x0001U
+# define STATX_MODE 0x0002U
+# define STATX_NLINK 0x0004U
+# define STATX_UID 0x0008U
+# define STATX_GID 0x0010U
+# define STATX_ATIME 0x0020U
+# define STATX_MTIME 0x0040U
+# define STATX_CTIME 0x0080U
+# define STATX_INO 0x0100U
+# define STATX_SIZE 0x0200U
+# define STATX_BLOCKS 0x0400U
+# define STATX_BASIC_STATS 0x07ffU
+# define STATX_ALL 0x0fffU
+# define STATX_BTIME 0x0800U
+# define STATX__RESERVED 0x80000000U
+
+# define STATX_ATTR_COMPRESSED 0x0004
+# define STATX_ATTR_IMMUTABLE 0x0010
+# define STATX_ATTR_APPEND 0x0020
+# define STATX_ATTR_NODUMP 0x0040
+# define STATX_ATTR_ENCRYPTED 0x0800
+# define STATX_ATTR_AUTOMOUNT 0x1000
+#endif /* !STATX_TYPE */
+
+__BEGIN_DECLS
+
+/* Fill *BUF with information about PATH in DIRFD.  */
+int statx (int __dirfd, const char *__restrict __path, int __flags,
+           unsigned int __mask, struct statx *__restrict __buf)
+  __THROW __nonnull ((2, 5));
+
+__END_DECLS

io/bits/statx.h

@@ -1,4 +1,4 @@
-/* statx-related definitions and declarations.
+/* statx-related definitions and declarations.  Generic version.
    Copyright (C) 2018-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -19,73 +19,8 @@
 /* This interface is based on <linux/stat.h> in Linux.  */
 
 #ifndef _SYS_STAT_H
-# error Never include <bits/stat.x.h> directly, include <sys/stat.h> instead.
+# error Never include <bits/statx.h> directly, include <sys/stat.h> instead.
 #endif
 
-struct statx_timestamp
+/* Use the generic definitions.  */
-{
+#include <bits/statx-generic.h>
-  __int64_t tv_sec;
-  __uint32_t tv_nsec;
-  __int32_t __statx_timestamp_pad1[1];
-};
-
-/* Warning: The kernel may add additional fields to this struct in the
-   future.  Only use this struct for calling the statx function, not
-   for storing data.  (Expansion will be controlled by the mask
-   argument of the statx function.)  */
-struct statx
-{
-  __uint32_t stx_mask;
-  __uint32_t stx_blksize;
-  __uint64_t stx_attributes;
-  __uint32_t stx_nlink;
-  __uint32_t stx_uid;
-  __uint32_t stx_gid;
-  __uint16_t stx_mode;
-  __uint16_t __statx_pad1[1];
-  __uint64_t stx_ino;
-  __uint64_t stx_size;
-  __uint64_t stx_blocks;
-  __uint64_t stx_attributes_mask;
-  struct statx_timestamp stx_atime;
-  struct statx_timestamp stx_btime;
-  struct statx_timestamp stx_ctime;
-  struct statx_timestamp stx_mtime;
-  __uint32_t stx_rdev_major;
-  __uint32_t stx_rdev_minor;
-  __uint32_t stx_dev_major;
-  __uint32_t stx_dev_minor;
-  __uint64_t __statx_pad2[14];
-};
-
-#define STATX_TYPE 0x0001U
-#define STATX_MODE 0x0002U
-#define STATX_NLINK 0x0004U
-#define STATX_UID 0x0008U
-#define STATX_GID 0x0010U
-#define STATX_ATIME 0x0020U
-#define STATX_MTIME 0x0040U
-#define STATX_CTIME 0x0080U
-#define STATX_INO 0x0100U
-#define STATX_SIZE 0x0200U
-#define STATX_BLOCKS 0x0400U
-#define STATX_BASIC_STATS 0x07ffU
-#define STATX_ALL 0x0fffU
-#define STATX_BTIME 0x0800U
-#define STATX__RESERVED 0x80000000U
-
-#define STATX_ATTR_COMPRESSED 0x0004
-#define STATX_ATTR_IMMUTABLE 0x0010
-#define STATX_ATTR_APPEND 0x0020
-#define STATX_ATTR_NODUMP 0x0040
-#define STATX_ATTR_ENCRYPTED 0x0800
-#define STATX_ATTR_AUTOMOUNT 0x1000
-
-__BEGIN_DECLS
-
-/* Fill *BUF with information about PATH in DIRFD.  */
-int statx (int __dirfd, const char *__restrict __path, int __flags,
-           unsigned int __mask, struct statx *__restrict __buf)
-  __THROW __nonnull ((2, 5));
-
-__END_DECLS

io/bits/types/struct_statx.h

@@ -0,0 +1,55 @@
+/* Definition of the generic version of struct statx.
+   Copyright (C) 2018-2019 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/types/struct_statx.h> directly, include <sys/stat.h> instead.
+#endif
+
+#ifndef __statx_defined
+#define __statx_defined 1
+
+/* Warning: The kernel may add additional fields to this struct in the
+   future.  Only use this struct for calling the statx function, not
+   for storing data.  (Expansion will be controlled by the mask
+   argument of the statx function.)  */
+struct statx
+{
+  __uint32_t stx_mask;
+  __uint32_t stx_blksize;
+  __uint64_t stx_attributes;
+  __uint32_t stx_nlink;
+  __uint32_t stx_uid;
+  __uint32_t stx_gid;
+  __uint16_t stx_mode;
+  __uint16_t __statx_pad1[1];
+  __uint64_t stx_ino;
+  __uint64_t stx_size;
+  __uint64_t stx_blocks;
+  __uint64_t stx_attributes_mask;
+  struct statx_timestamp stx_atime;
+  struct statx_timestamp stx_btime;
+  struct statx_timestamp stx_ctime;
+  struct statx_timestamp stx_mtime;
+  __uint32_t stx_rdev_major;
+  __uint32_t stx_rdev_minor;
+  __uint32_t stx_dev_major;
+  __uint32_t stx_dev_minor;
+  __uint64_t __statx_pad2[14];
+};
+
+#endif /* __statx_defined */

io/bits/types/struct_statx_timestamp.h

@@ -0,0 +1,33 @@
+/* Definition of the generic version of struct statx_timestamp.
+   Copyright (C) 2018-2019 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/types/struct_statx_timestamp.h> directly, include <sys/stat.h> instead.
+#endif
+
+#ifndef __statx_timestamp_defined
+#define __statx_timestamp_defined 1
+
+struct statx_timestamp
+{
+  __int64_t tv_sec;
+  __uint32_t tv_nsec;
+  __int32_t __statx_timestamp_pad1[1];
+};
+
+#endif /* __statx_timestamp_defined */

io/statx_generic.c

@@ -18,9 +18,16 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <string.h>
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
 
+/* Obtain the original definition of struct statx.  */
+#undef __statx_defined
+#define statx original_statx
+#include <bits/types/struct_statx.h>
+#undef statx
+
 static inline struct statx_timestamp
 statx_convert_timestamp (struct timespec tv)
 {
@@ -57,7 +64,7 @@ statx_generic (int fd, const char *path, int flags,
   /* The interface is defined in such a way that unused (padding)
      fields have to be cleared.  STATX_BASIC_STATS corresponds to the
      data which is available via fstatat64.  */
-  *buf = (struct statx)
+  struct original_statx obuf =
     {
       .stx_mask = STATX_BASIC_STATS,
       .stx_blksize = st.st_blksize,
@@ -76,6 +83,8 @@ statx_generic (int fd, const char *path, int flags,
       .stx_dev_major = major (st.st_dev),
       .stx_dev_minor = minor (st.st_dev),
     };
+  _Static_assert (sizeof (*buf) >= sizeof (obuf), "struct statx size");
+  memcpy (buf, &obuf, sizeof (obuf));
 
   return 0;
 }

sysdeps/unix/sysv/linux/bits/statx.h

@@ -0,0 +1,34 @@
+/* statx-related definitions and declarations.  Linux version.
+   Copyright (C) 2018-2019 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* This interface is based on <linux/stat.h> in Linux.  */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/statx.h> directly, include <sys/stat.h> instead.
+#endif
+
+/* Use the Linux kernel header if available.  */
+#if __glibc_has_include (<linux/stat.h>)
+# include <linux/stat.h>
+# ifdef STATX_TYPE
+#  define __statx_timestamp_defined 1
+#  define __statx_defined 1
+# endif
+#endif
+
+#include <bits/statx-generic.h>