Re: [RFC5 PATCH v6 00/21] ILP32 for ARM64

[Andreas Schwab]

Arnd Bergmann <arnd@xxxxxxxx> writes:

> In https://github.com/norov/glibc/commit/5d4290435e428267171ece871539b76e1d079d11
> you are defining a struct __kernel_stat64 in the glibc. Is this the expected
> way to do it? I would have thought you'd get the definition from the kernel
> headers.

The problem really is that struct stat64 does not match the kernel
struct stat64.  The latter uses the broken st_ino, where the 64-bit
inode is actually stored at the end of the structure, and there is
padding *before* the 32-bit inode, not after (so you cannot overlay a
64-bit inode field in little endian mode).  You need to add the attached
file as sysdeps/unix/sysv/linux/aarch64/bits/stat.h, then you can use
the user-space struct stat64 to communicate with the *stat64 syscalls,
and __kernel_stat64 is not needed any more.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@xxxxxxx
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
/* Copyright (C) 1992-2015 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/>.  */

#if !defined _SYS_STAT_H && !defined _FCNTL_H
# error "Never include <bits/stat.h> directly; use <sys/stat.h> instead."
#endif

#ifndef _BITS_STAT_H
#define _BITS_STAT_H	1

/* Versions of the `struct stat' data structure.  */
#define _STAT_VER_KERNEL	0
#define _STAT_VER_LINUX		0
#define _STAT_VER		_STAT_VER_KERNEL

/* Versions of the `xmknod' interface.  */
#define _MKNOD_VER_LINUX	0


struct stat
  {
    __dev_t st_dev;			/* Device.  */
#ifdef __ILP32__
    unsigned int __st_ino_pad;
# ifndef __USE_FILE_OFFSET64
    __ino_t st_ino;			/* File serial number.	*/
# else
    __ino_t __st_ino;			/* 32bit file serial number.	*/
# endif
#else
# ifndef __USE_FILE_OFFSET64
    __ino_t st_ino;			/* File serial number.	*/
# else
    __ino64_t st_ino;			/* 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.  */
    __dev_t __pad1;
#ifndef __USE_FILE_OFFSET64
    __off_t st_size;			/* Size of file, in bytes.  */
# ifdef __ILP32__
    int __st_size_pad;
# endif
#else
    __off64_t st_size;			/* Size of file, in bytes.  */
#endif
    __blksize_t st_blksize;		/* Optimal block size for I/O.  */
    int __pad2;

#ifndef __USE_FILE_OFFSET64
    __blkcnt_t st_blocks;		/* Number 512-byte blocks allocated. */
# ifdef __ILP32__
    int __st_blocks_pad;
# endif
#else
    __blkcnt64_t st_blocks;		/* Number 512-byte blocks allocated. */
#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
       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;		/* 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
    __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
#if !defined __ILP32__ || !defined __USE_FILE_OFFSET64
    int __glibc_reserved[2];
#else
    __ino64_t st_ino;			/* File serial number.	*/
#endif
  };

#ifdef __USE_LARGEFILE64
struct stat64
  {
    __dev_t st_dev;			/* Device.  */
# ifdef __ILP32__
    unsigned int __st_ino_pad;
    __ino_t __st_ino;			/* 32bit file serial number.	*/
# else
    __ino64_t st_ino;			/* File serial number.	*/
# 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.  */
    __dev_t __pad1;
    __off64_t st_size;			/* Size of file, in bytes.  */
    __blksize_t st_blksize;		/* Optimal block size for I/O.  */

    int __pad2;
    __blkcnt64_t st_blocks;		/* Number 512-byte blocks allocated. */
# 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
       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;		/* Time of last access.  */
    struct timespec st_mtim;		/* Time of last modification.  */
    struct timespec st_ctim;		/* Time of last status change.  */
# 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
# ifdef __ILP32__
    __ino64_t st_ino;			/* File serial number.	*/
# else
    int __glibc_reserved[2];
# endif
  };
#endif

/* Tell code we have these members.  */
#define	_STATBUF_ST_BLKSIZE
#define _STATBUF_ST_RDEV
/* Nanosecond resolution time values are supported.  */
#define _STATBUF_ST_NSEC

/* Encoding of the file mode.  */

#define	__S_IFMT	0170000	/* These bits determine file type.  */

/* File types.  */
#define	__S_IFDIR	0040000	/* Directory.  */
#define	__S_IFCHR	0020000	/* Character device.  */
#define	__S_IFBLK	0060000	/* Block device.  */
#define	__S_IFREG	0100000	/* Regular file.  */
#define	__S_IFIFO	0010000	/* FIFO.  */
#define	__S_IFLNK	0120000	/* Symbolic link.  */
#define	__S_IFSOCK	0140000	/* Socket.  */

/* POSIX.1b objects.  Note that these macros always evaluate to zero.  But
   they do it by enforcing the correct use of the macros.  */
#define __S_TYPEISMQ(buf)  ((buf)->st_mode - (buf)->st_mode)
#define __S_TYPEISSEM(buf) ((buf)->st_mode - (buf)->st_mode)
#define __S_TYPEISSHM(buf) ((buf)->st_mode - (buf)->st_mode)

/* Protection bits.  */

#define	__S_ISUID	04000	/* Set user ID on execution.  */
#define	__S_ISGID	02000	/* Set group ID on execution.  */
#define	__S_ISVTX	01000	/* Save swapped text after use (sticky).  */
#define	__S_IREAD	0400	/* Read by owner.  */
#define	__S_IWRITE	0200	/* Write by owner.  */
#define	__S_IEXEC	0100	/* Execute by owner.  */

#ifdef __USE_ATFILE
# define UTIME_NOW	((1l << 30) - 1l)
# define UTIME_OMIT	((1l << 30) - 2l)
#endif

#endif	/* bits/stat.h */