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

Andreas Schwab
2016-02-29T16:00:36Z

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Arnd Bergmann <arnd@arndb.de> 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@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

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/* 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 */