/* Generic implementation of statx based on fstatat64.

   Copyright (C) 2018 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/>.  */

#include <errno.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <sys/sysmacros.h>

static inline struct statx_timestamp

statx_convert_timestamp (struct timespec tv)

{

  return (struct statx_timestamp) { tv.tv_sec, tv.tv_nsec };

}

/* Approximate emulation of statx.  This will always fill in

   POSIX-mandated attributes even if the underlying file system does

   not actually support it (for example, GID and UID on file systems

   without UNIX-style permissions).  */

static __attribute__ ((unused)) int

statx_generic (int fd, const char *path, int flags,

               unsigned int mask, struct statx *buf)

{

  /* Flags which need to be cleared before passing them to

     fstatat64.  */

  static const int clear_flags = AT_STATX_SYNC_AS_STAT;

    /* Flags supported by our emulation.  */

  static const int supported_flags

    = AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW | clear_flags;

  if (__glibc_unlikely ((flags & ~supported_flags) != 0))

    {

      __set_errno (EINVAL);

      return -1;

    }

  struct stat64 st;

  int ret = __fstatat64 (fd, path, &st, flags & ~clear_flags);

  if (ret != 0)

    return ret;

  /* 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)

    {

      .stx_mask = STATX_BASIC_STATS,

      .stx_blksize = st.st_blksize,

      .stx_nlink = st.st_nlink,

      .stx_uid = st.st_uid,

      .stx_gid = st.st_gid,

      .stx_mode = st.st_mode,

      .stx_ino = st.st_ino,

      .stx_size = st.st_size,

      .stx_blocks = st.st_blocks,

      .stx_atime = statx_convert_timestamp (st.st_atim),

      .stx_ctime = statx_convert_timestamp (st.st_ctim),

      .stx_mtime = statx_convert_timestamp (st.st_mtim),

      .stx_rdev_major = major (st.st_rdev),

      .stx_rdev_minor = minor (st.st_rdev),

      .stx_dev_major = major (st.st_dev),

      .stx_dev_minor = minor (st.st_dev),

    };

  return 0;

}