/* Work around an fstatat bug on Solaris 9.

   Copyright (C) 2006, 2009-2017 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert and Jim Meyering.  */

/* If the user's config.h happens to include <sys/stat.h>, let it include only

   the system's <sys/stat.h> here, so that orig_fstatat doesn't recurse to

   rpl_fstatat.  */

#define __need_system_sys_stat_h

#include <config.h>

/* Get the original definition of fstatat.  It might be defined as a macro.  */

#include <sys/types.h>

#include <sys/stat.h>

#undef __need_system_sys_stat_h

#if HAVE_FSTATAT

static int

orig_fstatat (int fd, char const *filename, struct stat *buf, int flags)

{

  return fstatat (fd, filename, buf, flags);

}

#endif

/* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc

   eliminates this include because of the preliminary #include <sys/stat.h>

   above.  */

#include "sys/stat.h"

#include <errno.h>

#include <fcntl.h>

#include <string.h>

#if HAVE_FSTATAT && HAVE_WORKING_FSTATAT_ZERO_FLAG

# ifndef LSTAT_FOLLOWS_SLASHED_SYMLINK

#  define LSTAT_FOLLOWS_SLASHED_SYMLINK 0

# endif

/* fstatat should always follow symbolic links that end in /, but on

   Solaris 9 it doesn't if AT_SYMLINK_NOFOLLOW is specified.

   Likewise, trailing slash on a non-directory should be an error.

   These are the same problems that lstat.c and stat.c address, so

   solve it in a similar way.

   AIX 7.1 fstatat (AT_FDCWD, ..., 0) always fails, which is a bug.

   Work around this bug if FSTATAT_AT_FDCWD_0_BROKEN is nonzero.  */

int

rpl_fstatat (int fd, char const *file, struct stat *st, int flag)

{

  int result = orig_fstatat (fd, file, st, flag);

  size_t len;

  if (LSTAT_FOLLOWS_SLASHED_SYMLINK || result != 0)

    return result;

  len = strlen (file);

  if (flag & AT_SYMLINK_NOFOLLOW)

    {

      /* Fix lstat behavior.  */

      if (file[len - 1] != '/' || S_ISDIR (st->st_mode))

        return 0;

      if (!S_ISLNK (st->st_mode))

        {

          errno = ENOTDIR;

          return -1;

        }

      result = orig_fstatat (fd, file, st, flag & ~AT_SYMLINK_NOFOLLOW);

    }

  /* Fix stat behavior.  */

  if (result == 0 && !S_ISDIR (st->st_mode) && file[len - 1] == '/')

    {

      errno = ENOTDIR;

      return -1;

    }

  return result;

}

#else /* ! (HAVE_FSTATAT && HAVE_WORKING_FSTATAT_ZERO_FLAG) */

/* On mingw, the gnulib <sys/stat.h> defines 'stat' as a function-like

   macro; but using it in AT_FUNC_F2 causes compilation failure

   because the preprocessor sees a use of a macro that requires two

   arguments but is only given one.  Hence, we need an inline

   forwarder to get past the preprocessor.  */

static int

stat_func (char const *name, struct stat *st)

{

  return stat (name, st);

}

/* Likewise, if there is no native 'lstat', then the gnulib

   <sys/stat.h> defined it as stat, which also needs adjustment.  */

# if !HAVE_LSTAT

#  undef lstat

#  define lstat stat_func

# endif

/* Replacement for Solaris' function by the same name.

   <http://www.google.com/search?q=fstatat+site:docs.sun.com>

   First, try to simulate it via l?stat ("/proc/self/fd/FD/FILE").

   Failing that, simulate it via save_cwd/fchdir/(stat|lstat)/restore_cwd.

   If either the save_cwd or the restore_cwd fails (relatively unlikely),

   then give a diagnostic and exit nonzero.

   Otherwise, this function works just like Solaris' fstatat.  */

# define AT_FUNC_NAME fstatat

# define AT_FUNC_F1 lstat

# define AT_FUNC_F2 stat_func

# define AT_FUNC_USE_F1_COND AT_SYMLINK_NOFOLLOW

# define AT_FUNC_POST_FILE_PARAM_DECLS , struct stat *st, int flag

# define AT_FUNC_POST_FILE_ARGS        , st

# include "at-func.c"

# undef AT_FUNC_NAME

# undef AT_FUNC_F1

# undef AT_FUNC_F2

# undef AT_FUNC_USE_F1_COND

# undef AT_FUNC_POST_FILE_PARAM_DECLS

# undef AT_FUNC_POST_FILE_ARGS

#endif /* !HAVE_FSTATAT */