1/* Work around an fstatat bug on Solaris 9.
2
3   Copyright (C) 2006, 2009-2010 Free Software Foundation, Inc.
4
5   This program is free software: you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18/* Written by Paul Eggert and Jim Meyering.  */
19
20#include <config.h>
21
22#include <sys/stat.h>
23
24#include <errno.h>
25#include <fcntl.h>
26#include <string.h>
27
28#if HAVE_FSTATAT
29
30# undef fstatat
31
32/* fstatat should always follow symbolic links that end in /, but on
33   Solaris 9 it doesn't if AT_SYMLINK_NOFOLLOW is specified.
34   Likewise, trailing slash on a non-directory should be an error.
35   These are the same problems that lstat.c and stat.c address, so
36   solve it in a similar way.  */
37
38int
39rpl_fstatat (int fd, char const *file, struct stat *st, int flag)
40{
41  int result = fstatat (fd, file, st, flag);
42  size_t len;
43
44  if (result != 0)
45    return result;
46  len = strlen (file);
47  if (flag & AT_SYMLINK_NOFOLLOW)
48    {
49      /* Fix lstat behavior.  */
50      if (file[len - 1] != '/' || S_ISDIR (st->st_mode))
51        return 0;
52      if (!S_ISLNK (st->st_mode))
53        {
54          errno = ENOTDIR;
55          return -1;
56        }
57      result = fstatat (fd, file, st, flag & ~AT_SYMLINK_NOFOLLOW);
58    }
59  /* Fix stat behavior.  */
60  if (result == 0 && !S_ISDIR (st->st_mode) && file[len - 1] == '/')
61    {
62      errno = ENOTDIR;
63      return -1;
64    }
65  return result;
66}
67
68#else /* !HAVE_FSTATAT */
69
70/* On mingw, the gnulib <sys/stat.h> defines `stat' as a function-like
71   macro; but using it in AT_FUNC_F2 causes compilation failure
72   because the preprocessor sees a use of a macro that requires two
73   arguments but is only given one.  Hence, we need an inline
74   forwarder to get past the preprocessor.  */
75static inline int
76stat_func (char const *name, struct stat *st)
77{
78  return stat (name, st);
79}
80
81/* Likewise, if there is no native `lstat', then the gnulib
82   <sys/stat.h> defined it as stat, which also needs adjustment.  */
83# if !HAVE_LSTAT
84#  undef lstat
85#  define lstat stat_func
86# endif
87
88/* Replacement for Solaris' function by the same name.
89   <http://www.google.com/search?q=fstatat+site:docs.sun.com>
90   First, try to simulate it via l?stat ("/proc/self/fd/FD/FILE").
91   Failing that, simulate it via save_cwd/fchdir/(stat|lstat)/restore_cwd.
92   If either the save_cwd or the restore_cwd fails (relatively unlikely),
93   then give a diagnostic and exit nonzero.
94   Otherwise, this function works just like Solaris' fstatat.  */
95
96# define AT_FUNC_NAME fstatat
97# define AT_FUNC_F1 lstat
98# define AT_FUNC_F2 stat_func
99# define AT_FUNC_USE_F1_COND AT_SYMLINK_NOFOLLOW
100# define AT_FUNC_POST_FILE_PARAM_DECLS , struct stat *st, int flag
101# define AT_FUNC_POST_FILE_ARGS        , st
102# include "at-func.c"
103# undef AT_FUNC_NAME
104# undef AT_FUNC_F1
105# undef AT_FUNC_F2
106# undef AT_FUNC_USE_F1_COND
107# undef AT_FUNC_POST_FILE_PARAM_DECLS
108# undef AT_FUNC_POST_FILE_ARGS
109
110#endif /* !HAVE_FSTATAT */
111