1/* Work around a bug of lstat on some systems
2
3   Copyright (C) 1997-2006, 2008-2011 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 Jim Meyering */
19
20#include <config.h>
21
22#if !HAVE_LSTAT
23/* On systems that lack symlinks, our replacement <sys/stat.h> already
24   defined lstat as stat, so there is nothing further to do other than
25   avoid an empty file.  */
26typedef int dummy;
27#else /* HAVE_LSTAT */
28
29/* Get the original definition of lstat.  It might be defined as a macro.  */
30# define __need_system_sys_stat_h
31# include <sys/types.h>
32# include <sys/stat.h>
33# undef __need_system_sys_stat_h
34
35static inline int
36orig_lstat (const char *filename, struct stat *buf)
37{
38  return lstat (filename, buf);
39}
40
41/* Specification.  */
42# include <sys/stat.h>
43
44# include <string.h>
45# include <errno.h>
46
47/* lstat works differently on Linux and Solaris systems.  POSIX (see
48   `pathname resolution' in the glossary) requires that programs like
49   `ls' take into consideration the fact that FILE has a trailing slash
50   when FILE is a symbolic link.  On Linux and Solaris 10 systems, the
51   lstat function already has the desired semantics (in treating
52   `lstat ("symlink/", sbuf)' just like `lstat ("symlink/.", sbuf)',
53   but on Solaris 9 and earlier it does not.
54
55   If FILE has a trailing slash and specifies a symbolic link,
56   then use stat() to get more info on the referent of FILE.
57   If the referent is a non-directory, then set errno to ENOTDIR
58   and return -1.  Otherwise, return stat's result.  */
59
60int
61rpl_lstat (const char *file, struct stat *sbuf)
62{
63  size_t len;
64  int lstat_result = orig_lstat (file, sbuf);
65
66  if (lstat_result != 0)
67    return lstat_result;
68
69  /* This replacement file can blindly check against '/' rather than
70     using the ISSLASH macro, because all platforms with '\\' either
71     lack symlinks (mingw) or have working lstat (cygwin) and thus do
72     not compile this file.  0 len should have already been filtered
73     out above, with a failure return of ENOENT.  */
74  len = strlen (file);
75  if (file[len - 1] != '/' || S_ISDIR (sbuf->st_mode))
76    return 0;
77
78  /* At this point, a trailing slash is only permitted on
79     symlink-to-dir; but it should have found information on the
80     directory, not the symlink.  Call stat() to get info about the
81     link's referent.  Our replacement stat guarantees valid results,
82     even if the symlink is not pointing to a directory.  */
83  if (!S_ISLNK (sbuf->st_mode))
84    {
85      errno = ENOTDIR;
86      return -1;
87    }
88  return stat (file, sbuf);
89}
90
91#endif /* HAVE_LSTAT */
92