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8912421c LC |
1 | /* Work around a bug of lstat on some systems |
2 | ||
61cd9dc9 | 3 | Copyright (C) 1997-2006, 2008-2010 Free Software Foundation, Inc. |
8912421c LC |
4 | |
5 | This program is free software: you can redistribute it and/or modify | |
6 | it under the terms of the GNU Lesser 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 Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser 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. */ | |
26 | typedef 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 | ||
35 | static inline int | |
36 | orig_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 | ||
60 | int | |
61 | rpl_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 */ |