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1 | /* Work around a bug of lstat on some systems |
2 | ||
3 | Copyright (C) 1997-2006, 2008-2012 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 | /* If the user's config.h happens to include <sys/stat.h>, let it include only | |
21 | the system's <sys/stat.h> here, so that orig_lstat doesn't recurse to | |
22 | rpl_lstat. */ | |
23 | #define __need_system_sys_stat_h | |
24 | #include <config.h> | |
25 | ||
26 | #if !HAVE_LSTAT | |
27 | /* On systems that lack symlinks, our replacement <sys/stat.h> already | |
28 | defined lstat as stat, so there is nothing further to do other than | |
29 | avoid an empty file. */ | |
30 | typedef int dummy; | |
31 | #else /* HAVE_LSTAT */ | |
32 | ||
33 | /* Get the original definition of lstat. It might be defined as a macro. */ | |
34 | # include <sys/types.h> | |
35 | # include <sys/stat.h> | |
36 | # undef __need_system_sys_stat_h | |
37 | ||
38 | static int | |
39 | orig_lstat (const char *filename, struct stat *buf) | |
40 | { | |
41 | return lstat (filename, buf); | |
42 | } | |
43 | ||
44 | /* Specification. */ | |
45 | /* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc | |
46 | eliminates this include because of the preliminary #include <sys/stat.h> | |
47 | above. */ | |
48 | # include "sys/stat.h" | |
49 | ||
50 | # include <string.h> | |
51 | # include <errno.h> | |
52 | ||
53 | /* lstat works differently on Linux and Solaris systems. POSIX (see | |
54 | "pathname resolution" in the glossary) requires that programs like | |
55 | 'ls' take into consideration the fact that FILE has a trailing slash | |
56 | when FILE is a symbolic link. On Linux and Solaris 10 systems, the | |
57 | lstat function already has the desired semantics (in treating | |
58 | 'lstat ("symlink/", sbuf)' just like 'lstat ("symlink/.", sbuf)', | |
59 | but on Solaris 9 and earlier it does not. | |
60 | ||
61 | If FILE has a trailing slash and specifies a symbolic link, | |
62 | then use stat() to get more info on the referent of FILE. | |
63 | If the referent is a non-directory, then set errno to ENOTDIR | |
64 | and return -1. Otherwise, return stat's result. */ | |
65 | ||
66 | int | |
67 | rpl_lstat (const char *file, struct stat *sbuf) | |
68 | { | |
69 | size_t len; | |
70 | int lstat_result = orig_lstat (file, sbuf); | |
71 | ||
72 | if (lstat_result != 0) | |
73 | return lstat_result; | |
74 | ||
75 | /* This replacement file can blindly check against '/' rather than | |
76 | using the ISSLASH macro, because all platforms with '\\' either | |
77 | lack symlinks (mingw) or have working lstat (cygwin) and thus do | |
78 | not compile this file. 0 len should have already been filtered | |
79 | out above, with a failure return of ENOENT. */ | |
80 | len = strlen (file); | |
81 | if (file[len - 1] != '/' || S_ISDIR (sbuf->st_mode)) | |
82 | return 0; | |
83 | ||
84 | /* At this point, a trailing slash is only permitted on | |
85 | symlink-to-dir; but it should have found information on the | |
86 | directory, not the symlink. Call stat() to get info about the | |
87 | link's referent. Our replacement stat guarantees valid results, | |
88 | even if the symlink is not pointing to a directory. */ | |
89 | if (!S_ISLNK (sbuf->st_mode)) | |
90 | { | |
91 | errno = ENOTDIR; | |
92 | return -1; | |
93 | } | |
94 | return stat (file, sbuf); | |
95 | } | |
96 | ||
97 | #endif /* HAVE_LSTAT */ |