| 1 | /* Work around a bug of lstat on some systems |
| 2 | |
| 3 | Copyright (C) 1997-2006, 2008-2016 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 */ |