| 1 | /* Libiberty realpath. Like realpath, but more consistent behavior. |
| 2 | Based on gdb_realpath from GDB. |
| 3 | |
| 4 | Copyright 2003 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of the libiberty library. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 51 Franklin Street - Fifth Floor, |
| 21 | Boston, MA 02110-1301, USA. */ |
| 22 | |
| 23 | /* |
| 24 | |
| 25 | @deftypefn Replacement {const char*} lrealpath (const char *@var{name}) |
| 26 | |
| 27 | Given a pointer to a string containing a pathname, returns a canonical |
| 28 | version of the filename. Symlinks will be resolved, and ``.'' and ``..'' |
| 29 | components will be simplified. The returned value will be allocated using |
| 30 | @code{malloc}, or @code{NULL} will be returned on a memory allocation error. |
| 31 | |
| 32 | @end deftypefn |
| 33 | |
| 34 | */ |
| 35 | |
| 36 | #include "config.h" |
| 37 | #include "ansidecl.h" |
| 38 | #include "libiberty.h" |
| 39 | |
| 40 | #ifdef HAVE_LIMITS_H |
| 41 | #include <limits.h> |
| 42 | #endif |
| 43 | #ifdef HAVE_STDLIB_H |
| 44 | #include <stdlib.h> |
| 45 | #endif |
| 46 | #ifdef HAVE_UNISTD_H |
| 47 | #include <unistd.h> |
| 48 | #endif |
| 49 | #ifdef HAVE_STRING_H |
| 50 | #include <string.h> |
| 51 | #endif |
| 52 | |
| 53 | /* On GNU libc systems the declaration is only visible with _GNU_SOURCE. */ |
| 54 | #if defined(HAVE_CANONICALIZE_FILE_NAME) \ |
| 55 | && defined(NEED_DECLARATION_CANONICALIZE_FILE_NAME) |
| 56 | extern char *canonicalize_file_name (const char *); |
| 57 | #endif |
| 58 | |
| 59 | #if defined(HAVE_REALPATH) |
| 60 | # if defined (PATH_MAX) |
| 61 | # define REALPATH_LIMIT PATH_MAX |
| 62 | # else |
| 63 | # if defined (MAXPATHLEN) |
| 64 | # define REALPATH_LIMIT MAXPATHLEN |
| 65 | # endif |
| 66 | # endif |
| 67 | #else |
| 68 | /* cygwin has realpath, so it won't get here. */ |
| 69 | # if defined (_WIN32) |
| 70 | # define WIN32_LEAN_AND_MEAN |
| 71 | # include <windows.h> /* for GetFullPathName */ |
| 72 | # endif |
| 73 | #endif |
| 74 | |
| 75 | char * |
| 76 | lrealpath (const char *filename) |
| 77 | { |
| 78 | /* Method 1: The system has a compile time upper bound on a filename |
| 79 | path. Use that and realpath() to canonicalize the name. This is |
| 80 | the most common case. Note that, if there isn't a compile time |
| 81 | upper bound, you want to avoid realpath() at all costs. */ |
| 82 | #if defined(REALPATH_LIMIT) |
| 83 | { |
| 84 | char buf[REALPATH_LIMIT]; |
| 85 | const char *rp = realpath (filename, buf); |
| 86 | if (rp == NULL) |
| 87 | rp = filename; |
| 88 | return strdup (rp); |
| 89 | } |
| 90 | #endif /* REALPATH_LIMIT */ |
| 91 | |
| 92 | /* Method 2: The host system (i.e., GNU) has the function |
| 93 | canonicalize_file_name() which malloc's a chunk of memory and |
| 94 | returns that, use that. */ |
| 95 | #if defined(HAVE_CANONICALIZE_FILE_NAME) |
| 96 | { |
| 97 | char *rp = canonicalize_file_name (filename); |
| 98 | if (rp == NULL) |
| 99 | return strdup (filename); |
| 100 | else |
| 101 | return rp; |
| 102 | } |
| 103 | #endif |
| 104 | |
| 105 | /* Method 3: Now we're getting desperate! The system doesn't have a |
| 106 | compile time buffer size and no alternative function. Query the |
| 107 | OS, using pathconf(), for the buffer limit. Care is needed |
| 108 | though, some systems do not limit PATH_MAX (return -1 for |
| 109 | pathconf()) making it impossible to pass a correctly sized buffer |
| 110 | to realpath() (it could always overflow). On those systems, we |
| 111 | skip this. */ |
| 112 | #if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H) |
| 113 | { |
| 114 | /* Find out the max path size. */ |
| 115 | long path_max = pathconf ("/", _PC_PATH_MAX); |
| 116 | if (path_max > 0) |
| 117 | { |
| 118 | /* PATH_MAX is bounded. */ |
| 119 | char *buf, *rp, *ret; |
| 120 | buf = (char *) malloc (path_max); |
| 121 | if (buf == NULL) |
| 122 | return NULL; |
| 123 | rp = realpath (filename, buf); |
| 124 | ret = strdup (rp ? rp : filename); |
| 125 | free (buf); |
| 126 | return ret; |
| 127 | } |
| 128 | } |
| 129 | #endif |
| 130 | |
| 131 | /* The MS Windows method. If we don't have realpath, we assume we |
| 132 | don't have symlinks and just canonicalize to a Windows absolute |
| 133 | path. GetFullPath converts ../ and ./ in relative paths to |
| 134 | absolute paths, filling in current drive if one is not given |
| 135 | or using the current directory of a specified drive (eg, "E:foo"). |
| 136 | It also converts all forward slashes to back slashes. */ |
| 137 | #if defined (_WIN32) |
| 138 | { |
| 139 | char buf[MAX_PATH]; |
| 140 | char* basename; |
| 141 | DWORD len = GetFullPathName (filename, MAX_PATH, buf, &basename); |
| 142 | if (len == 0 || len > MAX_PATH - 1) |
| 143 | return strdup (filename); |
| 144 | else |
| 145 | { |
| 146 | /* The file system is case-preserving but case-insensitive, |
| 147 | Canonicalize to lowercase, using the codepage associated |
| 148 | with the process locale. */ |
| 149 | CharLowerBuff (buf, len); |
| 150 | return strdup (buf); |
| 151 | } |
| 152 | } |
| 153 | #endif |
| 154 | |
| 155 | /* This system is a lost cause, just duplicate the filename. */ |
| 156 | return strdup (filename); |
| 157 | } |