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ba61a412 DJ |
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., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, 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 | #endif | |
68 | ||
69 | char * | |
70 | lrealpath (filename) | |
71 | const char *filename; | |
72 | { | |
73 | /* Method 1: The system has a compile time upper bound on a filename | |
74 | path. Use that and realpath() to canonicalize the name. This is | |
75 | the most common case. Note that, if there isn't a compile time | |
76 | upper bound, you want to avoid realpath() at all costs. */ | |
77 | #if defined(REALPATH_LIMIT) | |
78 | { | |
79 | char buf[REALPATH_LIMIT]; | |
80 | const char *rp = realpath (filename, buf); | |
81 | if (rp == NULL) | |
82 | rp = filename; | |
83 | return strdup (rp); | |
84 | } | |
85 | #endif /* REALPATH_LIMIT */ | |
86 | ||
87 | /* Method 2: The host system (i.e., GNU) has the function | |
88 | canonicalize_file_name() which malloc's a chunk of memory and | |
89 | returns that, use that. */ | |
90 | #if defined(HAVE_CANONICALIZE_FILE_NAME) | |
91 | { | |
92 | char *rp = canonicalize_file_name (filename); | |
93 | if (rp == NULL) | |
94 | return strdup (filename); | |
95 | else | |
96 | return rp; | |
97 | } | |
98 | #endif | |
99 | ||
100 | /* Method 3: Now we're getting desperate! The system doesn't have a | |
101 | compile time buffer size and no alternative function. Query the | |
102 | OS, using pathconf(), for the buffer limit. Care is needed | |
103 | though, some systems do not limit PATH_MAX (return -1 for | |
104 | pathconf()) making it impossible to pass a correctly sized buffer | |
105 | to realpath() (it could always overflow). On those systems, we | |
106 | skip this. */ | |
107 | #if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H) | |
108 | { | |
109 | /* Find out the max path size. */ | |
110 | long path_max = pathconf ("/", _PC_PATH_MAX); | |
111 | if (path_max > 0) | |
112 | { | |
113 | /* PATH_MAX is bounded. */ | |
114 | char *buf, *rp, *ret; | |
115 | buf = malloc (path_max); | |
116 | if (buf == NULL) | |
117 | return NULL; | |
118 | rp = realpath (filename, buf); | |
119 | ret = strdup (rp ? rp : filename); | |
120 | free (buf); | |
121 | return ret; | |
122 | } | |
123 | } | |
124 | #endif | |
125 | ||
126 | /* This system is a lost cause, just duplicate the filename. */ | |
127 | return strdup (filename); | |
128 | } |