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comparison libiberty/lrealpath.c @ 0:a06113de4d67

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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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children 04ced10e8804
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-1:000000000000 0:a06113de4d67
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 }