1 /* Libiberty realpath. Like realpath, but more consistent behavior.
2 Based on gdb_realpath from GDB.
4 Copyright 2003 Free Software Foundation, Inc.
6 This file is part of the libiberty library.
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.
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.
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. */
25 @deftypefn Replacement {const char*} lrealpath (const char *@var{name})
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.
38 #include "libiberty.h"
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 *);
59 #if defined(HAVE_REALPATH)
60 # if defined (PATH_MAX)
61 # define REALPATH_LIMIT PATH_MAX
63 # if defined (MAXPATHLEN)
64 # define REALPATH_LIMIT MAXPATHLEN
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)
79 char buf
[REALPATH_LIMIT
];
80 const char *rp
= realpath (filename
, buf
);
85 #endif /* REALPATH_LIMIT */
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)
92 char *rp
= canonicalize_file_name (filename
);
94 return strdup (filename
);
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
107 #if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H)
109 /* Find out the max path size. */
110 long path_max
= pathconf ("/", _PC_PATH_MAX
);
113 /* PATH_MAX is bounded. */
114 char *buf
, *rp
, *ret
;
115 buf
= malloc (path_max
);
118 rp
= realpath (filename
, buf
);
119 ret
= strdup (rp
? rp
: filename
);
126 /* This system is a lost cause, just duplicate the filename. */
127 return strdup (filename
);
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