1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
/* Libiberty realpath. Like realpath, but more consistent behavior.
Based on gdb_realpath from GDB.
Copyright 2003 Free Software Foundation, Inc.
This file is part of the libiberty library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/*
@deftypefn Replacement {const char*} lrealpath (const char *@var{name})
Given a pointer to a string containing a pathname, returns a canonical
version of the filename. Symlinks will be resolved, and ``.'' and ``..''
components will be simplified. The returned value will be allocated using
@code{malloc}, or @code{NULL} will be returned on a memory allocation error.
@end deftypefn
*/
#include "config.h"
#include "ansidecl.h"
#include "libiberty.h"
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
/* On GNU libc systems the declaration is only visible with _GNU_SOURCE. */
#if defined(HAVE_CANONICALIZE_FILE_NAME) \
&& defined(NEED_DECLARATION_CANONICALIZE_FILE_NAME)
extern char *canonicalize_file_name (const char *);
#endif
#if defined(HAVE_REALPATH)
# if defined (PATH_MAX)
# define REALPATH_LIMIT PATH_MAX
# else
# if defined (MAXPATHLEN)
# define REALPATH_LIMIT MAXPATHLEN
# endif
# endif
#endif
char *
lrealpath (filename)
const char *filename;
{
/* Method 1: The system has a compile time upper bound on a filename
path. Use that and realpath() to canonicalize the name. This is
the most common case. Note that, if there isn't a compile time
upper bound, you want to avoid realpath() at all costs. */
#if defined(REALPATH_LIMIT)
{
char buf[REALPATH_LIMIT];
const char *rp = realpath (filename, buf);
if (rp == NULL)
rp = filename;
return strdup (rp);
}
#endif /* REALPATH_LIMIT */
/* Method 2: The host system (i.e., GNU) has the function
canonicalize_file_name() which malloc's a chunk of memory and
returns that, use that. */
#if defined(HAVE_CANONICALIZE_FILE_NAME)
{
char *rp = canonicalize_file_name (filename);
if (rp == NULL)
return strdup (filename);
else
return rp;
}
#endif
/* Method 3: Now we're getting desperate! The system doesn't have a
compile time buffer size and no alternative function. Query the
OS, using pathconf(), for the buffer limit. Care is needed
though, some systems do not limit PATH_MAX (return -1 for
pathconf()) making it impossible to pass a correctly sized buffer
to realpath() (it could always overflow). On those systems, we
skip this. */
#if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H)
{
/* Find out the max path size. */
long path_max = pathconf ("/", _PC_PATH_MAX);
if (path_max > 0)
{
/* PATH_MAX is bounded. */
char *buf, *rp, *ret;
buf = malloc (path_max);
if (buf == NULL)
return NULL;
rp = realpath (filename, buf);
ret = strdup (rp ? rp : filename);
free (buf);
return ret;
}
}
#endif
/* This system is a lost cause, just duplicate the filename. */
return strdup (filename);
}
|
