/[path-sandbox]/trunk/canonicalize.c
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Contents of /trunk/canonicalize.c

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Revision 30 - (show annotations) (download) (as text)
Wed Mar 2 09:04:45 2005 UTC (9 years, 7 months ago) by azarah
File MIME type: text/x-csrc
File size: 4784 byte(s)
White space fixes.

1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
19
20 /*
21 * $Header$
22 */
23
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 #include <limits.h>
28 #include <sys/param.h>
29 #include <sys/stat.h>
30 #include <errno.h>
31 #include <stddef.h>
32
33 #include "config.h"
34 #include "localdecls.h"
35
36 #ifndef __set_errno
37 # define __set_errno(val) errno = (val)
38 #endif
39
40 /* Return the canonical absolute name of file NAME. A canonical name
41 does not contain any `.', `..' components nor any repeated path
42 separators ('/') or symlinks. All path components must exist. If
43 RESOLVED is null, the result is malloc'd; otherwise, if the
44 canonical name is SB_PATH_MAX chars or more, returns null with `errno'
45 set to ENAMETOOLONG; if the name fits in fewer than SB_PATH_MAX chars,
46 returns the name in RESOLVED. If the name cannot be resolved and
47 RESOLVED is non-NULL, it contains the path of the first component
48 that cannot be resolved. If the path can be resolved, RESOLVED
49 holds the same value as the value returned. */
50
51 /* Modified: 19 Aug 2002; Martin Schlemmer <azarah@gentoo.org>
52 *
53 * Cleaned up unneeded stuff, and change so that it will not
54 * resolve symlinks. Also prepended a 'e' to functions that
55 * I did not rip out.
56 *
57 */
58
59 static char *
60 erealpath(const char *name, char *resolved)
61 {
62 char *rpath, *dest;
63 const char *start, *end, *rpath_limit;
64 long int path_max;
65
66 if (name == NULL) {
67 /* As per Single Unix Specification V2 we must return an error if
68 either parameter is a null pointer. We extend this to allow
69 the RESOLVED parameter to be NULL in case the we are expected to
70 allocate the room for the return value. */
71 __set_errno(EINVAL);
72 return NULL;
73 }
74
75 if (name[0] == '\0') {
76 /* As per Single Unix Specification V2 we must return an error if
77 the name argument points to an empty string. */
78 __set_errno(ENOENT);
79 return NULL;
80 }
81 #ifdef SB_PATH_MAX
82 path_max = SB_PATH_MAX;
83 #else
84 path_max = pathconf(name, _PC_PATH_MAX);
85 if (path_max <= 0)
86 path_max = 1024;
87 #endif
88
89 if (resolved == NULL) {
90 rpath = malloc(path_max);
91 if (rpath == NULL)
92 return NULL;
93 } else
94 rpath = resolved;
95 rpath_limit = rpath + path_max;
96
97 if (name[0] != '/') {
98 if (!egetcwd(rpath, path_max)) {
99 rpath[0] = '\0';
100 goto error;
101 }
102 dest = strchr(rpath, '\0');
103 } else {
104 rpath[0] = '/';
105 dest = rpath + 1;
106 }
107
108 for (start = end = name; *start; start = end) {
109 /* Skip sequence of multiple path-separators. */
110 while (*start == '/')
111 ++start;
112
113 /* Find end of path component. */
114 for (end = start; *end && *end != '/'; ++end)
115 /* Nothing. */ ;
116
117 if (end - start == 0)
118 break;
119 else if (end - start == 1 && start[0] == '.')
120 /* nothing */ ;
121 else if (end - start == 2 && start[0] == '.' && start[1] == '.') {
122 /* Back up to previous component, ignore if at root already. */
123 if (dest > rpath + 1)
124 while ((--dest)[-1] != '/') ;
125 } else {
126 size_t new_size;
127
128 if (dest[-1] != '/')
129 *dest++ = '/';
130
131 if (dest + (end - start) >= rpath_limit) {
132 ptrdiff_t dest_offset = dest - rpath;
133 char *new_rpath;
134
135 if (resolved) {
136 __set_errno(ENAMETOOLONG);
137 if (dest > rpath + 1)
138 dest--;
139 *dest = '\0';
140 goto error;
141 }
142 new_size = rpath_limit - rpath;
143 if (end - start + 1 > path_max)
144 new_size += end - start + 1;
145 else
146 new_size += path_max;
147 new_rpath = (char *) realloc(rpath, new_size);
148 if (new_rpath == NULL)
149 goto error;
150 rpath = new_rpath;
151 rpath_limit = rpath + new_size;
152
153 dest = rpath + dest_offset;
154 }
155
156 dest = __mempcpy(dest, start, end - start);
157 *dest = '\0';
158 }
159 }
160 #if 1
161 if (dest > rpath + 1 && dest[-1] == '/')
162 --dest;
163 #endif
164 *dest = '\0';
165
166 return resolved ? rpath : memcpy(resolved, rpath, dest - rpath + 1);
167
168 error:
169 if (resolved)
170 strncpy(resolved, rpath, path_max - 1);
171 else
172 free(rpath);
173 return NULL;
174 }
175
176 // vim:noexpandtab noai:cindent ai

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