2 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. The names of the authors may not be used to endorse or promote
13 * products derived from this software without specific prior written
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * @(#)realpath.c 8.1 (Berkeley) 2/16/94
29 * $FreeBSD: src/lib/libc/stdlib/realpath.c,v 1.20 2003/05/28 08:23:01 fjoe Exp $
30 * $DragonFly: src/lib/libc/stdlib/realpath.c,v 1.4 2005/04/28 13:47:15 joerg Exp $
33 #include "namespace.h"
34 #include <sys/param.h>
41 #include "un-namespace.h"
44 * char *realpath(const char *path, char resolved[PATH_MAX]);
46 * Find the real name of path, by removing all ".", ".." and symlink
47 * components. Returns (resolved) on success, or (NULL) on failure,
48 * in which case the path which caused trouble is left in (resolved).
51 realpath(const char *path
, char resolved
[PATH_MAX
])
55 size_t left_len
, resolved_len
;
58 char left
[PATH_MAX
], next_token
[PATH_MAX
], my_symlink
[PATH_MAX
];
68 left_len
= strlcpy(left
, path
+ 1, sizeof(left
));
70 if (getcwd(resolved
, PATH_MAX
) == NULL
) {
71 strlcpy(resolved
, ".", PATH_MAX
);
74 resolved_len
= strlen(resolved
);
75 left_len
= strlcpy(left
, path
, sizeof(left
));
77 if (left_len
>= sizeof(left
) || resolved_len
>= PATH_MAX
) {
83 * Iterate over path components in `left'.
85 while (left_len
!= 0) {
87 * Extract the next path component and adjust `left'
90 p
= strchr(left
, '/');
91 s
= p
? p
: left
+ left_len
;
92 if (s
>= left
+ sizeof(next_token
)) {
96 memcpy(next_token
, left
, s
- left
);
97 next_token
[s
- left
] = '\0';
100 memmove(left
, s
+ 1, left_len
+ 1);
101 if (resolved
[resolved_len
- 1] != '/') {
102 if (resolved_len
+ 1 >= PATH_MAX
) {
103 errno
= ENAMETOOLONG
;
106 resolved
[resolved_len
++] = '/';
107 resolved
[resolved_len
] = '\0';
109 if (next_token
[0] == '\0')
111 else if (strcmp(next_token
, ".") == 0)
113 else if (strcmp(next_token
, "..") == 0) {
115 * Strip the last path component except when we have
118 if (resolved_len
> 1) {
119 resolved
[resolved_len
- 1] = '\0';
120 q
= strrchr(resolved
, '/') + 1;
122 resolved_len
= q
- resolved
;
128 * Append the next path component and lstat() it. If
129 * lstat() fails we still can return successfully if
130 * there are no more path components left.
132 resolved_len
= strlcat(resolved
, next_token
, PATH_MAX
);
133 if (resolved_len
>= PATH_MAX
) {
134 errno
= ENAMETOOLONG
;
137 if (lstat(resolved
, &sb
) != 0) {
138 if (errno
== ENOENT
&& p
== NULL
) {
144 if (S_ISLNK(sb
.st_mode
)) {
145 if (symlinks
++ > MAXSYMLINKS
) {
149 slen
= readlink(resolved
, my_symlink
, sizeof(my_symlink
) - 1);
152 my_symlink
[slen
] = '\0';
153 if (my_symlink
[0] == '/') {
156 } else if (resolved_len
> 1) {
157 /* Strip the last path component. */
158 resolved
[resolved_len
- 1] = '\0';
159 q
= strrchr(resolved
, '/') + 1;
161 resolved_len
= q
- resolved
;
165 * If there are any path components left, then
166 * append them to symlink. The result is placed
170 if (my_symlink
[slen
- 1] != '/') {
171 if (slen
+ 1 >= (int)sizeof(my_symlink
)) {
172 errno
= ENAMETOOLONG
;
175 my_symlink
[slen
] = '/';
176 my_symlink
[slen
+ 1] = 0;
178 left_len
= strlcat(my_symlink
, left
, sizeof(left
));
179 if (left_len
>= sizeof(left
)) {
180 errno
= ENAMETOOLONG
;
184 left_len
= strlcpy(left
, my_symlink
, sizeof(left
));
189 * Remove trailing slash except when the resolved pathname
192 if (resolved_len
> 1 && resolved
[resolved_len
- 1] == '/')
193 resolved
[resolved_len
- 1] = '\0';