1 /* $OpenBSD: realpath.c,v 1.20 2015/10/13 20:55:37 millert Exp $ */
3 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The names of the authors may not be used to endorse or promote
14 * products derived from this software without specific prior written
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 /* OPENBSD ORIGINAL: lib/libc/stdlib/realpath.c */
34 #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH)
36 #include <sys/types.h>
37 #include <sys/param.h>
48 # define SYMLOOP_MAX 32
51 /* A slightly modified copy of this file exists in libexec/ld.so */
54 * char *realpath(const char *path, char resolved[PATH_MAX]);
56 * Find the real name of path, by removing all ".", ".." and symlink
57 * components. Returns (resolved) on success, or (NULL) on failure,
58 * in which case the path which caused trouble is left in (resolved).
61 realpath(const char *path
, char *resolved
)
65 size_t left_len
, resolved_len
;
67 int serrno
, slen
, mem_allocated
;
68 char left
[PATH_MAX
], next_token
[PATH_MAX
], symlink
[PATH_MAX
];
70 if (path
[0] == '\0') {
77 if (resolved
== NULL
) {
78 resolved
= malloc(PATH_MAX
);
92 left_len
= strlcpy(left
, path
+ 1, sizeof(left
));
94 if (getcwd(resolved
, PATH_MAX
) == NULL
) {
98 strlcpy(resolved
, ".", PATH_MAX
);
101 resolved_len
= strlen(resolved
);
102 left_len
= strlcpy(left
, path
, sizeof(left
));
104 if (left_len
>= sizeof(left
) || resolved_len
>= PATH_MAX
) {
105 errno
= ENAMETOOLONG
;
110 * Iterate over path components in `left'.
112 while (left_len
!= 0) {
114 * Extract the next path component and adjust `left'
117 p
= strchr(left
, '/');
118 s
= p
? p
: left
+ left_len
;
119 if (s
- left
>= (ptrdiff_t)sizeof(next_token
)) {
120 errno
= ENAMETOOLONG
;
123 memcpy(next_token
, left
, s
- left
);
124 next_token
[s
- left
] = '\0';
125 left_len
-= s
- left
;
127 memmove(left
, s
+ 1, left_len
+ 1);
128 if (resolved
[resolved_len
- 1] != '/') {
129 if (resolved_len
+ 1 >= PATH_MAX
) {
130 errno
= ENAMETOOLONG
;
133 resolved
[resolved_len
++] = '/';
134 resolved
[resolved_len
] = '\0';
136 if (next_token
[0] == '\0')
138 else if (strcmp(next_token
, ".") == 0)
140 else if (strcmp(next_token
, "..") == 0) {
142 * Strip the last path component except when we have
145 if (resolved_len
> 1) {
146 resolved
[resolved_len
- 1] = '\0';
147 q
= strrchr(resolved
, '/') + 1;
149 resolved_len
= q
- resolved
;
155 * Append the next path component and lstat() it. If
156 * lstat() fails we still can return successfully if
157 * there are no more path components left.
159 resolved_len
= strlcat(resolved
, next_token
, PATH_MAX
);
160 if (resolved_len
>= PATH_MAX
) {
161 errno
= ENAMETOOLONG
;
164 if (lstat(resolved
, &sb
) != 0) {
165 if (errno
== ENOENT
&& p
== NULL
) {
171 if (S_ISLNK(sb
.st_mode
)) {
172 if (symlinks
++ > SYMLOOP_MAX
) {
176 slen
= readlink(resolved
, symlink
, sizeof(symlink
) - 1);
179 symlink
[slen
] = '\0';
180 if (symlink
[0] == '/') {
183 } else if (resolved_len
> 1) {
184 /* Strip the last path component. */
185 resolved
[resolved_len
- 1] = '\0';
186 q
= strrchr(resolved
, '/') + 1;
188 resolved_len
= q
- resolved
;
192 * If there are any path components left, then
193 * append them to symlink. The result is placed
197 if (symlink
[slen
- 1] != '/') {
199 (ptrdiff_t)sizeof(symlink
)) {
200 errno
= ENAMETOOLONG
;
204 symlink
[slen
+ 1] = 0;
206 left_len
= strlcat(symlink
, left
, sizeof(symlink
));
207 if (left_len
>= sizeof(symlink
)) {
208 errno
= ENAMETOOLONG
;
212 left_len
= strlcpy(left
, symlink
, sizeof(left
));
217 * Remove trailing slash except when the resolved pathname
220 if (resolved_len
> 1 && resolved
[resolved_len
- 1] == '/')
221 resolved
[resolved_len
- 1] = '\0';
229 #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */