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];
66 if (path[0] == '\0') {
69 } else if (path[0] == '/') {
75 left_len = strlcpy(left, path + 1, sizeof(left));
77 if (getcwd(resolved, PATH_MAX) == NULL) {
78 strlcpy(resolved, ".", PATH_MAX);
81 resolved_len = strlen(resolved);
82 left_len = strlcpy(left, path, sizeof(left));
84 if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
90 * Iterate over path components in `left'.
92 while (left_len != 0) {
94 * Extract the next path component and adjust `left'
97 p = strchr(left, '/');
98 s = p ? p : left + left_len;
99 if (s >= left + sizeof(next_token)) {
100 errno = ENAMETOOLONG;
103 memcpy(next_token, left, s - left);
104 next_token[s - left] = '\0';
105 left_len -= s - left;
107 memmove(left, s + 1, left_len + 1);
108 if (resolved[resolved_len - 1] != '/') {
109 if (resolved_len + 1 >= PATH_MAX) {
110 errno = ENAMETOOLONG;
113 resolved[resolved_len++] = '/';
114 resolved[resolved_len] = '\0';
116 if (next_token[0] == '\0')
118 else if (strcmp(next_token, ".") == 0)
120 else if (strcmp(next_token, "..") == 0) {
122 * Strip the last path component except when we have
125 if (resolved_len > 1) {
126 resolved[resolved_len - 1] = '\0';
127 q = strrchr(resolved, '/') + 1;
129 resolved_len = q - resolved;
135 * Append the next path component and lstat() it. If
136 * lstat() fails we still can return successfully if
137 * there are no more path components left.
139 resolved_len = strlcat(resolved, next_token, PATH_MAX);
140 if (resolved_len >= PATH_MAX) {
141 errno = ENAMETOOLONG;
144 if (lstat(resolved, &sb) != 0) {
145 if (errno == ENOENT && p == NULL) {
151 if (S_ISLNK(sb.st_mode)) {
152 if (symlinks++ > MAXSYMLINKS) {
156 slen = readlink(resolved, my_symlink, sizeof(my_symlink) - 1);
159 my_symlink[slen] = '\0';
160 if (my_symlink[0] == '/') {
163 } else if (resolved_len > 1) {
164 /* Strip the last path component. */
165 resolved[resolved_len - 1] = '\0';
166 q = strrchr(resolved, '/') + 1;
168 resolved_len = q - resolved;
172 * If there are any path components left, then
173 * append them to symlink. The result is placed
177 if (my_symlink[slen - 1] != '/') {
178 if (slen + 1 >= (int)sizeof(my_symlink)) {
179 errno = ENAMETOOLONG;
182 my_symlink[slen] = '/';
183 my_symlink[slen + 1] = 0;
185 left_len = strlcat(my_symlink, left, sizeof(left));
186 if (left_len >= sizeof(left)) {
187 errno = ENAMETOOLONG;
191 left_len = strlcpy(left, my_symlink, sizeof(left));
196 * Remove trailing slash except when the resolved pathname
199 if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
200 resolved[resolved_len - 1] = '\0';