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 1.9.2.2 2003/06/02 13:31:16 fjoe Exp $
30 * $DragonFly: src/lib/libc/stdlib/realpath.c,v 1.3 2005/01/31 22:29:42 dillon 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], 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, symlink, sizeof(symlink) - 1);
152 symlink[slen] = '\0';
153 if (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 (symlink[slen - 1] != '/') {
171 if (slen + 1 >= sizeof(symlink)) {
172 errno = ENAMETOOLONG;
176 symlink[slen + 1] = 0;
178 left_len = strlcat(symlink, left, sizeof(left));
179 if (left_len >= sizeof(left)) {
180 errno = ENAMETOOLONG;
184 left_len = strlcpy(left, 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';