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 1.2 2003/06/17 04:26:46 dillon Exp $
33 #include <sys/param.h>
42 * char *realpath(const char *path, char resolved[PATH_MAX]);
44 * Find the real name of path, by removing all ".", ".." and symlink
45 * components. Returns (resolved) on success, or (NULL) on failure,
46 * in which case the path which caused trouble is left in (resolved).
49 realpath(const char *path, char resolved[PATH_MAX])
53 size_t left_len, resolved_len;
56 char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
66 left_len = strlcpy(left, path + 1, sizeof(left));
68 if (getcwd(resolved, PATH_MAX) == NULL) {
69 strlcpy(resolved, ".", PATH_MAX);
72 resolved_len = strlen(resolved);
73 left_len = strlcpy(left, path, sizeof(left));
75 if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
81 * Iterate over path components in `left'.
83 while (left_len != 0) {
85 * Extract the next path component and adjust `left'
88 p = strchr(left, '/');
89 s = p ? p : left + left_len;
90 if (s - left >= sizeof(next_token)) {
94 memcpy(next_token, left, s - left);
95 next_token[s - left] = '\0';
98 memmove(left, s + 1, left_len + 1);
99 if (resolved[resolved_len - 1] != '/') {
100 if (resolved_len + 1 >= PATH_MAX) {
101 errno = ENAMETOOLONG;
104 resolved[resolved_len++] = '/';
105 resolved[resolved_len] = '\0';
107 if (next_token[0] == '\0')
109 else if (strcmp(next_token, ".") == 0)
111 else if (strcmp(next_token, "..") == 0) {
113 * Strip the last path component except when we have
116 if (resolved_len > 1) {
117 resolved[resolved_len - 1] = '\0';
118 q = strrchr(resolved, '/') + 1;
120 resolved_len = q - resolved;
126 * Append the next path component and lstat() it. If
127 * lstat() fails we still can return successfully if
128 * there are no more path components left.
130 resolved_len = strlcat(resolved, next_token, PATH_MAX);
131 if (resolved_len >= PATH_MAX) {
132 errno = ENAMETOOLONG;
135 if (lstat(resolved, &sb) != 0) {
136 if (errno == ENOENT && p == NULL) {
142 if (S_ISLNK(sb.st_mode)) {
143 if (symlinks++ > MAXSYMLINKS) {
147 slen = readlink(resolved, symlink, sizeof(symlink) - 1);
150 symlink[slen] = '\0';
151 if (symlink[0] == '/') {
154 } else if (resolved_len > 1) {
155 /* Strip the last path component. */
156 resolved[resolved_len - 1] = '\0';
157 q = strrchr(resolved, '/') + 1;
159 resolved_len = q - resolved;
163 * If there are any path components left, then
164 * append them to symlink. The result is placed
168 if (symlink[slen - 1] != '/') {
169 if (slen + 1 >= sizeof(symlink)) {
170 errno = ENAMETOOLONG;
174 symlink[slen + 1] = 0;
176 left_len = strlcat(symlink, left, sizeof(left));
177 if (left_len >= sizeof(left)) {
178 errno = ENAMETOOLONG;
182 left_len = strlcpy(left, symlink, sizeof(left));
187 * Remove trailing slash except when the resolved pathname
190 if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
191 resolved[resolved_len - 1] = '\0';