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: head/lib/libc/stdlib/realpath.c 264417 2014-04-13 19:48:28Z jilles $
32 #include "namespace.h"
33 #include <sys/param.h>
41 #include "un-namespace.h"
43 int __realpath(const char *path, char *rbuf, size_t len);
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 * __restrict path, char * __restrict resolved)
55 size_t left_len, resolved_len;
58 char left[PATH_MAX], next_token[PATH_MAX], my_symlink[PATH_MAX];
64 if (path[0] == '\0') {
68 if (resolved == NULL) {
69 resolved = malloc(PATH_MAX);
77 if (getosreldate() >= 500710) {
78 if (__realpath(path, resolved, PATH_MAX) < 0) {
82 snprintf(resolved, PATH_MAX, "%s", path);
96 left_len = strlcpy(left, path + 1, sizeof(left));
98 if (getcwd(resolved, PATH_MAX) == NULL) {
107 resolved_len = strlen(resolved);
108 left_len = strlcpy(left, path, sizeof(left));
110 if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
113 errno = ENAMETOOLONG;
118 * Iterate over path components in `left'.
120 while (left_len != 0) {
122 * Extract the next path component and adjust `left'
125 p = strchr(left, '/');
126 s = p ? p : left + left_len;
127 if (s - left >= sizeof(next_token)) {
130 errno = ENAMETOOLONG;
133 memcpy(next_token, left, s - left);
134 next_token[s - left] = '\0';
135 left_len -= s - left;
137 memmove(left, s + 1, left_len + 1);
138 if (resolved[resolved_len - 1] != '/') {
139 if (resolved_len + 1 >= PATH_MAX) {
142 errno = ENAMETOOLONG;
145 resolved[resolved_len++] = '/';
146 resolved[resolved_len] = '\0';
148 if (next_token[0] == '\0') {
149 /* Handle consequential slashes. */
151 } else if (strcmp(next_token, ".") == 0) {
153 } else if (strcmp(next_token, "..") == 0) {
155 * Strip the last path component except when we have
158 if (resolved_len > 1) {
159 resolved[resolved_len - 1] = '\0';
160 q = strrchr(resolved, '/') + 1;
162 resolved_len = q - resolved;
168 * Append the next path component and lstat() it.
170 resolved_len = strlcat(resolved, next_token, PATH_MAX);
171 if (resolved_len >= PATH_MAX) {
174 errno = ENAMETOOLONG;
177 if (lstat(resolved, &sb) != 0) {
182 if (S_ISLNK(sb.st_mode)) {
183 if (symlinks++ > MAXSYMLINKS) {
189 slen = readlink(resolved, my_symlink, sizeof(my_symlink) - 1);
195 my_symlink[slen] = '\0';
196 if (my_symlink[0] == '/') {
199 } else if (resolved_len > 1) {
200 /* Strip the last path component. */
201 resolved[resolved_len - 1] = '\0';
202 q = strrchr(resolved, '/') + 1;
204 resolved_len = q - resolved;
208 * If there are any path components left, then
209 * append them to symlink. The result is placed
213 if (my_symlink[slen - 1] != '/') {
214 if (slen + 1 >= (int)sizeof(my_symlink)) {
217 errno = ENAMETOOLONG;
220 my_symlink[slen] = '/';
221 my_symlink[slen + 1] = 0;
223 left_len = strlcat(my_symlink, left,
225 if (left_len >= sizeof(left)) {
228 errno = ENAMETOOLONG;
232 left_len = strlcpy(left, my_symlink, sizeof(left));
233 } else if (!S_ISDIR(sb.st_mode) && p != NULL) {
242 * Remove trailing slash except when the resolved pathname
245 if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
246 resolved[resolved_len - 1] = '\0';