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
29 #if defined(LIBC_SCCS) && !defined(lint)
30 static char sccsid[] = "@(#)realpath.c 8.1 (Berkeley) 2/16/94";
31 #endif /* LIBC_SCCS and not lint */
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include "namespace.h"
36 #include <sys/param.h>
43 #include "un-namespace.h"
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 realpath1(const char *path, char *resolved)
55 size_t left_len, resolved_len, next_token_len;
58 char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
67 left_len = strlcpy(left, path + 1, sizeof(left));
69 if (getcwd(resolved, PATH_MAX) == NULL) {
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, '/');
92 next_token_len = p != NULL ? p - left : left_len;
93 memcpy(next_token, left, next_token_len);
94 next_token[next_token_len] = '\0';
97 left_len -= next_token_len + 1;
98 memmove(left, p + 1, left_len + 1);
104 if (resolved[resolved_len - 1] != '/') {
105 if (resolved_len + 1 >= PATH_MAX) {
106 errno = ENAMETOOLONG;
109 resolved[resolved_len++] = '/';
110 resolved[resolved_len] = '\0';
112 if (next_token[0] == '\0') {
113 /* Handle consequential slashes. */
115 } else if (strcmp(next_token, ".") == 0) {
117 } else if (strcmp(next_token, "..") == 0) {
119 * Strip the last path component except when we have
122 if (resolved_len > 1) {
123 resolved[resolved_len - 1] = '\0';
124 q = strrchr(resolved, '/') + 1;
126 resolved_len = q - resolved;
132 * Append the next path component and lstat() it.
134 resolved_len = strlcat(resolved, next_token, PATH_MAX);
135 if (resolved_len >= PATH_MAX) {
136 errno = ENAMETOOLONG;
139 if (lstat(resolved, &sb) != 0)
141 if (S_ISLNK(sb.st_mode)) {
142 if (symlinks++ > MAXSYMLINKS) {
146 slen = readlink(resolved, symlink, sizeof(symlink));
147 if (slen <= 0 || slen >= sizeof(symlink)) {
149 ; /* keep errno from readlink(2) call */
153 errno = ENAMETOOLONG;
156 symlink[slen] = '\0';
157 if (symlink[0] == '/') {
161 /* Strip the last path component. */
162 q = strrchr(resolved, '/') + 1;
164 resolved_len = q - resolved;
168 * If there are any path components left, then
169 * append them to symlink. The result is placed
173 if (symlink[slen - 1] != '/') {
174 if (slen + 1 >= sizeof(symlink)) {
175 errno = ENAMETOOLONG;
179 symlink[slen + 1] = 0;
181 left_len = strlcat(symlink, left,
183 if (left_len >= sizeof(symlink)) {
184 errno = ENAMETOOLONG;
188 left_len = strlcpy(left, symlink, sizeof(left));
189 } else if (!S_ISDIR(sb.st_mode) && p != NULL) {
196 * Remove trailing slash except when the resolved pathname
199 if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
200 resolved[resolved_len - 1] = '\0';
205 realpath(const char * __restrict path, char * __restrict resolved)
213 if (path[0] == '\0') {
217 if (resolved != NULL) {
220 m = resolved = malloc(PATH_MAX);
221 if (resolved == NULL)
224 res = realpath1(path, resolved);