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-rw-r--r--src/lib/libc/stdlib/realpath.c198
1 files changed, 198 insertions, 0 deletions
diff --git a/src/lib/libc/stdlib/realpath.c b/src/lib/libc/stdlib/realpath.c
new file mode 100644
index 0000000000..62e06b00be
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+++ b/src/lib/libc/stdlib/realpath.c
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1/*
2 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
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
14 * permission.
15 *
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
26 * SUCH DAMAGE.
27 */
28
29#if 0
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/lib/libc/stdlib/realpath.c,v 1.9.2.1 2003/05/22 17:11:44 fjoe Exp $");
32#endif
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char *rcsid = "$OpenBSD: realpath.c,v 1.12 2005/03/29 19:34:14 brad Exp $";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/param.h>
39#include <sys/stat.h>
40
41#include <errno.h>
42#include <stdlib.h>
43#include <string.h>
44#include <unistd.h>
45
46/*
47 * char *realpath(const char *path, char resolved[PATH_MAX]);
48 *
49 * Find the real name of path, by removing all ".", ".." and symlink
50 * components. Returns (resolved) on success, or (NULL) on failure,
51 * in which case the path which caused trouble is left in (resolved).
52 */
53char *
54realpath(const char *path, char resolved[PATH_MAX])
55{
56 struct stat sb;
57 char *p, *q, *s;
58 size_t left_len, resolved_len;
59 unsigned symlinks;
60 int serrno, slen;
61 char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
62
63 serrno = errno;
64 symlinks = 0;
65 if (path[0] == '/') {
66 resolved[0] = '/';
67 resolved[1] = '\0';
68 if (path[1] == '\0')
69 return (resolved);
70 resolved_len = 1;
71 left_len = strlcpy(left, path + 1, sizeof(left));
72 } else {
73 if (getcwd(resolved, PATH_MAX) == NULL) {
74 strlcpy(resolved, ".", PATH_MAX);
75 return (NULL);
76 }
77 resolved_len = strlen(resolved);
78 left_len = strlcpy(left, path, sizeof(left));
79 }
80 if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
81 errno = ENAMETOOLONG;
82 return (NULL);
83 }
84
85 /*
86 * Iterate over path components in `left'.
87 */
88 while (left_len != 0) {
89 /*
90 * Extract the next path component and adjust `left'
91 * and its length.
92 */
93 p = strchr(left, '/');
94 s = p ? p : left + left_len;
95 if (s - left >= sizeof(next_token)) {
96 errno = ENAMETOOLONG;
97 return (NULL);
98 }
99 memcpy(next_token, left, s - left);
100 next_token[s - left] = '\0';
101 left_len -= s - left;
102 if (p != NULL)
103 memmove(left, s + 1, left_len + 1);
104 if (resolved[resolved_len - 1] != '/') {
105 if (resolved_len + 1 >= PATH_MAX) {
106 errno = ENAMETOOLONG;
107 return (NULL);
108 }
109 resolved[resolved_len++] = '/';
110 resolved[resolved_len] = '\0';
111 }
112 if (next_token[0] == '\0')
113 continue;
114 else if (strcmp(next_token, ".") == 0)
115 continue;
116 else if (strcmp(next_token, "..") == 0) {
117 /*
118 * Strip the last path component except when we have
119 * single "/"
120 */
121 if (resolved_len > 1) {
122 resolved[resolved_len - 1] = '\0';
123 q = strrchr(resolved, '/') + 1;
124 *q = '\0';
125 resolved_len = q - resolved;
126 }
127 continue;
128 }
129
130 /*
131 * Append the next path component and lstat() it. If
132 * lstat() fails we still can return successfully if
133 * there are no more path components left.
134 */
135 resolved_len = strlcat(resolved, next_token, PATH_MAX);
136 if (resolved_len >= PATH_MAX) {
137 errno = ENAMETOOLONG;
138 return (NULL);
139 }
140 if (lstat(resolved, &sb) != 0) {
141 if (errno == ENOENT && p == NULL) {
142 errno = serrno;
143 return (resolved);
144 }
145 return (NULL);
146 }
147 if (S_ISLNK(sb.st_mode)) {
148 if (symlinks++ > MAXSYMLINKS) {
149 errno = ELOOP;
150 return (NULL);
151 }
152 slen = readlink(resolved, symlink, sizeof(symlink) - 1);
153 if (slen < 0)
154 return (NULL);
155 symlink[slen] = '\0';
156 if (symlink[0] == '/') {
157 resolved[1] = 0;
158 resolved_len = 1;
159 } else if (resolved_len > 1) {
160 /* Strip the last path component. */
161 resolved[resolved_len - 1] = '\0';
162 q = strrchr(resolved, '/') + 1;
163 *q = '\0';
164 resolved_len = q - resolved;
165 }
166
167 /*
168 * If there are any path components left, then
169 * append them to symlink. The result is placed
170 * in `left'.
171 */
172 if (p != NULL) {
173 if (symlink[slen - 1] != '/') {
174 if (slen + 1 >= sizeof(symlink)) {
175 errno = ENAMETOOLONG;
176 return (NULL);
177 }
178 symlink[slen] = '/';
179 symlink[slen + 1] = 0;
180 }
181 left_len = strlcat(symlink, left, sizeof(left));
182 if (left_len >= sizeof(left)) {
183 errno = ENAMETOOLONG;
184 return (NULL);
185 }
186 }
187 left_len = strlcpy(left, symlink, sizeof(left));
188 }
189 }
190
191 /*
192 * Remove trailing slash except when the resolved pathname
193 * is a single "/".
194 */
195 if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
196 resolved[resolved_len - 1] = '\0';
197 return (resolved);
198}
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