1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
/* $Id: realpath.c,v 1.3 2013/01/25 17:06:09 sjg Exp $ */
/* from: $NetBSD: getcwd.c,v 1.53 2012/06/21 23:29:23 enami Exp $ */
/*
* Copyright (c) 1989, 1991, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifndef HAVE_REALPATH
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#ifdef HAVE_STDLIB_H
# include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifndef __restrict
# define __restrict /* restrict */
#endif
/*
* char *realpath(const char *path, char *resolved);
*
* Find the real name of path, by removing all ".", ".." and symlink
* components. Returns (resolved) on success, or (NULL) on failure,
* in which case the path which caused trouble is left in (resolved).
*/
char *
realpath(const char * __restrict path, char * __restrict resolved)
{
struct stat sb;
int idx = 0, nlnk = 0;
const char *q;
char *p, wbuf[2][MAXPATHLEN], *fres;
size_t len;
ssize_t n;
/* POSIX sez we must test for this */
if (path == NULL) {
errno = EINVAL;
return NULL;
}
if (resolved == NULL) {
fres = resolved = malloc(MAXPATHLEN);
if (resolved == NULL)
return NULL;
} else
fres = NULL;
/*
* Build real path one by one with paying an attention to .,
* .. and symbolic link.
*/
/*
* `p' is where we'll put a new component with prepending
* a delimiter.
*/
p = resolved;
if (*path == '\0') {
*p = '\0';
errno = ENOENT;
goto out;
}
/* If relative path, start from current working directory. */
if (*path != '/') {
/* check for resolved pointer to appease coverity */
if (resolved && getcwd(resolved, MAXPATHLEN) == NULL) {
p[0] = '.';
p[1] = '\0';
goto out;
}
len = strlen(resolved);
if (len > 1)
p += len;
}
loop:
/* Skip any slash. */
while (*path == '/')
path++;
if (*path == '\0') {
if (p == resolved)
*p++ = '/';
*p = '\0';
return resolved;
}
/* Find the end of this component. */
q = path;
do
q++;
while (*q != '/' && *q != '\0');
/* Test . or .. */
if (path[0] == '.') {
if (q - path == 1) {
path = q;
goto loop;
}
if (path[1] == '.' && q - path == 2) {
/* Trim the last component. */
if (p != resolved)
while (*--p != '/')
continue;
path = q;
goto loop;
}
}
/* Append this component. */
if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) {
errno = ENAMETOOLONG;
if (p == resolved)
*p++ = '/';
*p = '\0';
goto out;
}
p[0] = '/';
memcpy(&p[1], path,
/* LINTED We know q > path. */
q - path);
p[1 + q - path] = '\0';
/*
* If this component is a symlink, toss it and prepend link
* target to unresolved path.
*/
if (lstat(resolved, &sb) == -1)
goto out;
if (S_ISLNK(sb.st_mode)) {
if (nlnk++ >= MAXSYMLINKS) {
errno = ELOOP;
goto out;
}
n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
if (n < 0)
goto out;
if (n == 0) {
errno = ENOENT;
goto out;
}
/* Append unresolved path to link target and switch to it. */
if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
errno = ENAMETOOLONG;
goto out;
}
memcpy(&wbuf[idx][n], q, len + 1);
path = wbuf[idx];
idx ^= 1;
/* If absolute symlink, start from root. */
if (*path == '/')
p = resolved;
goto loop;
}
if (*q == '/' && !S_ISDIR(sb.st_mode)) {
errno = ENOTDIR;
goto out;
}
/* Advance both resolved and unresolved path. */
p += 1 + q - path;
path = q;
goto loop;
out:
free(fres);
return NULL;
}
#endif
|
