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3c0ef626 | 1 | /* |
2 | * Copyright (c) 1994 | |
3 | * The Regents of the University of California. All rights reserved. | |
4 | * | |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * Jan-Simon Pendry. | |
7 | * | |
8 | * Redistribution and use in source and binary forms, with or without | |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * 1. Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in the | |
15 | * documentation and/or other materials provided with the distribution. | |
0fff78ff | 16 | * 3. Neither the name of the University nor the names of its contributors |
17 | * may be used to endorse or promote products derived from this software | |
18 | * without specific prior written permission. | |
3c0ef626 | 19 | * |
20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
30 | * SUCH DAMAGE. | |
31 | */ | |
32 | ||
33 | #include "includes.h" | |
34 | ||
35 | #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) | |
36 | ||
37 | #if defined(LIBC_SCCS) && !defined(lint) | |
0fff78ff | 38 | static char *rcsid = "$OpenBSD: realpath.c,v 1.10 2003/08/01 21:04:59 millert Exp $"; |
3c0ef626 | 39 | #endif /* LIBC_SCCS and not lint */ |
40 | ||
41 | #include <sys/param.h> | |
42 | #include <sys/stat.h> | |
43 | ||
44 | #include <errno.h> | |
45 | #include <fcntl.h> | |
46 | #include <stdlib.h> | |
47 | #include <string.h> | |
48 | #include <unistd.h> | |
49 | ||
50 | /* | |
51 | * MAXSYMLINKS | |
52 | */ | |
53 | #ifndef MAXSYMLINKS | |
54 | #define MAXSYMLINKS 5 | |
55 | #endif | |
56 | ||
57 | /* | |
58 | * char *realpath(const char *path, char resolved_path[MAXPATHLEN]); | |
59 | * | |
60 | * Find the real name of path, by removing all ".", ".." and symlink | |
61 | * components. Returns (resolved) on success, or (NULL) on failure, | |
62 | * in which case the path which caused trouble is left in (resolved). | |
63 | */ | |
64 | char * | |
65 | realpath(const char *path, char *resolved) | |
66 | { | |
67 | struct stat sb; | |
0fff78ff | 68 | int fd, n, needslash, serrno = 0; |
3c0ef626 | 69 | char *p, *q, wbuf[MAXPATHLEN], start[MAXPATHLEN]; |
70 | int symlinks = 0; | |
71 | ||
72 | /* Save the starting point. */ | |
73 | getcwd(start,MAXPATHLEN); | |
74 | if ((fd = open(".", O_RDONLY)) < 0) { | |
41b2f314 | 75 | (void)strlcpy(resolved, ".", MAXPATHLEN); |
3c0ef626 | 76 | return (NULL); |
77 | } | |
78 | close(fd); | |
79 | ||
e9a17296 | 80 | /* Convert "." -> "" to optimize away a needless lstat() and chdir() */ |
81 | if (path[0] == '.' && path[1] == '\0') | |
82 | path = ""; | |
83 | ||
3c0ef626 | 84 | /* |
85 | * Find the dirname and basename from the path to be resolved. | |
86 | * Change directory to the dirname component. | |
87 | * lstat the basename part. | |
88 | * if it is a symlink, read in the value and loop. | |
89 | * if it is a directory, then change to that directory. | |
90 | * get the current directory name and append the basename. | |
91 | */ | |
92 | strlcpy(resolved, path, MAXPATHLEN); | |
93 | loop: | |
94 | q = strrchr(resolved, '/'); | |
95 | if (q != NULL) { | |
96 | p = q + 1; | |
97 | if (q == resolved) | |
98 | q = "/"; | |
99 | else { | |
100 | do { | |
101 | --q; | |
102 | } while (q > resolved && *q == '/'); | |
103 | q[1] = '\0'; | |
104 | q = resolved; | |
105 | } | |
106 | if (chdir(q) < 0) | |
107 | goto err1; | |
108 | } else | |
109 | p = resolved; | |
110 | ||
111 | /* Deal with the last component. */ | |
e9a17296 | 112 | if (*p != '\0' && lstat(p, &sb) == 0) { |
3c0ef626 | 113 | if (S_ISLNK(sb.st_mode)) { |
114 | if (++symlinks > MAXSYMLINKS) { | |
115 | serrno = ELOOP; | |
116 | goto err1; | |
117 | } | |
118 | n = readlink(p, resolved, MAXPATHLEN-1); | |
119 | if (n < 0) | |
120 | goto err1; | |
121 | resolved[n] = '\0'; | |
122 | goto loop; | |
123 | } | |
124 | if (S_ISDIR(sb.st_mode)) { | |
125 | if (chdir(p) < 0) | |
126 | goto err1; | |
127 | p = ""; | |
128 | } | |
129 | } | |
130 | ||
131 | /* | |
132 | * Save the last component name and get the full pathname of | |
133 | * the current directory. | |
134 | */ | |
41b2f314 | 135 | (void)strlcpy(wbuf, p, sizeof wbuf); |
3c0ef626 | 136 | if (getcwd(resolved, MAXPATHLEN) == 0) |
137 | goto err1; | |
138 | ||
139 | /* | |
140 | * Join the two strings together, ensuring that the right thing | |
141 | * happens if the last component is empty, or the dirname is root. | |
142 | */ | |
143 | if (resolved[0] == '/' && resolved[1] == '\0') | |
0fff78ff | 144 | needslash = 0; |
3c0ef626 | 145 | else |
0fff78ff | 146 | needslash = 1; |
3c0ef626 | 147 | |
148 | if (*wbuf) { | |
0fff78ff | 149 | if (strlen(resolved) + strlen(wbuf) + needslash >= MAXPATHLEN) { |
3c0ef626 | 150 | serrno = ENAMETOOLONG; |
151 | goto err1; | |
152 | } | |
9cb1827b | 153 | if (needslash == 0) |
0fff78ff | 154 | strlcat(resolved, "/", MAXPATHLEN); |
155 | strlcat(resolved, wbuf, MAXPATHLEN); | |
3c0ef626 | 156 | } |
157 | ||
158 | /* Go back to where we came from. */ | |
159 | if (chdir(start) < 0) { | |
160 | serrno = errno; | |
161 | goto err2; | |
162 | } | |
163 | return (resolved); | |
164 | ||
165 | err1: chdir(start); | |
166 | err2: errno = serrno; | |
167 | return (NULL); | |
168 | } | |
169 | #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */ |