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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. | |
16 | * | |
17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
27 | * SUCH DAMAGE. | |
28 | */ | |
29 | ||
30 | #include "includes.h" | |
31 | ||
32 | #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) | |
33 | ||
34 | #if defined(LIBC_SCCS) && !defined(lint) | |
35 | static char *rcsid = "$OpenBSD: realpath.c,v 1.5 2001/06/27 00:58:56 lebel 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 <fcntl.h> | |
43 | #include <stdlib.h> | |
44 | #include <string.h> | |
45 | #include <unistd.h> | |
46 | ||
47 | /* | |
48 | * MAXSYMLINKS | |
49 | */ | |
50 | #ifndef MAXSYMLINKS | |
51 | #define MAXSYMLINKS 5 | |
52 | #endif | |
53 | ||
54 | /* | |
55 | * char *realpath(const char *path, char resolved_path[MAXPATHLEN]); | |
56 | * | |
57 | * Find the real name of path, by removing all ".", ".." and symlink | |
58 | * components. Returns (resolved) on success, or (NULL) on failure, | |
59 | * in which case the path which caused trouble is left in (resolved). | |
60 | */ | |
61 | char * | |
62 | realpath(const char *path, char *resolved) | |
63 | { | |
64 | struct stat sb; | |
65 | int fd, n, rootd, serrno = 0; | |
66 | char *p, *q, wbuf[MAXPATHLEN], start[MAXPATHLEN]; | |
67 | int symlinks = 0; | |
68 | ||
69 | /* Save the starting point. */ | |
70 | getcwd(start,MAXPATHLEN); | |
71 | if ((fd = open(".", O_RDONLY)) < 0) { | |
72 | (void)strcpy(resolved, "."); | |
73 | return (NULL); | |
74 | } | |
75 | close(fd); | |
76 | ||
77 | /* | |
78 | * Find the dirname and basename from the path to be resolved. | |
79 | * Change directory to the dirname component. | |
80 | * lstat the basename part. | |
81 | * if it is a symlink, read in the value and loop. | |
82 | * if it is a directory, then change to that directory. | |
83 | * get the current directory name and append the basename. | |
84 | */ | |
85 | strlcpy(resolved, path, MAXPATHLEN); | |
86 | loop: | |
87 | q = strrchr(resolved, '/'); | |
88 | if (q != NULL) { | |
89 | p = q + 1; | |
90 | if (q == resolved) | |
91 | q = "/"; | |
92 | else { | |
93 | do { | |
94 | --q; | |
95 | } while (q > resolved && *q == '/'); | |
96 | q[1] = '\0'; | |
97 | q = resolved; | |
98 | } | |
99 | if (chdir(q) < 0) | |
100 | goto err1; | |
101 | } else | |
102 | p = resolved; | |
103 | ||
104 | /* Deal with the last component. */ | |
105 | if (lstat(p, &sb) == 0) { | |
106 | if (S_ISLNK(sb.st_mode)) { | |
107 | if (++symlinks > MAXSYMLINKS) { | |
108 | serrno = ELOOP; | |
109 | goto err1; | |
110 | } | |
111 | n = readlink(p, resolved, MAXPATHLEN-1); | |
112 | if (n < 0) | |
113 | goto err1; | |
114 | resolved[n] = '\0'; | |
115 | goto loop; | |
116 | } | |
117 | if (S_ISDIR(sb.st_mode)) { | |
118 | if (chdir(p) < 0) | |
119 | goto err1; | |
120 | p = ""; | |
121 | } | |
122 | } | |
123 | ||
124 | /* | |
125 | * Save the last component name and get the full pathname of | |
126 | * the current directory. | |
127 | */ | |
128 | (void)strcpy(wbuf, p); | |
129 | if (getcwd(resolved, MAXPATHLEN) == 0) | |
130 | goto err1; | |
131 | ||
132 | /* | |
133 | * Join the two strings together, ensuring that the right thing | |
134 | * happens if the last component is empty, or the dirname is root. | |
135 | */ | |
136 | if (resolved[0] == '/' && resolved[1] == '\0') | |
137 | rootd = 1; | |
138 | else | |
139 | rootd = 0; | |
140 | ||
141 | if (*wbuf) { | |
142 | if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) { | |
143 | serrno = ENAMETOOLONG; | |
144 | goto err1; | |
145 | } | |
146 | if (rootd == 0) | |
147 | (void)strcat(resolved, "/"); | |
148 | (void)strcat(resolved, wbuf); | |
149 | } | |
150 | ||
151 | /* Go back to where we came from. */ | |
152 | if (chdir(start) < 0) { | |
153 | serrno = errno; | |
154 | goto err2; | |
155 | } | |
156 | return (resolved); | |
157 | ||
158 | err1: chdir(start); | |
159 | err2: errno = serrno; | |
160 | return (NULL); | |
161 | } | |
162 | #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */ |