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416fd2a8 | 1 | /* OPENBSD ORIGINAL: lib/libc/stdlib/realpath.c */ |
2 | ||
3c0ef626 | 3 | /* |
34fee935 | 4 | * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru> |
3c0ef626 | 5 | * |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions | |
8 | * are met: | |
9 | * 1. Redistributions of source code must retain the above copyright | |
10 | * notice, this list of conditions and the following disclaimer. | |
11 | * 2. Redistributions in binary form must reproduce the above copyright | |
12 | * notice, this list of conditions and the following disclaimer in the | |
13 | * documentation and/or other materials provided with the distribution. | |
34fee935 | 14 | * 3. The names of the authors may not be used to endorse or promote |
15 | * products derived from this software without specific prior written | |
16 | * permission. | |
3c0ef626 | 17 | * |
34fee935 | 18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
3c0ef626 | 19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
20 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
34fee935 | 21 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
3c0ef626 | 22 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
23 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
24 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
26 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
27 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
28 | * SUCH DAMAGE. | |
29 | */ | |
30 | ||
31 | #include "includes.h" | |
32 | ||
33 | #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) | |
34 | ||
3c0ef626 | 35 | #include <sys/param.h> |
36 | #include <sys/stat.h> | |
37 | ||
38 | #include <errno.h> | |
3c0ef626 | 39 | #include <stdlib.h> |
40 | #include <string.h> | |
41 | #include <unistd.h> | |
42 | ||
43 | /* | |
34fee935 | 44 | * char *realpath(const char *path, char resolved[PATH_MAX]); |
3c0ef626 | 45 | * |
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). | |
49 | */ | |
50 | char * | |
34fee935 | 51 | realpath(const char *path, char resolved[PATH_MAX]) |
3c0ef626 | 52 | { |
53 | struct stat sb; | |
34fee935 | 54 | char *p, *q, *s; |
55 | size_t left_len, resolved_len; | |
56 | unsigned symlinks; | |
57 | int serrno, slen; | |
58 | char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; | |
59 | ||
60 | serrno = errno; | |
61 | symlinks = 0; | |
62 | if (path[0] == '/') { | |
63 | resolved[0] = '/'; | |
64 | resolved[1] = '\0'; | |
65 | if (path[1] == '\0') | |
66 | return (resolved); | |
67 | resolved_len = 1; | |
68 | left_len = strlcpy(left, path + 1, sizeof(left)); | |
69 | } else { | |
70 | if (getcwd(resolved, PATH_MAX) == NULL) { | |
71 | strlcpy(resolved, ".", PATH_MAX); | |
72 | return (NULL); | |
73 | } | |
74 | resolved_len = strlen(resolved); | |
75 | left_len = strlcpy(left, path, sizeof(left)); | |
76 | } | |
77 | if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) { | |
78 | errno = ENAMETOOLONG; | |
3c0ef626 | 79 | return (NULL); |
80 | } | |
e9a17296 | 81 | |
3c0ef626 | 82 | /* |
34fee935 | 83 | * Iterate over path components in `left'. |
3c0ef626 | 84 | */ |
34fee935 | 85 | while (left_len != 0) { |
86 | /* | |
87 | * Extract the next path component and adjust `left' | |
88 | * and its length. | |
89 | */ | |
90 | p = strchr(left, '/'); | |
91 | s = p ? p : left + left_len; | |
92 | if (s - left >= sizeof(next_token)) { | |
93 | errno = ENAMETOOLONG; | |
94 | return (NULL); | |
3c0ef626 | 95 | } |
34fee935 | 96 | memcpy(next_token, left, s - left); |
97 | next_token[s - left] = '\0'; | |
98 | left_len -= s - left; | |
99 | if (p != NULL) | |
100 | memmove(left, s + 1, left_len + 1); | |
101 | if (resolved[resolved_len - 1] != '/') { | |
102 | if (resolved_len + 1 >= PATH_MAX) { | |
103 | errno = ENAMETOOLONG; | |
104 | return (NULL); | |
3c0ef626 | 105 | } |
34fee935 | 106 | resolved[resolved_len++] = '/'; |
107 | resolved[resolved_len] = '\0'; | |
3c0ef626 | 108 | } |
34fee935 | 109 | if (next_token[0] == '\0') |
110 | continue; | |
111 | else if (strcmp(next_token, ".") == 0) | |
112 | continue; | |
113 | else if (strcmp(next_token, "..") == 0) { | |
114 | /* | |
115 | * Strip the last path component except when we have | |
116 | * single "/" | |
117 | */ | |
118 | if (resolved_len > 1) { | |
119 | resolved[resolved_len - 1] = '\0'; | |
120 | q = strrchr(resolved, '/') + 1; | |
121 | *q = '\0'; | |
122 | resolved_len = q - resolved; | |
123 | } | |
124 | continue; | |
3c0ef626 | 125 | } |
3c0ef626 | 126 | |
34fee935 | 127 | /* |
128 | * Append the next path component and lstat() it. If | |
129 | * lstat() fails we still can return successfully if | |
130 | * there are no more path components left. | |
131 | */ | |
132 | resolved_len = strlcat(resolved, next_token, PATH_MAX); | |
133 | if (resolved_len >= PATH_MAX) { | |
134 | errno = ENAMETOOLONG; | |
135 | return (NULL); | |
136 | } | |
137 | if (lstat(resolved, &sb) != 0) { | |
138 | if (errno == ENOENT && p == NULL) { | |
139 | errno = serrno; | |
140 | return (resolved); | |
141 | } | |
142 | return (NULL); | |
143 | } | |
144 | if (S_ISLNK(sb.st_mode)) { | |
145 | if (symlinks++ > MAXSYMLINKS) { | |
146 | errno = ELOOP; | |
147 | return (NULL); | |
148 | } | |
149 | slen = readlink(resolved, symlink, sizeof(symlink) - 1); | |
150 | if (slen < 0) | |
151 | return (NULL); | |
152 | symlink[slen] = '\0'; | |
153 | if (symlink[0] == '/') { | |
154 | resolved[1] = 0; | |
155 | resolved_len = 1; | |
156 | } else if (resolved_len > 1) { | |
157 | /* Strip the last path component. */ | |
158 | resolved[resolved_len - 1] = '\0'; | |
159 | q = strrchr(resolved, '/') + 1; | |
160 | *q = '\0'; | |
161 | resolved_len = q - resolved; | |
162 | } | |
3c0ef626 | 163 | |
34fee935 | 164 | /* |
165 | * If there are any path components left, then | |
166 | * append them to symlink. The result is placed | |
167 | * in `left'. | |
168 | */ | |
169 | if (p != NULL) { | |
170 | if (symlink[slen - 1] != '/') { | |
171 | if (slen + 1 >= sizeof(symlink)) { | |
172 | errno = ENAMETOOLONG; | |
173 | return (NULL); | |
174 | } | |
175 | symlink[slen] = '/'; | |
176 | symlink[slen + 1] = 0; | |
177 | } | |
178 | left_len = strlcat(symlink, left, sizeof(left)); | |
179 | if (left_len >= sizeof(left)) { | |
180 | errno = ENAMETOOLONG; | |
181 | return (NULL); | |
182 | } | |
183 | } | |
184 | left_len = strlcpy(left, symlink, sizeof(left)); | |
3c0ef626 | 185 | } |
3c0ef626 | 186 | } |
187 | ||
34fee935 | 188 | /* |
189 | * Remove trailing slash except when the resolved pathname | |
190 | * is a single "/". | |
191 | */ | |
192 | if (resolved_len > 1 && resolved[resolved_len - 1] == '/') | |
193 | resolved[resolved_len - 1] = '\0'; | |
3c0ef626 | 194 | return (resolved); |
3c0ef626 | 195 | } |
196 | #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */ |