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281bbb02 | 1 | /* $OpenBSD: getcwd.c,v 1.14 2005/08/08 08:05:34 espie Exp $ */ |
443172c4 | 2 | /* |
3 | * Copyright (c) 1989, 1991, 1993 | |
4 | * The Regents of the University of California. All rights reserved. | |
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. | |
3e67f7df | 14 | * 3. Neither the name of the University nor the names of its contributors |
15 | * may be used to endorse or promote products derived from this software | |
16 | * without specific prior written permission. | |
443172c4 | 17 | * |
18 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
20 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
21 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
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 | ||
f6d4fb87 | 31 | /* OPENBSD ORIGINAL: lib/libc/gen/getcwd.c */ |
32 | ||
17962c40 | 33 | #include "includes.h" |
443172c4 | 34 | |
35 | #if !defined(HAVE_GETCWD) | |
36 | ||
443172c4 | 37 | #include <sys/param.h> |
38 | #include <sys/stat.h> | |
39 | #include <errno.h> | |
40 | #include <dirent.h> | |
41 | #include <sys/dir.h> | |
42 | #include <stdio.h> | |
43 | #include <stdlib.h> | |
44 | #include <string.h> | |
45 | #include "includes.h" | |
46 | ||
47 | #define ISDOT(dp) \ | |
48 | (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ | |
49 | (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) | |
50 | ||
51 | char * | |
510a42ce | 52 | getcwd(char *pt, size_t size) |
443172c4 | 53 | { |
281bbb02 | 54 | struct dirent *dp; |
55 | DIR *dir = NULL; | |
56 | dev_t dev; | |
57 | ino_t ino; | |
58 | int first; | |
59 | char *bpt, *bup; | |
443172c4 | 60 | struct stat s; |
61 | dev_t root_dev; | |
62 | ino_t root_ino; | |
63 | size_t ptsize, upsize; | |
64 | int save_errno; | |
65 | char *ept, *eup, *up; | |
66 | ||
67 | /* | |
68 | * If no buffer specified by the user, allocate one as necessary. | |
69 | * If a buffer is specified, the size has to be non-zero. The path | |
70 | * is built from the end of the buffer backwards. | |
71 | */ | |
72 | if (pt) { | |
73 | ptsize = 0; | |
74 | if (!size) { | |
75 | errno = EINVAL; | |
76 | return (NULL); | |
77 | } | |
78 | ept = pt + size; | |
79 | } else { | |
281bbb02 | 80 | if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL) |
443172c4 | 81 | return (NULL); |
82 | ept = pt + ptsize; | |
83 | } | |
84 | bpt = ept - 1; | |
85 | *bpt = '\0'; | |
86 | ||
87 | /* | |
281bbb02 | 88 | * Allocate bytes for the string of "../"'s. |
443172c4 | 89 | * Should always be enough (it's 340 levels). If it's not, allocate |
90 | * as necessary. Special * case the first stat, it's ".", not "..". | |
91 | */ | |
281bbb02 | 92 | if ((up = malloc(upsize = MAXPATHLEN)) == NULL) |
443172c4 | 93 | goto err; |
281bbb02 | 94 | eup = up + upsize; |
443172c4 | 95 | bup = up; |
96 | up[0] = '.'; | |
97 | up[1] = '\0'; | |
98 | ||
99 | /* Save root values, so know when to stop. */ | |
100 | if (stat("/", &s)) | |
101 | goto err; | |
102 | root_dev = s.st_dev; | |
103 | root_ino = s.st_ino; | |
104 | ||
105 | errno = 0; /* XXX readdir has no error return. */ | |
106 | ||
107 | for (first = 1;; first = 0) { | |
108 | /* Stat the current level. */ | |
109 | if (lstat(up, &s)) | |
110 | goto err; | |
111 | ||
112 | /* Save current node values. */ | |
113 | ino = s.st_ino; | |
114 | dev = s.st_dev; | |
115 | ||
116 | /* Check for reaching root. */ | |
117 | if (root_dev == dev && root_ino == ino) { | |
118 | *--bpt = '/'; | |
119 | /* | |
120 | * It's unclear that it's a requirement to copy the | |
121 | * path to the beginning of the buffer, but it's always | |
122 | * been that way and stuff would probably break. | |
123 | */ | |
8b3319f4 | 124 | memmove(pt, bpt, ept - bpt); |
443172c4 | 125 | free(up); |
126 | return (pt); | |
127 | } | |
128 | ||
129 | /* | |
130 | * Build pointer to the parent directory, allocating memory | |
131 | * as necessary. Max length is 3 for "../", the largest | |
7bb526ce | 132 | * possible component name, plus a trailing NUL. |
443172c4 | 133 | */ |
134 | if (bup + 3 + MAXNAMLEN + 1 >= eup) { | |
135 | char *nup; | |
136 | ||
137 | if ((nup = realloc(up, upsize *= 2)) == NULL) | |
138 | goto err; | |
281bbb02 | 139 | bup = nup + (bup - up); |
443172c4 | 140 | up = nup; |
443172c4 | 141 | eup = up + upsize; |
142 | } | |
143 | *bup++ = '.'; | |
144 | *bup++ = '.'; | |
145 | *bup = '\0'; | |
146 | ||
16d51c41 | 147 | /* Open and stat parent directory. */ |
148 | if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) | |
443172c4 | 149 | goto err; |
150 | ||
151 | /* Add trailing slash for next directory. */ | |
152 | *bup++ = '/'; | |
153 | ||
154 | /* | |
155 | * If it's a mount point, have to stat each element because | |
156 | * the inode number in the directory is for the entry in the | |
157 | * parent directory, not the inode number of the mounted file. | |
158 | */ | |
159 | save_errno = 0; | |
160 | if (s.st_dev == dev) { | |
161 | for (;;) { | |
162 | if (!(dp = readdir(dir))) | |
163 | goto notfound; | |
164 | if (dp->d_fileno == ino) | |
165 | break; | |
166 | } | |
167 | } else | |
168 | for (;;) { | |
169 | if (!(dp = readdir(dir))) | |
170 | goto notfound; | |
171 | if (ISDOT(dp)) | |
172 | continue; | |
281bbb02 | 173 | memcpy(bup, dp->d_name, dp->d_namlen + 1); |
443172c4 | 174 | |
175 | /* Save the first error for later. */ | |
176 | if (lstat(up, &s)) { | |
177 | if (!save_errno) | |
178 | save_errno = errno; | |
179 | errno = 0; | |
180 | continue; | |
181 | } | |
182 | if (s.st_dev == dev && s.st_ino == ino) | |
183 | break; | |
184 | } | |
185 | ||
186 | /* | |
187 | * Check for length of the current name, preceding slash, | |
188 | * leading slash. | |
189 | */ | |
190 | if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { | |
281bbb02 | 191 | size_t len; |
443172c4 | 192 | char *npt; |
193 | ||
194 | if (!ptsize) { | |
195 | errno = ERANGE; | |
196 | goto err; | |
197 | } | |
443172c4 | 198 | len = ept - bpt; |
199 | if ((npt = realloc(pt, ptsize *= 2)) == NULL) | |
200 | goto err; | |
281bbb02 | 201 | bpt = npt + (bpt - pt); |
443172c4 | 202 | pt = npt; |
443172c4 | 203 | ept = pt + ptsize; |
8b3319f4 | 204 | memmove(ept - len, bpt, len); |
443172c4 | 205 | bpt = ept - len; |
206 | } | |
207 | if (!first) | |
208 | *--bpt = '/'; | |
209 | bpt -= dp->d_namlen; | |
281bbb02 | 210 | memcpy(bpt, dp->d_name, dp->d_namlen); |
443172c4 | 211 | (void)closedir(dir); |
212 | ||
213 | /* Truncate any file name. */ | |
214 | *bup = '\0'; | |
215 | } | |
216 | ||
217 | notfound: | |
218 | /* | |
219 | * If readdir set errno, use it, not any saved error; otherwise, | |
220 | * didn't find the current directory in its parent directory, set | |
221 | * errno to ENOENT. | |
222 | */ | |
223 | if (!errno) | |
224 | errno = save_errno ? save_errno : ENOENT; | |
225 | /* FALLTHROUGH */ | |
226 | err: | |
281bbb02 | 227 | save_errno = errno; |
228 | ||
443172c4 | 229 | if (ptsize) |
230 | free(pt); | |
281bbb02 | 231 | free(up); |
443172c4 | 232 | if (dir) |
233 | (void)closedir(dir); | |
281bbb02 | 234 | |
235 | errno = save_errno; | |
236 | ||
443172c4 | 237 | return (NULL); |
238 | } | |
239 | ||
240 | #endif /* !defined(HAVE_GETCWD) */ |