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443172c4 | 1 | /* |
2 | * Copyright (c) 1989, 1991, 1993 | |
3 | * The Regents of the University of California. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * | |
14 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
24 | * SUCH DAMAGE. | |
25 | */ | |
26 | ||
27 | #include "config.h" | |
28 | ||
29 | #if !defined(HAVE_GETCWD) | |
30 | ||
31 | #if defined(LIBC_SCCS) && !defined(lint) | |
32 | static char rcsid[] = "$OpenBSD: getcwd.c,v 1.6 2000/07/19 15:25:13 deraadt Exp $"; | |
33 | #endif /* LIBC_SCCS and not lint */ | |
34 | ||
35 | #include <sys/param.h> | |
36 | #include <sys/stat.h> | |
37 | #include <errno.h> | |
38 | #include <dirent.h> | |
39 | #include <sys/dir.h> | |
40 | #include <stdio.h> | |
41 | #include <stdlib.h> | |
42 | #include <string.h> | |
43 | #include "includes.h" | |
44 | ||
45 | #define ISDOT(dp) \ | |
46 | (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ | |
47 | (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) | |
48 | ||
49 | char * | |
50 | getcwd(char *pt,size_t size) | |
51 | { | |
52 | register struct dirent *dp; | |
53 | register DIR *dir = NULL; | |
54 | register dev_t dev; | |
55 | register ino_t ino; | |
56 | register int first; | |
57 | register char *bpt, *bup; | |
58 | struct stat s; | |
59 | dev_t root_dev; | |
60 | ino_t root_ino; | |
61 | size_t ptsize, upsize; | |
62 | int save_errno; | |
63 | char *ept, *eup, *up; | |
64 | ||
65 | /* | |
66 | * If no buffer specified by the user, allocate one as necessary. | |
67 | * If a buffer is specified, the size has to be non-zero. The path | |
68 | * is built from the end of the buffer backwards. | |
69 | */ | |
70 | if (pt) { | |
71 | ptsize = 0; | |
72 | if (!size) { | |
73 | errno = EINVAL; | |
74 | return (NULL); | |
75 | } | |
76 | ept = pt + size; | |
77 | } else { | |
78 | if ((pt = malloc(ptsize = 1024 - 4)) == NULL) | |
79 | return (NULL); | |
80 | ept = pt + ptsize; | |
81 | } | |
82 | bpt = ept - 1; | |
83 | *bpt = '\0'; | |
84 | ||
85 | /* | |
86 | * Allocate bytes (1024 - malloc space) for the string of "../"'s. | |
87 | * Should always be enough (it's 340 levels). If it's not, allocate | |
88 | * as necessary. Special * case the first stat, it's ".", not "..". | |
89 | */ | |
90 | if ((up = malloc(upsize = 1024 - 4)) == NULL) | |
91 | goto err; | |
92 | eup = up + MAXPATHLEN; | |
93 | bup = up; | |
94 | up[0] = '.'; | |
95 | up[1] = '\0'; | |
96 | ||
97 | /* Save root values, so know when to stop. */ | |
98 | if (stat("/", &s)) | |
99 | goto err; | |
100 | root_dev = s.st_dev; | |
101 | root_ino = s.st_ino; | |
102 | ||
103 | errno = 0; /* XXX readdir has no error return. */ | |
104 | ||
105 | for (first = 1;; first = 0) { | |
106 | /* Stat the current level. */ | |
107 | if (lstat(up, &s)) | |
108 | goto err; | |
109 | ||
110 | /* Save current node values. */ | |
111 | ino = s.st_ino; | |
112 | dev = s.st_dev; | |
113 | ||
114 | /* Check for reaching root. */ | |
115 | if (root_dev == dev && root_ino == ino) { | |
116 | *--bpt = '/'; | |
117 | /* | |
118 | * It's unclear that it's a requirement to copy the | |
119 | * path to the beginning of the buffer, but it's always | |
120 | * been that way and stuff would probably break. | |
121 | */ | |
8b3319f4 | 122 | memmove(pt, bpt, ept - bpt); |
443172c4 | 123 | free(up); |
124 | return (pt); | |
125 | } | |
126 | ||
127 | /* | |
128 | * Build pointer to the parent directory, allocating memory | |
129 | * as necessary. Max length is 3 for "../", the largest | |
130 | * possible component name, plus a trailing NULL. | |
131 | */ | |
132 | if (bup + 3 + MAXNAMLEN + 1 >= eup) { | |
133 | char *nup; | |
134 | ||
135 | if ((nup = realloc(up, upsize *= 2)) == NULL) | |
136 | goto err; | |
137 | up = nup; | |
138 | bup = up; | |
139 | eup = up + upsize; | |
140 | } | |
141 | *bup++ = '.'; | |
142 | *bup++ = '.'; | |
143 | *bup = '\0'; | |
144 | ||
145 | /* Open and stat parent directory. | |
146 | * RACE?? - replaced fstat(dirfd(dir), &s) w/ lstat(up,&s) | |
147 | */ | |
148 | if (!(dir = opendir(up)) || lstat(up,&s)) | |
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; | |
8b3319f4 | 173 | memmove(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)) { | |
191 | size_t len, off; | |
192 | char *npt; | |
193 | ||
194 | if (!ptsize) { | |
195 | errno = ERANGE; | |
196 | goto err; | |
197 | } | |
198 | off = bpt - pt; | |
199 | len = ept - bpt; | |
200 | if ((npt = realloc(pt, ptsize *= 2)) == NULL) | |
201 | goto err; | |
202 | pt = npt; | |
203 | bpt = pt + off; | |
204 | ept = pt + ptsize; | |
8b3319f4 | 205 | memmove(ept - len, bpt, len); |
443172c4 | 206 | bpt = ept - len; |
207 | } | |
208 | if (!first) | |
209 | *--bpt = '/'; | |
210 | bpt -= dp->d_namlen; | |
8b3319f4 | 211 | memmove(bpt, dp->d_name, dp->d_namlen); |
443172c4 | 212 | (void)closedir(dir); |
213 | ||
214 | /* Truncate any file name. */ | |
215 | *bup = '\0'; | |
216 | } | |
217 | ||
218 | notfound: | |
219 | /* | |
220 | * If readdir set errno, use it, not any saved error; otherwise, | |
221 | * didn't find the current directory in its parent directory, set | |
222 | * errno to ENOENT. | |
223 | */ | |
224 | if (!errno) | |
225 | errno = save_errno ? save_errno : ENOENT; | |
226 | /* FALLTHROUGH */ | |
227 | err: | |
228 | if (ptsize) | |
229 | free(pt); | |
230 | if (up) | |
231 | free(up); | |
232 | if (dir) | |
233 | (void)closedir(dir); | |
234 | return (NULL); | |
235 | } | |
236 | ||
237 | #endif /* !defined(HAVE_GETCWD) */ |