1 /* $NetBSD: old_getcwd.c,v 1.3 2003/08/07 09:51:08 agc Exp $ */
2
3 /*
4 * Copyright (c) 1989, 1991, 1993, 1995
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Jan-Simon Pendry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 /*
36 * This file copied from NetBSD's src/lib/libc/gen/getcwd.c 1.15, and edited
37 * to remove namespace stuff and the unused realpath function.
38 */
39
40
41 #include <sys/cdefs.h>
42 #if defined(LIBC_SCCS) && !defined(lint)
43 #if 0
44 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95";
45 #else
46 __RCSID("$NetBSD: old_getcwd.c,v 1.3 2003/08/07 09:51:08 agc Exp $");
47 #endif
48 #endif /* LIBC_SCCS and not lint */
49
50 #include <sys/param.h>
51 #include <sys/stat.h>
52
53 #include <dirent.h>
54 #include <errno.h>
55 #include <fcntl.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60
61 #include "getcwd.h"
62
63 #define ISDOT(dp) \
64 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
65 (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
66
67
68 #if defined(__SVR4) || defined(__svr4__)
69 #define d_fileno d_ino
70 #endif
71
72 char *
old_getcwd(pt,size)73 old_getcwd(pt, size)
74 char *pt;
75 size_t size;
76 {
77 struct dirent *dp;
78 DIR *dir;
79 dev_t dev;
80 ino_t ino;
81 int first;
82 char *bpt, *bup;
83 struct stat s;
84 dev_t root_dev;
85 ino_t root_ino;
86 size_t ptsize, upsize;
87 int save_errno;
88 char *ept, *eup, *up;
89 size_t dlen;
90
91 /*
92 * If no buffer specified by the user, allocate one as necessary.
93 * If a buffer is specified, the size has to be non-zero. The path
94 * is built from the end of the buffer backwards.
95 */
96 if (pt) {
97 ptsize = 0;
98 if (!size) {
99 errno = EINVAL;
100 return (NULL);
101 }
102 ept = pt + size;
103 } else {
104 if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
105 return (NULL);
106 ept = pt + ptsize;
107 }
108 bpt = ept - 1;
109 *bpt = '\0';
110
111 /*
112 * Allocate bytes (1024 - malloc space) for the string of "../"'s.
113 * Should always be enough (it's 340 levels). If it's not, allocate
114 * as necessary. Special case the first stat, it's ".", not "..".
115 */
116 if ((up = malloc(upsize = 1024 - 4)) == NULL)
117 goto err;
118 eup = up + MAXPATHLEN;
119 bup = up;
120 up[0] = '.';
121 up[1] = '\0';
122
123 /* Save root values, so know when to stop. */
124 if (stat("/", &s))
125 goto err;
126 root_dev = s.st_dev;
127 root_ino = s.st_ino;
128
129 errno = 0; /* XXX readdir has no error return. */
130
131 for (first = 1;; first = 0) {
132 /* Stat the current level. */
133 if (lstat(up, &s))
134 goto err;
135
136 /* Save current node values. */
137 ino = s.st_ino;
138 dev = s.st_dev;
139
140 /* Check for reaching root. */
141 if (root_dev == dev && root_ino == ino) {
142 *--bpt = '/';
143 /*
144 * It's unclear that it's a requirement to copy the
145 * path to the beginning of the buffer, but it's always
146 * been that way and stuff would probably break.
147 */
148 memmove(pt, bpt, (size_t)(ept - bpt));
149 free(up);
150 return (pt);
151 }
152
153 /*
154 * Build pointer to the parent directory, allocating memory
155 * as necessary. Max length is 3 for "../", the largest
156 * possible component name, plus a trailing NULL.
157 */
158 if (bup + 3 + MAXNAMLEN + 1 >= eup) {
159 if ((up = realloc(up, upsize *= 2)) == NULL)
160 goto err;
161 bup = up;
162 eup = up + upsize;
163 }
164 *bup++ = '.';
165 *bup++ = '.';
166 *bup = '\0';
167
168 /* Open and stat parent directory. */
169 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
170 goto err;
171
172 /* Add trailing slash for next directory. */
173 *bup++ = '/';
174
175 /*
176 * If it's a mount point, have to stat each element because
177 * the inode number in the directory is for the entry in the
178 * parent directory, not the inode number of the mounted file.
179 */
180 save_errno = 0;
181 if (s.st_dev == dev) {
182 for (;;) {
183 if (!(dp = readdir(dir)))
184 goto notfound;
185 if (dp->d_fileno == ino) {
186 #if defined(__SVR4) || defined(__svr4__)
187 dlen = strlen(dp->d_name);
188 #else
189 dlen = dp->d_namlen;
190 #endif
191 break;
192 }
193 }
194 } else
195 for (;;) {
196 if (!(dp = readdir(dir)))
197 goto notfound;
198 if (ISDOT(dp))
199 continue;
200 #if defined(__SVR4) || defined(__svr4__)
201 dlen = strlen(dp->d_name);
202 #else
203 dlen = dp->d_namlen;
204 #endif
205 memmove(bup, dp->d_name, dlen + 1);
206
207 /* Save the first error for later. */
208 if (lstat(up, &s)) {
209 if (!save_errno)
210 save_errno = errno;
211 errno = 0;
212 continue;
213 }
214 if (s.st_dev == dev && s.st_ino == ino)
215 break;
216 }
217
218 /*
219 * Check for length of the current name, preceding slash,
220 * leading slash.
221 */
222 if (bpt - pt <= dlen + (first ? 1 : 2)) {
223 size_t len, off;
224
225 if (!ptsize) {
226 errno = ERANGE;
227 goto err;
228 }
229 off = bpt - pt;
230 len = ept - bpt;
231 if ((pt = realloc(pt, ptsize *= 2)) == NULL)
232 goto err;
233 bpt = pt + off;
234 ept = pt + ptsize;
235 memmove(ept - len, bpt, len);
236 bpt = ept - len;
237 }
238 if (!first)
239 *--bpt = '/';
240 bpt -= dlen;
241 memmove(bpt, dp->d_name, dlen);
242 (void)closedir(dir);
243
244 /* Truncate any file name. */
245 *bup = '\0';
246 }
247
248 notfound:
249 /*
250 * If readdir set errno, use it, not any saved error; otherwise,
251 * didn't find the current directory in its parent directory, set
252 * errno to ENOENT.
253 */
254 if (!errno)
255 errno = save_errno ? save_errno : ENOENT;
256 /* FALLTHROUGH */
257 err:
258 if (ptsize)
259 free(pt);
260 free(up);
261 return (NULL);
262 }
263