1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* Copyright (c) 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: getcwd.c,v 1.6 2000/07/19 15:25:13 deraadt Exp $";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define ISDOT(dp) \
(dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
(dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
char *
getcwd(pt, size)
char *pt;
size_t size;
{
register struct dirent *dp;
register DIR *dir = NULL;
register dev_t dev;
register ino_t ino;
register int first;
register char *bpt, *bup;
struct stat s;
dev_t root_dev;
ino_t root_ino;
size_t ptsize, upsize;
int save_errno;
char *ept, *eup, *up;
/*
* If no buffer specified by the user, allocate one as necessary.
* If a buffer is specified, the size has to be non-zero. The path
* is built from the end of the buffer backwards.
*/
if (pt) {
ptsize = 0;
if (!size) {
errno = EINVAL;
return (NULL);
}
ept = pt + size;
} else {
if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
return (NULL);
ept = pt + ptsize;
}
bpt = ept - 1;
*bpt = '\0';
/*
* Allocate bytes (1024 - malloc space) for the string of "../"'s.
* Should always be enough (it's 340 levels). If it's not, allocate
* as necessary. Special * case the first stat, it's ".", not "..".
*/
if ((up = malloc(upsize = 1024 - 4)) == NULL)
goto err;
eup = up + MAXPATHLEN;
bup = up;
up[0] = '.';
up[1] = '\0';
/* Save root values, so know when to stop. */
if (stat("/", &s))
goto err;
root_dev = s.st_dev;
root_ino = s.st_ino;
errno = 0; /* XXX readdir has no error return. */
for (first = 1;; first = 0) {
/* Stat the current level. */
if (lstat(up, &s))
goto err;
/* Save current node values. */
ino = s.st_ino;
dev = s.st_dev;
/* Check for reaching root. */
if (root_dev == dev && root_ino == ino) {
*--bpt = '/';
/*
* It's unclear that it's a requirement to copy the
* path to the beginning of the buffer, but it's always
* been that way and stuff would probably break.
*/
bcopy(bpt, pt, ept - bpt);
free(up);
return (pt);
}
/*
* Build pointer to the parent directory, allocating memory
* as necessary. Max length is 3 for "../", the largest
* possible component name, plus a trailing NULL.
*/
if (bup + 3 + MAXNAMLEN + 1 >= eup) {
char *nup;
if ((nup = realloc(up, upsize *= 2)) == NULL)
goto err;
up = nup;
bup = up;
eup = up + upsize;
}
*bup++ = '.';
*bup++ = '.';
*bup = '\0';
/* Open and stat parent directory. */
if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
goto err;
/* Add trailing slash for next directory. */
*bup++ = '/';
/*
* If it's a mount point, have to stat each element because
* the inode number in the directory is for the entry in the
* parent directory, not the inode number of the mounted file.
*/
save_errno = 0;
if (s.st_dev == dev) {
for (;;) {
if (!(dp = readdir(dir)))
goto notfound;
if (dp->d_fileno == ino)
break;
}
} else
for (;;) {
if (!(dp = readdir(dir)))
goto notfound;
if (ISDOT(dp))
continue;
bcopy(dp->d_name, bup, dp->d_namlen + 1);
/* Save the first error for later. */
if (lstat(up, &s)) {
if (!save_errno)
save_errno = errno;
errno = 0;
continue;
}
if (s.st_dev == dev && s.st_ino == ino)
break;
}
/*
* Check for length of the current name, preceding slash,
* leading slash.
*/
if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
size_t len, off;
char *npt;
if (!ptsize) {
errno = ERANGE;
goto err;
}
off = bpt - pt;
len = ept - bpt;
if ((npt = realloc(pt, ptsize *= 2)) == NULL)
goto err;
pt = npt;
bpt = pt + off;
ept = pt + ptsize;
bcopy(bpt, ept - len, len);
bpt = ept - len;
}
if (!first)
*--bpt = '/';
bpt -= dp->d_namlen;
bcopy(dp->d_name, bpt, dp->d_namlen);
(void)closedir(dir);
/* Truncate any file name. */
*bup = '\0';
}
notfound:
/*
* If readdir set errno, use it, not any saved error; otherwise,
* didn't find the current directory in its parent directory, set
* errno to ENOENT.
*/
if (!errno)
errno = save_errno ? save_errno : ENOENT;
/* FALLTHROUGH */
err:
if (ptsize)
free(pt);
if (up)
free(up);
if (dir)
(void)closedir(dir);
return (NULL);
}
|
