1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include <sys/copyops.h>
30 #include <sys/errno.h>
31 #include <sys/kmem.h>
32 #include <sys/param.h>
33 #include <sys/pathname.h>
34 #include <sys/sysmacros.h>
35 #include <sys/systm.h>
36 #include <sys/types.h>
37 #include <sys/vnode.h>
38
39 int
getcwd(char * buf,size_t buflen)40 getcwd(char *buf, size_t buflen)
41 {
42 int err;
43 char *kbuf;
44 size_t kbuflen;
45
46 /*
47 * The user should be able to specify any size buffer, but we don't want
48 * to arbitrarily allocate huge kernel buffers just because the user
49 * requests it. So we'll start with MAXPATHLEN (which should hold any
50 * normal path), and only increase it if we fail with ERANGE.
51 */
52 kbuflen = MIN(buflen, MAXPATHLEN);
53
54 for (;;) {
55 kbuf = kmem_alloc(kbuflen, KM_SLEEP);
56
57 if (((err = dogetcwd(kbuf, kbuflen)) == 0) &&
58 (copyout(kbuf, buf, strlen(kbuf) + 1) != 0))
59 err = EFAULT;
60
61 kmem_free(kbuf, kbuflen);
62
63 if (err == ENAMETOOLONG) {
64 /*
65 * If the user's buffer really was too small, give up.
66 * For some reason, getcwd() uses ERANGE for this case.
67 */
68 if (kbuflen == buflen) {
69 err = ERANGE;
70 break;
71 }
72 kbuflen = MIN(kbuflen * 2, buflen);
73 } else {
74 break;
75 }
76 }
77
78 return ((err != 0) ? set_errno(err) : 0);
79 }
80