xref: /freebsd/sys/contrib/openzfs/module/zfs/pathname.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 /*
30  * University Copyright- Copyright (c) 1982, 1986, 1988
31  * The Regents of the University of California
32  * All Rights Reserved
33  *
34  * University Acknowledgment- Portions of this document are derived from
35  * software developed by the University of California, Berkeley, and its
36  * contributors.
37  */
38 
39 
40 #include <sys/types.h>
41 #include <sys/pathname.h>
42 #include <sys/kmem.h>
43 #include <sys/sysmacros.h>
44 
45 /*
46  * Pathname utilities.
47  *
48  * In translating file names we copy each argument file
49  * name into a pathname structure where we operate on it.
50  * Each pathname structure can hold "pn_bufsize" characters
51  * including a terminating null, and operations here support
52  * allocating and freeing pathname structures, fetching
53  * strings from user space, getting the next character from
54  * a pathname, combining two pathnames (used in symbolic
55  * link processing), and peeling off the first component
56  * of a pathname.
57  */
58 
59 /*
60  * Allocate contents of pathname structure.  Structure is typically
61  * an automatic variable in calling routine for convenience.
62  *
63  * May sleep in the call to kmem_alloc() and so must not be called
64  * from interrupt level.
65  */
66 void
67 pn_alloc(struct pathname *pnp)
68 {
69 	pn_alloc_sz(pnp, MAXPATHLEN);
70 }
71 void
72 pn_alloc_sz(struct pathname *pnp, size_t sz)
73 {
74 	pnp->pn_buf = kmem_alloc(sz, KM_SLEEP);
75 	pnp->pn_bufsize = sz;
76 }
77 
78 /*
79  * Free pathname resources.
80  */
81 void
82 pn_free(struct pathname *pnp)
83 {
84 	/* pn_bufsize is usually MAXPATHLEN, but may not be */
85 	kmem_free(pnp->pn_buf, pnp->pn_bufsize);
86 	pnp->pn_buf = NULL;
87 	pnp->pn_bufsize = 0;
88 }
89