xref: /freebsd/sys/cddl/compat/opensolaris/kern/opensolaris_uio.c (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*      Copyright (c) 1984, 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  */
41 
42 #include <sys/types.h>
43 #include <sys/uio.h>
44 #include <sys/vnode.h>
45 
46 /*
47  * same as uiomove() but doesn't modify uio structure.
48  * return in cbytes how many bytes were copied.
49  */
50 int
51 uiocopy(void *p, size_t n, enum uio_rw rw, struct uio *uio, size_t *cbytes)
52 {
53 	struct iovec small_iovec[1];
54 	struct uio small_uio_clone;
55 	struct uio *uio_clone;
56 	int error;
57 
58 	ASSERT3U(uio->uio_rw, ==, rw);
59 	if (uio->uio_iovcnt == 1) {
60 		small_uio_clone = *uio;
61 		small_iovec[0] = *uio->uio_iov;
62 		small_uio_clone.uio_iov = small_iovec;
63 		uio_clone = &small_uio_clone;
64 	} else {
65 		uio_clone = cloneuio(uio);
66 	}
67 
68 	error = vn_io_fault_uiomove(p, n, uio_clone);
69 	*cbytes = uio->uio_resid - uio_clone->uio_resid;
70 	if (uio_clone != &small_uio_clone)
71 		freeuio(uio_clone);
72 	return (error);
73 }
74 
75 /*
76  * Drop the next n chars out of *uiop.
77  */
78 void
79 uioskip(uio_t *uio, size_t n)
80 {
81 	enum uio_seg segflg;
82 
83 	/* For the full compatibility with illumos. */
84 	if (n > uio->uio_resid)
85 		return;
86 
87 	segflg = uio->uio_segflg;
88 	uio->uio_segflg = UIO_NOCOPY;
89 	uiomove(NULL, n, uio->uio_rw, uio);
90 	uio->uio_segflg = segflg;
91 }
92