1/*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source.  A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12/*
13 * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
14 */
15
16#include <sys/types.h>
17#include <sys/sysmacros.h>
18#include <sys/param.h>
19#include <sys/systm.h>
20#include <sys/uio.h>
21#include <sys/errno.h>
22
23/*
24 * Move "n" bytes at byte address "p"; "rw" indicates the direction
25 * of the move, and the I/O parameters are provided in "uio", which is
26 * update to reflect the data which was moved.  Returns 0 on success or
27 * a non-zero errno on failure.
28 */
29int
30uiomove(void *p, size_t n, enum uio_rw rw, struct uio *uio)
31{
32	struct iovec *iov;
33	ulong_t cnt;
34
35	while (n && uio->uio_resid) {
36		iov = uio->uio_iov;
37		cnt = MIN(iov->iov_len, n);
38		if (cnt == 0L) {
39			uio->uio_iov++;
40			uio->uio_iovcnt--;
41			continue;
42		}
43		switch (uio->uio_segflg) {
44
45		case UIO_USERISPACE:
46			return (EINVAL);
47
48		case UIO_USERSPACE:
49		case UIO_SYSSPACE:
50			if (rw == UIO_READ)
51				bcopy(p, iov->iov_base, cnt);
52			else
53				bcopy(iov->iov_base, p, cnt);
54			break;
55		}
56		iov->iov_base += cnt;
57		iov->iov_len -= cnt;
58		uio->uio_resid -= cnt;
59		uio->uio_loffset += cnt;
60		p = (caddr_t)p + cnt;
61		n -= cnt;
62	}
63	return (0);
64}
65
66/*
67 * Drop the next n chars out of *uiop.
68 */
69void
70uioskip(uio_t *uiop, size_t n)
71{
72	if (n > uiop->uio_resid)
73		return;
74	while (n != 0) {
75		iovec_t	*iovp = uiop->uio_iov;
76		size_t	niovb = MIN(iovp->iov_len, n);
77
78		if (niovb == 0) {
79			uiop->uio_iov++;
80			uiop->uio_iovcnt--;
81			continue;
82		}
83		iovp->iov_base += niovb;
84		uiop->uio_loffset += niovb;
85		iovp->iov_len -= niovb;
86		uiop->uio_resid -= niovb;
87		n -= niovb;
88	}
89}
90