uio.c revision a90cf9f29973990687fa61de9f1f6ea22e924e40
/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright 2015 Nexenta Systems, Inc. All rights reserved.
*/
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/errno.h>
/*
* Move "n" bytes at byte address "p"; "rw" indicates the direction
* of the move, and the I/O parameters are provided in "uio", which is
* update to reflect the data which was moved. Returns 0 on success or
* a non-zero errno on failure.
*/
int
uiomove(void *p, size_t n, enum uio_rw rw, struct uio *uio)
{
struct iovec *iov;
ulong_t cnt;
while (n && uio->uio_resid) {
iov = uio->uio_iov;
cnt = MIN(iov->iov_len, n);
if (cnt == 0L) {
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
switch (uio->uio_segflg) {
case UIO_USERSPACE:
case UIO_USERISPACE:
return (EINVAL);
case UIO_SYSSPACE:
if (rw == UIO_READ)
bcopy(p, iov->iov_base, cnt);
else
bcopy(iov->iov_base, p, cnt);
break;
}
iov->iov_base += cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_loffset += cnt;
p = (caddr_t)p + cnt;
n -= cnt;
}
return (0);
}
/*
* Drop the next n chars out of *uiop.
*/
void
uioskip(uio_t *uiop, size_t n)
{
if (n > uiop->uio_resid)
return;
while (n != 0) {
iovec_t *iovp = uiop->uio_iov;
size_t niovb = MIN(iovp->iov_len, n);
if (niovb == 0) {
uiop->uio_iov++;
uiop->uio_iovcnt--;
continue;
}
iovp->iov_base += niovb;
uiop->uio_loffset += niovb;
iovp->iov_len -= niovb;
uiop->uio_resid -= niovb;
n -= niovb;
}
}