/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License, Version 1.0 only

 * (the "License").  You may not use this file except in compliance

 * with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/

/*	  All Rights Reserved  	*/

/*

 * University Copyright- Copyright (c) 1982, 1986, 1988

 * The Regents of the University of California

 * All Rights Reserved

 *

 * University Acknowledgment- Portions of this document are derived from

 * software developed by the University of California, Berkeley, and its

 * contributors.

 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#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;

	int error;

	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:

			if (rw == UIO_READ) {

				error = xcopyout_nta(p, iov->iov_base, cnt,

				    (uio->uio_extflg & UIO_COPY_CACHED));

			} else {

				error = xcopyin_nta(iov->iov_base, p, cnt,

				    (uio->uio_extflg & UIO_COPY_CACHED));

			}

			if (error)

				return (error);

			break;

		case UIO_SYSSPACE:

			if (rw == UIO_READ)

				error = kcopy_nta(p, iov->iov_base, cnt,

				    (uio->uio_extflg & UIO_COPY_CACHED));

			else

				error = kcopy_nta(iov->iov_base, p, cnt,

				    (uio->uio_extflg & UIO_COPY_CACHED));

			if (error)

				return (error);

			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);

}

/*

 * transfer a character value into the address space

 * delineated by a uio and update fields within the

 * uio for next character. Return 0 for success, EFAULT

 * for error.

 */

int

ureadc(int val, struct uio *uiop)

{

	struct iovec *iovp;

	unsigned char c;

	/*

	 * first determine if uio is valid.  uiop should be

	 * non-NULL and the resid count > 0.

	 */

	if (!(uiop && uiop->uio_resid > 0))

		return (EFAULT);

	/*

	 * scan through iovecs until one is found that is non-empty.

	 * Return EFAULT if none found.

	 */

	while (uiop->uio_iovcnt > 0) {

		iovp = uiop->uio_iov;

		if (iovp->iov_len <= 0) {

			uiop->uio_iovcnt--;

			uiop->uio_iov++;

		} else

			break;

	}

	if (uiop->uio_iovcnt <= 0)

		return (EFAULT);

	/*

	 * Transfer character to uio space.

	 */

	c = (unsigned char) (val & 0xFF);

	switch (uiop->uio_segflg) {

	case UIO_USERISPACE:

	case UIO_USERSPACE:

		if (copyout(&c, iovp->iov_base, sizeof (unsigned char)))

			return (EFAULT);

		break;

	case UIO_SYSSPACE: /* can do direct copy since kernel-kernel */

		*iovp->iov_base = c;

		break;

	default:

		return (EFAULT); /* invalid segflg value */

	}

	/*

	 * bump up/down iovec and uio members to reflect transfer.

	 */

	iovp->iov_base++;

	iovp->iov_len--;

	uiop->uio_resid--;

	uiop->uio_loffset++;

	return (0); /* success */

}

/*

 * return a character value from the address space

 * delineated by a uio and update fields within the

 * uio for next character. Return the character for success,

 * -1 for error.

 */

int

uwritec(struct uio *uiop)

{

	struct iovec *iovp;

	unsigned char c;

	/*

	 * verify we were passed a valid uio structure.

	 * (1) non-NULL uiop, (2) positive resid count

	 * (3) there is an iovec with positive length

	 */

	if (!(uiop && uiop->uio_resid > 0))

		return (-1);

	while (uiop->uio_iovcnt > 0) {

		iovp = uiop->uio_iov;

		if (iovp->iov_len <= 0) {

			uiop->uio_iovcnt--;

			uiop->uio_iov++;

		} else

			break;

	}

	if (uiop->uio_iovcnt <= 0)

		return (-1);

	/*

	 * Get the character from the uio address space.

	 */

	switch (uiop->uio_segflg) {

	case UIO_USERISPACE:

	case UIO_USERSPACE:

		if (copyin(iovp->iov_base, &c, sizeof (unsigned char)))

			return (-1);

		break;

	case UIO_SYSSPACE:

		c = *iovp->iov_base;

		break;

	default:

		return (-1); /* invalid segflg */

	}

	/*

	 * Adjust fields of iovec and uio appropriately.

	 */

	iovp->iov_base++;

	iovp->iov_len--;

	uiop->uio_resid--;

	uiop->uio_loffset++;

	return ((int)c & 0xFF); /* success */

}

/*

 * 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) {

		register iovec_t	*iovp = uiop->uio_iov;

		register 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;

	}

}

/*

 * Dup the suio into the duio and diovec of size diov_cnt. If diov

 * is too small to dup suio then an error will be returned, else 0.

 */

int

uiodup(uio_t *suio, uio_t *duio, iovec_t *diov, int diov_cnt)

{

	int ix;

	iovec_t *siov = suio->uio_iov;

	*duio = *suio;

	for (ix = 0; ix < suio->uio_iovcnt; ix++) {

		diov[ix] = siov[ix];

		if (ix >= diov_cnt)

			return (1);

	}

	duio->uio_iov = diov;

	return (0);

}