xref: /src/sys/kern/subr_copy.c

/*	$NetBSD: subr_copy.c,v 1.7 2016/05/25 17:43:58 christos Exp $	*/

/*-
 * Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1982, 1986, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * All advertising materials mentioning features or use of this software
 * must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Lawrence Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)kern_subr.c	8.4 (Berkeley) 2/14/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_copy.c,v 1.7 2016/05/25 17:43:58 christos Exp $");

#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/proc.h>
#include <sys/systm.h>

#include <uvm/uvm_extern.h>

void
uio_setup_sysspace(struct uio *uio)
{

	uio->uio_vmspace = vmspace_kernel();
}

int
uiomove(void *buf, size_t n, struct uio *uio)
{
	struct vmspace *vm = uio->uio_vmspace;
	struct iovec *iov;
	size_t cnt;
	int error = 0;
	char *cp = buf;

	ASSERT_SLEEPABLE();

	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE);
	while (n > 0 && uio->uio_resid) {
		iov = uio->uio_iov;
		cnt = iov->iov_len;
		if (cnt == 0) {
			KASSERT(uio->uio_iovcnt > 0);
			uio->uio_iov++;
			uio->uio_iovcnt--;
			continue;
		}
		if (cnt > n)
			cnt = n;
		if (!VMSPACE_IS_KERNEL_P(vm)) {
			if (curcpu()->ci_schedstate.spc_flags &
			    SPCF_SHOULDYIELD)
				preempt();
		}

		if (uio->uio_rw == UIO_READ) {
			error = copyout_vmspace(vm, cp, iov->iov_base,
			    cnt);
		} else {
			error = copyin_vmspace(vm, iov->iov_base, cp,
			    cnt);
		}
		if (error) {
			break;
		}
		iov->iov_base = (char *)iov->iov_base + cnt;
		iov->iov_len -= cnt;
		uio->uio_resid -= cnt;
		uio->uio_offset += cnt;
		cp += cnt;
		KDASSERT(cnt <= n);
		n -= cnt;
	}

	return (error);
}

/*
 * Wrapper for uiomove() that validates the arguments against a known-good
 * kernel buffer.
 */
int
uiomove_frombuf(void *buf, size_t buflen, struct uio *uio)
{
	size_t offset;

	if (uio->uio_offset < 0 || /* uio->uio_resid < 0 || */
	    (offset = uio->uio_offset) != uio->uio_offset)
		return (EINVAL);
	if (offset >= buflen)
		return (0);
	return (uiomove((char *)buf + offset, buflen - offset, uio));
}

/*
 * Give next character to user as result of read.
 */
int
ureadc(int c, struct uio *uio)
{
	struct iovec *iov;

	if (uio->uio_resid <= 0)
		panic("ureadc: non-positive resid");
again:
	if (uio->uio_iovcnt <= 0)
		panic("ureadc: non-positive iovcnt");
	iov = uio->uio_iov;
	if (iov->iov_len <= 0) {
		uio->uio_iovcnt--;
		uio->uio_iov++;
		goto again;
	}
	if (!VMSPACE_IS_KERNEL_P(uio->uio_vmspace)) {
		if (subyte(iov->iov_base, c) < 0)
			return (EFAULT);
	} else {
		*(char *)iov->iov_base = c;
	}
	iov->iov_base = (char *)iov->iov_base + 1;
	iov->iov_len--;
	uio->uio_resid--;
	uio->uio_offset++;
	return (0);
}

/*
 * Like copyin(), but operates on an arbitrary vmspace.
 */
int
copyin_vmspace(struct vmspace *vm, const void *uaddr, void *kaddr, size_t len)
{
	struct iovec iov;
	struct uio uio;
	int error;

	if (len == 0)
		return (0);

	if (VMSPACE_IS_KERNEL_P(vm)) {
		return kcopy(uaddr, kaddr, len);
	}
	if (__predict_true(vm == curproc->p_vmspace)) {
		return copyin(uaddr, kaddr, len);
	}

	iov.iov_base = kaddr;
	iov.iov_len = len;
	uio.uio_iov = &iov;
	uio.uio_iovcnt = 1;
	uio.uio_offset = (off_t)(uintptr_t)uaddr;
	uio.uio_resid = len;
	uio.uio_rw = UIO_READ;
	UIO_SETUP_SYSSPACE(&uio);
	error = uvm_io(&vm->vm_map, &uio, 0);

	return (error);
}

/*
 * Like copyout(), but operates on an arbitrary vmspace.
 */
int
copyout_vmspace(struct vmspace *vm, const void *kaddr, void *uaddr, size_t len)
{
	struct iovec iov;
	struct uio uio;
	int error;

	if (len == 0)
		return (0);

	if (VMSPACE_IS_KERNEL_P(vm)) {
		return kcopy(kaddr, uaddr, len);
	}
	if (__predict_true(vm == curproc->p_vmspace)) {
		return copyout(kaddr, uaddr, len);
	}

	iov.iov_base = __UNCONST(kaddr); /* XXXUNCONST cast away const */
	iov.iov_len = len;
	uio.uio_iov = &iov;
	uio.uio_iovcnt = 1;
	uio.uio_offset = (off_t)(uintptr_t)uaddr;
	uio.uio_resid = len;
	uio.uio_rw = UIO_WRITE;
	UIO_SETUP_SYSSPACE(&uio);
	error = uvm_io(&vm->vm_map, &uio, 0);

	return (error);
}

/*
 * Like copyin(), but operates on an arbitrary process.
 */
int
copyin_proc(struct proc *p, const void *uaddr, void *kaddr, size_t len)
{
	struct vmspace *vm;
	int error;

	error = proc_vmspace_getref(p, &vm);
	if (error) {
		return error;
	}
	error = copyin_vmspace(vm, uaddr, kaddr, len);
	uvmspace_free(vm);

	return error;
}

/*
 * Like copyout(), but operates on an arbitrary process.
 */
int
copyout_proc(struct proc *p, const void *kaddr, void *uaddr, size_t len)
{
	struct vmspace *vm;
	int error;

	error = proc_vmspace_getref(p, &vm);
	if (error) {
		return error;
	}
	error = copyout_vmspace(vm, kaddr, uaddr, len);
	uvmspace_free(vm);

	return error;
}

/*
 * Like copyin(), except it operates on kernel addresses when the FKIOCTL
 * flag is passed in `ioctlflags' from the ioctl call.
 */
int
ioctl_copyin(int ioctlflags, const void *src, void *dst, size_t len)
{
	if (ioctlflags & FKIOCTL)
		return kcopy(src, dst, len);
	return copyin(src, dst, len);
}

/*
 * Like copyout(), except it operates on kernel addresses when the FKIOCTL
 * flag is passed in `ioctlflags' from the ioctl call.
 */
int
ioctl_copyout(int ioctlflags, const void *src, void *dst, size_t len)
{
	if (ioctlflags & FKIOCTL)
		return kcopy(src, dst, len);
	return copyout(src, dst, len);
}