freebsd-dev/sys/vm/vm_mmap.c

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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. 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, Berkeley and its contributors.
 * 4. 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.
 *
 * from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
 *
 *	@(#)vm_mmap.c	8.4 (Berkeley) 1/12/94
 * $Id: vm_mmap.c,v 1.17 1995/03/21 10:15:52 davidg Exp $
 */

/*
 * Mapped file (mmap) interface to VM
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/resourcevar.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/conf.h>

#include <miscfs/specfs/specdev.h>

#include <vm/vm.h>
#include <vm/vm_pager.h>
#include <vm/vm_pageout.h>
#include <vm/vm_prot.h>

#ifdef DEBUG
int mmapdebug = 0;

#define MDB_FOLLOW	0x01
#define MDB_SYNC	0x02
#define MDB_MAPIT	0x04
#endif

void pmap_object_init_pt();

struct sbrk_args {
	int incr;
};

/* ARGSUSED */
int
sbrk(p, uap, retval)
	struct proc *p;
	struct sbrk_args *uap;
	int *retval;
{

	/* Not yet implemented */
	return (EOPNOTSUPP);
}

struct sstk_args {
	int incr;
};

/* ARGSUSED */
int
sstk(p, uap, retval)
	struct proc *p;
	struct sstk_args *uap;
	int *retval;
{

	/* Not yet implemented */
	return (EOPNOTSUPP);
}

#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
struct getpagesize_args {
	int dummy;
};

/* ARGSUSED */
int
ogetpagesize(p, uap, retval)
	struct proc *p;
	struct getpagesize_args *uap;
	int *retval;
{

	*retval = PAGE_SIZE;
	return (0);
}
#endif				/* COMPAT_43 || COMPAT_SUNOS */

struct mmap_args {
	caddr_t addr;
	size_t len;
	int prot;
	int flags;
	int fd;
	long pad;
	off_t pos;
};

int
mmap(p, uap, retval)
	struct proc *p;
	register struct mmap_args *uap;
	int *retval;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct vnode *vp;
	vm_offset_t addr;
	vm_size_t size;
	vm_prot_t prot, maxprot;
	caddr_t handle;
	int flags, error;

	prot = uap->prot & VM_PROT_ALL;
	flags = uap->flags;
#ifdef DEBUG
	if (mmapdebug & MDB_FOLLOW)
		printf("mmap(%d): addr %x len %x pro %x flg %x fd %d pos %x\n",
		    p->p_pid, uap->addr, uap->len, prot,
		    flags, uap->fd, (vm_offset_t) uap->pos);
#endif
	/*
	 * Address (if FIXED) must be page aligned. Size is implicitly rounded
	 * to a page boundary.
	 */
	addr = (vm_offset_t) uap->addr;
	if (((flags & MAP_FIXED) && (addr & PAGE_MASK)) ||
	    (ssize_t) uap->len < 0 || ((flags & MAP_ANON) && uap->fd != -1))
		return (EINVAL);
	size = (vm_size_t) round_page(uap->len);
	/*
	 * Check for illegal addresses.  Watch out for address wrap... Note
	 * that VM_*_ADDRESS are not constants due to casts (argh).
	 */
	if (flags & MAP_FIXED) {
		if (VM_MAXUSER_ADDRESS > 0 && addr + size > VM_MAXUSER_ADDRESS)
			return (EINVAL);
#ifndef i386
		if (VM_MIN_ADDRESS > 0 && addr < VM_MIN_ADDRESS)
			return (EINVAL);
#endif
		if (addr + size < addr)
			return (EINVAL);
	}
	/*
	 * XXX if no hint provided for a non-fixed mapping place it after the
	 * end of the largest possible heap.
	 * 
	 * There should really be a pmap call to determine a reasonable location.
	 */
	if (addr == 0 && (flags & MAP_FIXED) == 0)
		addr = round_page(p->p_vmspace->vm_daddr + MAXDSIZ);
	if (flags & MAP_ANON) {
		/*
		 * Mapping blank space is trivial.
		 */
		handle = NULL;
		maxprot = VM_PROT_ALL;
	} else {
		/*
		 * Mapping file, get fp for validation. Obtain vnode and make
		 * sure it is of appropriate type.
		 */
		if (((unsigned) uap->fd) >= fdp->fd_nfiles ||
		    (fp = fdp->fd_ofiles[uap->fd]) == NULL)
			return (EBADF);
		if (fp->f_type != DTYPE_VNODE)
			return (EINVAL);
		vp = (struct vnode *) fp->f_data;
		if (vp->v_type != VREG && vp->v_type != VCHR)
			return (EINVAL);
		/*
		 * XXX hack to handle use of /dev/zero to map anon memory (ala
		 * SunOS).
		 */
		if (vp->v_type == VCHR && iszerodev(vp->v_rdev)) {
			handle = NULL;
			maxprot = VM_PROT_ALL;
			flags |= MAP_ANON;
		} else {
			/*
			 * Ensure that file and memory protections are
			 * compatible.  Note that we only worry about
			 * writability if mapping is shared; in this case,
			 * current and max prot are dictated by the open file.
			 * XXX use the vnode instead?  Problem is: what
			 * credentials do we use for determination? What if
			 * proc does a setuid?
			 */
			maxprot = VM_PROT_EXECUTE;	/* ??? */
			if (fp->f_flag & FREAD)
				maxprot |= VM_PROT_READ;
			else if (prot & PROT_READ)
				return (EACCES);
			if (flags & MAP_SHARED) {
				if (fp->f_flag & FWRITE)
					maxprot |= VM_PROT_WRITE;
				else if (prot & PROT_WRITE)
					return (EACCES);
			} else
				maxprot |= VM_PROT_WRITE;
			handle = (caddr_t) vp;
		}
	}
	error = vm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot,
	    flags, handle, (vm_offset_t) uap->pos);
	if (error == 0)
		*retval = (int) addr;
	return (error);
}

#ifdef COMPAT_43
struct ommap_args {
	caddr_t addr;
	int len;
	int prot;
	int flags;
	int fd;
	long pos;
};
int
ommap(p, uap, retval)
	struct proc *p;
	register struct ommap_args *uap;
	int *retval;
{
	struct mmap_args nargs;
	static const char cvtbsdprot[8] = {
		0,
		PROT_EXEC,
		PROT_WRITE,
		PROT_EXEC | PROT_WRITE,
		PROT_READ,
		PROT_EXEC | PROT_READ,
		PROT_WRITE | PROT_READ,
		PROT_EXEC | PROT_WRITE | PROT_READ,
	};

#define	OMAP_ANON	0x0002
#define	OMAP_COPY	0x0020
#define	OMAP_SHARED	0x0010
#define	OMAP_FIXED	0x0100
#define	OMAP_INHERIT	0x0800

	nargs.addr = uap->addr;
	nargs.len = uap->len;
	nargs.prot = cvtbsdprot[uap->prot & 0x7];
	nargs.flags = 0;
	if (uap->flags & OMAP_ANON)
		nargs.flags |= MAP_ANON;
	if (uap->flags & OMAP_COPY)
		nargs.flags |= MAP_COPY;
	if (uap->flags & OMAP_SHARED)
		nargs.flags |= MAP_SHARED;
	else
		nargs.flags |= MAP_PRIVATE;
	if (uap->flags & OMAP_FIXED)
		nargs.flags |= MAP_FIXED;
	if (uap->flags & OMAP_INHERIT)
		nargs.flags |= MAP_INHERIT;
	nargs.fd = uap->fd;
	nargs.pos = uap->pos;
	return (mmap(p, &nargs, retval));
}
#endif				/* COMPAT_43 */


struct msync_args {
	caddr_t addr;
	int len;
};
int
msync(p, uap, retval)
	struct proc *p;
	struct msync_args *uap;
	int *retval;
{
	vm_offset_t addr;
	vm_size_t size;
	vm_map_t map;
	int rv;
	boolean_t syncio, invalidate;

#ifdef DEBUG
	if (mmapdebug & (MDB_FOLLOW | MDB_SYNC))
		printf("msync(%d): addr %x len %x\n",
		    p->p_pid, uap->addr, uap->len);
#endif
	if (((int) uap->addr & PAGE_MASK) || uap->addr + uap->len < uap->addr)
		return (EINVAL);
	map = &p->p_vmspace->vm_map;
	addr = (vm_offset_t) uap->addr;
	size = (vm_size_t) uap->len;
	/*
	 * XXX Gak!  If size is zero we are supposed to sync "all modified
	 * pages with the region containing addr".  Unfortunately, we don't
	 * really keep track of individual mmaps so we approximate by flushing
	 * the range of the map entry containing addr. This can be incorrect
	 * if the region splits or is coalesced with a neighbor.
	 */
	if (size == 0) {
		vm_map_entry_t entry;

		vm_map_lock_read(map);
		rv = vm_map_lookup_entry(map, addr, &entry);
		vm_map_unlock_read(map);
		if (rv == FALSE)
			return (EINVAL);
		addr = entry->start;
		size = entry->end - entry->start;
	}
#ifdef DEBUG
	if (mmapdebug & MDB_SYNC)
		printf("msync: cleaning/flushing address range [%x-%x)\n",
		    addr, addr + size);
#endif
	/*
	 * Could pass this in as a third flag argument to implement Sun's
	 * MS_ASYNC.
	 */
	syncio = TRUE;
	/*
	 * XXX bummer, gotta flush all cached pages to ensure consistency with
	 * the file system cache.  Otherwise, we could pass this in to
	 * implement Sun's MS_INVALIDATE.
	 */
	invalidate = TRUE;
	/*
	 * Clean the pages and interpret the return value.
	 */
	rv = vm_map_clean(map, addr, addr + size, syncio, invalidate);
	switch (rv) {
	case KERN_SUCCESS:
		break;
	case KERN_INVALID_ADDRESS:
		return (EINVAL);	/* Sun returns ENOMEM? */
	case KERN_FAILURE:
		return (EIO);
	default:
		return (EINVAL);
	}
	return (0);
}

struct munmap_args {
	caddr_t addr;
	int len;
};
int
munmap(p, uap, retval)
	register struct proc *p;
	register struct munmap_args *uap;
	int *retval;
{
	vm_offset_t addr;
	vm_size_t size;
	vm_map_t map;

#ifdef DEBUG
	if (mmapdebug & MDB_FOLLOW)
		printf("munmap(%d): addr %x len %x\n",
		    p->p_pid, uap->addr, uap->len);
#endif

	addr = (vm_offset_t) uap->addr;
	if ((addr & PAGE_MASK) || uap->len < 0)
		return (EINVAL);
	size = (vm_size_t) round_page(uap->len);
	if (size == 0)
		return (0);
	/*
	 * Check for illegal addresses.  Watch out for address wrap... Note
	 * that VM_*_ADDRESS are not constants due to casts (argh).
	 */
	if (VM_MAXUSER_ADDRESS > 0 && addr + size > VM_MAXUSER_ADDRESS)
		return (EINVAL);
#ifndef i386
	if (VM_MIN_ADDRESS > 0 && addr < VM_MIN_ADDRESS)
		return (EINVAL);
#endif
	if (addr + size < addr)
		return (EINVAL);
	map = &p->p_vmspace->vm_map;
	/*
	 * Make sure entire range is allocated.
	 */
	if (!vm_map_check_protection(map, addr, addr + size, VM_PROT_NONE))
		return (EINVAL);
	/* returns nothing but KERN_SUCCESS anyway */
	(void) vm_map_remove(map, addr, addr + size);
	return (0);
}

void
munmapfd(p, fd)
	struct proc *p;
	int fd;
{
#ifdef DEBUG
	if (mmapdebug & MDB_FOLLOW)
		printf("munmapfd(%d): fd %d\n", p->p_pid, fd);
#endif

	/*
	 * XXX should unmap any regions mapped to this file
	 */
	p->p_fd->fd_ofileflags[fd] &= ~UF_MAPPED;
}

struct mprotect_args {
	caddr_t addr;
	int len;
	int prot;
};
int
mprotect(p, uap, retval)
	struct proc *p;
	struct mprotect_args *uap;
	int *retval;
{
	vm_offset_t addr;
	vm_size_t size;
	register vm_prot_t prot;

#ifdef DEBUG
	if (mmapdebug & MDB_FOLLOW)
		printf("mprotect(%d): addr %x len %x prot %d\n",
		    p->p_pid, uap->addr, uap->len, uap->prot);
#endif

	addr = (vm_offset_t) uap->addr;
	if ((addr & PAGE_MASK) || uap->len < 0)
		return (EINVAL);
	size = (vm_size_t) uap->len;
	prot = uap->prot & VM_PROT_ALL;

	switch (vm_map_protect(&p->p_vmspace->vm_map, addr, addr + size, prot,
		FALSE)) {
	case KERN_SUCCESS:
		return (0);
	case KERN_PROTECTION_FAILURE:
		return (EACCES);
	}
	return (EINVAL);
}

struct madvise_args {
	caddr_t addr;
	int len;
	int behav;
};

/* ARGSUSED */
int
madvise(p, uap, retval)
	struct proc *p;
	struct madvise_args *uap;
	int *retval;
{

	/* Not yet implemented */
	return (EOPNOTSUPP);
}

struct mincore_args {
	caddr_t addr;
	int len;
	char *vec;
};

/* ARGSUSED */
int
mincore(p, uap, retval)
	struct proc *p;
	struct mincore_args *uap;
	int *retval;
{

	/* Not yet implemented */
	return (EOPNOTSUPP);
}

struct mlock_args {
	caddr_t addr;
	size_t len;
};
int
mlock(p, uap, retval)
	struct proc *p;
	struct mlock_args *uap;
	int *retval;
{
	vm_offset_t addr;
	vm_size_t size;
	int error;

#ifdef DEBUG
	if (mmapdebug & MDB_FOLLOW)
		printf("mlock(%d): addr %x len %x\n",
		    p->p_pid, uap->addr, uap->len);
#endif
	addr = (vm_offset_t) uap->addr;
	if ((addr & PAGE_MASK) || uap->addr + uap->len < uap->addr)
		return (EINVAL);
	size = round_page((vm_size_t) uap->len);
	if (atop(size) + cnt.v_wire_count > vm_page_max_wired)
		return (EAGAIN);
#ifdef pmap_wired_count
	if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
	    p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur)
		return (EAGAIN);
#else
	error = suser(p->p_ucred, &p->p_acflag);
	if (error)
		return (error);
#endif

	error = vm_map_pageable(&p->p_vmspace->vm_map, addr, addr + size, FALSE);
	return (error == KERN_SUCCESS ? 0 : ENOMEM);
}

struct munlock_args {
	caddr_t addr;
	size_t len;
};
int
munlock(p, uap, retval)
	struct proc *p;
	struct munlock_args *uap;
	int *retval;
{
	vm_offset_t addr;
	vm_size_t size;
	int error;

#ifdef DEBUG
	if (mmapdebug & MDB_FOLLOW)
		printf("munlock(%d): addr %x len %x\n",
		    p->p_pid, uap->addr, uap->len);
#endif
	addr = (vm_offset_t) uap->addr;
	if ((addr & PAGE_MASK) || uap->addr + uap->len < uap->addr)
		return (EINVAL);
#ifndef pmap_wired_count
	error = suser(p->p_ucred, &p->p_acflag);
	if (error)
		return (error);
#endif
	size = round_page((vm_size_t) uap->len);

	error = vm_map_pageable(&p->p_vmspace->vm_map, addr, addr + size, TRUE);
	return (error == KERN_SUCCESS ? 0 : ENOMEM);
}

/*
 * Internal version of mmap.
 * Currently used by mmap, exec, and sys5 shared memory.
 * Handle is either a vnode pointer or NULL for MAP_ANON.
 */
int
vm_mmap(map, addr, size, prot, maxprot, flags, handle, foff)
	register vm_map_t map;
	register vm_offset_t *addr;
	register vm_size_t size;
	vm_prot_t prot, maxprot;
	register int flags;
	caddr_t handle;		/* XXX should be vp */
	vm_offset_t foff;
{
	register vm_pager_t pager;
	boolean_t fitit;
	vm_object_t object;
	struct vnode *vp = NULL;
	int type;
	int rv = KERN_SUCCESS;

	if (size == 0)
		return (0);

	size = round_page(size);

	if ((flags & MAP_FIXED) == 0) {
		fitit = TRUE;
		*addr = round_page(*addr);
	} else {
		if (*addr != trunc_page(*addr))
			return (EINVAL);
		fitit = FALSE;
		(void) vm_map_remove(map, *addr, *addr + size);
	}

	/*
	 * We currently can only deal with page aligned file offsets.
	 * The check is here rather than in the syscall because the
	 * kernel calls this function internally for other mmaping
	 * operations (such as in exec) and non-aligned offsets will
	 * cause pmap inconsistencies...so we want to be sure to
	 * disallow this in all cases.
	 */
	if (foff & PAGE_MASK)
		return (EINVAL);

	/*
	 * Lookup/allocate pager.  All except an unnamed anonymous lookup gain
	 * a reference to ensure continued existance of the object. (XXX the
	 * exception is to appease the pageout daemon)
	 */
	if (flags & MAP_ANON)
		type = PG_DFLT;
	else {
		vp = (struct vnode *) handle;
		if (vp->v_type == VCHR) {
			type = PG_DEVICE;
			handle = (caddr_t) vp->v_rdev;
		} else
			type = PG_VNODE;
	}
	pager = vm_pager_allocate(type, handle, size, prot, foff);
	if (pager == NULL)
		return (type == PG_DEVICE ? EINVAL : ENOMEM);
	/*
	 * Guarantee that the pager has an object.
	 */
	object = vm_object_lookup(pager);
	if (object == NULL) {
		if (handle != NULL)
			panic("vm_mmap: pager didn't allocate an object (and should have)");
		/*
		 * Should only happen for unnamed anonymous regions.
		 */
		object = vm_object_allocate(size);
		object->pager = pager;
	} else {
		/*
		 * Lose vm_object_lookup() reference. Retain reference
		 * gained by vm_pager_allocate().
		 */
		vm_object_deallocate(object);
	}
	/*
	 * At this point, our actions above have gained a total of
	 * one reference to the object, and we have a pager.
	 */

	/*
	 * Anonymous memory, shared file, or character special file.
	 */
	if ((flags & (MAP_ANON|MAP_SHARED)) || (type == PG_DEVICE)) {
		rv = vm_map_find(map, object, foff, addr, size, fitit);
		if (rv != KERN_SUCCESS) {
			/*
			 * Lose the object reference. This will also destroy
			 * the pager if there are no other references.
			 */
			vm_object_deallocate(object);
			goto out;
		}
	}
	/*
	 * mmap a COW regular file
	 */
	else {
		vm_map_t tmap;
		vm_offset_t off;
		vm_map_entry_t entry;

		if (flags & MAP_COPY) {
			/* locate and allocate the target address space */
			rv = vm_map_find(map, NULL, 0, addr, size, fitit);
			if (rv != KERN_SUCCESS) {
				vm_object_deallocate(object);
				goto out;
			}

			off = VM_MIN_ADDRESS;
			tmap = vm_map_create(NULL, off, off + size, TRUE);
			rv = vm_map_find(tmap, object, foff, &off, size, FALSE);
			if (rv != KERN_SUCCESS) {
				/*
				 * Deallocate and delete the temporary map.
				 * Note that since the object insertion
				 * above has failed, the vm_map_deallocate
				 * doesn't lose the object reference - we
				 * must do it explicitly.
				 */
				vm_object_deallocate(object);
				vm_map_deallocate(tmap);
				goto out;
			}
			rv = vm_map_copy(map, tmap, *addr, size, off,
		   	 FALSE, FALSE);
			/*
			 * Deallocate temporary map. XXX - depending
			 * on events, this may leave the object with
			 * no net gain in reference count! ...this
			 * needs to be looked at!
			 */
			vm_map_deallocate(tmap);
			if (rv != KERN_SUCCESS)
				goto out;

		} else {
			vm_object_t user_object;

			/*
			 * Create a new object and make the original object
			 * the backing object. NOTE: the object reference gained
			 * above is now changed into the reference held by
			 * user_object. Since we don't map 'object', we want
			 * only this one reference.
			 */
			user_object = vm_object_allocate(object->size);
			user_object->shadow = object;
			TAILQ_INSERT_TAIL(&object->reverse_shadow_head,
				    user_object, reverse_shadow_list);

			rv = vm_map_find(map, user_object, foff, addr, size, fitit);
			if( rv != KERN_SUCCESS) {
				vm_object_deallocate(user_object);
				goto out;
			}
			
			/*
			 * this is a consistancy check, gets the map entry, and should
			 * never fail
			 */
			if (!vm_map_lookup_entry(map, *addr, &entry)) {
				panic("vm_mmap: missing map entry!!!");
			}

			entry->copy_on_write = TRUE;
		}

		/*
		 * set pages COW and protect for read access only
		 */
		vm_object_pmap_copy(object, foff, foff + size);

	}

	/*
	 * "Pre-fault" resident pages.
	 */
	if ((type == PG_VNODE) && (map->pmap != NULL)) {
		pmap_object_init_pt(map->pmap, *addr, object, foff, size);
	}

	/*
	 * Correct protection (default is VM_PROT_ALL). If maxprot is
	 * different than prot, we must set both explicitly.
	 */
	rv = KERN_SUCCESS;
	if (maxprot != VM_PROT_ALL)
		rv = vm_map_protect(map, *addr, *addr + size, maxprot, TRUE);
	if (rv == KERN_SUCCESS && prot != maxprot)
		rv = vm_map_protect(map, *addr, *addr + size, prot, FALSE);
	if (rv != KERN_SUCCESS) {
		(void) vm_map_remove(map, *addr, *addr + size);
		goto out;
	}
	/*
	 * Shared memory is also shared with children.
	 */
	if (flags & MAP_SHARED) {
		rv = vm_map_inherit(map, *addr, *addr + size, VM_INHERIT_SHARE);
		if (rv != KERN_SUCCESS) {
			(void) vm_map_remove(map, *addr, *addr + size);
			goto out;
		}
	}
out:
#ifdef DEBUG
	if (mmapdebug & MDB_MAPIT)
		printf("vm_mmap: rv %d\n", rv);
#endif
	switch (rv) {
	case KERN_SUCCESS:
		return (0);
	case KERN_INVALID_ADDRESS:
	case KERN_NO_SPACE:
		return (ENOMEM);
	case KERN_PROTECTION_FAILURE:
		return (EACCES);
	default:
		return (EINVAL);
	}
}