vm_mmap.c

open bsd vm device design

	 */
#if 0
	if (!vm_map_check_protection(map, addr, addr + size, VM_PROT_NONE))
		return(EINVAL);
#endif
	/* 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 vm_deallocate any regions mapped to this file
	 */
	p->p_fd->fd_ofileflags[fd] &= ~UF_MAPPED;
}

int
mprotect(p, uap, retval)
	struct proc *p;
	struct mprotect_args /* {
		syscallarg(caddr_t) addr;
		syscallarg(int) len;
		syscallarg(int) prot;
	} */ *uap;
	register_t *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, SCARG(uap, addr), SCARG(uap, len), SCARG(uap, prot));
#endif

	addr = (vm_offset_t)SCARG(uap, addr);
	if ((addr & PAGE_MASK) || SCARG(uap, len) < 0)
		return(EINVAL);
	size = (vm_size_t)SCARG(uap, len);
	prot = SCARG(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);
}

/* ARGSUSED */
int
madvise(p, uap, retval)
	struct proc *p;
	struct madvise_args /* {
		syscallarg(caddr_t) addr;
		syscallarg(int) len;
		syscallarg(int) behav;
	} */ *uap;
	register_t *retval;
{

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

/* ARGSUSED */
int
mincore(p, uap, retval)
	struct proc *p;
	struct mincore_args /* {
		syscallarg(caddr_t) addr;
		syscallarg(int) len;
		syscallarg(char *) vec;
	} */ *uap;
	register_t *retval;
{

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

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

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

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

int
munlock(p, uap, retval)
	struct proc *p;
	struct munlock_args /* {
		syscallarg(caddr_t) addr;
		syscallarg(size_t) len;
	} */ *uap;
	register_t *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, SCARG(uap, addr), SCARG(uap, len));
#endif
	addr = (vm_offset_t)SCARG(uap, addr);
	if ((addr & PAGE_MASK) || SCARG(uap, addr) + SCARG(uap, len) < SCARG(uap, addr))
		return (EINVAL);
#ifndef pmap_wired_count
	if (error = suser(p->p_ucred, &p->p_acflag))
		return (error);
#endif
	size = round_page((vm_size_t)SCARG(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);

	if ((flags & MAP_FIXED) == 0) {
		fitit = TRUE;
		*addr = round_page(*addr);
	} else {
		fitit = FALSE;
		(void)vm_deallocate(map, *addr, size);
	}

	/*
	 * 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);
	/*
	 * Find object and release extra reference gained by lookup
	 */
	object = vm_object_lookup(pager);
	vm_object_deallocate(object);

	/*
	 * Anonymous memory.
	 */
	if (flags & MAP_ANON) {
		rv = vm_allocate_with_pager(map, addr, size, fitit,
					    pager, foff, TRUE);
		if (rv != KERN_SUCCESS) {
			if (handle == NULL)
				vm_pager_deallocate(pager);
			else
				vm_object_deallocate(object);
			goto out;
		}
		/*
		 * Don't cache anonymous objects.
		 * Loses the reference gained by vm_pager_allocate.
		 * Note that object will be NULL when handle == NULL,
		 * this is ok since vm_allocate_with_pager has made
		 * sure that these objects are uncached.
		 */
		(void) pager_cache(object, FALSE);
#ifdef DEBUG
		if (mmapdebug & MDB_MAPIT)
			printf("vm_mmap(%d): ANON *addr %x size %x pager %x\n",
			       curproc->p_pid, *addr, size, pager);
#endif
	}
	/*
	 * Must be a mapped file.
	 * Distinguish between character special and regular files.
	 */
	else if (vp->v_type == VCHR) {
		rv = vm_allocate_with_pager(map, addr, size, fitit,
					    pager, foff, FALSE);
		/*
		 * Uncache the object and lose the reference gained
		 * by vm_pager_allocate().  If the call to
		 * vm_allocate_with_pager() was sucessful, then we
		 * gained an additional reference ensuring the object
		 * will continue to exist.  If the call failed then
		 * the deallocate call below will terminate the
		 * object which is fine.
		 */
		(void) pager_cache(object, FALSE);
		if (rv != KERN_SUCCESS)
			goto out;
	}
	/*
	 * A regular file
	 */
	else {
#ifdef DEBUG
		if (object == NULL)
			printf("vm_mmap: no object: vp %x, pager %x\n",
			       vp, pager);
#endif
		/*
		 * Map it directly.
		 * Allows modifications to go out to the vnode.
		 */
		if (flags & MAP_SHARED) {
			rv = vm_allocate_with_pager(map, addr, size,
						    fitit, pager,
						    foff, FALSE);
			if (rv != KERN_SUCCESS) {
				vm_object_deallocate(object);
				goto out;
			}
			/*
			 * Don't cache the object.  This is the easiest way
			 * of ensuring that data gets back to the filesystem
			 * because vnode_pager_deallocate() will fsync the
			 * vnode.  pager_cache() will lose the extra ref.
			 */
			if (prot & VM_PROT_WRITE)
				pager_cache(object, FALSE);
			else
				vm_object_deallocate(object);
		}
		/*
		 * Copy-on-write of file.  Two flavors.
		 * MAP_COPY is true COW, you essentially get a snapshot of
		 * the region at the time of mapping.  MAP_PRIVATE means only
		 * that your changes are not reflected back to the object.
		 * Changes made by others will be seen.
		 */
		else {
			vm_map_t tmap;
			vm_offset_t off;

			/* locate and allocate the target address space */
			rv = vm_map_find(map, NULL, (vm_offset_t)0,
					 addr, size, fitit);
			if (rv != KERN_SUCCESS) {
				vm_object_deallocate(object);
				goto out;
			}
			tmap = vm_map_create(pmap_create(size), VM_MIN_ADDRESS,
					     VM_MIN_ADDRESS+size, TRUE);
			off = VM_MIN_ADDRESS;
			rv = vm_allocate_with_pager(tmap, &off, size,
						    TRUE, pager,
						    foff, FALSE);
			if (rv != KERN_SUCCESS) {
				vm_object_deallocate(object);
				vm_map_deallocate(tmap);
				goto out;
			}
			/*
			 * (XXX)
			 * MAP_PRIVATE implies that we see changes made by
			 * others.  To ensure that we need to guarentee that
			 * no copy object is created (otherwise original
			 * pages would be pushed to the copy object and we
			 * would never see changes made by others).  We
			 * totally sleeze it right now by marking the object
			 * internal temporarily.
			 */
			if ((flags & MAP_COPY) == 0)
				object->flags |= OBJ_INTERNAL;
			rv = vm_map_copy(map, tmap, *addr, size, off,
					 FALSE, FALSE);
			object->flags &= ~OBJ_INTERNAL;
			/*
			 * (XXX)
			 * My oh my, this only gets worse...
			 * Force creation of a shadow object so that
			 * vm_map_fork will do the right thing.
			 */
			if ((flags & MAP_COPY) == 0) {
				vm_map_t tmap;
				vm_map_entry_t tentry;
				vm_object_t tobject;
				vm_offset_t toffset;
				vm_prot_t tprot;
				boolean_t twired, tsu;

				tmap = map;
				vm_map_lookup(&tmap, *addr, VM_PROT_WRITE,
					      &tentry, &tobject, &toffset,
					      &tprot, &twired, &tsu);
				vm_map_lookup_done(tmap, tentry);
			}
			/*
			 * (XXX)
			 * Map copy code cannot detect sharing unless a
			 * sharing map is involved.  So we cheat and write
			 * protect everything ourselves.
			 */
			vm_object_pmap_copy(object, foff, foff + size);
			vm_object_deallocate(object);
			vm_map_deallocate(tmap);
			if (rv != KERN_SUCCESS)
				goto out;
		}
#ifdef DEBUG
		if (mmapdebug & MDB_MAPIT)
			printf("vm_mmap(%d): FILE *addr %x size %x pager %x\n",
			       curproc->p_pid, *addr, size, pager);
#endif
	}
	/*
	 * 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_deallocate(map, *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_deallocate(map, *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);
	}
}