Date: Sat, 16 Mar 1996 00:46:42 +0000 () From: "John S. Dyson" <toor@dyson.iquest.net> To: current@freebsd.org, mmead@glock.com Subject: Try this vm_mmap.c -- please Message-ID: <199603160046.AAA00402@dyson.iquest.net>
next in thread | raw e-mail | index | archive | help
This vm_mmap.c contains what I believe some fixes to the mmap code. Note
that there were some severe bogons in the code, and one that I cannot
easily get rid of. Firstly we allow mmaps that don't have either MAP_PRIVATE or
MAP_SHARED set. This is wrong because logically one is necessary. The
solution is that I default to MAP_PRIVATE for vnodes and MAP_SHARED for
devices (video memory.) Also, the old code did not allow for shared
anonymous mappings, this is very bogus. Eventually, we should enforce
a MAP_PRIVATE or MAP_SHARED bit being set, but there is code out there
like XFree that doesn't specify either bit, and since it was originally
not "wrong", it is a PROBLEM :-(. PLEASE PLEASE give me some feedback on
this, as my entire life for this weekend is dedicated to fixing this
problem (not really, but you know what I mean.) :-).
Here it is: vm_mmap.c -- remember to save your old one :-).
/*
* 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 1.39 1996/03/12 02:27:20 dyson Exp $
*/
/*
* Mapped file (mmap) interface to VM
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.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 <sys/vmmeter.h>
#include <miscfs/specfs/specdev.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <vm/vm_inherit.h>
#include <vm/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_pageout.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#ifndef _SYS_SYSPROTO_H_
struct sbrk_args {
int incr;
};
#endif
/* ARGSUSED */
int
sbrk(p, uap, retval)
struct proc *p;
struct sbrk_args *uap;
int *retval;
{
/* Not yet implemented */
return (EOPNOTSUPP);
}
#ifndef _SYS_SYSPROTO_H_
struct sstk_args {
int incr;
};
#endif
/* 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)
#ifndef _SYS_SYSPROTO_H_
struct getpagesize_args {
int dummy;
};
#endif
/* 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 */
#ifndef _SYS_SYSPROTO_H_
struct mmap_args {
caddr_t addr;
size_t len;
int prot;
int flags;
int fd;
long pad;
off_t pos;
};
#endif
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, pageoff;
vm_prot_t prot, maxprot;
caddr_t handle;
int flags, error;
prot = uap->prot & VM_PROT_ALL;
flags = uap->flags;
/*
* 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);
/*
* Round page if not already disallowed by above test
* XXX: Is there any point in the MAP_FIXED align requirement above?
*/
size = uap->len;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
/*
* 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, uap->pos);
if (error == 0)
*retval = (int) addr;
return (error);
}
#ifdef COMPAT_43
#ifndef _SYS_SYSPROTO_H_
struct ommap_args {
caddr_t addr;
int len;
int prot;
int flags;
int fd;
long pos;
};
#endif
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 */
#ifndef _SYS_SYSPROTO_H_
struct msync_args {
caddr_t addr;
int len;
int flags;
};
#endif
int
msync(p, uap, retval)
struct proc *p;
struct msync_args *uap;
int *retval;
{
vm_offset_t addr;
vm_size_t size, pageoff;
int flags;
vm_map_t map;
int rv;
addr = (vm_offset_t) uap->addr;
size = uap->len;
flags = uap->flags;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if (addr + size < addr)
return(EINVAL);
if ((flags & (MS_ASYNC|MS_INVALIDATE)) == (MS_ASYNC|MS_INVALIDATE))
return (EINVAL);
map = &p->p_vmspace->vm_map;
/*
* 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;
}
/*
* Clean the pages and interpret the return value.
*/
rv = vm_map_clean(map, addr, addr + size, (flags & MS_ASYNC) == 0,
(flags & MS_INVALIDATE) != 0);
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);
}
#ifndef _SYS_SYSPROTO_H_
struct munmap_args {
caddr_t addr;
size_t len;
};
#endif
int
munmap(p, uap, retval)
register struct proc *p;
register struct munmap_args *uap;
int *retval;
{
vm_offset_t addr;
vm_size_t size, pageoff;
vm_map_t map;
addr = (vm_offset_t) uap->addr;
size = uap->len;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if (addr + size < addr)
return(EINVAL);
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;
{
/*
* XXX should unmap any regions mapped to this file
*/
p->p_fd->fd_ofileflags[fd] &= ~UF_MAPPED;
}
#ifndef _SYS_SYSPROTO_H_
struct mprotect_args {
caddr_t addr;
size_t len;
int prot;
};
#endif
int
mprotect(p, uap, retval)
struct proc *p;
struct mprotect_args *uap;
int *retval;
{
vm_offset_t addr;
vm_size_t size, pageoff;
register vm_prot_t prot;
addr = (vm_offset_t) uap->addr;
size = uap->len;
prot = uap->prot & VM_PROT_ALL;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if (addr + size < addr)
return(EINVAL);
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);
}
#ifndef _SYS_SYSPROTO_H_
struct minherit_args {
caddr_t addr;
size_t len;
int inherit;
};
#endif
int
minherit(p, uap, retval)
struct proc *p;
struct minherit_args *uap;
int *retval;
{
vm_offset_t addr;
vm_size_t size, pageoff;
register vm_inherit_t inherit;
addr = (vm_offset_t)uap->addr;
size = uap->len;
inherit = uap->inherit;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if (addr + size < addr)
return(EINVAL);
switch (vm_map_inherit(&p->p_vmspace->vm_map, addr, addr+size,
inherit)) {
case KERN_SUCCESS:
return (0);
case KERN_PROTECTION_FAILURE:
return (EACCES);
}
return (EINVAL);
}
#ifndef _SYS_SYSPROTO_H_
struct madvise_args {
caddr_t addr;
size_t len;
int behav;
};
#endif
/* ARGSUSED */
int
madvise(p, uap, retval)
struct proc *p;
struct madvise_args *uap;
int *retval;
{
/* Not yet implemented */
return (EOPNOTSUPP);
}
#ifndef _SYS_SYSPROTO_H_
struct mincore_args {
caddr_t addr;
size_t len;
char *vec;
};
#endif
/* ARGSUSED */
int
mincore(p, uap, retval)
struct proc *p;
struct mincore_args *uap;
int *retval;
{
vm_offset_t addr;
vm_offset_t end;
char *vec;
addr = trunc_page((vm_offset_t) uap->addr);
end = addr + (vm_size_t)round_page(uap->len);
if (VM_MAXUSER_ADDRESS > 0 && end > VM_MAXUSER_ADDRESS)
return (EINVAL);
if (end < addr)
return (EINVAL);
vec = uap->vec;
while(addr < end) {
int error;
if (pmap_extract(&p->p_vmspace->vm_pmap, addr)) {
error = subyte( vec, 1);
} else {
error = subyte( vec, 0);
}
if (error)
return EFAULT;
vec++;
addr += PAGE_SIZE;
}
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct mlock_args {
caddr_t addr;
size_t len;
};
#endif
int
mlock(p, uap, retval)
struct proc *p;
struct mlock_args *uap;
int *retval;
{
vm_offset_t addr;
vm_size_t size, pageoff;
int error;
addr = (vm_offset_t) uap->addr;
size = uap->len;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
/* disable wrap around */
if (addr + size < addr)
return (EINVAL);
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);
}
#ifndef _SYS_SYSPROTO_H_
struct munlock_args {
caddr_t addr;
size_t len;
};
#endif
int
munlock(p, uap, retval)
struct proc *p;
struct munlock_args *uap;
int *retval;
{
vm_offset_t addr;
vm_size_t size, pageoff;
int error;
addr = (vm_offset_t) uap->addr;
size = uap->len;
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
/* disable wrap around */
if (addr + size < addr)
return (EINVAL);
#ifndef pmap_wired_count
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, 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_ooffset_t foff;
{
boolean_t fitit;
vm_object_t object, object2;
struct vnode *vp = NULL;
objtype_t type;
int rv = KERN_SUCCESS;
vm_ooffset_t objsize;
int docow;
struct proc *p = curproc;
if (size == 0)
return (0);
objsize = size = round_page(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);
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);
}
/*
* Lookup/allocate object.
*/
if (flags & MAP_ANON) {
type = OBJT_SWAP;
/*
* Unnamed anonymous regions always start at 0.
*/
if (handle == 0)
foff = 0;
} else {
vp = (struct vnode *) handle;
if (vp->v_type == VCHR) {
type = OBJT_DEVICE;
handle = (caddr_t) vp->v_rdev;
} else {
struct vattr vat;
int error;
error = VOP_GETATTR(vp, &vat, p->p_ucred, p);
if (error)
return (error);
objsize = round_page(vat.va_size);
type = OBJT_VNODE;
}
}
object = vm_pager_allocate(type, handle, OFF_TO_IDX(objsize), prot, foff);
if (object == NULL)
return (type == OBJT_DEVICE ? EINVAL : ENOMEM);
/*
* On device mmaps we default to map shared -- makes the most
* sense in this case. Does MAP_PRIVATE even make sense on
* devices mmaps???
*/
if ((type == OBJT_DEVICE) &&
(flags & (MAP_PRIVATE|MAP_SHARED)) == 0)
flags |= MAP_SHARED;
/*
* On vnode mmaps we default to map private -- it is safer.
*/
else if ((type == OBJT_VNODE) &&
(flags & (MAP_PRIVATE|MAP_SHARED)) == 0)
flags |= MAP_PRIVATE;
object2 = NULL;
docow = 0;
if (flags & MAP_PRIVATE) {
docow = MAP_COPY_ON_WRITE;
if (objsize < size) {
object2 = vm_object_allocate( OBJT_DEFAULT,
OFF_TO_IDX(size - (foff & ~(PAGE_SIZE - 1))));
object2->backing_object = object;
object2->backing_object_offset = foff;
TAILQ_INSERT_TAIL(&object->shadow_head,
object2, shadow_list);
++object->shadow_count;
} else {
docow |= MAP_COPY_NEEDED;
}
}
if (object2)
rv = vm_map_find(map, object2, 0, addr, size, fitit,
prot, maxprot, docow);
else
rv = vm_map_find(map, object, foff, addr, size, fitit,
prot, maxprot, docow);
if (rv != KERN_SUCCESS) {
/*
* Lose the object reference. Will destroy the
* object if it's an unnamed anonymous mapping
* or named anonymous without other references.
*/
if (object2)
vm_object_deallocate(object2);
else
vm_object_deallocate(object);
goto out;
}
/*
* "Pre-fault" resident pages.
*/
if ((map != kernel_map) &&
(type == OBJT_VNODE) && (map->pmap != NULL)) {
pmap_object_init_pt(map->pmap, *addr,
object, (vm_pindex_t) OFF_TO_IDX(foff), size);
}
/*
* Shared memory is also directly shared with children, otherwise the
* mappings are copy on write.
*/
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:
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);
}
}
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199603160046.AAA00402>