NetBSD/sys/vm/vm_mmap.c

1031 lines
25 KiB
C

/* $NetBSD: vm_mmap.c,v 1.58 1998/05/30 22:21:03 kleink Exp $ */
/*
* 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 8.10 (Berkeley) 2/19/95
*/
/*
* 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 <sys/stat.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <miscfs/specfs/specdev.h>
#include <vm/vm.h>
#include <vm/vm_pager.h>
#include <vm/vm_prot.h>
#ifdef DEBUG
int mmapdebug = 0;
#define MDB_FOLLOW 0x01
#define MDB_SYNC 0x02
#define MDB_MAPIT 0x04
#endif
/* ARGSUSED */
int
sys_sbrk(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
#if 0
struct sys_sbrk_args /* {
syscallarg(int) incr;
} */ *uap = v;
#endif
/* Not yet implemented */
return (EOPNOTSUPP);
}
/* ARGSUSED */
int
sys_sstk(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
#if 0
struct sys_sstk_args /* {
syscallarg(int) incr;
} */ *uap = v;
#endif
/* Not yet implemented */
return (EOPNOTSUPP);
}
/*
* Memory Map (mmap) system call. Note that the file offset
* and address are allowed to be NOT page aligned, though if
* the MAP_FIXED flag it set, both must have the same remainder
* modulo the PAGE_SIZE (POSIX 1003.1b). If the address is not
* page-aligned, the actual mapping starts at trunc_page(addr)
* and the return value is adjusted up by the page offset.
*/
int
sys_mmap(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
register struct sys_mmap_args /* {
syscallarg(void *) addr;
syscallarg(size_t) len;
syscallarg(int) prot;
syscallarg(int) flags;
syscallarg(int) fd;
syscallarg(long) pad;
syscallarg(off_t) pos;
} */ *uap = v;
struct vattr va;
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
struct vnode *vp;
vm_offset_t addr;
off_t pos;
vm_size_t size, pageoff;
vm_prot_t prot, maxprot;
caddr_t handle;
int fd, flags, error;
vm_offset_t vm_min_address = VM_MIN_ADDRESS;
addr = (vm_offset_t) SCARG(uap, addr);
size = (vm_size_t) SCARG(uap, len);
prot = SCARG(uap, prot) & VM_PROT_ALL;
flags = SCARG(uap, flags);
fd = SCARG(uap, fd);
pos = SCARG(uap, pos);
#ifdef DEBUG
if (mmapdebug & MDB_FOLLOW)
printf("mmap(%d): addr %lx len %lx pro %x flg %x fd %d pos %qx\n",
p->p_pid, addr, size, prot, flags, fd, pos);
#endif
/* make sure mapping fits into numeric range */
if (pos + size > (vm_offset_t)-PAGE_SIZE) {
#ifdef DEBUG
printf("mmap: pos=%qx, size=%lx too big\n", pos, size);
#endif
return(EINVAL);
}
/*
* Align the file position to a page boundary,
* and save its page offset component.
*/
pageoff = (pos & PAGE_MASK);
pos -= pageoff;
/* Adjust size for rounding (on both ends). */
size += pageoff; /* low end... */
size = (vm_size_t) round_page(size); /* hi end */
/* Do not allow mappings that cause address wrap... */
if ((ssize_t)size < 0)
return (EINVAL);
/*
* Check for illegal addresses. Watch out for address wrap...
* Note that VM_*_ADDRESS are not constants due to casts (argh).
*/
if (flags & MAP_FIXED) {
/*
* The specified address must have the same remainder
* as the file offset taken modulo PAGE_SIZE, so it
* should be aligned after adjustment by pageoff.
*/
addr -= pageoff;
if (addr & PAGE_MASK)
return (EINVAL);
/* Address range must be all in user VM space. */
if (VM_MAXUSER_ADDRESS > 0 &&
addr + size > VM_MAXUSER_ADDRESS)
return (EINVAL);
if (vm_min_address > 0 && addr < vm_min_address)
return (EINVAL);
if (addr > addr + size)
return (EINVAL);
}
/*
* XXX for non-fixed mappings where no hint is provided or
* the hint would fall in the potential heap space,
* place it after the end of the largest possible heap.
*
* There should really be a pmap call to determine a reasonable
* location. (To avoid VA cache alias problems, for example!)
*/
else if (addr < round_page(p->p_vmspace->vm_daddr + MAXDSIZ))
addr = round_page(p->p_vmspace->vm_daddr + MAXDSIZ);
if ((flags & MAP_ANON) == 0) {
/*
* Mapping file, get fp for validation.
* Obtain vnode and make sure it is of appropriate type.
*/
if (((unsigned)fd) >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[fd]) == NULL)
return (EBADF);
if (fp->f_type != DTYPE_VNODE)
return (ENODEV);
vp = (struct vnode *)fp->f_data;
if (vp->v_type != VREG && vp->v_type != VCHR)
return (ENODEV);
/*
* XXX hack to handle use of /dev/zero to map anon
* memory (ala SunOS).
*/
if (vp->v_type == VCHR && iszerodev(vp->v_rdev)) {
flags |= MAP_ANON;
goto is_anon;
}
/*
* Old programs may not select a specific sharing type, so
* default to an appropriate one.
*/
if ((flags & (MAP_SHARED|MAP_PRIVATE|MAP_COPY)) == 0) {
if (vp->v_type == VCHR)
flags |= MAP_SHARED; /* for a device */
else
flags |= MAP_PRIVATE; /* for a file */
}
/*
* MAP_PRIVATE device mappings don't make sense (and aren't
* supported anyway). However, some programs rely on this,
* so just change it to MAP_SHARED.
*/
if (vp->v_type == VCHR && (flags & MAP_PRIVATE) != 0)
flags = (flags & ~MAP_PRIVATE) | MAP_SHARED;
/*
* 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 the file is writable, only add PROT_WRITE to
* maxprot if the file is not immutable, append-only.
* otherwise, if we have asked for PROT_WRITE, return
* EPERM.
*/
if (fp->f_flag & FWRITE) {
if ((error =
VOP_GETATTR(vp, &va, p->p_ucred, p)))
return (error);
if ((va.va_flags & (IMMUTABLE|APPEND)) == 0)
maxprot |= VM_PROT_WRITE;
else if (prot & PROT_WRITE)
return (EPERM);
}
else if (prot & PROT_WRITE)
return (EACCES);
} else
maxprot |= VM_PROT_WRITE;
handle = (caddr_t)vp;
} else {
/*
* (flags & MAP_ANON) == TRUE
* Mapping blank space is trivial.
*/
if (fd != -1)
return (EINVAL);
is_anon:
handle = NULL;
maxprot = VM_PROT_ALL;
pos = 0;
}
error = vm_mmap(&p->p_vmspace->vm_map, &addr, size, prot, maxprot,
flags, handle, pos);
if (error == 0)
*retval = (register_t)(addr + pageoff);
return (error);
}
int
sys___msync13(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys___msync13_args /* {
syscallarg(void *) addr;
syscallarg(size_t) len;
syscallarg(int) flags;
} */ *uap = v;
vm_offset_t addr;
vm_size_t size, pageoff;
vm_map_t map;
int rv, flags;
boolean_t syncio, invalidate;
addr = (vm_offset_t)SCARG(uap, addr);
size = (vm_size_t)SCARG(uap, len);
flags = SCARG(uap, flags);
#ifdef DEBUG
if (mmapdebug & (MDB_FOLLOW|MDB_SYNC))
printf("msync(%d): addr %lx len %lx flags %x\n",
p->p_pid, addr, size, flags);
#endif
/* sanity check flags */
if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE)) != 0 ||
(flags & (MS_ASYNC | MS_SYNC | MS_INVALIDATE)) == 0 ||
(flags & (MS_ASYNC | MS_SYNC)) == (MS_ASYNC | MS_SYNC))
return (EINVAL);
if ((flags & (MS_ASYNC | MS_SYNC)) == 0)
flags |= MS_SYNC;
/*
* Align the address to a page boundary,
* and adjust the size accordingly.
*/
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
/* Disallow wrap-around. */
if (addr + size < addr)
return (ENOMEM);
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 (ENOMEM);
addr = entry->start;
size = entry->end - entry->start;
}
#ifdef DEBUG
if (mmapdebug & MDB_SYNC)
printf("msync: cleaning/flushing address range [%lx-%lx)\n",
addr, addr+size);
#endif
#if 0
/*
* XXX Asynchronous msync() causes:
* . the process to hang on wchan "vospgw", and
* . a "vm_object_page_clean: pager_put error" message to
* be printed by the kernel.
*/
syncio = (flags & MS_SYNC) ? TRUE : FALSE;
#else
syncio = TRUE;
#endif
invalidate = (flags & MS_INVALIDATE) ? TRUE : FALSE;
/*
* 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 (ENOMEM);
case KERN_FAILURE:
return (EIO);
case KERN_PAGES_LOCKED:
return (EBUSY);
default:
return (EINVAL);
}
return (0);
}
int
sys_munmap(p, v, retval)
register struct proc *p;
void *v;
register_t *retval;
{
register struct sys_munmap_args /* {
syscallarg(void *) addr;
syscallarg(size_t) len;
} */ *uap = v;
vm_offset_t addr;
vm_size_t size, pageoff;
vm_map_t map;
vm_offset_t vm_min_address = VM_MIN_ADDRESS;
addr = (vm_offset_t) SCARG(uap, addr);
size = (vm_size_t) SCARG(uap, len);
#ifdef DEBUG
if (mmapdebug & MDB_FOLLOW)
printf("munmap(%d): addr %lx len %lx\n",
p->p_pid, addr, size);
#endif
/*
* Align the address to a page boundary,
* and adjust the size accordingly.
*/
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if ((int)size < 0)
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);
if (vm_min_address > 0 && addr < vm_min_address)
return (EINVAL);
if (addr > addr + size)
return (EINVAL);
map = &p->p_vmspace->vm_map;
#if 0
/*
* Make sure entire range is allocated.
* XXX Too strict?
*/
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
sys_mprotect(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_mprotect_args /* {
syscallarg(void *) addr;
syscallarg(int) len;
syscallarg(int) prot;
} */ *uap = v;
vm_offset_t addr;
vm_size_t size, pageoff;
register vm_prot_t prot;
addr = (vm_offset_t)SCARG(uap, addr);
size = (vm_size_t)SCARG(uap, len);
prot = SCARG(uap, prot) & VM_PROT_ALL;
#ifdef DEBUG
if (mmapdebug & MDB_FOLLOW)
printf("mprotect(%d): addr %lx len %lx prot %d\n", p->p_pid,
addr, size, prot);
#endif
/*
* Align the address to a page boundary,
* and adjust the size accordingly.
*/
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if ((int)size < 0)
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);
}
int
sys_minherit(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_minherit_args /* {
syscallarg(void *) addr;
syscallarg(int) len;
syscallarg(int) inherit;
} */ *uap = v;
vm_offset_t addr;
vm_size_t size, pageoff;
register vm_inherit_t inherit;
addr = (vm_offset_t)SCARG(uap, addr);
size = (vm_size_t)SCARG(uap, len);
inherit = SCARG(uap, inherit);
#ifdef DEBUG
if (mmapdebug & MDB_FOLLOW)
printf("minherit(%d): addr 0x%lx len %lx inherit %d\n", p->p_pid,
addr, size, inherit);
#endif
/*
* Align the address to a page boundary,
* and adjust the size accordingly.
*/
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if ((int)size < 0)
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);
}
/* ARGSUSED */
int
sys_madvise(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
#if 0
struct sys_madvise_args /* {
syscallarg(void *) addr;
syscallarg(size_t) len;
syscallarg(int) behav;
} */ *uap = v;
#endif
/* Not yet implemented */
return (EOPNOTSUPP);
}
/* ARGSUSED */
int
sys_mincore(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
#if 0
struct sys_mincore_args /* {
syscallarg(void *) addr;
syscallarg(size_t) len;
syscallarg(char *) vec;
} */ *uap = v;
#endif
/* Not yet implemented */
return (EOPNOTSUPP);
}
int
sys_mlock(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_mlock_args /* {
syscallarg(const void *) addr;
syscallarg(size_t) len;
} */ *uap = v;
vm_offset_t addr;
vm_size_t size, pageoff;
int error;
extern int vm_page_max_wired;
addr = (vm_offset_t)SCARG(uap, addr);
size = (vm_size_t)SCARG(uap, len);
#ifdef DEBUG
if (mmapdebug & MDB_FOLLOW)
printf("mlock(%d): addr %lx len %lx\n",
p->p_pid, addr, size);
#endif
/*
* Align the address to a page boundary,
* and adjust the size accordingly.
*/
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
/* Disallow wrap-around. */
if (addr + (int)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
if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
return (error);
#endif
error = vm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, FALSE);
return (error == KERN_SUCCESS ? 0 : ENOMEM);
}
int
sys_munlock(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_munlock_args /* {
syscallarg(const void *) addr;
syscallarg(size_t) len;
} */ *uap = v;
vm_offset_t addr;
vm_size_t size, pageoff;
int error;
addr = (vm_offset_t)SCARG(uap, addr);
size = (vm_size_t)SCARG(uap, len);
#ifdef DEBUG
if (mmapdebug & MDB_FOLLOW)
printf("munlock(%d): addr %lx len %lx\n",
p->p_pid, addr, size);
#endif
/*
* Align the address to a page boundary,
* and adjust the size accordingly.
*/
pageoff = (addr & PAGE_MASK);
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
/* Disallow wrap-around. */
if (addr + (int)size < addr)
return (EINVAL);
#ifndef pmap_wired_count
if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
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.
* This (internal) interface requires the file offset to be
* page-aligned by the caller. (Also addr, if MAP_FIXED).
*/
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);
/* The file offset must be page aligned. */
if (foff & PAGE_MASK)
return (EINVAL);
if ((flags & MAP_FIXED) == 0) {
/* The address is just a hint */
fitit = TRUE;
*addr = round_page(*addr);
} else {
/*
* Use the specified address exactly
* (but check alignment first).
*/
fitit = FALSE;
if (*addr & PAGE_MASK)
return (EINVAL);
(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;
foff = 0;
} else {
vp = (struct vnode *)handle;
if (vp->v_type == VCHR) {
type = PG_DEVICE;
handle = (caddr_t)(long)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 %lx size %lx pager %p\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 %p, pager %p\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 */
vm_map_lock(map);
if (fitit) {
/*
* Find space in the map at a location
* that is compatible with the object/offset
* we're going to attach there.
*/
again:
if (vm_map_findspace(map, *addr, size,
addr) == 1) {
rv = KERN_NO_SPACE;
} else {
#ifdef PMAP_PREFER
PMAP_PREFER(foff, addr);
#endif
rv = vm_map_insert(map, NULL,
(vm_offset_t)0,
*addr, *addr+size);
/*
* vm_map_insert() may fail if
* PMAP_PREFER() has altered
* the initial address.
* If so, we start again.
*/
if (rv == KERN_NO_SPACE)
goto again;
}
} else {
rv = vm_map_insert(map, NULL, (vm_offset_t)0,
*addr, *addr + size);
#ifdef DEBUG
/*
* Check against PMAP preferred address. If
* there's a mismatch, these pages should not
* be shared with others. <howto?>
*/
if (rv == KERN_SUCCESS &&
(mmapdebug & MDB_MAPIT)) {
vm_offset_t paddr = *addr;
#ifdef PMAP_PREFER
PMAP_PREFER(foff, &paddr);
#endif
if (paddr != *addr)
printf(
"vm_mmap: pmap botch! "
"[foff %lx, addr %lx, paddr %lx]\n",
foff, *addr, paddr);
}
#endif
}
vm_map_unlock(map);
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,
FALSE, 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 %lx size %lx pager %p\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);
}
}