freebsd-dev/sys/miscfs/procfs/procfs_mem.c
1996-10-24 02:47:05 +00:00

325 lines
8.1 KiB
C

/*
* Copyright (c) 1993 Jan-Simon Pendry
* Copyright (c) 1993 Sean Eric Fagan
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry and Sean Eric Fagan.
*
* 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.
*
* @(#)procfs_mem.c 8.4 (Berkeley) 1/21/94
*
* $Id: procfs_mem.c,v 1.19 1996/07/02 01:40:52 dyson Exp $
*/
/*
* This is a lightly hacked and merged version
* of sef's pread/pwrite functions
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <miscfs/procfs/procfs.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <vm/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_extern.h>
#include <sys/user.h>
static int procfs_rwmem __P((struct proc *p, struct uio *uio));
static int
procfs_rwmem(p, uio)
struct proc *p;
struct uio *uio;
{
int error;
int writing;
struct vmspace *vm;
int fix_prot = 0;
vm_map_t map;
vm_object_t object = NULL;
vm_offset_t pageno = 0; /* page number */
/*
* if the vmspace is in the midst of being deallocated or the
* process is exiting, don't try to grab anything. The page table
* usage in that process can be messed up.
*/
vm = p->p_vmspace;
if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1))
return EFAULT;
++vm->vm_refcnt;
/*
* The map we want...
*/
map = &vm->vm_map;
writing = uio->uio_rw == UIO_WRITE;
/*
* Only map in one page at a time. We don't have to, but it
* makes things easier. This way is trivial - right?
*/
do {
vm_map_t tmap;
vm_offset_t kva = 0;
vm_offset_t uva;
int page_offset; /* offset into page */
vm_map_entry_t out_entry;
vm_prot_t out_prot;
boolean_t wired, single_use;
vm_pindex_t pindex;
u_int len;
fix_prot = 0;
object = NULL;
uva = (vm_offset_t) uio->uio_offset;
/*
* Get the page number of this segment.
*/
pageno = trunc_page(uva);
page_offset = uva - pageno;
/*
* How many bytes to copy
*/
len = min(PAGE_SIZE - page_offset, uio->uio_resid);
if (uva >= VM_MAXUSER_ADDRESS) {
if (writing || (uva >= (VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE))) {
error = 0;
break;
}
/* we are reading the "U area", force it into core */
PHOLD(p);
/* sanity check */
if (!(p->p_flag & P_INMEM)) {
/* aiee! */
PRELE(p);
error = EFAULT;
break;
}
/* populate the ptrace/procfs area */
p->p_addr->u_kproc.kp_proc = *p;
fill_eproc (p, &p->p_addr->u_kproc.kp_eproc);
/* locate the in-core address */
kva = (u_int)p->p_addr + uva - VM_MAXUSER_ADDRESS;
/* transfer it */
error = uiomove((caddr_t)kva, len, uio);
/* let the pages go */
PRELE(p);
continue;
}
/*
* Check the permissions for the area we're interested
* in.
*/
if (writing) {
fix_prot = !vm_map_check_protection(map, pageno,
pageno + PAGE_SIZE, VM_PROT_WRITE);
if (fix_prot) {
/*
* If the page is not writable, we make it so.
* XXX It is possible that a page may *not* be
* read/executable, if a process changes that!
* We will assume, for now, that a page is either
* VM_PROT_ALL, or VM_PROT_READ|VM_PROT_EXECUTE.
*/
error = vm_map_protect(map, pageno,
pageno + PAGE_SIZE, VM_PROT_ALL, 0);
if (error) {
/*
* We don't have to undo something
* that didn't work, so we clear the
* flag.
*/
fix_prot = 0;
break;
}
}
}
/*
* Now we need to get the page. out_entry, out_prot, wired,
* and single_use aren't used. One would think the vm code
* would be a *bit* nicer... We use tmap because
* vm_map_lookup() can change the map argument.
*/
tmap = map;
error = vm_map_lookup(&tmap, pageno,
writing ? VM_PROT_WRITE : VM_PROT_READ,
&out_entry, &object, &pindex, &out_prot,
&wired, &single_use);
if (error) {
/*
* Make sure that there is no residue in 'object' from
* an error return on vm_map_lookup.
*/
object = NULL;
break;
}
/*
* We're done with tmap now.
* But reference the object first, so that we won't loose
* it.
*/
vm_object_reference(object);
vm_map_lookup_done(tmap, out_entry);
/*
* Fault the page in...
*/
if (writing && object->backing_object) {
error = vm_fault(map, pageno,
VM_PROT_WRITE, FALSE);
if (error)
break;
}
/* Find space in kernel_map for the page we're interested in */
error = vm_map_find(kernel_map, object,
IDX_TO_OFF(pindex), &kva, PAGE_SIZE, 1,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error) {
break;
}
/*
* Mark the page we just found as pageable.
*/
error = vm_map_pageable(kernel_map, kva,
kva + PAGE_SIZE, 0);
if (error) {
vm_map_remove(kernel_map, kva, kva + PAGE_SIZE);
object = NULL;
break;
}
/*
* Now do the i/o move.
*/
error = uiomove((caddr_t)(kva + page_offset),
len, uio);
/*
* vm_map_remove gets rid of the object reference, so
* we need to get rid of our 'object' pointer if there
* is subsequently an error.
*/
vm_map_remove(kernel_map, kva, kva + PAGE_SIZE);
object = NULL;
/*
* Undo the protection 'damage'.
*/
if (fix_prot) {
vm_map_protect(map, pageno, pageno + PAGE_SIZE,
VM_PROT_READ|VM_PROT_EXECUTE, 0);
fix_prot = 0;
}
} while (error == 0 && uio->uio_resid > 0);
if (object)
vm_object_deallocate(object);
if (fix_prot)
vm_map_protect(map, pageno, pageno + PAGE_SIZE,
VM_PROT_READ|VM_PROT_EXECUTE, 0);
vmspace_free(vm);
return (error);
}
/*
* Copy data in and out of the target process.
* We do this by mapping the process's page into
* the kernel and then doing a uiomove direct
* from the kernel address space.
*/
int
procfs_domem(curp, p, pfs, uio)
struct proc *curp;
struct proc *p;
struct pfsnode *pfs;
struct uio *uio;
{
int error;
if (uio->uio_resid == 0)
return (0);
error = procfs_rwmem(p, uio);
return (error);
}
/*
* Given process (p), find the vnode from which
* it's text segment is being executed.
*
* It would be nice to grab this information from
* the VM system, however, there is no sure-fire
* way of doing that. Instead, fork(), exec() and
* wait() all maintain the p_textvp field in the
* process proc structure which contains a held
* reference to the exec'ed vnode.
*/
struct vnode *
procfs_findtextvp(p)
struct proc *p;
{
return (p->p_textvp);
}