a04c970a7a
by Alan Cox <alc@cs.rice.edu>, and his description of the problem. The bug was primarily in procfs_mem, but the mistake likely happened due to the lack of vm system support for the operation. I added better support for selective marking of page dirty flags so that vm_map_pageable(wiring) will not cause this problem again. The code in procfs_mem is now less bogus (but maybe still a little so.)
290 lines
7.1 KiB
C
290 lines
7.1 KiB
C
/*
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* Copyright (c) 1993 Jan-Simon Pendry
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* Copyright (c) 1993 Sean Eric Fagan
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry and Sean Eric Fagan.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94
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*
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* $Id: procfs_mem.c,v 1.23 1997/02/22 09:40:28 peter Exp $
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*/
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/*
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* This is a lightly hacked and merged version
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* of sef's pread/pwrite functions
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <miscfs/procfs/procfs.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_prot.h>
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#include <sys/lock.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_extern.h>
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#include <sys/user.h>
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static int procfs_rwmem __P((struct proc *p, struct uio *uio));
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static int
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procfs_rwmem(p, uio)
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struct proc *p;
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struct uio *uio;
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{
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int error;
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int writing;
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struct vmspace *vm;
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vm_map_t map;
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vm_object_t object = NULL;
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vm_offset_t pageno = 0; /* page number */
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vm_prot_t reqprot;
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vm_offset_t kva;
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/*
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* if the vmspace is in the midst of being deallocated or the
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* process is exiting, don't try to grab anything. The page table
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* usage in that process can be messed up.
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*/
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vm = p->p_vmspace;
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if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1))
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return EFAULT;
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++vm->vm_refcnt;
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/*
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* The map we want...
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*/
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map = &vm->vm_map;
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writing = uio->uio_rw == UIO_WRITE;
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reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) : VM_PROT_READ;
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kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE);
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/*
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* Only map in one page at a time. We don't have to, but it
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* makes things easier. This way is trivial - right?
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*/
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do {
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vm_map_t tmap;
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vm_offset_t uva;
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int page_offset; /* offset into page */
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vm_map_entry_t out_entry;
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vm_prot_t out_prot;
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boolean_t wired, single_use;
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vm_pindex_t pindex;
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u_int len;
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vm_page_t m;
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object = NULL;
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uva = (vm_offset_t) uio->uio_offset;
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/*
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* Get the page number of this segment.
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*/
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pageno = trunc_page(uva);
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page_offset = uva - pageno;
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/*
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* How many bytes to copy
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*/
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len = min(PAGE_SIZE - page_offset, uio->uio_resid);
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if (uva >= VM_MAXUSER_ADDRESS) {
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vm_offset_t tkva;
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if (writing || (uva >= (VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE))) {
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error = 0;
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break;
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}
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/* we are reading the "U area", force it into core */
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PHOLD(p);
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/* sanity check */
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if (!(p->p_flag & P_INMEM)) {
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/* aiee! */
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PRELE(p);
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error = EFAULT;
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break;
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}
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/* populate the ptrace/procfs area */
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p->p_addr->u_kproc.kp_proc = *p;
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fill_eproc (p, &p->p_addr->u_kproc.kp_eproc);
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/* locate the in-core address */
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tkva = (u_int)p->p_addr + uva - VM_MAXUSER_ADDRESS;
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/* transfer it */
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error = uiomove((caddr_t)tkva, len, uio);
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/* let the pages go */
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PRELE(p);
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continue;
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}
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/*
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* Fault the page on behalf of the process
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*/
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error = vm_fault(map, pageno, reqprot, FALSE);
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if (error) {
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error = EFAULT;
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break;
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}
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/*
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* Now we need to get the page. out_entry, out_prot, wired,
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* and single_use aren't used. One would think the vm code
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* would be a *bit* nicer... We use tmap because
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* vm_map_lookup() can change the map argument.
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*/
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tmap = map;
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error = vm_map_lookup(&tmap, pageno, reqprot,
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&out_entry, &object, &pindex, &out_prot,
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&wired, &single_use);
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if (error) {
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error = EFAULT;
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/*
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* Make sure that there is no residue in 'object' from
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* an error return on vm_map_lookup.
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*/
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object = NULL;
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break;
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}
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m = vm_page_lookup(object, pindex);
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if (m == NULL) {
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error = EFAULT;
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/*
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* Make sure that there is no residue in 'object' from
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* an error return on vm_map_lookup.
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*/
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object = NULL;
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break;
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}
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/*
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* Wire the page into memory
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*/
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vm_page_wire(m);
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/*
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* We're done with tmap now.
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* But reference the object first, so that we won't loose
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* it.
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*/
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vm_object_reference(object);
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vm_map_lookup_done(tmap, out_entry);
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pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
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/*
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* Now do the i/o move.
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*/
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error = uiomove((caddr_t)(kva + page_offset), len, uio);
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pmap_kremove(kva);
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/*
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* release the page and the object
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*/
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vm_page_unwire(m);
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vm_object_deallocate(object);
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object = NULL;
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} while (error == 0 && uio->uio_resid > 0);
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if (object)
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vm_object_deallocate(object);
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kmem_free(kernel_map, kva, PAGE_SIZE);
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vmspace_free(vm);
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return (error);
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}
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/*
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* Copy data in and out of the target process.
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* We do this by mapping the process's page into
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* the kernel and then doing a uiomove direct
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* from the kernel address space.
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*/
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int
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procfs_domem(curp, p, pfs, uio)
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struct proc *curp;
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struct proc *p;
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struct pfsnode *pfs;
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struct uio *uio;
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{
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if (uio->uio_resid == 0)
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return (0);
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return (procfs_rwmem(p, uio));
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}
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/*
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* Given process (p), find the vnode from which
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* it's text segment is being executed.
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*
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* It would be nice to grab this information from
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* the VM system, however, there is no sure-fire
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* way of doing that. Instead, fork(), exec() and
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* wait() all maintain the p_textvp field in the
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* process proc structure which contains a held
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* reference to the exec'ed vnode.
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*/
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struct vnode *
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procfs_findtextvp(p)
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struct proc *p;
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{
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return (p->p_textvp);
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}
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