text: /*
   * 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 1.20.2.2 1998/09/22 01:30:51 jdp 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;
  	vm_map_t map;
  	vm_object_t object = NULL;
  	vm_offset_t pageno = 0;		/* page number */
  	vm_prot_t reqprot;
  	vm_offset_t kva;
  
  	/*
  	 * 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;
  	reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) : VM_PROT_READ;
  
  	kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE);
  
  	/*
  	 * 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 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;
  		vm_page_t m;
  
  		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) {
  			vm_offset_t tkva;
  
  			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 */
  			tkva = (u_int)p->p_addr + uva - VM_MAXUSER_ADDRESS;
  
  			/* transfer it */
  			error = uiomove((caddr_t)tkva, len, uio);
  
  			/* let the pages go */
  			PRELE(p);
  
  			continue;
  		}
  
  		/*
  		 * Fault the page on behalf of the process
  		 */
  		error = vm_fault(map, pageno, reqprot, FALSE);
  		if (error) {
  			error = EFAULT;
  			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, reqprot,
  			      &out_entry, &object, &pindex, &out_prot,
  			      &wired, &single_use);
  
  		if (error) {
  			error = EFAULT;
  
  			/*
  			 * Make sure that there is no residue in 'object' from
  			 * an error return on vm_map_lookup.
  			 */
  			object = NULL;
  
  			break;
  		}
  
  		m = vm_page_lookup(object, pindex);
  
  		/* Allow fallback to backing objects if we are reading */
  
  		while (m == NULL && !writing && object->backing_object) {
  
  		  pindex += OFF_TO_IDX(object->backing_object_offset);
  		  object = object->backing_object;
  
  		  m = vm_page_lookup(object, pindex);
  		}
  
  		if (m == NULL) {
  			error = EFAULT;
  
  			/*
  			 * Make sure that there is no residue in 'object' from
  			 * an error return on vm_map_lookup.
  			 */
  			object = NULL;
  
  			vm_map_lookup_done(tmap, out_entry);
  
  			break;
  		}
  
  		/*
  		 * Wire the page into memory
  		 */
  		vm_page_wire(m);
  
  		/*
  		 * 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);
  
  		pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
  
  		/*
  		 * Now do the i/o move.
  		 */
  		error = uiomove((caddr_t)(kva + page_offset), len, uio);
  
  		pmap_kremove(kva);
  
  		/*
  		 * release the page and the object
  		 */
  		vm_page_unwire(m);
  		vm_object_deallocate(object);
  
  		object = NULL;
  
  	} while (error == 0 && uio->uio_resid > 0);
  
  	if (object)
  		vm_object_deallocate(object);
  
  	kmem_free(kernel_map, kva, PAGE_SIZE);
  	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);
  
   	/*
   	 * XXX
   	 * We need to check for KMEM_GROUP because ps is sgid kmem;
   	 * not allowing it here causes ps to not work properly.  Arguably,
   	 * this is a bug with what ps does.  We only need to do this
   	 * for Pmem nodes, and only if it's reading.  This is still not
   	 * good, as it may still be possible to grab illicit data if
   	 * a process somehow gets to be KMEM_GROUP.  Note that this also
   	 * means that KMEM_GROUP can't change without editing procfs.h!
   	 * All in all, quite yucky.
   	 */
    
  	if (!CHECKIO(curp, p) &&
   	    !(curp->p_cred->pc_ucred->cr_gid == KMEM_GROUP &&
   	      uio->uio_rw == UIO_READ))
    		return EPERM;
   
  	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);
  }
  