Home | History | Annotate | Line # | Download | only in procfs
procfs_mem.c revision 1.18.2.1
      1  1.18.2.1       eeh /*	$NetBSD: procfs_mem.c,v 1.18.2.1 1998/07/30 14:04:06 eeh Exp $	*/
      2       1.6       cgd 
      3       1.1       cgd /*
      4       1.1       cgd  * Copyright (c) 1993 Jan-Simon Pendry
      5       1.4   mycroft  * Copyright (c) 1993 Sean Eric Fagan
      6       1.4   mycroft  * Copyright (c) 1993
      7       1.4   mycroft  *	The Regents of the University of California.  All rights reserved.
      8       1.1       cgd  *
      9       1.1       cgd  * This code is derived from software contributed to Berkeley by
     10       1.4   mycroft  * Jan-Simon Pendry and Sean Eric Fagan.
     11       1.1       cgd  *
     12       1.1       cgd  * Redistribution and use in source and binary forms, with or without
     13       1.1       cgd  * modification, are permitted provided that the following conditions
     14       1.1       cgd  * are met:
     15       1.1       cgd  * 1. Redistributions of source code must retain the above copyright
     16       1.1       cgd  *    notice, this list of conditions and the following disclaimer.
     17       1.1       cgd  * 2. Redistributions in binary form must reproduce the above copyright
     18       1.1       cgd  *    notice, this list of conditions and the following disclaimer in the
     19       1.1       cgd  *    documentation and/or other materials provided with the distribution.
     20       1.1       cgd  * 3. All advertising materials mentioning features or use of this software
     21       1.1       cgd  *    must display the following acknowledgement:
     22       1.1       cgd  *	This product includes software developed by the University of
     23       1.1       cgd  *	California, Berkeley and its contributors.
     24       1.1       cgd  * 4. Neither the name of the University nor the names of its contributors
     25       1.1       cgd  *    may be used to endorse or promote products derived from this software
     26       1.1       cgd  *    without specific prior written permission.
     27       1.1       cgd  *
     28       1.1       cgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29       1.1       cgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30       1.1       cgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31       1.1       cgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32       1.1       cgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33       1.1       cgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34       1.1       cgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35       1.1       cgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36       1.1       cgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37       1.1       cgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38       1.1       cgd  * SUCH DAMAGE.
     39       1.1       cgd  *
     40       1.6       cgd  *	@(#)procfs_mem.c	8.5 (Berkeley) 6/15/94
     41       1.1       cgd  */
     42       1.1       cgd 
     43       1.1       cgd /*
     44       1.1       cgd  * This is a lightly hacked and merged version
     45       1.1       cgd  * of sef's pread/pwrite functions
     46       1.1       cgd  */
     47      1.18       mrg 
     48      1.18       mrg #include "opt_uvm.h"
     49       1.1       cgd 
     50       1.1       cgd #include <sys/param.h>
     51       1.1       cgd #include <sys/systm.h>
     52       1.1       cgd #include <sys/time.h>
     53       1.1       cgd #include <sys/kernel.h>
     54       1.1       cgd #include <sys/proc.h>
     55       1.1       cgd #include <sys/vnode.h>
     56       1.1       cgd #include <miscfs/procfs/procfs.h>
     57       1.1       cgd #include <vm/vm.h>
     58       1.1       cgd #include <vm/vm_kern.h>
     59       1.1       cgd #include <vm/vm_page.h>
     60       1.1       cgd 
     61      1.17       mrg #if defined(UVM)
     62      1.17       mrg #include <uvm/uvm_extern.h>
     63      1.17       mrg #endif
     64      1.17       mrg 
     65      1.13  explorer #define	ISSET(t, f)	((t) & (f))
     66      1.13  explorer 
     67      1.17       mrg #if !defined(UVM)
     68       1.8  christos static int procfs_rwmem __P((struct proc *, struct uio *));
     69       1.8  christos 
     70       1.1       cgd static int
     71       1.4   mycroft procfs_rwmem(p, uio)
     72       1.1       cgd 	struct proc *p;
     73       1.1       cgd 	struct uio *uio;
     74       1.1       cgd {
     75       1.1       cgd 	int error;
     76       1.1       cgd 	int writing;
     77       1.1       cgd 
     78       1.1       cgd 	writing = uio->uio_rw == UIO_WRITE;
     79       1.1       cgd 
     80       1.1       cgd 	/*
     81       1.1       cgd 	 * Only map in one page at a time.  We don't have to, but it
     82       1.1       cgd 	 * makes things easier.  This way is trivial - right?
     83       1.1       cgd 	 */
     84       1.1       cgd 	do {
     85       1.1       cgd 		vm_map_t map, tmap;
     86       1.1       cgd 		vm_object_t object;
     87  1.18.2.1       eeh 		vaddr_t kva;
     88  1.18.2.1       eeh 		vaddr_t uva;
     89       1.1       cgd 		int page_offset;		/* offset into page */
     90  1.18.2.1       eeh 		vaddr_t pageno;		/* page number */
     91       1.1       cgd 		vm_map_entry_t out_entry;
     92       1.1       cgd 		vm_prot_t out_prot;
     93       1.1       cgd 		vm_page_t m;
     94       1.1       cgd 		boolean_t wired, single_use;
     95  1.18.2.1       eeh 		vaddr_t off;
     96       1.1       cgd 		u_int len;
     97       1.1       cgd 		int fix_prot;
     98       1.1       cgd 
     99  1.18.2.1       eeh 		uva = (vaddr_t) uio->uio_offset;
    100       1.1       cgd 		if (uva > VM_MAXUSER_ADDRESS) {
    101       1.1       cgd 			error = 0;
    102       1.1       cgd 			break;
    103       1.1       cgd 		}
    104       1.1       cgd 
    105       1.1       cgd 		/*
    106       1.1       cgd 		 * Get the page number of this segment.
    107       1.1       cgd 		 */
    108       1.1       cgd 		pageno = trunc_page(uva);
    109       1.1       cgd 		page_offset = uva - pageno;
    110       1.1       cgd 
    111       1.1       cgd 		/*
    112       1.1       cgd 		 * How many bytes to copy
    113       1.1       cgd 		 */
    114       1.1       cgd 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
    115       1.1       cgd 
    116       1.1       cgd 		/*
    117       1.1       cgd 		 * The map we want...
    118       1.1       cgd 		 */
    119       1.1       cgd 		map = &p->p_vmspace->vm_map;
    120       1.1       cgd 
    121       1.1       cgd 		/*
    122       1.1       cgd 		 * Check the permissions for the area we're interested
    123       1.1       cgd 		 * in.
    124       1.1       cgd 		 */
    125       1.1       cgd 		fix_prot = 0;
    126       1.1       cgd 		if (writing)
    127       1.1       cgd 			fix_prot = !vm_map_check_protection(map, pageno,
    128       1.1       cgd 					pageno + PAGE_SIZE, VM_PROT_WRITE);
    129       1.1       cgd 
    130       1.1       cgd 		if (fix_prot) {
    131       1.1       cgd 			/*
    132       1.1       cgd 			 * If the page is not writable, we make it so.
    133       1.1       cgd 			 * XXX It is possible that a page may *not* be
    134       1.1       cgd 			 * read/executable, if a process changes that!
    135       1.1       cgd 			 * We will assume, for now, that a page is either
    136       1.1       cgd 			 * VM_PROT_ALL, or VM_PROT_READ|VM_PROT_EXECUTE.
    137       1.1       cgd 			 */
    138       1.1       cgd 			error = vm_map_protect(map, pageno,
    139       1.1       cgd 					pageno + PAGE_SIZE, VM_PROT_ALL, 0);
    140       1.1       cgd 			if (error)
    141       1.1       cgd 				break;
    142       1.1       cgd 		}
    143       1.1       cgd 
    144       1.1       cgd 		/*
    145       1.1       cgd 		 * Now we need to get the page.  out_entry, out_prot, wired,
    146       1.1       cgd 		 * and single_use aren't used.  One would think the vm code
    147       1.1       cgd 		 * would be a *bit* nicer...  We use tmap because
    148       1.1       cgd 		 * vm_map_lookup() can change the map argument.
    149       1.1       cgd 		 */
    150       1.1       cgd 		tmap = map;
    151       1.1       cgd 		error = vm_map_lookup(&tmap, pageno,
    152       1.1       cgd 				      writing ? VM_PROT_WRITE : VM_PROT_READ,
    153       1.1       cgd 				      &out_entry, &object, &off, &out_prot,
    154       1.1       cgd 				      &wired, &single_use);
    155       1.1       cgd 		/*
    156       1.1       cgd 		 * We're done with tmap now.
    157       1.1       cgd 		 */
    158       1.1       cgd 		if (!error)
    159       1.1       cgd 			vm_map_lookup_done(tmap, out_entry);
    160       1.1       cgd 
    161       1.1       cgd 		/*
    162       1.1       cgd 		 * Fault the page in...
    163       1.1       cgd 		 */
    164       1.1       cgd 		if (!error && writing && object->shadow) {
    165       1.1       cgd 			m = vm_page_lookup(object, off);
    166       1.3    briggs 			if (m == 0 || (m->flags & PG_COPYONWRITE))
    167       1.1       cgd 				error = vm_fault(map, pageno,
    168       1.1       cgd 							VM_PROT_WRITE, FALSE);
    169       1.1       cgd 		}
    170       1.1       cgd 
    171       1.1       cgd 		/* Find space in kernel_map for the page we're interested in */
    172       1.7    chopps 		if (!error) {
    173       1.7    chopps 			kva = VM_MIN_KERNEL_ADDRESS;
    174       1.1       cgd 			error = vm_map_find(kernel_map, object, off, &kva,
    175       1.1       cgd 					PAGE_SIZE, 1);
    176       1.7    chopps 		}
    177       1.1       cgd 
    178       1.1       cgd 		if (!error) {
    179       1.1       cgd 			/*
    180       1.1       cgd 			 * Neither vm_map_lookup() nor vm_map_find() appear
    181       1.1       cgd 			 * to add a reference count to the object, so we do
    182       1.1       cgd 			 * that here and now.
    183       1.1       cgd 			 */
    184       1.1       cgd 			vm_object_reference(object);
    185       1.1       cgd 
    186       1.1       cgd 			/*
    187       1.1       cgd 			 * Mark the page we just found as pageable.
    188       1.1       cgd 			 */
    189       1.1       cgd 			error = vm_map_pageable(kernel_map, kva,
    190       1.1       cgd 				kva + PAGE_SIZE, 0);
    191       1.1       cgd 
    192       1.1       cgd 			/*
    193       1.1       cgd 			 * Now do the i/o move.
    194       1.1       cgd 			 */
    195       1.1       cgd 			if (!error)
    196       1.8  christos 				error = uiomove((caddr_t) (kva + page_offset),
    197       1.8  christos 						len, uio);
    198       1.1       cgd 
    199       1.1       cgd 			vm_map_remove(kernel_map, kva, kva + PAGE_SIZE);
    200       1.1       cgd 		}
    201       1.1       cgd 		if (fix_prot)
    202       1.1       cgd 			vm_map_protect(map, pageno, pageno + PAGE_SIZE,
    203       1.1       cgd 					VM_PROT_READ|VM_PROT_EXECUTE, 0);
    204       1.1       cgd 	} while (error == 0 && uio->uio_resid > 0);
    205       1.1       cgd 
    206       1.1       cgd 	return (error);
    207       1.1       cgd }
    208      1.17       mrg #endif
    209       1.1       cgd 
    210       1.1       cgd /*
    211       1.1       cgd  * Copy data in and out of the target process.
    212       1.1       cgd  * We do this by mapping the process's page into
    213       1.1       cgd  * the kernel and then doing a uiomove direct
    214       1.1       cgd  * from the kernel address space.
    215       1.1       cgd  */
    216       1.4   mycroft int
    217       1.4   mycroft procfs_domem(curp, p, pfs, uio)
    218      1.14   thorpej 	struct proc *curp;		/* tracer */
    219      1.14   thorpej 	struct proc *p;			/* traced */
    220       1.1       cgd 	struct pfsnode *pfs;
    221       1.1       cgd 	struct uio *uio;
    222       1.1       cgd {
    223       1.9   mycroft 	int error;
    224       1.1       cgd 
    225       1.1       cgd 	if (uio->uio_resid == 0)
    226       1.1       cgd 		return (0);
    227      1.12   thorpej 
    228      1.12   thorpej 	if ((error = procfs_checkioperm(curp, p)) != 0)
    229      1.12   thorpej 		return (error);
    230       1.1       cgd 
    231      1.17       mrg #if defined(UVM)
    232      1.17       mrg 	/* XXXCDC: how should locking work here? */
    233      1.17       mrg 	if ((p->p_flag & P_WEXIT) || (p->p_vmspace->vm_refcnt < 1))
    234      1.17       mrg 		return(EFAULT);
    235      1.17       mrg 	PHOLD(p);
    236      1.17       mrg 	p->p_vmspace->vm_refcnt++;  /* XXX */
    237      1.17       mrg 	error = uvm_io(&p->p_vmspace->vm_map, uio);
    238      1.17       mrg 	PRELE(p);
    239      1.17       mrg 	uvmspace_free(p->p_vmspace);
    240      1.17       mrg #else
    241       1.9   mycroft 	PHOLD(p);
    242       1.9   mycroft 	error = procfs_rwmem(p, uio);
    243       1.9   mycroft 	PRELE(p);
    244      1.17       mrg #endif
    245       1.9   mycroft 	return (error);
    246       1.1       cgd }
    247       1.1       cgd 
    248       1.1       cgd /*
    249       1.1       cgd  * Given process (p), find the vnode from which
    250       1.1       cgd  * it's text segment is being executed.
    251       1.1       cgd  *
    252       1.1       cgd  * It would be nice to grab this information from
    253       1.1       cgd  * the VM system, however, there is no sure-fire
    254       1.1       cgd  * way of doing that.  Instead, fork(), exec() and
    255       1.1       cgd  * wait() all maintain the p_textvp field in the
    256       1.1       cgd  * process proc structure which contains a held
    257       1.1       cgd  * reference to the exec'ed vnode.
    258       1.1       cgd  */
    259       1.1       cgd struct vnode *
    260       1.1       cgd procfs_findtextvp(p)
    261       1.1       cgd 	struct proc *p;
    262       1.1       cgd {
    263       1.4   mycroft 
    264       1.1       cgd 	return (p->p_textvp);
    265       1.1       cgd }
    266       1.1       cgd 
    267      1.14   thorpej /*
    268      1.14   thorpej  * Ensure that a process has permission to perform I/O on another.
    269      1.14   thorpej  * Arguments:
    270      1.14   thorpej  *	p	The process wishing to do the I/O (the tracer).
    271      1.14   thorpej  *	t	The process who's memory/registers will be read/written.
    272      1.14   thorpej  */
    273      1.13  explorer int
    274      1.14   thorpej procfs_checkioperm(p, t)
    275      1.14   thorpej 	struct proc *p, *t;
    276      1.13  explorer {
    277      1.13  explorer 	int error;
    278      1.13  explorer 
    279      1.13  explorer 	/*
    280      1.13  explorer 	 * You cannot attach to a processes mem/regs if:
    281      1.13  explorer 	 *
    282      1.13  explorer 	 *	(1) it's not owned by you, or is set-id on exec
    283      1.13  explorer 	 *	    (unless you're root), or...
    284      1.13  explorer 	 */
    285      1.13  explorer 	if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
    286      1.16     enami 		ISSET(t->p_flag, P_SUGID)) &&
    287      1.13  explorer 	    (error = suser(p->p_ucred, &p->p_acflag)) != 0)
    288      1.13  explorer 		return (error);
    289      1.13  explorer 
    290      1.13  explorer 	/*
    291      1.13  explorer 	 *	(2) ...it's init, which controls the security level
    292      1.13  explorer 	 *	    of the entire system, and the system was not
    293      1.13  explorer 	 *	    compiled with permanetly insecure mode turned on.
    294      1.13  explorer 	 */
    295      1.13  explorer 	if (t == initproc && securelevel > -1)
    296      1.13  explorer 		return (EPERM);
    297      1.13  explorer 
    298      1.13  explorer 	return (0);
    299      1.13  explorer }
    300       1.1       cgd 
    301       1.1       cgd #ifdef probably_never
    302       1.1       cgd /*
    303       1.1       cgd  * Given process (p), find the vnode from which
    304       1.1       cgd  * it's text segment is being mapped.
    305       1.1       cgd  *
    306       1.1       cgd  * (This is here, rather than in procfs_subr in order
    307       1.1       cgd  * to keep all the VM related code in one place.)
    308       1.1       cgd  */
    309       1.1       cgd struct vnode *
    310       1.1       cgd procfs_findtextvp(p)
    311       1.1       cgd 	struct proc *p;
    312       1.1       cgd {
    313       1.1       cgd 	int error;
    314       1.1       cgd 	vm_object_t object;
    315  1.18.2.1       eeh 	vaddr_t pageno;		/* page number */
    316       1.1       cgd 
    317       1.1       cgd 	/* find a vnode pager for the user address space */
    318       1.1       cgd 
    319       1.1       cgd 	for (pageno = VM_MIN_ADDRESS;
    320       1.1       cgd 			pageno < VM_MAXUSER_ADDRESS;
    321       1.1       cgd 			pageno += PAGE_SIZE) {
    322       1.1       cgd 		vm_map_t map;
    323       1.1       cgd 		vm_map_entry_t out_entry;
    324       1.1       cgd 		vm_prot_t out_prot;
    325       1.1       cgd 		boolean_t wired, single_use;
    326  1.18.2.1       eeh 		vaddr_t off;
    327       1.1       cgd 
    328       1.1       cgd 		map = &p->p_vmspace->vm_map;
    329       1.1       cgd 		error = vm_map_lookup(&map, pageno,
    330       1.1       cgd 			      VM_PROT_READ,
    331       1.1       cgd 			      &out_entry, &object, &off, &out_prot,
    332       1.1       cgd 			      &wired, &single_use);
    333       1.1       cgd 
    334       1.1       cgd 		if (!error) {
    335       1.1       cgd 			vm_pager_t pager;
    336       1.1       cgd 
    337      1.11  christos 			printf("procfs: found vm object\n");
    338       1.1       cgd 			vm_map_lookup_done(map, out_entry);
    339      1.15  christos 			printf("procfs: vm object = %p\n", object);
    340       1.1       cgd 
    341       1.1       cgd 			/*
    342       1.1       cgd 			 * At this point, assuming no errors, object
    343       1.1       cgd 			 * is the VM object mapping UVA (pageno).
    344       1.1       cgd 			 * Ensure it has a vnode pager, then grab
    345       1.1       cgd 			 * the vnode from that pager's handle.
    346       1.1       cgd 			 */
    347       1.1       cgd 
    348       1.1       cgd 			pager = object->pager;
    349      1.15  christos 			printf("procfs: pager = %p\n", pager);
    350       1.1       cgd 			if (pager)
    351      1.11  christos 				printf("procfs: found pager, type = %d\n",
    352      1.10  christos 				    pager->pg_type);
    353       1.1       cgd 			if (pager && pager->pg_type == PG_VNODE) {
    354       1.1       cgd 				struct vnode *vp;
    355       1.1       cgd 
    356       1.1       cgd 				vp = (struct vnode *) pager->pg_handle;
    357      1.15  christos 				printf("procfs: vp = %p\n", vp);
    358       1.1       cgd 				return (vp);
    359       1.1       cgd 			}
    360       1.1       cgd 		}
    361       1.1       cgd 	}
    362       1.1       cgd 
    363      1.11  christos 	printf("procfs: text object not found\n");
    364       1.1       cgd 	return (0);
    365       1.1       cgd }
    366       1.4   mycroft #endif /* probably_never */
    367