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procfs_mem.c revision 1.22
      1 /*	$NetBSD: procfs_mem.c,v 1.22 1999/03/24 05:51:27 mrg Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1993 Jan-Simon Pendry
      5  * Copyright (c) 1993 Sean Eric Fagan
      6  * Copyright (c) 1993
      7  *	The Regents of the University of California.  All rights reserved.
      8  *
      9  * This code is derived from software contributed to Berkeley by
     10  * Jan-Simon Pendry and Sean Eric Fagan.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  *
     40  *	@(#)procfs_mem.c	8.5 (Berkeley) 6/15/94
     41  */
     42 
     43 /*
     44  * This is a lightly hacked and merged version
     45  * of sef's pread/pwrite functions
     46  */
     47 
     48 #include <sys/param.h>
     49 #include <sys/systm.h>
     50 #include <sys/time.h>
     51 #include <sys/kernel.h>
     52 #include <sys/proc.h>
     53 #include <sys/vnode.h>
     54 
     55 #include <miscfs/procfs/procfs.h>
     56 
     57 #include <vm/vm.h>
     58 #include <vm/vm_kern.h>
     59 #include <vm/vm_page.h>
     60 
     61 #include <uvm/uvm_extern.h>
     62 
     63 #define	ISSET(t, f)	((t) & (f))
     64 
     65 /*
     66  * Copy data in and out of the target process.
     67  * We do this by mapping the process's page into
     68  * the kernel and then doing a uiomove direct
     69  * from the kernel address space.
     70  */
     71 int
     72 procfs_domem(curp, p, pfs, uio)
     73 	struct proc *curp;		/* tracer */
     74 	struct proc *p;			/* traced */
     75 	struct pfsnode *pfs;
     76 	struct uio *uio;
     77 {
     78 	int error;
     79 
     80 	size_t len;
     81 	vaddr_t	addr;
     82 
     83 	len = uio->uio_resid;
     84 
     85 	if (len == 0)
     86 		return (0);
     87 
     88 	addr = uio->uio_offset;
     89 
     90 	if ((error = procfs_checkioperm(curp, p)) != 0)
     91 		return (error);
     92 
     93 	/* XXXCDC: how should locking work here? */
     94 	if ((p->p_flag & P_WEXIT) || (p->p_vmspace->vm_refcnt < 1))
     95 		return(EFAULT);
     96 	PHOLD(p);
     97 	p->p_vmspace->vm_refcnt++;  /* XXX */
     98 	error = uvm_io(&p->p_vmspace->vm_map, uio);
     99 	PRELE(p);
    100 	uvmspace_free(p->p_vmspace);
    101 
    102 #ifdef PMAP_NEED_PROCWR
    103 	if (uio->uio_rw == UIO_WRITE)
    104 		pmap_procwr(p, addr, len);
    105 #endif
    106 	return (error);
    107 }
    108 
    109 /*
    110  * Given process (p), find the vnode from which
    111  * it's text segment is being executed.
    112  *
    113  * It would be nice to grab this information from
    114  * the VM system, however, there is no sure-fire
    115  * way of doing that.  Instead, fork(), exec() and
    116  * wait() all maintain the p_textvp field in the
    117  * process proc structure which contains a held
    118  * reference to the exec'ed vnode.
    119  */
    120 struct vnode *
    121 procfs_findtextvp(p)
    122 	struct proc *p;
    123 {
    124 
    125 	return (p->p_textvp);
    126 }
    127 
    128 /*
    129  * Ensure that a process has permission to perform I/O on another.
    130  * Arguments:
    131  *	p	The process wishing to do the I/O (the tracer).
    132  *	t	The process who's memory/registers will be read/written.
    133  */
    134 int
    135 procfs_checkioperm(p, t)
    136 	struct proc *p, *t;
    137 {
    138 	int error;
    139 
    140 	/*
    141 	 * You cannot attach to a processes mem/regs if:
    142 	 *
    143 	 *	(1) it's not owned by you, or is set-id on exec
    144 	 *	    (unless you're root), or...
    145 	 */
    146 	if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
    147 		ISSET(t->p_flag, P_SUGID)) &&
    148 	    (error = suser(p->p_ucred, &p->p_acflag)) != 0)
    149 		return (error);
    150 
    151 	/*
    152 	 *	(2) ...it's init, which controls the security level
    153 	 *	    of the entire system, and the system was not
    154 	 *	    compiled with permanetly insecure mode turned on.
    155 	 */
    156 	if (t == initproc && securelevel > -1)
    157 		return (EPERM);
    158 
    159 	return (0);
    160 }
    161 
    162 #ifdef probably_never
    163 /*
    164  * Given process (p), find the vnode from which
    165  * it's text segment is being mapped.
    166  *
    167  * (This is here, rather than in procfs_subr in order
    168  * to keep all the VM related code in one place.)
    169  */
    170 struct vnode *
    171 procfs_findtextvp(p)
    172 	struct proc *p;
    173 {
    174 	int error;
    175 	vm_object_t object;
    176 	vaddr_t pageno;		/* page number */
    177 
    178 	/* find a vnode pager for the user address space */
    179 
    180 	for (pageno = VM_MIN_ADDRESS;
    181 			pageno < VM_MAXUSER_ADDRESS;
    182 			pageno += PAGE_SIZE) {
    183 		vm_map_t map;
    184 		vm_map_entry_t out_entry;
    185 		vm_prot_t out_prot;
    186 		boolean_t wired, single_use;
    187 		vaddr_t off;
    188 
    189 		map = &p->p_vmspace->vm_map;
    190 		error = vm_map_lookup(&map, pageno,
    191 			      VM_PROT_READ,
    192 			      &out_entry, &object, &off, &out_prot,
    193 			      &wired, &single_use);
    194 
    195 		if (!error) {
    196 			vm_pager_t pager;
    197 
    198 			printf("procfs: found vm object\n");
    199 			vm_map_lookup_done(map, out_entry);
    200 			printf("procfs: vm object = %p\n", object);
    201 
    202 			/*
    203 			 * At this point, assuming no errors, object
    204 			 * is the VM object mapping UVA (pageno).
    205 			 * Ensure it has a vnode pager, then grab
    206 			 * the vnode from that pager's handle.
    207 			 */
    208 
    209 			pager = object->pager;
    210 			printf("procfs: pager = %p\n", pager);
    211 			if (pager)
    212 				printf("procfs: found pager, type = %d\n",
    213 				    pager->pg_type);
    214 			if (pager && pager->pg_type == PG_VNODE) {
    215 				struct vnode *vp;
    216 
    217 				vp = (struct vnode *) pager->pg_handle;
    218 				printf("procfs: vp = %p\n", vp);
    219 				return (vp);
    220 			}
    221 		}
    222 	}
    223 
    224 	printf("procfs: text object not found\n");
    225 	return (0);
    226 }
    227 #endif /* probably_never */
    228