procfs_mem.c revision 1.23 1 /* $NetBSD: procfs_mem.c,v 1.23 1999/03/25 04:45:57 sommerfe 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 /*
160 * (3) the tracer is chrooted, and its root directory is
161 * not at or above the root directory of the tracee
162 */
163
164 if (!proc_isunder(t, p))
165 return EPERM;
166
167 return (0);
168 }
169
170 #ifdef probably_never
171 /*
172 * Given process (p), find the vnode from which
173 * it's text segment is being mapped.
174 *
175 * (This is here, rather than in procfs_subr in order
176 * to keep all the VM related code in one place.)
177 */
178 struct vnode *
179 procfs_findtextvp(p)
180 struct proc *p;
181 {
182 int error;
183 vm_object_t object;
184 vaddr_t pageno; /* page number */
185
186 /* find a vnode pager for the user address space */
187
188 for (pageno = VM_MIN_ADDRESS;
189 pageno < VM_MAXUSER_ADDRESS;
190 pageno += PAGE_SIZE) {
191 vm_map_t map;
192 vm_map_entry_t out_entry;
193 vm_prot_t out_prot;
194 boolean_t wired, single_use;
195 vaddr_t off;
196
197 map = &p->p_vmspace->vm_map;
198 error = vm_map_lookup(&map, pageno,
199 VM_PROT_READ,
200 &out_entry, &object, &off, &out_prot,
201 &wired, &single_use);
202
203 if (!error) {
204 vm_pager_t pager;
205
206 printf("procfs: found vm object\n");
207 vm_map_lookup_done(map, out_entry);
208 printf("procfs: vm object = %p\n", object);
209
210 /*
211 * At this point, assuming no errors, object
212 * is the VM object mapping UVA (pageno).
213 * Ensure it has a vnode pager, then grab
214 * the vnode from that pager's handle.
215 */
216
217 pager = object->pager;
218 printf("procfs: pager = %p\n", pager);
219 if (pager)
220 printf("procfs: found pager, type = %d\n",
221 pager->pg_type);
222 if (pager && pager->pg_type == PG_VNODE) {
223 struct vnode *vp;
224
225 vp = (struct vnode *) pager->pg_handle;
226 printf("procfs: vp = %p\n", vp);
227 return (vp);
228 }
229 }
230 }
231
232 printf("procfs: text object not found\n");
233 return (0);
234 }
235 #endif /* probably_never */
236