procfs_mem.c revision 2807
1/* 2 * Copyright (c) 1993 Jan-Simon Pendry 3 * Copyright (c) 1993 Sean Eric Fagan 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Jan-Simon Pendry and Sean Eric Fagan. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)procfs_mem.c 8.4 (Berkeley) 1/21/94 39 * 40 * $Id: procfs_mem.c,v 1.2 1994/08/02 07:45:13 davidg Exp $ 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#include <miscfs/procfs/procfs.h> 55#include <vm/vm.h> 56#include <vm/vm_kern.h> 57#include <vm/vm_page.h> 58 59static int 60procfs_rwmem(p, uio) 61 struct proc *p; 62 struct uio *uio; 63{ 64 int error; 65 int writing; 66 67 writing = uio->uio_rw == UIO_WRITE; 68 69 /* 70 * Only map in one page at a time. We don't have to, but it 71 * makes things easier. This way is trivial - right? 72 */ 73 do { 74 vm_map_t map, tmap; 75 vm_object_t object; 76 vm_offset_t kva; 77 vm_offset_t uva; 78 int page_offset; /* offset into page */ 79 vm_offset_t pageno; /* page number */ 80 vm_map_entry_t out_entry; 81 vm_prot_t out_prot; 82 vm_page_t m; 83 boolean_t wired, single_use; 84 vm_offset_t off; 85 u_int len; 86 int fix_prot; 87 88 uva = (vm_offset_t) uio->uio_offset; 89 if (uva > VM_MAXUSER_ADDRESS) { 90 error = 0; 91 break; 92 } 93 94 /* 95 * Get the page number of this segment. 96 */ 97 pageno = trunc_page(uva); 98 page_offset = uva - pageno; 99 100 /* 101 * How many bytes to copy 102 */ 103 len = min(PAGE_SIZE - page_offset, uio->uio_resid); 104 105 /* 106 * The map we want... 107 */ 108 map = &p->p_vmspace->vm_map; 109 110 /* 111 * Check the permissions for the area we're interested 112 * in. 113 */ 114 fix_prot = 0; 115 if (writing) 116 fix_prot = !vm_map_check_protection(map, pageno, 117 pageno + PAGE_SIZE, VM_PROT_WRITE); 118 119 if (fix_prot) { 120 /* 121 * If the page is not writable, we make it so. 122 * XXX It is possible that a page may *not* be 123 * read/executable, if a process changes that! 124 * We will assume, for now, that a page is either 125 * VM_PROT_ALL, or VM_PROT_READ|VM_PROT_EXECUTE. 126 */ 127 error = vm_map_protect(map, pageno, 128 pageno + PAGE_SIZE, VM_PROT_ALL, 0); 129 if (error) 130 break; 131 } 132 133 /* 134 * Now we need to get the page. out_entry, out_prot, wired, 135 * and single_use aren't used. One would think the vm code 136 * would be a *bit* nicer... We use tmap because 137 * vm_map_lookup() can change the map argument. 138 */ 139 tmap = map; 140 error = vm_map_lookup(&tmap, pageno, 141 writing ? VM_PROT_WRITE : VM_PROT_READ, 142 &out_entry, &object, &off, &out_prot, 143 &wired, &single_use); 144 /* 145 * We're done with tmap now. 146 */ 147 if (!error) 148 vm_map_lookup_done(tmap, out_entry); 149 150 /* 151 * Fault the page in... 152 */ 153 if (!error && writing && object->shadow) { 154 m = vm_page_lookup(object, off); 155 if (m == 0 || (m->flags & PG_COPYONWRITE)) 156 error = vm_fault(map, pageno, 157 VM_PROT_WRITE, FALSE); 158 } 159 160 /* Find space in kernel_map for the page we're interested in */ 161 if (!error) 162 error = vm_map_find(kernel_map, object, off, &kva, 163 PAGE_SIZE, 1); 164 165 if (!error) { 166 /* 167 * Neither vm_map_lookup() nor vm_map_find() appear 168 * to add a reference count to the object, so we do 169 * that here and now. 170 */ 171 vm_object_reference(object); 172 173 /* 174 * Mark the page we just found as pageable. 175 */ 176 error = vm_map_pageable(kernel_map, kva, 177 kva + PAGE_SIZE, 0); 178 179 /* 180 * Now do the i/o move. 181 */ 182 if (!error) 183 error = uiomove((caddr_t)(kva + page_offset), 184 len, uio); 185 186 vm_map_remove(kernel_map, kva, kva + PAGE_SIZE); 187 } 188 if (fix_prot) 189 vm_map_protect(map, pageno, pageno + PAGE_SIZE, 190 VM_PROT_READ|VM_PROT_EXECUTE, 0); 191 } while (error == 0 && uio->uio_resid > 0); 192 193 return (error); 194} 195 196/* 197 * Copy data in and out of the target process. 198 * We do this by mapping the process's page into 199 * the kernel and then doing a uiomove direct 200 * from the kernel address space. 201 */ 202int 203procfs_domem(curp, p, pfs, uio) 204 struct proc *curp; 205 struct proc *p; 206 struct pfsnode *pfs; 207 struct uio *uio; 208{ 209 int error; 210 211 if (uio->uio_resid == 0) 212 return (0); 213 214 error = procfs_rwmem(p, uio); 215 216 return (error); 217} 218 219/* 220 * Given process (p), find the vnode from which 221 * it's text segment is being executed. 222 * 223 * It would be nice to grab this information from 224 * the VM system, however, there is no sure-fire 225 * way of doing that. Instead, fork(), exec() and 226 * wait() all maintain the p_textvp field in the 227 * process proc structure which contains a held 228 * reference to the exec'ed vnode. 229 */ 230struct vnode * 231procfs_findtextvp(p) 232 struct proc *p; 233{ 234 return (p->p_textvp); 235} 236 237 238#ifdef probably_never 239/* 240 * Given process (p), find the vnode from which 241 * it's text segment is being mapped. 242 * 243 * (This is here, rather than in procfs_subr in order 244 * to keep all the VM related code in one place.) 245 */ 246struct vnode * 247procfs_findtextvp(p) 248 struct proc *p; 249{ 250 int error; 251 vm_object_t object; 252 vm_offset_t pageno; /* page number */ 253 254 /* find a vnode pager for the user address space */ 255 256 for (pageno = VM_MIN_ADDRESS; 257 pageno < VM_MAXUSER_ADDRESS; 258 pageno += PAGE_SIZE) { 259 vm_map_t map; 260 vm_map_entry_t out_entry; 261 vm_prot_t out_prot; 262 boolean_t wired, single_use; 263 vm_offset_t off; 264 265 map = &p->p_vmspace->vm_map; 266 error = vm_map_lookup(&map, pageno, 267 VM_PROT_READ, 268 &out_entry, &object, &off, &out_prot, 269 &wired, &single_use); 270 271 if (!error) { 272 vm_pager_t pager; 273 274 printf("procfs: found vm object\n"); 275 vm_map_lookup_done(map, out_entry); 276 printf("procfs: vm object = %x\n", object); 277 278 /* 279 * At this point, assuming no errors, object 280 * is the VM object mapping UVA (pageno). 281 * Ensure it has a vnode pager, then grab 282 * the vnode from that pager's handle. 283 */ 284 285 pager = object->pager; 286 printf("procfs: pager = %x\n", pager); 287 if (pager) 288 printf("procfs: found pager, type = %d\n", pager->pg_type); 289 if (pager && pager->pg_type == PG_VNODE) { 290 struct vnode *vp; 291 292 vp = (struct vnode *) pager->pg_handle; 293 printf("procfs: vp = 0x%x\n", vp); 294 return (vp); 295 } 296 } 297 } 298 299 printf("procfs: text object not found\n"); 300 return (0); 301} 302#endif /* probably_never */ 303