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 8.5 (Berkeley) 6/15/94 39 * 40 * $Id$ 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_param.h> 57 #include <vm/vm_prot.h> 58 #include <sys/lock.h> 59 #include <vm/pmap.h> 60 #include <vm/vm_map.h> 61 #include <vm/vm_kern.h> 62 #include <vm/vm_object.h> 63 #include <vm/vm_page.h> 64 #include <vm/vm_extern.h> 65 #include <sys/user.h> 66 67 static int procfs_rwmem __P((struct proc *p, struct uio *uio)); 68 69 static int 70 procfs_rwmem(p, uio) 71 struct proc *p; 72 struct uio *uio; 73 { 74 int error; 75 int writing; 76 struct vmspace *vm; 77 int fix_prot = 0; 78 vm_map_t map; 79 vm_object_t object = NULL; 80 vm_offset_t pageno = 0; /* page number */ 81 82 /* 83 * if the vmspace is in the midst of being deallocated or the 84 * process is exiting, don't try to grab anything. The page table 85 * usage in that process can be messed up. 86 */ 87 vm = p->p_vmspace; 88 if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1)) 89 return EFAULT; 90 ++vm->vm_refcnt; 91 /* 92 * The map we want... 93 */ 94 map = &vm->vm_map; 95 96 writing = uio->uio_rw == UIO_WRITE; 97 98 /* 99 * Only map in one page at a time. We don't have to, but it 100 * makes things easier. This way is trivial - right? 101 */ 102 do { 103 vm_map_t tmap; 104 vm_offset_t kva = 0; 105 vm_offset_t uva; 106 int page_offset; /* offset into page */ 107 vm_map_entry_t out_entry; 108 vm_prot_t out_prot; 109 boolean_t wired, single_use; 110 vm_pindex_t pindex; 111 u_int len; 112 113 fix_prot = 0; 114 object = NULL; 115 116 uva = (vm_offset_t) uio->uio_offset; 117 118 /* 119 * Get the page number of this segment. 120 */ 121 pageno = trunc_page(uva); 122 page_offset = uva - pageno; 123 124 /* 125 * How many bytes to copy 126 */ 127 len = min(PAGE_SIZE - page_offset, uio->uio_resid); 128 129 if (uva >= VM_MAXUSER_ADDRESS) { 130 if (writing || (uva >= (VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE))) { 131 error = 0; 132 break; 133 } 134 135 /* we are reading the "U area", force it into core */ 136 PHOLD(p); 137 138 /* sanity check */ 139 if (!(p->p_flag & P_INMEM)) { 140 /* aiee! */ 141 PRELE(p); 142 error = EFAULT; 143 break; 144 } 145 146 /* populate the ptrace/procfs area */ 147 p->p_addr->u_kproc.kp_proc = *p; 148 fill_eproc (p, &p->p_addr->u_kproc.kp_eproc); 149 150 /* locate the in-core address */ 151 kva = (u_int)p->p_addr + uva - VM_MAXUSER_ADDRESS; 152 153 /* transfer it */ 154 error = uiomove((caddr_t)kva, len, uio); 155 156 /* let the pages go */ 157 PRELE(p); 158 159 continue; 160 } 161 162 /* 163 * Check the permissions for the area we're interested 164 * in. 165 */ 166 if (writing) { 167 fix_prot = !vm_map_check_protection(map, pageno, 168 pageno + PAGE_SIZE, VM_PROT_WRITE); 169 170 if (fix_prot) { 171 /* 172 * If the page is not writable, we make it so. 173 * XXX It is possible that a page may *not* be 174 * read/executable, if a process changes that! 175 * We will assume, for now, that a page is either 176 * VM_PROT_ALL, or VM_PROT_READ|VM_PROT_EXECUTE. 177 */ 178 error = vm_map_protect(map, pageno, 179 pageno + PAGE_SIZE, VM_PROT_ALL, 0); 180 if (error) { 181 /* 182 * We don't have to undo something 183 * that didn't work, so we clear the 184 * flag. 185 */ 186 fix_prot = 0; 187 break; 188 } 189 } 190 } 191 192 /* 193 * Now we need to get the page. out_entry, out_prot, wired, 194 * and single_use aren't used. One would think the vm code 195 * would be a *bit* nicer... We use tmap because 196 * vm_map_lookup() can change the map argument. 197 */ 198 tmap = map; 199 error = vm_map_lookup(&tmap, pageno, 200 writing ? VM_PROT_WRITE : VM_PROT_READ, 201 &out_entry, &object, &pindex, &out_prot, 202 &wired, &single_use); 203 204 if (error) { 205 /* 206 * Make sure that there is no residue in 'object' from 207 * an error return on vm_map_lookup. 208 */ 209 object = NULL; 210 break; 211 } 212 213 /* 214 * We're done with tmap now. 215 * But reference the object first, so that we won't loose 216 * it. 217 */ 218 vm_object_reference(object); 219 vm_map_lookup_done(tmap, out_entry); 220 221 /* 222 * Fault the page in... 223 */ 224 if (writing && object->backing_object) { 225 error = vm_fault(map, pageno, 226 VM_PROT_WRITE, FALSE); 227 if (error) 228 break; 229 } 230 231 /* Find space in kernel_map for the page we're interested in */ 232 error = vm_map_find(kernel_map, object, 233 IDX_TO_OFF(pindex), &kva, PAGE_SIZE, 1, 234 VM_PROT_ALL, VM_PROT_ALL, 0); 235 if (error) { 236 break; 237 } 238 239 /* 240 * Mark the page we just found as pageable. 241 */ 242 error = vm_map_pageable(kernel_map, kva, 243 kva + PAGE_SIZE, 0); 244 if (error) { 245 vm_map_remove(kernel_map, kva, kva + PAGE_SIZE); 246 object = NULL; 247 break; 248 } 249 250 /* 251 * Now do the i/o move. 252 */ 253 error = uiomove((caddr_t)(kva + page_offset), 254 len, uio); 255 256 /* 257 * vm_map_remove gets rid of the object reference, so 258 * we need to get rid of our 'object' pointer if there 259 * is subsequently an error. 260 */ 261 vm_map_remove(kernel_map, kva, kva + PAGE_SIZE); 262 object = NULL; 263 264 /* 265 * Undo the protection 'damage'. 266 */ 267 if (fix_prot) { 268 vm_map_protect(map, pageno, pageno + PAGE_SIZE, 269 VM_PROT_READ|VM_PROT_EXECUTE, 0); 270 fix_prot = 0; 271 } 272 } while (error == 0 && uio->uio_resid > 0); 273 274 if (object) 275 vm_object_deallocate(object); 276 277 if (fix_prot) 278 vm_map_protect(map, pageno, pageno + PAGE_SIZE, 279 VM_PROT_READ|VM_PROT_EXECUTE, 0); 280 281 vmspace_free(vm); 282 return (error); 283 } 284 285 /* 286 * Copy data in and out of the target process. 287 * We do this by mapping the process's page into 288 * the kernel and then doing a uiomove direct 289 * from the kernel address space. 290 */ 291 int 292 procfs_domem(curp, p, pfs, uio) 293 struct proc *curp; 294 struct proc *p; 295 struct pfsnode *pfs; 296 struct uio *uio; 297 { 298 299 if (uio->uio_resid == 0) 300 return (0); 301 302 return (procfs_rwmem(p, uio)); 303 } 304 305 /* 306 * Given process (p), find the vnode from which 307 * it's text segment is being executed. 308 * 309 * It would be nice to grab this information from 310 * the VM system, however, there is no sure-fire 311 * way of doing that. Instead, fork(), exec() and 312 * wait() all maintain the p_textvp field in the 313 * process proc structure which contains a held 314 * reference to the exec'ed vnode. 315 */ 316 struct vnode * 317 procfs_findtextvp(p) 318 struct proc *p; 319 { 320 321 return (p->p_textvp); 322 } 323