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: procfs_mem.c,v 1.26 1997/08/02 14:32:14 bde 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/proc.h> 51 #include <sys/vnode.h> 52 #include <miscfs/procfs/procfs.h> 53 #include <vm/vm.h> 54 #include <vm/vm_param.h> 55 #include <vm/vm_prot.h> 56 #include <sys/lock.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_map.h> 59 #include <vm/vm_kern.h> 60 #include <vm/vm_object.h> 61 #include <vm/vm_page.h> 62 #include <vm/vm_extern.h> 63 #include <sys/user.h> 64 65 static int procfs_rwmem __P((struct proc *p, struct uio *uio)); 66 67 static int 68 procfs_rwmem(p, uio) 69 struct proc *p; 70 struct uio *uio; 71 { 72 int error; 73 int writing; 74 struct vmspace *vm; 75 vm_map_t map; 76 vm_object_t object = NULL; 77 vm_offset_t pageno = 0; /* page number */ 78 vm_prot_t reqprot; 79 vm_offset_t kva; 80 81 /* 82 * if the vmspace is in the midst of being deallocated or the 83 * process is exiting, don't try to grab anything. The page table 84 * usage in that process can be messed up. 85 */ 86 vm = p->p_vmspace; 87 if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1)) 88 return EFAULT; 89 ++vm->vm_refcnt; 90 /* 91 * The map we want... 92 */ 93 map = &vm->vm_map; 94 95 writing = uio->uio_rw == UIO_WRITE; 96 reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) : VM_PROT_READ; 97 98 kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE); 99 100 /* 101 * Only map in one page at a time. We don't have to, but it 102 * makes things easier. This way is trivial - right? 103 */ 104 do { 105 vm_map_t tmap; 106 vm_offset_t uva; 107 int page_offset; /* offset into page */ 108 vm_map_entry_t out_entry; 109 vm_prot_t out_prot; 110 boolean_t wired, single_use; 111 vm_pindex_t pindex; 112 u_int len; 113 vm_page_t m; 114 115 object = NULL; 116 117 uva = (vm_offset_t) uio->uio_offset; 118 119 /* 120 * Get the page number of this segment. 121 */ 122 pageno = trunc_page(uva); 123 page_offset = uva - pageno; 124 125 /* 126 * How many bytes to copy 127 */ 128 len = min(PAGE_SIZE - page_offset, uio->uio_resid); 129 130 if (uva >= VM_MAXUSER_ADDRESS) { 131 vm_offset_t tkva; 132 133 if (writing || (uva >= (VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE))) { 134 error = 0; 135 break; 136 } 137 138 /* we are reading the "U area", force it into core */ 139 PHOLD(p); 140 141 /* sanity check */ 142 if (!(p->p_flag & P_INMEM)) { 143 /* aiee! */ 144 PRELE(p); 145 error = EFAULT; 146 break; 147 } 148 149 /* populate the ptrace/procfs area */ 150 p->p_addr->u_kproc.kp_proc = *p; 151 fill_eproc (p, &p->p_addr->u_kproc.kp_eproc); 152 153 /* locate the in-core address */ 154 tkva = (u_int)p->p_addr + uva - VM_MAXUSER_ADDRESS; 155 156 /* transfer it */ 157 error = uiomove((caddr_t)tkva, len, uio); 158 159 /* let the pages go */ 160 PRELE(p); 161 162 continue; 163 } 164 165 /* 166 * Fault the page on behalf of the process 167 */ 168 error = vm_fault(map, pageno, reqprot, FALSE); 169 if (error) { 170 error = EFAULT; 171 break; 172 } 173 174 /* 175 * Now we need to get the page. out_entry, out_prot, wired, 176 * and single_use aren't used. One would think the vm code 177 * would be a *bit* nicer... We use tmap because 178 * vm_map_lookup() can change the map argument. 179 */ 180 tmap = map; 181 error = vm_map_lookup(&tmap, pageno, reqprot, 182 &out_entry, &object, &pindex, &out_prot, 183 &wired, &single_use); 184 185 if (error) { 186 error = EFAULT; 187 188 /* 189 * Make sure that there is no residue in 'object' from 190 * an error return on vm_map_lookup. 191 */ 192 object = NULL; 193 194 break; 195 } 196 197 m = vm_page_lookup(object, pindex); 198 199 /* Allow fallback to backing objects if we are reading */ 200 201 while (m == NULL && !writing && object->backing_object) { 202 203 pindex += OFF_TO_IDX(object->backing_object_offset); 204 object = object->backing_object; 205 206 m = vm_page_lookup(object, pindex); 207 } 208 209 if (m == NULL) { 210 error = EFAULT; 211 212 /* 213 * Make sure that there is no residue in 'object' from 214 * an error return on vm_map_lookup. 215 */ 216 object = NULL; 217 218 vm_map_lookup_done(tmap, out_entry); 219 220 break; 221 } 222 223 /* 224 * Wire the page into memory 225 */ 226 vm_page_wire(m); 227 228 /* 229 * We're done with tmap now. 230 * But reference the object first, so that we won't loose 231 * it. 232 */ 233 vm_object_reference(object); 234 vm_map_lookup_done(tmap, out_entry); 235 236 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 237 238 /* 239 * Now do the i/o move. 240 */ 241 error = uiomove((caddr_t)(kva + page_offset), len, uio); 242 243 pmap_kremove(kva); 244 245 /* 246 * release the page and the object 247 */ 248 vm_page_unwire(m); 249 vm_object_deallocate(object); 250 251 object = NULL; 252 253 } while (error == 0 && uio->uio_resid > 0); 254 255 if (object) 256 vm_object_deallocate(object); 257 258 kmem_free(kernel_map, kva, PAGE_SIZE); 259 vmspace_free(vm); 260 return (error); 261 } 262 263 /* 264 * Copy data in and out of the target process. 265 * We do this by mapping the process's page into 266 * the kernel and then doing a uiomove direct 267 * from the kernel address space. 268 */ 269 int 270 procfs_domem(curp, p, pfs, uio) 271 struct proc *curp; 272 struct proc *p; 273 struct pfsnode *pfs; 274 struct uio *uio; 275 { 276 277 if (uio->uio_resid == 0) 278 return (0); 279 280 /* 281 * XXX 282 * We need to check for KMEM_GROUP because ps is sgid kmem; 283 * not allowing it here causes ps to not work properly. Arguably, 284 * this is a bug with what ps does. We only need to do this 285 * for Pmem nodes, and only if it's reading. This is still not 286 * good, as it may still be possible to grab illicit data if 287 * a process somehow gets to be KMEM_GROUP. Note that this also 288 * means that KMEM_GROUP can't change without editing procfs.h! 289 * All in all, quite yucky. 290 */ 291 292 if (!CHECKIO(curp, p) && 293 !(curp->p_cred->pc_ucred->cr_gid == KMEM_GROUP && 294 uio->uio_rw == UIO_READ)) 295 return EPERM; 296 297 return (procfs_rwmem(p, uio)); 298 } 299 300 /* 301 * Given process (p), find the vnode from which 302 * it's text segment is being executed. 303 * 304 * It would be nice to grab this information from 305 * the VM system, however, there is no sure-fire 306 * way of doing that. Instead, fork(), exec() and 307 * wait() all maintain the p_textvp field in the 308 * process proc structure which contains a held 309 * reference to the exec'ed vnode. 310 */ 311 struct vnode * 312 procfs_findtextvp(p) 313 struct proc *p; 314 { 315 316 return (p->p_textvp); 317 } 318