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 * $FreeBSD: src/sys/miscfs/procfs/procfs_mem.c,v 1.46.2.3 2002/01/22 17:22:59 nectar Exp $ 41 * $DragonFly: src/sys/vfs/procfs/procfs_mem.c,v 1.7 2003/09/03 11:47:04 hmp Exp $ 42 */ 43 44 /* 45 * This is a lightly hacked and merged version 46 * of sef's pread/pwrite functions 47 */ 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/proc.h> 52 #include <sys/vnode.h> 53 #include <vfs/procfs/procfs.h> 54 #include <vm/vm.h> 55 #include <vm/vm_param.h> 56 #include <sys/lock.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_extern.h> 59 #include <vm/vm_map.h> 60 #include <vm/vm_kern.h> 61 #include <vm/vm_object.h> 62 #include <vm/vm_page.h> 63 #include <sys/user.h> 64 #include <sys/ptrace.h> 65 66 static int procfs_rwmem (struct proc *curp, 67 struct proc *p, struct uio *uio); 68 69 static int 70 procfs_rwmem(curp, p, uio) 71 struct proc *curp; 72 struct proc *p; 73 struct uio *uio; 74 { 75 int error; 76 int writing; 77 struct vmspace *vm; 78 vm_map_t map; 79 vm_object_t object = NULL; 80 vm_offset_t pageno = 0; /* page number */ 81 vm_prot_t reqprot; 82 vm_offset_t kva; 83 84 /* 85 * if the vmspace is in the midst of being deallocated or the 86 * process is exiting, don't try to grab anything. The page table 87 * usage in that process can be messed up. 88 */ 89 vm = p->p_vmspace; 90 if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1)) 91 return EFAULT; 92 ++vm->vm_refcnt; 93 /* 94 * The map we want... 95 */ 96 map = &vm->vm_map; 97 98 writing = uio->uio_rw == UIO_WRITE; 99 reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) : VM_PROT_READ; 100 101 kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE); 102 103 /* 104 * Only map in one page at a time. We don't have to, but it 105 * makes things easier. This way is trivial - right? 106 */ 107 do { 108 vm_map_t tmap; 109 vm_offset_t uva; 110 int page_offset; /* offset into page */ 111 vm_map_entry_t out_entry; 112 vm_prot_t out_prot; 113 boolean_t wired; 114 vm_pindex_t pindex; 115 u_int len; 116 vm_page_t m; 117 118 object = NULL; 119 120 uva = (vm_offset_t) uio->uio_offset; 121 122 /* 123 * Get the page number of this segment. 124 */ 125 pageno = trunc_page(uva); 126 page_offset = uva - pageno; 127 128 /* 129 * How many bytes to copy 130 */ 131 len = min(PAGE_SIZE - page_offset, uio->uio_resid); 132 133 /* 134 * Fault the page on behalf of the process 135 */ 136 error = vm_fault(map, pageno, reqprot, VM_FAULT_NORMAL); 137 if (error) { 138 error = EFAULT; 139 break; 140 } 141 142 /* 143 * Now we need to get the page. out_entry, out_prot, wired, 144 * and single_use aren't used. One would think the vm code 145 * would be a *bit* nicer... We use tmap because 146 * vm_map_lookup() can change the map argument. 147 */ 148 tmap = map; 149 error = vm_map_lookup(&tmap, pageno, reqprot, 150 &out_entry, &object, &pindex, &out_prot, 151 &wired); 152 153 if (error) { 154 error = EFAULT; 155 156 /* 157 * Make sure that there is no residue in 'object' from 158 * an error return on vm_map_lookup. 159 */ 160 object = NULL; 161 162 break; 163 } 164 165 m = vm_page_lookup(object, pindex); 166 167 /* Allow fallback to backing objects if we are reading */ 168 169 while (m == NULL && !writing && object->backing_object) { 170 171 pindex += OFF_TO_IDX(object->backing_object_offset); 172 object = object->backing_object; 173 174 m = vm_page_lookup(object, pindex); 175 } 176 177 if (m == NULL) { 178 error = EFAULT; 179 180 /* 181 * Make sure that there is no residue in 'object' from 182 * an error return on vm_map_lookup. 183 */ 184 object = NULL; 185 186 vm_map_lookup_done(tmap, out_entry, 0); 187 188 break; 189 } 190 191 /* 192 * Wire the page into memory 193 */ 194 vm_page_hold(m); 195 196 /* 197 * We're done with tmap now. 198 * But reference the object first, so that we won't loose 199 * it. 200 */ 201 vm_object_reference(object); 202 vm_map_lookup_done(tmap, out_entry, 0); 203 204 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 205 206 /* 207 * Now do the i/o move. 208 */ 209 error = uiomove((caddr_t)(kva + page_offset), len, uio); 210 211 pmap_kremove(kva); 212 213 /* 214 * release the page and the object 215 */ 216 vm_page_unhold(m); 217 vm_object_deallocate(object); 218 219 object = NULL; 220 221 } while (error == 0 && uio->uio_resid > 0); 222 223 if (object) 224 vm_object_deallocate(object); 225 226 kmem_free(kernel_map, kva, PAGE_SIZE); 227 vmspace_free(vm); 228 return (error); 229 } 230 231 /* 232 * Copy data in and out of the target process. 233 * We do this by mapping the process's page into 234 * the kernel and then doing a uiomove direct 235 * from the kernel address space. 236 */ 237 int 238 procfs_domem(curp, p, pfs, uio) 239 struct proc *curp; 240 struct proc *p; 241 struct pfsnode *pfs; 242 struct uio *uio; 243 { 244 245 if (uio->uio_resid == 0) 246 return (0); 247 248 /* Can't trace a process that's currently exec'ing. */ 249 if ((p->p_flag & P_INEXEC) != 0) 250 return EAGAIN; 251 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 252 return EPERM; 253 254 return (procfs_rwmem(curp, p, uio)); 255 } 256 257 /* 258 * Given process (p), find the vnode from which 259 * its text segment is being executed. 260 * 261 * It would be nice to grab this information from 262 * the VM system, however, there is no sure-fire 263 * way of doing that. Instead, fork(), exec() and 264 * wait() all maintain the p_textvp field in the 265 * process proc structure which contains a held 266 * reference to the exec'ed vnode. 267 * 268 * XXX - Currently, this is not not used, as the 269 * /proc/pid/file object exposes an information leak 270 * that shouldn't happen. Using a mount option would 271 * make it configurable on a per-system (or, at least, 272 * per-mount) basis; however, that's not really best. 273 * The best way to do it, I think, would be as an 274 * ioctl; this would restrict it to the uid running 275 * program, or root, which seems a reasonable compromise. 276 * However, the number of applications for this is 277 * minimal, if it can't be seen in the filesytem space, 278 * and doint it as an ioctl makes it somewhat less 279 * useful due to the, well, inelegance. 280 * 281 */ 282 struct vnode * 283 procfs_findtextvp(p) 284 struct proc *p; 285 { 286 287 return (p->p_textvp); 288 } 289