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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94 35 * 36 * $FreeBSD: src/sys/miscfs/procfs/procfs_mem.c,v 1.46.2.3 2002/01/22 17:22:59 nectar Exp $ 37 */ 38 39 /* 40 * This is a lightly hacked and merged version 41 * of sef's pread/pwrite functions 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/priv.h> 48 #include <sys/vnode.h> 49 #include <vfs/procfs/procfs.h> 50 #include <vm/vm.h> 51 #include <vm/vm_param.h> 52 #include <sys/lock.h> 53 #include <vm/pmap.h> 54 #include <vm/vm_extern.h> 55 #include <vm/vm_map.h> 56 #include <vm/vm_kern.h> 57 #include <vm/vm_object.h> 58 #include <vm/vm_page.h> 59 #include <sys/ptrace.h> 60 61 #include <machine/vmm.h> 62 63 static int procfs_rwmem (struct proc *curp, 64 struct proc *p, struct uio *uio); 65 66 /* 67 * p->p_token is held on entry. 68 */ 69 static int 70 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) 71 { 72 int error; 73 int writing; 74 struct vmspace *vm; 75 vm_map_t map; 76 vm_offset_t pageno = 0; /* page number */ 77 vm_prot_t reqprot; 78 vm_offset_t kva; 79 80 /* 81 * if the vmspace is in the midst of being allocated or deallocated, 82 * or the process is exiting, don't try to grab anything. The 83 * page table usage in that process may be messed up. 84 */ 85 vm = p->p_vmspace; 86 if (p->p_stat == SIDL || p->p_stat == SZOMB) 87 return EFAULT; 88 if ((p->p_flags & (P_WEXIT | P_INEXEC)) || vmspace_getrefs(vm) < 0) 89 return EFAULT; 90 91 /* 92 * The map we want... 93 */ 94 vmspace_hold(vm); 95 map = &vm->vm_map; 96 97 writing = (uio->uio_rw == UIO_WRITE); 98 reqprot = VM_PROT_READ; 99 if (writing) 100 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; 101 102 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE, VM_SUBSYS_PROC); 103 104 /* 105 * Only map in one page at a time. We don't have to, but it 106 * makes things easier. This way is trivial - right? 107 */ 108 do { 109 vm_offset_t uva; 110 vm_offset_t page_offset; /* offset into page */ 111 size_t len; 112 vm_page_t m; 113 int busy; 114 115 uva = (vm_offset_t) uio->uio_offset; 116 117 /* 118 * Get the page number of this segment. 119 */ 120 pageno = trunc_page(uva); 121 page_offset = uva - pageno; 122 123 /* 124 * If the target process is running in VMM mode 125 * translate the address into a GPA (Guest Physical 126 * Address) via the EPT before doing the lookup. 127 */ 128 if (p->p_vmm) { 129 register_t gpa; 130 vmm_vm_get_gpa(p, &gpa, (register_t) pageno); 131 pageno = (vm_offset_t)gpa; 132 } 133 134 /* 135 * How many bytes to copy 136 */ 137 len = szmin(PAGE_SIZE - page_offset, uio->uio_resid); 138 139 /* 140 * Fault the page on behalf of the process 141 * 142 * XXX busied page on write fault can deadlock against our 143 * uiomove. 144 */ 145 m = vm_fault_page(map, pageno, reqprot, 146 VM_FAULT_NORMAL, 147 &error, &busy); 148 if (error) { 149 KKASSERT(m == NULL); 150 error = EFAULT; 151 break; 152 } 153 154 /* 155 * Cleanup pmap then create a temporary KVA mapping and 156 * do the I/O. We can switch between cpus so don't bother 157 * synchronizing across all cores. 158 */ 159 pmap_kenter_quick(kva, VM_PAGE_TO_PHYS(m)); 160 error = uiomove((caddr_t)(kva + page_offset), len, uio); 161 pmap_kremove_quick(kva); 162 163 /* 164 * Release the page and we are done 165 */ 166 if (busy) 167 vm_page_wakeup(m); 168 else 169 vm_page_unhold(m); 170 } while (error == 0 && uio->uio_resid > 0); 171 172 vmspace_drop(vm); 173 kmem_free(&kernel_map, kva, PAGE_SIZE); 174 175 return (error); 176 } 177 178 /* 179 * Copy data in and out of the target process. 180 * We do this by mapping the process's page into 181 * the kernel and then doing a uiomove direct 182 * from the kernel address space. 183 * 184 * lp->lwp_proc->p_token is held on entry. 185 */ 186 int 187 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 188 struct uio *uio) 189 { 190 struct proc *p = lp->lwp_proc; 191 int error; 192 193 if (uio->uio_resid == 0) 194 return (0); 195 196 if ((p->p_flags & P_INEXEC) != 0) { 197 /* 198 * Can't trace a process that's currently exec'ing. 199 */ 200 error = EAGAIN; 201 } else if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) { 202 /* 203 * Can't trace processes outside our jail 204 */ 205 error = EPERM; 206 } else { 207 error = procfs_rwmem(curp, p, uio); 208 } 209 return(error); 210 } 211 212 /* 213 * Given process (p), find the vnode from which 214 * its text segment is being executed. 215 * 216 * It would be nice to grab this information from 217 * the VM system, however, there is no sure-fire 218 * way of doing that. Instead, fork(), exec() and 219 * wait() all maintain the p_textvp field in the 220 * process proc structure which contains a held 221 * reference to the exec'ed vnode. 222 * 223 * XXX - Currently, this is not not used, as the 224 * /proc/pid/file object exposes an information leak 225 * that shouldn't happen. Using a mount option would 226 * make it configurable on a per-system (or, at least, 227 * per-mount) basis; however, that's not really best. 228 * The best way to do it, I think, would be as an 229 * ioctl; this would restrict it to the uid running 230 * program, or root, which seems a reasonable compromise. 231 * However, the number of applications for this is 232 * minimal, if it can't be seen in the filesytem space, 233 * and doint it as an ioctl makes it somewhat less 234 * useful due to the, well, inelegance. 235 * 236 */ 237 struct vnode * 238 procfs_findtextvp(struct proc *p) 239 { 240 return (p->p_textvp); 241 } 242