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 1.16 2007/04/29 18:25:40 dillon 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/priv.h> 53 #include <sys/vnode.h> 54 #include <vfs/procfs/procfs.h> 55 #include <vm/vm.h> 56 #include <vm/vm_param.h> 57 #include <sys/lock.h> 58 #include <vm/pmap.h> 59 #include <vm/vm_extern.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 <sys/user.h> 65 #include <sys/ptrace.h> 66 67 #include <sys/thread2.h> 68 #include <sys/sysref2.h> 69 70 static int procfs_rwmem (struct proc *curp, 71 struct proc *p, struct uio *uio); 72 73 /* 74 * p->p_token is held on entry. 75 */ 76 static int 77 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) 78 { 79 int error; 80 int writing; 81 struct vmspace *vm; 82 vm_map_t map; 83 vm_offset_t pageno = 0; /* page number */ 84 vm_prot_t reqprot; 85 vm_offset_t kva; 86 87 /* 88 * if the vmspace is in the midst of being allocated or deallocated, 89 * or the process is exiting, don't try to grab anything. The 90 * page table usage in that process may be messed up. 91 */ 92 vm = p->p_vmspace; 93 if (p->p_stat == SIDL || p->p_stat == SZOMB) 94 return EFAULT; 95 if ((p->p_flags & (P_WEXIT | P_INEXEC)) || 96 sysref_isinactive(&vm->vm_sysref)) 97 return EFAULT; 98 99 /* 100 * The map we want... 101 */ 102 vmspace_hold(vm); 103 map = &vm->vm_map; 104 105 writing = (uio->uio_rw == UIO_WRITE); 106 reqprot = VM_PROT_READ; 107 if (writing) 108 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; 109 110 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE); 111 112 /* 113 * Only map in one page at a time. We don't have to, but it 114 * makes things easier. This way is trivial - right? 115 */ 116 do { 117 vm_offset_t uva; 118 vm_offset_t page_offset; /* offset into page */ 119 size_t len; 120 vm_page_t m; 121 122 uva = (vm_offset_t) uio->uio_offset; 123 124 /* 125 * Get the page number of this segment. 126 */ 127 pageno = trunc_page(uva); 128 page_offset = uva - pageno; 129 130 /* 131 * How many bytes to copy 132 */ 133 len = szmin(PAGE_SIZE - page_offset, uio->uio_resid); 134 135 /* 136 * Fault the page on behalf of the process 137 */ 138 m = vm_fault_page(map, pageno, reqprot, 139 VM_FAULT_NORMAL, &error); 140 if (error) { 141 KKASSERT(m == NULL); 142 error = EFAULT; 143 break; 144 } 145 146 /* 147 * Cleanup tmap then create a temporary KVA mapping and 148 * do the I/O. We can switch between cpus so don't bother 149 * synchronizing across all cores. 150 */ 151 pmap_kenter_quick(kva, VM_PAGE_TO_PHYS(m)); 152 error = uiomove((caddr_t)(kva + page_offset), len, uio); 153 pmap_kremove_quick(kva); 154 155 /* 156 * release the page and we are done 157 */ 158 vm_page_unhold(m); 159 } while (error == 0 && uio->uio_resid > 0); 160 161 vmspace_drop(vm); 162 kmem_free(&kernel_map, kva, PAGE_SIZE); 163 164 return (error); 165 } 166 167 /* 168 * Copy data in and out of the target process. 169 * We do this by mapping the process's page into 170 * the kernel and then doing a uiomove direct 171 * from the kernel address space. 172 * 173 * lp->lwp_proc->p_token is held on entry. 174 */ 175 int 176 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 177 struct uio *uio) 178 { 179 struct proc *p = lp->lwp_proc; 180 int error; 181 182 if (uio->uio_resid == 0) 183 return (0); 184 185 if ((p->p_flags & P_INEXEC) != 0) { 186 /* 187 * Can't trace a process that's currently exec'ing. 188 */ 189 error = EAGAIN; 190 } else if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) { 191 /* 192 * Can't trace processes outside our jail 193 */ 194 error = EPERM; 195 } else { 196 error = procfs_rwmem(curp, p, uio); 197 } 198 return(error); 199 } 200 201 /* 202 * Given process (p), find the vnode from which 203 * its text segment is being executed. 204 * 205 * It would be nice to grab this information from 206 * the VM system, however, there is no sure-fire 207 * way of doing that. Instead, fork(), exec() and 208 * wait() all maintain the p_textvp field in the 209 * process proc structure which contains a held 210 * reference to the exec'ed vnode. 211 * 212 * XXX - Currently, this is not not used, as the 213 * /proc/pid/file object exposes an information leak 214 * that shouldn't happen. Using a mount option would 215 * make it configurable on a per-system (or, at least, 216 * per-mount) basis; however, that's not really best. 217 * The best way to do it, I think, would be as an 218 * ioctl; this would restrict it to the uid running 219 * program, or root, which seems a reasonable compromise. 220 * However, the number of applications for this is 221 * minimal, if it can't be seen in the filesytem space, 222 * and doint it as an ioctl makes it somewhat less 223 * useful due to the, well, inelegance. 224 * 225 */ 226 struct vnode * 227 procfs_findtextvp(struct proc *p) 228 { 229 return (p->p_textvp); 230 } 231