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/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 #include <sys/thread2.h> 67 #include <sys/sysref2.h> 68 69 static int procfs_rwmem (struct proc *curp, 70 struct proc *p, struct uio *uio); 71 72 static int 73 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) 74 { 75 int error; 76 int writing; 77 struct vmspace *vm; 78 vm_map_t map; 79 vm_offset_t pageno = 0; /* page number */ 80 vm_prot_t reqprot; 81 vm_offset_t kva; 82 83 /* 84 * if the vmspace is in the midst of being allocated or deallocated, 85 * or the process is exiting, don't try to grab anything. The 86 * page table usage in that process may be messed up. 87 */ 88 vm = p->p_vmspace; 89 sysref_get(&vm->vm_sysref); 90 if ((p->p_flag & P_WEXIT) || sysref_isinactive(&vm->vm_sysref)) { 91 sysref_put(&vm->vm_sysref); 92 return EFAULT; 93 } 94 95 /* 96 * The map we want... 97 */ 98 map = &vm->vm_map; 99 100 writing = uio->uio_rw == UIO_WRITE; 101 reqprot = VM_PROT_READ; 102 if (writing) 103 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; 104 105 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE); 106 107 /* 108 * Only map in one page at a time. We don't have to, but it 109 * makes things easier. This way is trivial - right? 110 */ 111 do { 112 vm_offset_t uva; 113 int page_offset; /* offset into page */ 114 u_int len; 115 vm_page_t m; 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 /* 131 * Fault the page on behalf of the process 132 */ 133 m = vm_fault_page(map, pageno, reqprot, 134 VM_FAULT_NORMAL, &error); 135 if (error) { 136 KKASSERT(m == NULL); 137 error = EFAULT; 138 break; 139 } 140 141 /* 142 * Cleanup tmap then create a temporary KVA mapping and 143 * do the I/O. 144 */ 145 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 146 error = uiomove((caddr_t)(kva + page_offset), len, uio); 147 pmap_kremove(kva); 148 149 /* 150 * release the page and we are done 151 */ 152 crit_enter(); 153 vm_page_unhold(m); 154 crit_exit(); 155 } while (error == 0 && uio->uio_resid > 0); 156 157 kmem_free(&kernel_map, kva, PAGE_SIZE); 158 sysref_put(&vm->vm_sysref); 159 return (error); 160 } 161 162 /* 163 * Copy data in and out of the target process. 164 * We do this by mapping the process's page into 165 * the kernel and then doing a uiomove direct 166 * from the kernel address space. 167 */ 168 int 169 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 170 struct uio *uio) 171 { 172 struct proc *p = lp->lwp_proc; 173 174 if (uio->uio_resid == 0) 175 return (0); 176 177 /* Can't trace a process that's currently exec'ing. */ 178 if ((p->p_flag & P_INEXEC) != 0) 179 return EAGAIN; 180 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 181 return EPERM; 182 183 return (procfs_rwmem(curp, p, uio)); 184 } 185 186 /* 187 * Given process (p), find the vnode from which 188 * its text segment is being executed. 189 * 190 * It would be nice to grab this information from 191 * the VM system, however, there is no sure-fire 192 * way of doing that. Instead, fork(), exec() and 193 * wait() all maintain the p_textvp field in the 194 * process proc structure which contains a held 195 * reference to the exec'ed vnode. 196 * 197 * XXX - Currently, this is not not used, as the 198 * /proc/pid/file object exposes an information leak 199 * that shouldn't happen. Using a mount option would 200 * make it configurable on a per-system (or, at least, 201 * per-mount) basis; however, that's not really best. 202 * The best way to do it, I think, would be as an 203 * ioctl; this would restrict it to the uid running 204 * program, or root, which seems a reasonable compromise. 205 * However, the number of applications for this is 206 * minimal, if it can't be seen in the filesytem space, 207 * and doint it as an ioctl makes it somewhat less 208 * useful due to the, well, inelegance. 209 * 210 */ 211 struct vnode * 212 procfs_findtextvp(struct proc *p) 213 { 214 return (p->p_textvp); 215 } 216