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 1.15 2007/02/19 01:14:24 corecode 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 68 static int procfs_rwmem (struct proc *curp, 69 struct proc *p, struct uio *uio); 70 71 static int 72 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) 73 { 74 int error; 75 int writing; 76 struct vmspace *vm; 77 vm_map_t map; 78 vm_offset_t pageno = 0; /* page number */ 79 vm_prot_t reqprot; 80 vm_offset_t kva; 81 82 /* 83 * if the vmspace is in the midst of being deallocated or the 84 * process is exiting, don't try to grab anything. The page table 85 * usage in that process can be messed up. 86 */ 87 vm = p->p_vmspace; 88 if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1)) 89 return EFAULT; 90 ++vm->vm_refcnt; 91 /* 92 * The map we want... 93 */ 94 map = &vm->vm_map; 95 96 writing = uio->uio_rw == UIO_WRITE; 97 reqprot = VM_PROT_READ; 98 if (writing) 99 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; 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_offset_t uva; 109 int page_offset; /* offset into page */ 110 u_int len; 111 vm_page_t m; 112 113 uva = (vm_offset_t) uio->uio_offset; 114 115 /* 116 * Get the page number of this segment. 117 */ 118 pageno = trunc_page(uva); 119 page_offset = uva - pageno; 120 121 /* 122 * How many bytes to copy 123 */ 124 len = min(PAGE_SIZE - page_offset, uio->uio_resid); 125 126 /* 127 * Fault the page on behalf of the process 128 */ 129 m = vm_fault_page(map, pageno, reqprot, 130 VM_FAULT_NORMAL, &error); 131 if (error) { 132 KKASSERT(m == NULL); 133 error = EFAULT; 134 break; 135 } 136 137 /* 138 * Cleanup tmap then create a temporary KVA mapping and 139 * do the I/O. 140 */ 141 pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); 142 error = uiomove((caddr_t)(kva + page_offset), len, uio); 143 pmap_kremove(kva); 144 145 /* 146 * release the page and we are done 147 */ 148 crit_enter(); 149 vm_page_unhold(m); 150 crit_exit(); 151 } while (error == 0 && uio->uio_resid > 0); 152 153 kmem_free(&kernel_map, kva, PAGE_SIZE); 154 vmspace_free(vm); 155 return (error); 156 } 157 158 /* 159 * Copy data in and out of the target process. 160 * We do this by mapping the process's page into 161 * the kernel and then doing a uiomove direct 162 * from the kernel address space. 163 */ 164 int 165 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 166 struct uio *uio) 167 { 168 struct proc *p = lp->lwp_proc; 169 170 if (uio->uio_resid == 0) 171 return (0); 172 173 /* Can't trace a process that's currently exec'ing. */ 174 if ((p->p_flag & P_INEXEC) != 0) 175 return EAGAIN; 176 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 177 return EPERM; 178 179 return (procfs_rwmem(curp, p, uio)); 180 } 181 182 /* 183 * Given process (p), find the vnode from which 184 * its text segment is being executed. 185 * 186 * It would be nice to grab this information from 187 * the VM system, however, there is no sure-fire 188 * way of doing that. Instead, fork(), exec() and 189 * wait() all maintain the p_textvp field in the 190 * process proc structure which contains a held 191 * reference to the exec'ed vnode. 192 * 193 * XXX - Currently, this is not not used, as the 194 * /proc/pid/file object exposes an information leak 195 * that shouldn't happen. Using a mount option would 196 * make it configurable on a per-system (or, at least, 197 * per-mount) basis; however, that's not really best. 198 * The best way to do it, I think, would be as an 199 * ioctl; this would restrict it to the uid running 200 * program, or root, which seems a reasonable compromise. 201 * However, the number of applications for this is 202 * minimal, if it can't be seen in the filesytem space, 203 * and doint it as an ioctl makes it somewhat less 204 * useful due to the, well, inelegance. 205 * 206 */ 207 struct vnode * 208 procfs_findtextvp(struct proc *p) 209 { 210 return (p->p_textvp); 211 } 212