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) || sysref_isinactive(&vm->vm_sysref)) 96 return EFAULT; 97 98 /* 99 * The map we want... 100 */ 101 map = &vm->vm_map; 102 103 writing = (uio->uio_rw == UIO_WRITE); 104 reqprot = VM_PROT_READ; 105 if (writing) 106 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; 107 108 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE); 109 110 /* 111 * Only map in one page at a time. We don't have to, but it 112 * makes things easier. This way is trivial - right? 113 */ 114 do { 115 vm_offset_t uva; 116 vm_offset_t page_offset; /* offset into page */ 117 size_t len; 118 vm_page_t m; 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 = szmin(PAGE_SIZE - page_offset, uio->uio_resid); 132 133 /* 134 * Fault the page on behalf of the process 135 */ 136 m = vm_fault_page(map, pageno, reqprot, 137 VM_FAULT_NORMAL, &error); 138 if (error) { 139 KKASSERT(m == NULL); 140 error = EFAULT; 141 break; 142 } 143 144 /* 145 * Cleanup tmap then create a temporary KVA mapping and 146 * do the I/O. We can switch between cpus so don't bother 147 * synchronizing across all cores. 148 */ 149 pmap_kenter_quick(kva, VM_PAGE_TO_PHYS(m)); 150 error = uiomove((caddr_t)(kva + page_offset), len, uio); 151 pmap_kremove_quick(kva); 152 153 /* 154 * release the page and we are done 155 */ 156 vm_page_unhold(m); 157 } while (error == 0 && uio->uio_resid > 0); 158 159 kmem_free(&kernel_map, kva, PAGE_SIZE); 160 161 return (error); 162 } 163 164 /* 165 * Copy data in and out of the target process. 166 * We do this by mapping the process's page into 167 * the kernel and then doing a uiomove direct 168 * from the kernel address space. 169 * 170 * lp->lwp_proc->p_token is held on entry. 171 */ 172 int 173 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 174 struct uio *uio) 175 { 176 struct proc *p = lp->lwp_proc; 177 int error; 178 179 if (uio->uio_resid == 0) 180 return (0); 181 182 if ((p->p_flags & P_INEXEC) != 0) { 183 /* 184 * Can't trace a process that's currently exec'ing. 185 */ 186 error = EAGAIN; 187 } else if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) { 188 /* 189 * Can't trace processes outside our jail 190 */ 191 error = EPERM; 192 } else { 193 error = procfs_rwmem(curp, p, uio); 194 } 195 return(error); 196 } 197 198 /* 199 * Given process (p), find the vnode from which 200 * its text segment is being executed. 201 * 202 * It would be nice to grab this information from 203 * the VM system, however, there is no sure-fire 204 * way of doing that. Instead, fork(), exec() and 205 * wait() all maintain the p_textvp field in the 206 * process proc structure which contains a held 207 * reference to the exec'ed vnode. 208 * 209 * XXX - Currently, this is not not used, as the 210 * /proc/pid/file object exposes an information leak 211 * that shouldn't happen. Using a mount option would 212 * make it configurable on a per-system (or, at least, 213 * per-mount) basis; however, that's not really best. 214 * The best way to do it, I think, would be as an 215 * ioctl; this would restrict it to the uid running 216 * program, or root, which seems a reasonable compromise. 217 * However, the number of applications for this is 218 * minimal, if it can't be seen in the filesytem space, 219 * and doint it as an ioctl makes it somewhat less 220 * useful due to the, well, inelegance. 221 * 222 */ 223 struct vnode * 224 procfs_findtextvp(struct proc *p) 225 { 226 return (p->p_textvp); 227 } 228