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/uio.h> 47 #include <sys/proc.h> 48 #include <sys/caps.h> 49 #include <sys/vnode.h> 50 #include <vfs/procfs/procfs.h> 51 #include <vm/vm.h> 52 #include <vm/vm_param.h> 53 #include <sys/lock.h> 54 #include <vm/pmap.h> 55 #include <vm/vm_extern.h> 56 #include <vm/vm_map.h> 57 #include <vm/vm_kern.h> 58 #include <vm/vm_object.h> 59 #include <vm/vm_page.h> 60 #include <sys/ptrace.h> 61 62 static int procfs_rwmem (struct proc *curp, 63 struct proc *p, struct uio *uio); 64 65 /* 66 * p->p_token is held on entry. 67 */ 68 static int 69 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) 70 { 71 int error; 72 int writing; 73 struct vmspace *vm; 74 vm_map_t map; 75 vm_offset_t pageno = 0; /* page number */ 76 vm_prot_t reqprot; 77 vm_offset_t kva; 78 79 /* 80 * if the vmspace is in the midst of being allocated or deallocated, 81 * or the process is exiting, don't try to grab anything. The 82 * page table usage in that process may be messed up. 83 */ 84 vm = p->p_vmspace; 85 if (p->p_stat == SIDL || p->p_stat == SZOMB) 86 return EFAULT; 87 if ((p->p_flags & (P_WEXIT | P_INEXEC)) || vmspace_getrefs(vm) < 0) 88 return EFAULT; 89 90 /* 91 * The map we want... 92 */ 93 vmspace_hold(vm); 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, VM_SUBSYS_PROC); 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 vm_offset_t page_offset; /* offset into page */ 110 size_t len; 111 vm_page_t m; 112 int busy; 113 114 uva = (vm_offset_t) uio->uio_offset; 115 116 /* 117 * Get the page number of this segment. 118 */ 119 pageno = trunc_page(uva); 120 page_offset = uva - pageno; 121 122 /* 123 * How many bytes to copy 124 */ 125 len = szmin(PAGE_SIZE - page_offset, uio->uio_resid); 126 127 /* 128 * Fault the page on behalf of the process 129 * 130 * XXX busied page on write fault can deadlock against our 131 * uiomove. 132 */ 133 m = vm_fault_page(map, pageno, reqprot, 134 VM_FAULT_NORMAL, 135 &error, &busy); 136 if (error) { 137 KKASSERT(m == NULL); 138 error = EFAULT; 139 break; 140 } 141 142 /* 143 * Cleanup pmap then create a temporary KVA mapping and 144 * do the I/O. We can switch between cpus so don't bother 145 * synchronizing across all cores. 146 */ 147 pmap_kenter_quick(kva, VM_PAGE_TO_PHYS(m)); 148 error = uiomove((caddr_t)(kva + page_offset), len, uio); 149 pmap_kremove_quick(kva); 150 151 /* 152 * Release the page and we are done 153 */ 154 if (busy) 155 vm_page_wakeup(m); 156 else 157 vm_page_unhold(m); 158 } while (error == 0 && uio->uio_resid > 0); 159 160 vmspace_drop(vm); 161 kmem_free(kernel_map, kva, PAGE_SIZE); 162 163 return (error); 164 } 165 166 /* 167 * Copy data in and out of the target process. 168 * We do this by mapping the process's page into 169 * the kernel and then doing a uiomove direct 170 * from the kernel address space. 171 * 172 * lp->lwp_proc->p_token is held on entry. 173 */ 174 int 175 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 176 struct uio *uio) 177 { 178 struct proc *p = lp->lwp_proc; 179 int error; 180 181 if (uio->uio_resid == 0) 182 return (0); 183 184 if ((p->p_flags & P_INEXEC) != 0) { 185 /* 186 * Can't trace a process that's currently exec'ing. 187 */ 188 error = EAGAIN; 189 } else if (!CHECKIO(curp, p) || 190 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