kvm_vnet.c revision 204435
1/*- 2 * Copyright (c) 2009 Robert N. M. Watson 3 * Copyright (c) 2009 Bjoern A. Zeeb <bz@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <sys/cdefs.h> 29__FBSDID("$FreeBSD: head/lib/libkvm/kvm_vnet.c 204435 2010-02-27 21:58:55Z rwatson $"); 30 31#include <sys/param.h> 32 33#define _WANT_PRISON 34#define _WANT_UCRED 35#define _WANT_VNET 36 37#include <sys/_lock.h> 38#include <sys/_mutex.h> 39#include <sys/_task.h> 40#include <sys/jail.h> 41#include <sys/proc.h> 42#include <sys/types.h> 43 44#include <net/vnet.h> 45 46#include <nlist.h> 47#include <kvm.h> 48#include <limits.h> 49#include <stdlib.h> 50#include <unistd.h> 51 52#include "kvm_private.h" 53 54/* 55 * Set up libkvm to handle virtual network stack symbols by selecting a 56 * starting pid. 57 */ 58int 59_kvm_vnet_selectpid(kvm_t *kd, pid_t pid) 60{ 61 struct proc proc; 62 struct thread td; 63 struct ucred cred; 64 struct prison prison; 65 struct vnet vnet; 66 struct nlist nl[] = { 67 /* 68 * Note: kvm_nlist strips the first '_' so add an extra one 69 * here to __{start,stop}_set_vnet. 70 */ 71#define NLIST_START_VNET 0 72 { .n_name = "___start_" VNET_SETNAME }, 73#define NLIST_STOP_VNET 1 74 { .n_name = "___stop_" VNET_SETNAME }, 75#define NLIST_VNET_HEAD 2 76 { .n_name = "vnet_head" }, 77#define NLIST_ALLPROC 3 78 { .n_name = "allproc" }, 79#define NLIST_DUMPTID 4 80 { .n_name = "dumptid" }, 81#define NLIST_PROC0 5 82 { .n_name = "proc0" }, 83 { .n_name = NULL }, 84 }; 85 uintptr_t procp, tdp, credp; 86 lwpid_t dumptid; 87 88 /* 89 * Locate and cache locations of important symbols 90 * using the internal version of _kvm_nlist, turning 91 * off initialization to avoid recursion in case of 92 * unresolveable symbols. 93 */ 94 if (_kvm_nlist(kd, nl, 0) != 0) { 95 /* 96 * XXX-BZ: ___start_/___stop_VNET_SETNAME may fail. 97 * For now do not report an error here as we are called 98 * internally and in `void context' until we merge the 99 * functionality to optionally activate this into programs. 100 * By that time we can properly fail and let the callers 101 * handle the error. 102 */ 103 /* _kvm_err(kd, kd->program, "%s: no namelist", __func__); */ 104 return (-1); 105 } 106 107 /* 108 * Auto-detect if this is a crashdump by reading dumptid. 109 */ 110 dumptid = 0; 111 if (nl[NLIST_DUMPTID].n_value) { 112 if (kvm_read(kd, nl[NLIST_DUMPTID].n_value, &dumptid, 113 sizeof(dumptid)) != sizeof(dumptid)) { 114 _kvm_err(kd, kd->program, "%s: dumptid", __func__); 115 return (-1); 116 } 117 } 118 119 /* 120 * First, find the process for this pid. If we are working on a 121 * dump, either locate the thread dumptid is refering to or proc0. 122 * Based on either, take the address of the ucred. 123 */ 124 credp = 0; 125 126 procp = nl[NLIST_ALLPROC].n_value; 127#define VMCORE_VNET_OF_PROC0 128#ifdef VMCORE_VNET_OF_PROC0 129 if (dumptid > 0) { 130 procp = nl[NLIST_PROC0].n_value; 131 pid = 0; 132 } 133#endif 134 while (procp != 0) { 135 if (kvm_read(kd, procp, &proc, sizeof(proc)) != sizeof(proc)) { 136 _kvm_err(kd, kd->program, "%s: proc", __func__); 137 return (-1); 138 } 139#ifndef VMCORE_VNET_OF_PROC0 140 if (dumptid > 0) { 141 tdp = (uintptr_t)TAILQ_FIRST(&proc.p_threads); 142 while (tdp != 0) { 143 if (kvm_read(kd, tdp, &td, sizeof(td)) != 144 sizeof(td)) { 145 _kvm_err(kd, kd->program, "%s: thread", 146 __func__); 147 return (-1); 148 } 149 if (td.td_tid == dumptid) { 150 credp = (uintptr_t)td.td_ucred; 151 break; 152 } 153 tdp = (uintptr_t)TAILQ_NEXT(&td, td_plist); 154 } 155 } else 156#endif 157 if (proc.p_pid == pid) 158 credp = (uintptr_t)proc.p_ucred; 159 if (credp != 0) 160 break; 161 procp = (uintptr_t)LIST_NEXT(&proc, p_list); 162 } 163 if (credp == 0) { 164 _kvm_err(kd, kd->program, "%s: pid/tid not found", __func__); 165 return (-1); 166 } 167 if (kvm_read(kd, (uintptr_t)credp, &cred, sizeof(cred)) != 168 sizeof(cred)) { 169 _kvm_err(kd, kd->program, "%s: cred", __func__); 170 return (-1); 171 } 172 if (cred.cr_prison == NULL) { 173 _kvm_err(kd, kd->program, "%s: no jail", __func__); 174 return (-1); 175 } 176 if (kvm_read(kd, (uintptr_t)cred.cr_prison, &prison, sizeof(prison)) != 177 sizeof(prison)) { 178 _kvm_err(kd, kd->program, "%s: prison", __func__); 179 return (-1); 180 } 181 if (prison.pr_vnet == NULL) { 182 _kvm_err(kd, kd->program, "%s: no vnet", __func__); 183 return (-1); 184 } 185 if (kvm_read(kd, (uintptr_t)prison.pr_vnet, &vnet, sizeof(vnet)) != 186 sizeof(vnet)) { 187 _kvm_err(kd, kd->program, "%s: vnet", __func__); 188 return (-1); 189 } 190 if (vnet.vnet_magic_n != VNET_MAGIC_N) { 191 _kvm_err(kd, kd->program, "%s: invalid vnet magic#", __func__); 192 return (-1); 193 } 194 kd->vnet_initialized = 1; 195 kd->vnet_start = nl[NLIST_START_VNET].n_value; 196 kd->vnet_stop = nl[NLIST_STOP_VNET].n_value; 197 kd->vnet_current = (uintptr_t)prison.pr_vnet; 198 kd->vnet_base = vnet.vnet_data_base; 199 return (0); 200} 201 202/* 203 * Check whether the vnet module has been initialized sucessfully 204 * or not, intialize it if permitted. 205 */ 206int 207_kvm_vnet_initialized(kvm_t *kd, int intialize) 208{ 209 210 if (kd->vnet_initialized || !intialize) 211 return (kd->vnet_initialized); 212 213 (void) _kvm_vnet_selectpid(kd, getpid()); 214 215 return (kd->vnet_initialized); 216} 217 218/* 219 * Check whether the value is within the vnet symbol range and 220 * only if so adjust the offset relative to the current base. 221 */ 222uintptr_t 223_kvm_vnet_validaddr(kvm_t *kd, uintptr_t value) 224{ 225 226 if (value == 0) 227 return (value); 228 229 if (!kd->vnet_initialized) 230 return (value); 231 232 if (value < kd->vnet_start || value >= kd->vnet_stop) 233 return (value); 234 235 return (kd->vnet_base + value); 236} 237