1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2008 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #include <sys/types.h> 31 #include <sys/sysctl.h> 32 33 #include <err.h> 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <kvm.h> 37 #include <limits.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <sysexits.h> 42 #include <unistd.h> 43 44 #include "ddb.h" 45 46 /* 47 * Interface with the ddb(4) capture buffer of a live kernel using sysctl, or 48 * for a crash dump using libkvm. 49 */ 50 #define SYSCTL_DDB_CAPTURE_BUFOFF "debug.ddb.capture.bufoff" 51 #define SYSCTL_DDB_CAPTURE_BUFSIZE "debug.ddb.capture.bufsize" 52 #define SYSCTL_DDB_CAPTURE_MAXBUFSIZE "debug.ddb.capture.maxbufsize" 53 #define SYSCTL_DDB_CAPTURE_DATA "debug.ddb.capture.data" 54 #define SYSCTL_DDB_CAPTURE_INPROGRESS "debug.ddb.capture.inprogress" 55 56 static struct nlist namelist[] = { 57 #define X_DB_CAPTURE_BUF 0 58 { .n_name = "_db_capture_buf" }, 59 #define X_DB_CAPTURE_BUFSIZE 1 60 { .n_name = "_db_capture_bufsize" }, 61 #define X_DB_CAPTURE_MAXBUFSIZE 2 62 { .n_name = "_db_capture_maxbufsize" }, 63 #define X_DB_CAPTURE_BUFOFF 3 64 { .n_name = "_db_capture_bufoff" }, 65 #define X_DB_CAPTURE_INPROGRESS 4 66 { .n_name = "_db_capture_inprogress" }, 67 { .n_name = "" }, 68 }; 69 70 static int 71 kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size, 72 size_t offset) 73 { 74 ssize_t ret; 75 76 ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address, 77 size); 78 if (ret < 0 || (size_t)ret != size) 79 return (-1); 80 return (0); 81 } 82 83 static int 84 kread_symbol(kvm_t *kvm, int read_index, void *address, size_t size, 85 size_t offset) 86 { 87 ssize_t ret; 88 89 ret = kvm_read(kvm, namelist[read_index].n_value + offset, address, size); 90 if (ret < 0 || (size_t)ret != size) 91 return (-1); 92 return (0); 93 } 94 95 static void 96 ddb_capture_print_kvm(kvm_t *kvm) 97 { 98 u_int db_capture_bufoff; 99 char *buffer, *db_capture_buf; 100 101 if (kread_symbol(kvm, X_DB_CAPTURE_BUF, &db_capture_buf, 102 sizeof(db_capture_buf), 0) < 0) 103 errx(-1, "kvm: unable to read db_capture_buf"); 104 105 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff, 106 sizeof(db_capture_bufoff), 0) < 0) 107 errx(-1, "kvm: unable to read db_capture_bufoff"); 108 109 buffer = malloc(db_capture_bufoff + 1); 110 if (buffer == NULL) 111 err(-1, "malloc: db_capture_bufoff (%u)", 112 db_capture_bufoff); 113 bzero(buffer, db_capture_bufoff + 1); 114 115 if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0) 116 errx(-1, "kvm: unable to read buffer"); 117 118 printf("%s\n", buffer); 119 free(buffer); 120 } 121 122 static void 123 ddb_capture_print_sysctl(void) 124 { 125 size_t buflen, len; 126 char *buffer; 127 int ret; 128 129 repeat: 130 if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0) 131 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA); 132 if (buflen == 0) 133 return; 134 buffer = malloc(buflen); 135 if (buffer == NULL) 136 err(EX_OSERR, "malloc"); 137 bzero(buffer, buflen); 138 len = buflen; 139 ret = sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, buffer, &len, NULL, 0); 140 if (ret < 0 && errno != ENOMEM) 141 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA); 142 if (ret < 0) { 143 free(buffer); 144 goto repeat; 145 } 146 147 printf("%s\n", buffer); 148 free(buffer); 149 } 150 151 static void 152 ddb_capture_status_kvm(kvm_t *kvm) 153 { 154 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress; 155 156 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff, 157 sizeof(db_capture_bufoff), 0) < 0) 158 errx(-1, "kvm: unable to read db_capture_bufoff"); 159 if (kread_symbol(kvm, X_DB_CAPTURE_BUFSIZE, &db_capture_bufsize, 160 sizeof(db_capture_bufsize), 0) < 0) 161 errx(-1, "kvm: unable to read db_capture_bufsize"); 162 if (kread_symbol(kvm, X_DB_CAPTURE_INPROGRESS, 163 &db_capture_inprogress, sizeof(db_capture_inprogress), 0) < 0) 164 err(-1, "kvm: unable to read db_capture_inprogress"); 165 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize); 166 if (db_capture_inprogress) 167 printf("capture is on\n"); 168 else 169 printf("capture is off\n"); 170 171 } 172 173 static void 174 ddb_capture_status_sysctl(void) 175 { 176 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress; 177 size_t len; 178 179 len = sizeof(db_capture_bufoff); 180 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len, 181 NULL, 0) < 0) 182 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFOFF); 183 len = sizeof(db_capture_bufoff); 184 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFSIZE, &db_capture_bufsize, 185 &len, NULL, 0) < 0) 186 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFSIZE); 187 len = sizeof(db_capture_inprogress); 188 if (sysctlbyname(SYSCTL_DDB_CAPTURE_INPROGRESS, 189 &db_capture_inprogress, &len, NULL, 0) < 0) 190 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_INPROGRESS); 191 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize); 192 if (db_capture_inprogress) 193 printf("capture is on\n"); 194 else 195 printf("capture is off\n"); 196 } 197 198 void 199 ddb_capture(int argc, char *argv[]) 200 { 201 char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX]; 202 kvm_t *kvm; 203 int ch; 204 205 mflag = NULL; 206 nflag = NULL; 207 kvm = NULL; 208 while ((ch = getopt(argc, argv, "M:N:")) != -1) { 209 switch (ch) { 210 case 'M': 211 mflag = optarg; 212 break; 213 214 case 'N': 215 nflag = optarg; 216 break; 217 218 default: 219 usage(); 220 } 221 } 222 argc -= optind; 223 argv += optind; 224 225 if (argc != 1) 226 usage(); 227 228 if (mflag != NULL) { 229 kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf); 230 if (kvm == NULL) 231 errx(-1, "ddb_capture: kvm_openfiles: %s", errbuf); 232 if (kvm_nlist(kvm, namelist) != 0) 233 errx(-1, "ddb_capture: kvm_nlist"); 234 } else if (nflag != NULL) 235 usage(); 236 if (strcmp(argv[0], "print") == 0) { 237 if (kvm != NULL) 238 ddb_capture_print_kvm(kvm); 239 else 240 ddb_capture_print_sysctl(); 241 } else if (strcmp(argv[0], "status") == 0) { 242 if (kvm != NULL) 243 ddb_capture_status_kvm(kvm); 244 else 245 ddb_capture_status_sysctl(); 246 } else 247 usage(); 248 } 249