| 1 | /*- |
| 2 | * Copyright (c) 1991, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. Neither the name of the University nor the names of its contributors |
| 14 | * may be used to endorse or promote products derived from this software |
| 15 | * without specific prior written permission. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 27 | * SUCH DAMAGE. |
| 28 | * |
| 29 | * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved. |
| 30 | * @(#)dmesg.c 8.1 (Berkeley) 6/5/93 |
| 31 | * $FreeBSD: src/sbin/dmesg/dmesg.c,v 1.11.2.3 2001/08/08 22:32:15 obrien Exp $ |
| 32 | */ |
| 33 | |
| 34 | #include <sys/types.h> |
| 35 | #include <sys/msgbuf.h> |
| 36 | #include <sys/sysctl.h> |
| 37 | |
| 38 | #include <err.h> |
| 39 | #include <fcntl.h> |
| 40 | #include <kvm.h> |
| 41 | #include <locale.h> |
| 42 | #include <stdio.h> |
| 43 | #include <stdlib.h> |
| 44 | #include <unistd.h> |
| 45 | #include <vis.h> |
| 46 | #include <sys/syslog.h> |
| 47 | |
| 48 | struct nlist nl[] = { |
| 49 | #define X_MSGBUF 0 |
| 50 | { "_msgbufp", 0, 0, 0, 0 }, |
| 51 | { NULL, 0, 0, 0, 0 }, |
| 52 | }; |
| 53 | |
| 54 | static void dumpbuf(char *bp, size_t bufpos, size_t buflen, |
| 55 | int *newl, int *skip, int *pri); |
| 56 | void usage(void); |
| 57 | |
| 58 | #define KREAD(addr, var) \ |
| 59 | kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) |
| 60 | |
| 61 | #define INCRBUFSIZE 65536 |
| 62 | |
| 63 | int all_opt; |
| 64 | |
| 65 | int |
| 66 | main(int argc, char **argv) |
| 67 | { |
| 68 | int newl, skip; |
| 69 | struct msgbuf *bufp, cur; |
| 70 | char *bp, *memf, *nlistf; |
| 71 | kvm_t *kd; |
| 72 | int ch; |
| 73 | int clear = 0; |
| 74 | int pri = 0; |
| 75 | int tailmode = 0; |
| 76 | int kno; |
| 77 | size_t buflen, bufpos; |
| 78 | |
| 79 | setlocale(LC_CTYPE, ""); |
| 80 | memf = nlistf = NULL; |
| 81 | while ((ch = getopt(argc, argv, "acfM:N:n:")) != -1) { |
| 82 | switch(ch) { |
| 83 | case 'a': |
| 84 | all_opt++; |
| 85 | break; |
| 86 | case 'c': |
| 87 | clear = 1; |
| 88 | break; |
| 89 | case 'f': |
| 90 | ++tailmode; |
| 91 | break; |
| 92 | case 'M': |
| 93 | memf = optarg; |
| 94 | break; |
| 95 | case 'N': |
| 96 | nlistf = optarg; |
| 97 | break; |
| 98 | case 'n': |
| 99 | kno = strtol(optarg, NULL, 0); |
| 100 | asprintf(&memf, "/var/crash/vmcore.%d", kno); |
| 101 | asprintf(&nlistf, "/var/crash/kern.%d", kno); |
| 102 | break; |
| 103 | case '?': |
| 104 | default: |
| 105 | usage(); |
| 106 | } |
| 107 | } |
| 108 | argc -= optind; |
| 109 | argv += optind; |
| 110 | |
| 111 | newl = 0; |
| 112 | skip = 0; |
| 113 | pri = 0; |
| 114 | |
| 115 | if (memf == NULL && nlistf == NULL && tailmode == 0) { |
| 116 | /* Running kernel. Use sysctl. */ |
| 117 | buflen = 0; |
| 118 | if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1) |
| 119 | err(1, "sysctl kern.msgbuf"); |
| 120 | if ((bp = malloc(buflen)) == NULL) |
| 121 | errx(1, "malloc failed"); |
| 122 | if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1) |
| 123 | err(1, "sysctl kern.msgbuf"); |
| 124 | /* We get a dewrapped buffer using sysctl. */ |
| 125 | bufpos = 0; |
| 126 | dumpbuf(bp, bufpos, buflen, &newl, &skip, &pri); |
| 127 | } else { |
| 128 | u_int rindex; |
| 129 | u_int xindex; |
| 130 | u_int ri; |
| 131 | u_int xi; |
| 132 | u_int n; |
| 133 | |
| 134 | /* Read in kernel message buffer, do sanity checks. */ |
| 135 | kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); |
| 136 | if (kd == NULL) |
| 137 | exit (1); |
| 138 | if (kvm_nlist(kd, nl) == -1) |
| 139 | errx(1, "kvm_nlist: %s", kvm_geterr(kd)); |
| 140 | if (nl[X_MSGBUF].n_type == 0) |
| 141 | errx(1, "%s: msgbufp not found", |
| 142 | nlistf ? nlistf : "namelist"); |
| 143 | bp = malloc(INCRBUFSIZE); |
| 144 | if (!bp) |
| 145 | errx(1, "malloc failed"); |
| 146 | if (KREAD(nl[X_MSGBUF].n_value, bufp)) |
| 147 | errx(1, "kvm_read: %s", kvm_geterr(kd)); |
| 148 | if (KREAD((long)bufp, cur)) |
| 149 | errx(1, "kvm_read: %s", kvm_geterr(kd)); |
| 150 | if (cur.msg_magic != MSG_MAGIC && cur.msg_magic != MSG_OMAGIC) |
| 151 | errx(1, "kernel message buffer has different magic " |
| 152 | "number"); |
| 153 | |
| 154 | /* |
| 155 | * NOTE: current algorithm is compatible with both old and |
| 156 | * new msgbuf structures. The new structure doesn't |
| 157 | * modulo the indexes (so we do), and adds a separate |
| 158 | * log index which we don't access here. |
| 159 | */ |
| 160 | |
| 161 | rindex = cur.msg_bufr; |
| 162 | |
| 163 | for (;;) { |
| 164 | /* |
| 165 | * Calculate index for dump and do sanity clipping. |
| 166 | */ |
| 167 | xindex = cur.msg_bufx; |
| 168 | n = xindex - rindex; |
| 169 | if (n > cur.msg_size - 1024) { |
| 170 | rindex = xindex - cur.msg_size + 2048; |
| 171 | n = xindex - rindex; |
| 172 | } |
| 173 | ri = rindex % cur.msg_size; |
| 174 | xi = xindex % cur.msg_size; |
| 175 | |
| 176 | if (ri < xi) |
| 177 | buflen = xi - ri; |
| 178 | else |
| 179 | buflen = cur.msg_size - ri; |
| 180 | if (buflen > n) |
| 181 | buflen = n; |
| 182 | if (buflen > INCRBUFSIZE) |
| 183 | buflen = INCRBUFSIZE; |
| 184 | |
| 185 | if (kvm_read(kd, (long)cur.msg_ptr + ri, |
| 186 | bp, buflen) != (ssize_t)buflen) { |
| 187 | errx(1, "kvm_read: %s", kvm_geterr(kd)); |
| 188 | } |
| 189 | if (buflen) |
| 190 | dumpbuf(bp, 0, buflen, &newl, &skip, &pri); |
| 191 | ri = (ri + buflen) % cur.msg_size; |
| 192 | n = n - buflen; |
| 193 | rindex += buflen; |
| 194 | if ((int)n <= 0) { |
| 195 | if (tailmode == 0) |
| 196 | break; |
| 197 | fflush(stdout); |
| 198 | if (tailmode == 1) |
| 199 | sleep(1); |
| 200 | } |
| 201 | if (KREAD((long)bufp, cur)) |
| 202 | errx(1, "kvm_read: %s", kvm_geterr(kd)); |
| 203 | } |
| 204 | kvm_close(kd); |
| 205 | } |
| 206 | if (!newl) |
| 207 | putchar('\n'); |
| 208 | if (clear) { |
| 209 | if (sysctlbyname("kern.msgbuf_clear", NULL, NULL, |
| 210 | &clear, sizeof(int)) != 0) { |
| 211 | err(1, "sysctl kern.msgbuf_clear"); |
| 212 | } |
| 213 | } |
| 214 | return(0); |
| 215 | } |
| 216 | |
| 217 | static |
| 218 | void |
| 219 | dumpbuf(char *bp, size_t bufpos, size_t buflen, |
| 220 | int *newl, int *skip, int *pri) |
| 221 | { |
| 222 | int ch; |
| 223 | char *p, *ep; |
| 224 | char buf[5]; |
| 225 | |
| 226 | /* |
| 227 | * The message buffer is circular. If the buffer has wrapped, the |
| 228 | * write pointer points to the oldest data. Otherwise, the write |
| 229 | * pointer points to \0's following the data. Read the entire |
| 230 | * buffer starting at the write pointer and ignore nulls so that |
| 231 | * we effectively start at the oldest data. |
| 232 | */ |
| 233 | p = bp + bufpos; |
| 234 | ep = (bufpos == 0 ? bp + buflen : p); |
| 235 | do { |
| 236 | if (p == bp + buflen) |
| 237 | p = bp; |
| 238 | ch = *p; |
| 239 | /* Skip "\n<.*>" syslog sequences. */ |
| 240 | if (*skip) { |
| 241 | if (ch == '\n') { |
| 242 | *skip = 0; |
| 243 | *newl = 1; |
| 244 | } if (ch == '>') { |
| 245 | if (LOG_FAC(*pri) == LOG_KERN) |
| 246 | *newl = *skip = 0; |
| 247 | } else if (ch >= '0' && ch <= '9') { |
| 248 | *pri *= 10; |
| 249 | *pri += ch - '0'; |
| 250 | } |
| 251 | continue; |
| 252 | } |
| 253 | if (*newl && ch == '<' && all_opt == 0) { |
| 254 | *pri = 0; |
| 255 | *skip = 1; |
| 256 | continue; |
| 257 | } |
| 258 | if (ch == '\0') |
| 259 | continue; |
| 260 | *newl = (ch == '\n'); |
| 261 | vis(buf, ch, 0, 0); |
| 262 | if (buf[1] == 0) |
| 263 | putchar(buf[0]); |
| 264 | else |
| 265 | printf("%s", buf); |
| 266 | } while (++p != ep); |
| 267 | } |
| 268 | |
| 269 | void |
| 270 | usage(void) |
| 271 | { |
| 272 | fprintf(stderr, "usage: dmesg [-ac] [-M core] [-N system]\n"); |
| 273 | exit(1); |
| 274 | } |