dmesg.c revision 1.32
1 /* $NetBSD: dmesg.c,v 1.32 2018/04/11 06:41:23 wiz Exp $ */ 2 /*- 3 * Copyright (c) 1991, 1993 4 * The Regents of the University of California. 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 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 #ifndef lint 33 __COPYRIGHT("@(#) Copyright (c) 1991, 1993\ 34 The Regents of the University of California. All rights reserved."); 35 #endif /* not lint */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93"; 40 #else 41 __RCSID("$NetBSD: dmesg.c,v 1.32 2018/04/11 06:41:23 wiz Exp $"); 42 #endif 43 #endif /* not lint */ 44 45 #include <sys/param.h> 46 #include <sys/msgbuf.h> 47 #include <sys/sysctl.h> 48 49 #include <err.h> 50 #include <fcntl.h> 51 #include <time.h> 52 #include <kvm.h> 53 #include <nlist.h> 54 #include <stdio.h> 55 #include <stddef.h> 56 #include <stdlib.h> 57 #include <unistd.h> 58 #include <vis.h> 59 60 #ifndef SMALL 61 static struct nlist nl[] = { 62 #define X_MSGBUF 0 63 { .n_name = "_msgbufp" }, 64 { .n_name = NULL }, 65 }; 66 67 __dead static void usage(void); 68 69 #define KREAD(addr, var) \ 70 kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) 71 #endif 72 73 int 74 main(int argc, char *argv[]) 75 { 76 struct kern_msgbuf cur; 77 int ch, newl, log, i; 78 size_t tstamp, size; 79 char *p, *bufdata; 80 char buf[5]; 81 #ifndef SMALL 82 char tbuf[64]; 83 char *memf, *nlistf; 84 struct timeval boottime; 85 struct timespec lasttime; 86 intmax_t sec; 87 long nsec; 88 int deltas, quiet, humantime; 89 90 static const int bmib[] = { CTL_KERN, KERN_BOOTTIME }; 91 size = sizeof(boottime); 92 93 boottime.tv_sec = 0; 94 boottime.tv_usec = 0; 95 lasttime.tv_sec = 0; 96 lasttime.tv_nsec = 0; 97 deltas = quiet = humantime = 0; 98 99 (void)sysctl(bmib, 2, &boottime, &size, NULL, 0); 100 101 memf = nlistf = NULL; 102 while ((ch = getopt(argc, argv, "dM:N:tT")) != -1) 103 switch(ch) { 104 case 'd': 105 deltas = 1; 106 break; 107 case 'M': 108 memf = optarg; 109 break; 110 case 'N': 111 nlistf = optarg; 112 break; 113 case 't': 114 quiet = 1; 115 break; 116 case 'T': 117 humantime = 1; 118 break; 119 case '?': 120 default: 121 usage(); 122 } 123 argc -= optind; 124 argv += optind; 125 if (quiet && humantime) 126 err(EXIT_FAILURE, "-t cannot be used with -T"); 127 128 if (memf == NULL) { 129 #endif 130 static const int mmib[2] = { CTL_KERN, KERN_MSGBUF }; 131 132 if (sysctl(mmib, 2, NULL, &size, NULL, 0) == -1 || 133 (bufdata = malloc(size)) == NULL || 134 sysctl(mmib, 2, bufdata, &size, NULL, 0) == -1) 135 err(1, "can't get msgbuf"); 136 137 /* make a dummy struct msgbuf for the display logic */ 138 cur.msg_bufx = 0; 139 cur.msg_bufs = size; 140 #ifndef SMALL 141 } else { 142 kvm_t *kd; 143 struct kern_msgbuf *bufp; 144 145 /* 146 * Read in message buffer header and data, and do sanity 147 * checks. 148 */ 149 kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); 150 if (kd == NULL) 151 exit (1); 152 if (kvm_nlist(kd, nl) == -1) 153 errx(1, "kvm_nlist: %s", kvm_geterr(kd)); 154 if (nl[X_MSGBUF].n_type == 0) 155 errx(1, "%s: msgbufp not found", nlistf ? nlistf : 156 "namelist"); 157 if (KREAD(nl[X_MSGBUF].n_value, bufp)) 158 errx(1, "kvm_read: %s (0x%lx)", kvm_geterr(kd), 159 nl[X_MSGBUF].n_value); 160 if (kvm_read(kd, (long)bufp, &cur, 161 offsetof(struct kern_msgbuf, msg_bufc)) != 162 offsetof(struct kern_msgbuf, msg_bufc)) 163 errx(1, "kvm_read: %s (0x%lx)", kvm_geterr(kd), 164 (unsigned long)bufp); 165 if (cur.msg_magic != MSG_MAGIC) 166 errx(1, "magic number incorrect"); 167 bufdata = malloc(cur.msg_bufs); 168 if (bufdata == NULL) 169 errx(1, "couldn't allocate space for buffer data"); 170 if (kvm_read(kd, (long)&bufp->msg_bufc, bufdata, 171 cur.msg_bufs) != cur.msg_bufs) 172 errx(1, "kvm_read: %s", kvm_geterr(kd)); 173 kvm_close(kd); 174 if (cur.msg_bufx >= cur.msg_bufs) 175 cur.msg_bufx = 0; 176 } 177 #endif 178 179 /* 180 * The message buffer is circular; start at the write pointer 181 * (which points the oldest character), and go to the write 182 * pointer - 1 (which points the newest character). I.e, loop 183 * over cur.msg_bufs times. Unused area is skipped since it 184 * contains nul. 185 */ 186 for (tstamp = 0, newl = 1, log = i = 0, p = bufdata + cur.msg_bufx; 187 i < cur.msg_bufs; i++, p++) { 188 #ifndef SMALL 189 if (p == bufdata + cur.msg_bufs) 190 p = bufdata; 191 #define ADDC(c) \ 192 do \ 193 if (tstamp < sizeof(tbuf) - 1) \ 194 tbuf[tstamp++] = (c); \ 195 while (/*CONSTCOND*/0) 196 #else 197 #define ADDC(c) 198 #endif 199 ch = *p; 200 if (ch == '\0') 201 continue; 202 /* Skip "\n<.*>" syslog sequences. */ 203 /* Gather timestamp sequences */ 204 if (newl) { 205 switch (ch) { 206 case '[': 207 ADDC(ch); 208 continue; 209 case '<': 210 log = 1; 211 continue; 212 case '>': 213 log = 0; 214 continue; 215 case ']': 216 ADDC(ch); 217 ADDC('\0'); 218 tstamp = 0; 219 #ifndef SMALL 220 sscanf(tbuf, "[%jd.%ld]", &sec, &nsec); 221 if (!quiet || deltas) 222 printf("["); 223 if (humantime) { 224 time_t t; 225 struct tm tm; 226 t = boottime.tv_sec + sec; 227 if (localtime_r(&t, &tm) != NULL) { 228 strftime(tbuf, sizeof(tbuf), 229 "%a %b %e %H:%M:%S %Z %Y", 230 &tm); 231 printf("%s", tbuf); 232 } 233 } else if (!quiet) { 234 printf("% 9jd.%06ld", 235 sec, nsec / 1000); 236 } 237 if (deltas) { 238 struct timespec nt = { sec, nsec }; 239 struct timespec dt; 240 timespecsub(&nt, &lasttime, &dt); 241 if (humantime || !quiet) 242 printf(" "); 243 printf("<% 4jd.%06ld>", (intmax_t) 244 dt.tv_sec, dt.tv_nsec / 1000); 245 lasttime = nt; 246 } 247 if (!quiet || deltas) 248 printf("] "); 249 #endif 250 continue; 251 case ' ': 252 if (!tstamp) 253 continue; 254 /*FALLTHROUGH*/ 255 default: 256 if (tstamp) { 257 ADDC(ch); 258 continue; 259 } 260 if (log) 261 continue; 262 break; 263 } 264 newl = 0; 265 } 266 newl = ch == '\n'; 267 (void)vis(buf, ch, VIS_NOSLASH, 0); 268 #ifndef SMALL 269 if (buf[1] == 0) 270 (void)putchar(buf[0]); 271 else 272 #endif 273 (void)printf("%s", buf); 274 } 275 if (!newl) 276 (void)putchar('\n'); 277 return EXIT_SUCCESS; 278 } 279 280 #ifndef SMALL 281 static void 282 usage(void) 283 { 284 285 (void)fprintf(stderr, "Usage: %s [-dTt] [-M core] [-N system]\n", 286 getprogname()); 287 exit(EXIT_FAILURE); 288 } 289 #endif 290
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