dmesg.c revision 156076
1100384Speter/*- 2100384Speter * Copyright (c) 1991, 1993 3114987Speter * The Regents of the University of California. All rights reserved. 4100384Speter * 5100384Speter * Redistribution and use in source and binary forms, with or without 6100384Speter * modification, are permitted provided that the following conditions 7100384Speter * are met: 8100384Speter * 1. Redistributions of source code must retain the above copyright 9100384Speter * notice, this list of conditions and the following disclaimer. 10100384Speter * 2. Redistributions in binary form must reproduce the above copyright 11100384Speter * notice, this list of conditions and the following disclaimer in the 12100384Speter * documentation and/or other materials provided with the distribution. 13100384Speter * 4. Neither the name of the University nor the names of its contributors 14100384Speter * may be used to endorse or promote products derived from this software 15100384Speter * without specific prior written permission. 16100384Speter * 17100384Speter * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18100384Speter * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19100384Speter * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20100384Speter * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21100384Speter * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22100384Speter * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23100384Speter * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24100384Speter * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25100384Speter * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26100384Speter * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27100384Speter * SUCH DAMAGE. 28118031Sobrien */ 29118031Sobrien 30118031Sobrien#if 0 31114987Speter#ifndef lint 32114987Speterstatic const char copyright[] = 33100384Speter"@(#) Copyright (c) 1991, 1993\n\ 34100384Speter The Regents of the University of California. All rights reserved.\n"; 35100384Speter#endif /* not lint */ 36100384Speter 37100384Speter#ifndef lint 38100384Speterstatic const char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93"; 39100384Speter#endif /* not lint */ 40100384Speter#endif 41100384Speter#include <sys/cdefs.h> 42100384Speter__FBSDID("$FreeBSD: head/sbin/dmesg/dmesg.c 156076 2006-02-27 19:13:47Z dwmalone $"); 43100384Speter 44100384Speter#include <sys/types.h> 45100384Speter#include <sys/msgbuf.h> 46100384Speter#include <sys/sysctl.h> 47100384Speter 48100384Speter#include <ctype.h> 49100384Speter#include <err.h> 50100384Speter#include <errno.h> 51100384Speter#include <fcntl.h> 52100384Speter#include <kvm.h> 53100384Speter#include <limits.h> 54100384Speter#include <locale.h> 55100384Speter#include <nlist.h> 56100384Speter#include <stdio.h> 57100384Speter#include <stdlib.h> 58100384Speter#include <string.h> 59100384Speter#include <unistd.h> 60100384Speter#include <vis.h> 61100384Speter#include <sys/syslog.h> 62100384Speter 63100384Speterchar s_msgbufp[] = "_msgbufp"; 64100384Speter 65100384Speterstruct nlist nl[] = { 66100384Speter#define X_MSGBUF 0 67119336Speter { s_msgbufp, 0, 0, 0, 0 }, 68119336Speter { NULL, 0, 0, 0, 0 }, 69123422Speter}; 70119336Speter 71123423Spetervoid usage(void) __dead2; 72114987Speter 73114987Speter#define KREAD(addr, var) \ 74114987Speter kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) 75123423Speter 76123423Speterint 77123423Spetermain(int argc, char *argv[]) 78123423Speter{ 79123423Speter struct msgbuf *bufp, cur; 80100384Speter char *bp, *ep, *memf, *nextp, *nlistf, *p, *q, *visbp; 81100384Speter kvm_t *kd; 82114987Speter size_t buflen, bufpos; 83114987Speter long pri; 84100384Speter int all, ch; 85121720Speter 86121720Speter all = 0; 87121720Speter (void) setlocale(LC_CTYPE, ""); 88121720Speter memf = nlistf = NULL; 89121720Speter while ((ch = getopt(argc, argv, "aM:N:")) != -1) 90121720Speter switch(ch) { 91121720Speter case 'a': 92121720Speter all++; 93121720Speter break; 94121720Speter case 'M': 95100384Speter memf = optarg; 96120422Speter break; 97100384Speter case 'N': 98119334Speter nlistf = optarg; 99100384Speter break; 100120422Speter case '?': 101120422Speter default: 102100384Speter usage(); 103123422Speter } 104119334Speter argc -= optind; 105100384Speter if (argc != 0) 106100384Speter usage(); 107102808Sjake 108100384Speter if (memf == NULL) { 109102808Sjake /* 110102808Sjake * Running kernel. Use sysctl. This gives an unwrapped 111100384Speter * buffer as a side effect. 112114987Speter */ 113100384Speter if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1) 114114987Speter err(1, "sysctl kern.msgbuf"); 115102808Sjake if ((bp = malloc(buflen + 2)) == NULL) 116114987Speter errx(1, "malloc failed"); 117100384Speter if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1) 118100384Speter err(1, "sysctl kern.msgbuf"); 119100384Speter } else { 120123423Speter /* Read in kernel message buffer and do sanity checks. */ 121102808Sjake kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); 122119336Speter if (kd == NULL) 123119336Speter exit (1); 124119336Speter if (kvm_nlist(kd, nl) == -1) 125102808Sjake errx(1, "kvm_nlist: %s", kvm_geterr(kd)); 126100384Speter if (nl[X_MSGBUF].n_type == 0) 127120422Speter errx(1, "%s: msgbufp not found", 128120422Speter nlistf ? nlistf : "namelist"); 129100384Speter if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) 130100384Speter errx(1, "kvm_read: %s", kvm_geterr(kd)); 131114987Speter if (cur.msg_magic != MSG_MAGIC) 132100384Speter errx(1, "kernel message buffer has different magic " 133100384Speter "number"); 134100384Speter if ((bp = malloc(cur.msg_size + 2)) == NULL) 135100384Speter errx(1, "malloc failed"); 136123742Speter 137123742Speter /* Unwrap the circular buffer to start from the oldest data. */ 138123742Speter bufpos = MSGBUF_SEQ_TO_POS(&cur, cur.msg_wseq); 139127251Speter if (kvm_read(kd, (long)&cur.msg_ptr[bufpos], bp, 140100384Speter cur.msg_size - bufpos) != (ssize_t)(cur.msg_size - bufpos)) 141100384Speter errx(1, "kvm_read: %s", kvm_geterr(kd)); 142100384Speter if (bufpos != 0 && kvm_read(kd, (long)cur.msg_ptr, 143100384Speter &bp[cur.msg_size - bufpos], bufpos) != (ssize_t)bufpos) 144100384Speter errx(1, "kvm_read: %s", kvm_geterr(kd)); 145100384Speter kvm_close(kd); 146123742Speter buflen = cur.msg_size; 147123742Speter } 148123742Speter 149123742Speter /* 150123742Speter * Ensure that the buffer ends with a newline and a \0 to avoid 151123742Speter * complications below. We left space above. 152123742Speter */ 153132263Sobrien if (buflen == 0 || bp[buflen - 1] != '\n') 154123742Speter bp[buflen++] = '\n'; 155123742Speter bp[buflen] = '\0'; 156123742Speter 157123742Speter if ((visbp = malloc(4 * buflen + 1)) == NULL) 158123742Speter errx(1, "malloc failed"); 159123742Speter 160133464Smarcel /* 161133464Smarcel * The message buffer is circular, but has been unwrapped so that 162133464Smarcel * the oldest data comes first. The data will be preceded by \0's 163133464Smarcel * if the message buffer was not full. 164133464Smarcel */ 165133464Smarcel p = bp; 166133464Smarcel ep = &bp[buflen]; 167133464Smarcel if (*p == '\0') { 168119334Speter /* Strip leading \0's */ 169100384Speter while (*p == '\0') 170100384Speter p++; 171100384Speter } else if (!all) { 172100384Speter /* Skip the first line, since it is probably incomplete. */ 173100384Speter p = memchr(p, '\n', ep - p); 174100384Speter p++; 175100384Speter } 176119336Speter for (; p < ep; p = nextp) { 177100384Speter nextp = memchr(p, '\n', ep - p); 178100384Speter nextp++; 179100384Speter 180100384Speter /* Skip ^<[0-9]+> syslog sequences. */ 181100384Speter if (*p == '<' && isdigit(*(p+1))) { 182100384Speter errno = 0; 183119336Speter pri = strtol(p + 1, &q, 10); 184100384Speter if (*q == '>' && pri >= 0 && pri < INT_MAX && 185100384Speter errno == 0) { 186100384Speter if (LOG_FAC(pri) != LOG_KERN && !all) 187100384Speter continue; 188100384Speter p = q + 1; 189100384Speter } 190100384Speter } 191100384Speter 192100384Speter (void)strvisx(visbp, p, nextp - p, 0); 193100384Speter (void)printf("%s", visbp); 194100384Speter } 195100384Speter exit(0); 196100384Speter} 197100384Speter 198100384Spetervoid 199100384Speterusage(void) 200100384Speter{ 201100384Speter (void)fprintf(stderr, "usage: dmesg [-a] [-M core [-N system]]\n"); 202100384Speter exit(1); 203100384Speter} 204100384Speter