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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 static const char copyright[] = 36 "@(#) Copyright (c) 1991, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 #if 0 42 static const char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93"; 43 #endif 44 static const char rcsid[] = 45 "$FreeBSD$"; 46 #endif /* not lint */ 47 48 #include <sys/types.h> 49 #include <sys/msgbuf.h> 50 #include <sys/sysctl.h> 51 52 #include <err.h> 53 #include <fcntl.h> 54 #include <kvm.h> 55 #include <locale.h> 56 #include <nlist.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <unistd.h> 60 #include <vis.h> 61 #include <sys/syslog.h> 62 63 struct nlist nl[] = { 64 #define X_MSGBUF 0 65 { "_msgbufp" }, 66 { NULL }, 67 }; 68 69 void usage(void) __dead2; 70 71 #define KREAD(addr, var) \ 72 kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var) 73 74 int 75 main(int argc, char *argv[]) 76 { 77 int ch, newl, skip; 78 char *p, *ep; 79 struct msgbuf *bufp, cur; 80 char *bp, *memf, *nlistf; 81 kvm_t *kd; 82 char buf[5]; 83 int all = 0; 84 int pri; 85 size_t buflen; 86 int bufpos; 87 88 (void) setlocale(LC_CTYPE, ""); 89 memf = nlistf = NULL; 90 while ((ch = getopt(argc, argv, "aM:N:")) != -1) 91 switch(ch) { 92 case 'a': 93 all++; 94 break; 95 case 'M': 96 memf = optarg; 97 break; 98 case 'N': 99 nlistf = optarg; 100 break; 101 case '?': 102 default: 103 usage(); 104 } 105 argc -= optind; 106 argv += optind; 107 108 if (memf == NULL && nlistf == NULL) { 109 /* Running kernel. Use sysctl. */ 110 if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1) 111 err(1, "sysctl kern.msgbuf"); 112 if ((bp = malloc(buflen)) == NULL) 113 errx(1, "malloc failed"); 114 if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1) 115 err(1, "sysctl kern.msgbuf"); 116 /* We get a dewrapped buffer using sysctl. */ 117 bufpos = 0; 118 } else { 119 /* Read in kernel message buffer, do sanity checks. */ 120 kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg"); 121 if (kd == NULL) 122 exit (1); 123 if (kvm_nlist(kd, nl) == -1) 124 errx(1, "kvm_nlist: %s", kvm_geterr(kd)); 125 if (nl[X_MSGBUF].n_type == 0) 126 errx(1, "%s: msgbufp not found", 127 nlistf ? nlistf : "namelist"); 128 if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur)) 129 errx(1, "kvm_read: %s", kvm_geterr(kd)); 130 if (cur.msg_magic != MSG_MAGIC) 131 errx(1, "kernel message buffer has different magic " 132 "number"); 133 bp = malloc(cur.msg_size); 134 if (!bp) 135 errx(1, "malloc failed"); 136 if (kvm_read(kd, (long)cur.msg_ptr, bp, cur.msg_size) != 137 cur.msg_size) 138 errx(1, "kvm_read: %s", kvm_geterr(kd)); 139 kvm_close(kd); 140 buflen = cur.msg_size; 141 bufpos = cur.msg_bufx; 142 if (bufpos >= buflen) 143 bufpos = 0; 144 } 145 146 /* 147 * The message buffer is circular. If the buffer has wrapped, the 148 * write pointer points to the oldest data. Otherwise, the write 149 * pointer points to \0's following the data. Read the entire 150 * buffer starting at the write pointer and ignore nulls so that 151 * we effectively start at the oldest data. 152 */ 153 p = bp + bufpos; 154 ep = (bufpos == 0 ? bp + buflen : p); 155 newl = skip = 0; 156 do { 157 if (p == bp + buflen) 158 p = bp; 159 ch = *p; 160 /* Skip "\n<.*>" syslog sequences. */ 161 if (skip) { 162 if (ch == '\n') { 163 skip = 0; 164 newl = 1; 165 } if (ch == '>') { 166 if (LOG_FAC(pri) == LOG_KERN || all) 167 newl = skip = 0; 168 } else if (ch >= '0' && ch <= '9') { 169 pri *= 10; 170 pri += ch - '0'; 171 } 172 continue; 173 } 174 if (newl && ch == '<') { 175 pri = 0; 176 skip = 1; 177 continue; 178 } 179 if (ch == '\0') 180 continue; 181 newl = ch == '\n'; 182 (void)vis(buf, ch, 0, 0); 183 if (buf[1] == 0) 184 (void)putchar(buf[0]); 185 else 186 (void)printf("%s", buf); 187 } while (++p != ep); 188 if (!newl) 189 (void)putchar('\n'); 190 exit(0); 191 } 192 193 void 194 usage(void) 195 { 196 (void)fprintf(stderr, "usage: dmesg [-a] [-M core] [-N system]\n"); 197 exit(1); 198 } 199