2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
33 * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved.
34 * @(#)dmesg.c 8.1 (Berkeley) 6/5/93
35 * $FreeBSD: src/sbin/dmesg/dmesg.c,v 1.11.2.3 2001/08/08 22:32:15 obrien Exp $
36 * $DragonFly: src/sbin/dmesg/dmesg.c,v 1.5 2004/02/04 17:39:59 joerg Exp $
39 #include <sys/types.h>
40 #include <sys/msgbuf.h>
41 #include <sys/sysctl.h>
51 #include <sys/syslog.h>
61 #define KREAD(addr, var) \
62 kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var)
65 main(int argc, char **argv)
69 struct msgbuf *bufp, cur;
70 char *bp, *memf, *nlistf;
78 (void) setlocale(LC_CTYPE, "");
80 while ((ch = getopt(argc, argv, "aM:N:")) != -1)
98 if (memf == NULL && nlistf == NULL) {
99 /* Running kernel. Use sysctl. */
100 if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1)
101 err(1, "sysctl kern.msgbuf");
102 if ((bp = malloc(buflen)) == NULL)
103 errx(1, "malloc failed");
104 if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1)
105 err(1, "sysctl kern.msgbuf");
106 /* We get a dewrapped buffer using sysctl. */
109 /* Read in kernel message buffer, do sanity checks. */
110 kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg");
113 if (kvm_nlist(kd, nl) == -1)
114 errx(1, "kvm_nlist: %s", kvm_geterr(kd));
115 if (nl[X_MSGBUF].n_type == 0)
116 errx(1, "%s: msgbufp not found",
117 nlistf ? nlistf : "namelist");
118 if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur))
119 errx(1, "kvm_read: %s", kvm_geterr(kd));
120 if (cur.msg_magic != MSG_MAGIC)
121 errx(1, "kernel message buffer has different magic "
123 bp = malloc(cur.msg_size);
125 errx(1, "malloc failed");
126 if (kvm_read(kd, (long)cur.msg_ptr, bp, cur.msg_size) !=
128 errx(1, "kvm_read: %s", kvm_geterr(kd));
130 buflen = cur.msg_size;
131 bufpos = cur.msg_bufx;
132 if (bufpos >= buflen)
137 * The message buffer is circular. If the buffer has wrapped, the
138 * write pointer points to the oldest data. Otherwise, the write
139 * pointer points to \0's following the data. Read the entire
140 * buffer starting at the write pointer and ignore nulls so that
141 * we effectively start at the oldest data.
144 ep = (bufpos == 0 ? bp + buflen : p);
147 if (p == bp + buflen)
150 /* Skip "\n<.*>" syslog sequences. */
156 if (LOG_FAC(pri) == LOG_KERN || all)
158 } else if (ch >= '0' && ch <= '9') {
164 if (newl && ch == '<') {
172 (void)vis(buf, ch, 0, 0);
174 (void)putchar(buf[0]);
176 (void)printf("%s", buf);
186 (void)fprintf(stderr, "usage: dmesg [-a] [-M core] [-N system]\n");