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 * 4. 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.
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
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 * $DragonFly: src/sbin/dmesg/dmesg.c,v 1.7 2005/01/14 06:38:41 cpressey Exp $
35 #include <sys/types.h>
36 #include <sys/msgbuf.h>
37 #include <sys/sysctl.h>
47 #include <sys/syslog.h>
51 { "_msgbufp", 0, 0, 0, 0 },
57 #define KREAD(addr, var) \
58 kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var)
61 main(int argc, char **argv)
65 struct msgbuf *bufp, cur;
66 char *bp, *memf, *nlistf;
71 size_t buflen, bufpos;
73 setlocale(LC_CTYPE, "");
75 while ((ch = getopt(argc, argv, "aM:N:")) != -1)
93 if (memf == NULL && nlistf == NULL) {
94 /* Running kernel. Use sysctl. */
95 if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1)
96 err(1, "sysctl kern.msgbuf");
97 buflen += 4096; /* add some slop */
98 if ((bp = malloc(buflen)) == NULL)
99 errx(1, "malloc failed");
100 if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1)
101 err(1, "sysctl kern.msgbuf");
102 /* We get a dewrapped buffer using sysctl. */
105 /* Read in kernel message buffer, do sanity checks. */
106 kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg");
109 if (kvm_nlist(kd, nl) == -1)
110 errx(1, "kvm_nlist: %s", kvm_geterr(kd));
111 if (nl[X_MSGBUF].n_type == 0)
112 errx(1, "%s: msgbufp not found",
113 nlistf ? nlistf : "namelist");
114 if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur))
115 errx(1, "kvm_read: %s", kvm_geterr(kd));
116 if (cur.msg_magic != MSG_MAGIC)
117 errx(1, "kernel message buffer has different magic "
119 bp = malloc(cur.msg_size);
121 errx(1, "malloc failed");
122 if (kvm_read(kd, (long)cur.msg_ptr, bp, cur.msg_size) !=
123 (ssize_t)cur.msg_size)
124 errx(1, "kvm_read: %s", kvm_geterr(kd));
126 buflen = cur.msg_size;
127 bufpos = cur.msg_bufx;
128 if (bufpos >= buflen)
133 * The message buffer is circular. If the buffer has wrapped, the
134 * write pointer points to the oldest data. Otherwise, the write
135 * pointer points to \0's following the data. Read the entire
136 * buffer starting at the write pointer and ignore nulls so that
137 * we effectively start at the oldest data.
140 ep = (bufpos == 0 ? bp + buflen : p);
143 if (p == bp + buflen)
146 /* Skip "\n<.*>" syslog sequences. */
152 if (LOG_FAC(pri) == LOG_KERN || all)
154 } else if (ch >= '0' && ch <= '9') {
160 if (newl && ch == '<') {
182 fprintf(stderr, "usage: dmesg [-a] [-M core] [-N system]\n");