msg.c revision 272461 
1/*-
2 * Copyright (c) 1998 Andrzej Bialecki <abial@freebsd.org>
3 * 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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/10.1/release/picobsd/tinyware/msg/msg.c 173926 2007-11-26 05:03:55Z sam $
27 */
28
29/*
30 * Small replacement for 'dmesg'. It doesn't need libkvm nor /dev/kmem.
31 */
32
33
34#include <stdio.h>
35#include <stdlib.h>
36#include <sys/types.h>
37#include <sys/sysctl.h>
38
39int
40main(int argc, char *argv[])
41{
42	int len,i;
43	char *buf,*p;
44	char *mib="kern.msgbuf";
45
46	/* We use sysctlbyname, because the oid is unknown (OID_AUTO) */
47
48	/* get the buffer size */
49	i=sysctlbyname(mib,NULL,&len,NULL,0);
50	if(i) {
51		perror("buffer sizing");
52		exit(-1);
53	}
54	buf=(char *)malloc(len*sizeof(char));
55	i=sysctlbyname(mib,buf,&len,NULL,0);
56	if(i) {
57		perror("retrieving data");
58		exit(-1);
59	}
60	p=buf;
61	i=0;
62	while(p<(buf+len)) {
63		switch(*p) {
64		case '\0':
65			/* skip initial NULLs */
66			break;
67		default:
68			putchar(*p);
69		}
70		p++;
71	}
72	if(*--p!='\n') putchar('\n');
73	free(buf);
74	exit(0);
75}
76