xref: /netbsd-src/sbin/dmesg/dmesg.c (revision 5f7096188587a2c7c95fa3c69b78e1ec9c7923d0)
1 /*-
2  * Copyright (c) 1991 The Regents of the University of California.
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  * 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 char copyright[] =
36 "@(#) Copyright (c) 1991 The Regents of the University of California.\n\
37  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 /*static char sccsid[] = "from: @(#)dmesg.c	5.9 (Berkeley) 5/2/91";*/
42 static char rcsid[] = "$Id: dmesg.c,v 1.5 1993/10/13 18:33:58 jtc Exp $";
43 #endif /* not lint */
44 
45 #include <sys/cdefs.h>
46 #include <sys/msgbuf.h>
47 #include <time.h>
48 #include <nlist.h>
49 #include <kvm.h>
50 #include <stdlib.h>
51 #include <stdio.h>
52 #include <ctype.h>
53 #include <unistd.h>
54 
55 struct nlist nl[] = {
56 #define	X_MSGBUFP	0
57 	{ "_msgbufp" },
58 	{ NULL },
59 };
60 
61 void usage(), vputc();
62 void err __P((const char *, ...));
63 
64 main(argc, argv)
65 	int argc;
66 	char **argv;
67 {
68 	register int ch, newl, skip;
69 	register char *p, *ep;
70 	struct msgbuf cur;
71 	int msgbufat;
72 	char *core, *namelist;
73 
74 	core = namelist = NULL;
75 	while ((ch = getopt(argc, argv, "M:N:")) != EOF)
76 		switch(ch) {
77 		case 'M':
78 			core = optarg;
79 			break;
80 		case 'N':
81 			namelist = optarg;
82 			break;
83 		case '?':
84 		default:
85 			usage();
86 		}
87 	argc -= optind;
88 	argv += optind;
89 
90 	/* Read in kernel message buffer, do sanity checks. */
91 	if (kvm_openfiles(namelist, core, NULL) == -1)
92 		err("kvm_openfiles: %s", kvm_geterr());
93 	if (kvm_nlist(nl) == -1)
94 		err("kvm_nlist: %s", kvm_geterr());
95 	if (nl[X_MSGBUFP].n_type == 0)
96 		err("msgbufp not found namelist");
97 
98         kvm_read((void *)nl[X_MSGBUFP].n_value, (void *)&msgbufat, sizeof(msgbufat));
99         kvm_read((void *)msgbufat, (void *)&cur, sizeof(cur));
100 	if (cur.msg_magic != MSG_MAGIC)
101 		err("magic number incorrect");
102 	if (cur.msg_bufx >= MSG_BSIZE)
103 		cur.msg_bufx = 0;
104 
105 	/*
106 	 * The message buffer is circular; start at the read pointer, and
107 	 * go to the write pointer - 1.
108 	 */
109 	p = cur.msg_bufc + cur.msg_bufx;
110 	ep = cur.msg_bufc + cur.msg_bufx - 1;
111 	for (newl = skip = 0; p != ep; ++p) {
112 		if (p == cur.msg_bufc + MSG_BSIZE)
113 			p = cur.msg_bufc;
114 		ch = *p;
115 		/* Skip "\n<.*>" syslog sequences. */
116 		if (skip) {
117 			if (ch == '>')
118 				newl = skip = 0;
119 			continue;
120 		}
121 		if (newl && ch == '<') {
122 			skip = 1;
123 			continue;
124 		}
125 		if (ch == '\0')
126 			continue;
127 		newl = (ch = *p) == '\n';
128 		vputc(ch);
129 	}
130 	if (!newl)
131 		(void)putchar('\n');
132 	exit(0);
133 }
134 
135 void
136 vputc(ch)
137 	register int ch;
138 {
139 	int meta;
140 
141 	if (!isascii(ch)) {
142 		(void)putchar('M');
143 		(void)putchar('-');
144 		ch = toascii(ch);
145 		meta = 1;
146 	} else
147 		meta = 0;
148 	if (isprint(ch) || !meta && (ch == ' ' || ch == '\t' || ch == '\n'))
149 		(void)putchar(ch);
150 	else {
151 		(void)putchar('^');
152 		(void)putchar(ch == '\177' ? '?' : ch | 0100);
153 	}
154 }
155 
156 #if __STDC__
157 #include <stdarg.h>
158 #else
159 #include <varargs.h>
160 #endif
161 
162 void
163 #if __STDC__
164 err(const char *fmt, ...)
165 #else
166 err(fmt, va_alist)
167 	char *fmt;
168         va_dcl
169 #endif
170 {
171 	va_list ap;
172 #if __STDC__
173 	va_start(ap, fmt);
174 #else
175 	va_start(ap);
176 #endif
177 	(void)fprintf(stderr, "dmesg: ");
178 	(void)vfprintf(stderr, fmt, ap);
179 	va_end(ap);
180 	(void)fprintf(stderr, "\n");
181 	exit(1);
182 	/* NOTREACHED */
183 }
184 
185 void
186 usage()
187 {
188 	(void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n");
189 	exit(1);
190 }
191