/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1991, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static const char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93";
#endif
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/msgbuf.h>
#include <err.h>
#include <fcntl.h>
#include <kvm.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <vis.h>
struct nlist nl[] = {
#define X_MSGBUF 0
{ "_msgbufp" },
{ NULL },
};
void usage __P((void));
#define KREAD(addr, var) \
kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var)
int
main(argc, argv)
int argc;
char *argv[];
{
register int ch, newl, skip;
register char *p, *ep;
struct msgbuf *bufp, cur;
char *bp, *memf, *nlistf;
kvm_t *kd;
char buf[5];
(void) setlocale(LC_CTYPE, "");
memf = nlistf = NULL;
while ((ch = getopt(argc, argv, "M:N:")) != -1)
switch(ch) {
case 'M':
memf = optarg;
break;
case 'N':
nlistf = optarg;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
/*
* Discard setgid privileges if not the running kernel so that bad
* guys can't print interesting stuff from kernel memory.
*/
if (memf != NULL || nlistf != NULL)
setgid(getgid());
/* Read in kernel message buffer, do sanity checks. */
if ((kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg")) == NULL)
exit (1);
if (kvm_nlist(kd, nl) == -1)
errx(1, "kvm_nlist: %s", kvm_geterr(kd));
if (nl[X_MSGBUF].n_type == 0)
errx(1, "%s: msgbufp not found", nlistf ? nlistf : "namelist");
if (KREAD(nl[X_MSGBUF].n_value, bufp) || KREAD((long)bufp, cur))
errx(1, "kvm_read: %s", kvm_geterr(kd));
if (cur.msg_magic != MSG_MAGIC)
errx(1, "kernel message buffer has different magic number");
bp = malloc(cur.msg_size);
if (!bp)
errx(1, "malloc failed");
if (kvm_read(kd, (long)cur.msg_ptr, bp, cur.msg_size) !=
cur.msg_size)
errx(1, "kvm_read: %s", kvm_geterr(kd));
if (cur.msg_bufx >= cur.msg_size)
cur.msg_bufx = 0;
kvm_close(kd);
/*
* The message buffer is circular. If the buffer has wrapped, the
* write pointer points to the oldest data. Otherwise, the write
* pointer points to \0's following the data. Read the entire
* buffer starting at the write pointer and ignore nulls so that
* we effectively start at the oldest data.
*/
p = bp + cur.msg_bufx;
ep = (cur.msg_bufx == 0 ? bp + cur.msg_size : p);
newl = skip = 0;
do {
if (p == bp + cur.msg_size)
p = bp;
ch = *p;
/* Skip "\n<.*>" syslog sequences. */
if (skip) {
if (ch == '>')
newl = skip = 0;
continue;
}
if (newl && ch == '<') {
skip = 1;
continue;
}
if (ch == '\0')
continue;
newl = ch == '\n';
(void)vis(buf, ch, 0, 0);
if (buf[1] == 0)
(void)putchar(buf[0]);
else
(void)printf("%s", buf);
} while (++p != ep);
if (!newl)
(void)putchar('\n');
exit(0);
}
void
usage()
{
(void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n");
exit(1);
}
