NetBSD/sbin/dmesg/dmesg.c

204 lines
5.3 KiB
C

/* $NetBSD: dmesg.c,v 1.26 2008/07/20 01:20:22 lukem Exp $ */
/*-
* 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. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1991, 1993\
The Regents of the University of California. All rights reserved.");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93";
#else
__RCSID("$NetBSD: dmesg.c,v 1.26 2008/07/20 01:20:22 lukem Exp $");
#endif
#endif /* not lint */
#include <sys/param.h>
#include <sys/msgbuf.h>
#include <sys/sysctl.h>
#include <err.h>
#include <fcntl.h>
#include <kvm.h>
#include <nlist.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <vis.h>
#ifndef SMALL
struct nlist nl[] = {
#define X_MSGBUF 0
{ .n_name = "_msgbufp" },
{ .n_name = NULL },
};
void usage(void);
#define KREAD(addr, var) \
kvm_read(kd, addr, &var, sizeof(var)) != sizeof(var)
#endif
int
main(int argc, char *argv[])
{
struct kern_msgbuf cur;
int ch, newl, skip, i;
char *p, *bufdata;
#ifndef SMALL
char *memf, *nlistf;
#endif
char buf[5];
#ifndef SMALL
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;
if (memf == NULL) {
#endif
size_t size;
int mib[2];
mib[0] = CTL_KERN;
mib[1] = KERN_MSGBUF;
if (sysctl(mib, 2, NULL, &size, NULL, 0) == -1 ||
(bufdata = malloc(size)) == NULL ||
sysctl(mib, 2, bufdata, &size, NULL, 0) == -1)
err(1, "can't get msgbuf");
/* make a dummy struct msgbuf for the display logic */
cur.msg_bufx = 0;
cur.msg_bufs = size;
#ifndef SMALL
} else {
kvm_t *kd;
struct kern_msgbuf *bufp;
/*
* Read in message buffer header and data, and do sanity
* checks.
*/
kd = kvm_open(nlistf, memf, NULL, O_RDONLY, "dmesg");
if (kd == 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))
errx(1, "kvm_read: %s (0x%lx)", kvm_geterr(kd),
nl[X_MSGBUF].n_value);
if (kvm_read(kd, (long)bufp, &cur,
offsetof(struct kern_msgbuf, msg_bufc)) !=
offsetof(struct kern_msgbuf, msg_bufc))
errx(1, "kvm_read: %s (0x%lx)", kvm_geterr(kd),
(unsigned long)bufp);
if (cur.msg_magic != MSG_MAGIC)
errx(1, "magic number incorrect");
bufdata = malloc(cur.msg_bufs);
if (bufdata == NULL)
errx(1, "couldn't allocate space for buffer data");
if (kvm_read(kd, (long)&bufp->msg_bufc, bufdata,
cur.msg_bufs) != cur.msg_bufs)
errx(1, "kvm_read: %s", kvm_geterr(kd));
kvm_close(kd);
if (cur.msg_bufx >= cur.msg_bufs)
cur.msg_bufx = 0;
}
#endif
/*
* The message buffer is circular; start at the write pointer
* (which points the oldest character), and go to the write
* pointer - 1 (which points the newest character). I.e, loop
* over cur.msg_bufs times. Unused area is skipped since it
* contains nul.
*/
for (newl = skip = i = 0, p = bufdata + cur.msg_bufx;
i < cur.msg_bufs; i++, p++) {
#ifndef SMALL
if (p == bufdata + cur.msg_bufs)
p = bufdata;
#endif
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, VIS_NOSLASH, 0);
#ifndef SMALL
if (buf[1] == 0)
(void)putchar(buf[0]);
else
#endif
(void)printf("%s", buf);
}
if (!newl)
(void)putchar('\n');
exit(0);
}
#ifndef SMALL
void
usage(void)
{
(void)fprintf(stderr, "usage: dmesg [-M core] [-N system]\n");
exit(1);
}
#endif