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Code Issues Releases Activity

Who would have though that dmesg didn't understand message buffers?

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Fixed the following bugs:
- the buffer was reprinted endlessly when msg.bufx == 0 and (for a
  different reason) when msg.bufx == 1.
- the last byte of the buffer wasn't printed except in the the infinite
  loop cases.
- the comment about walking the buffer didn't match the (correct) code.
- minor -Wall and style bugs.
Not fixed:
- excessive newline processing which hid the non-printing of the last
  byte of the buffer.
This commit is contained in:
Bruce Evans 1996-09-21 08:11:22 +00:00
parent bb8ba0e06e
commit 301e6a175a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=18439
1 changed files with 16 additions and 8 deletions
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24
sbin/dmesg/dmesg.c
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@ -32,13 +32,17 @@
*/
#ifndef lint
static char copyright[] =
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
static char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93";
#if 0
static const char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93";
#endif
static const char rcsid[] =
"$Id$";
#endif /* not lint */
#include <sys/cdefs.h>
@ -48,13 +52,13 @@ static char sccsid[] = "@(#)dmesg.c 8.1 (Berkeley) 6/5/93";
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <locale.h>
#include <nlist.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <vis.h>
#include <locale.h>
struct nlist nl[] = {
#define X_MSGBUF 0
@ -119,12 +123,16 @@ main(argc, argv)
cur.msg_bufx = 0;
/*
* The message buffer is circular; start at the read pointer, and
* go to the write pointer - 1.
* 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 = cur.msg_bufc + cur.msg_bufx;
ep = cur.msg_bufc + cur.msg_bufx - 1;
for (newl = skip = 0; p != ep; ++p) {
ep = (cur.msg_bufx == 0 ? cur.msg_bufc + MSG_BSIZE : p);
newl = skip = 0;
do {
if (p == cur.msg_bufc + MSG_BSIZE)
p = cur.msg_bufc;
ch = *p;
@ -146,7 +154,7 @@ main(argc, argv)
(void)putchar(buf[0]);
else
(void)printf("%s", buf);
}
} while (++p != ep);
if (!newl)
(void)putchar('\n');
exit(0);