misc/178295: small change to dmesg utility

[Levent Serinol]

>Number:         178295
>Category:       misc
>Synopsis:       small change to dmesg utility
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Thu May 02 09:30:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Levent Serinol
>Release:        9 and 10
>Organization:
Mynet
>Environment:
FreeBSD webmail105.mynet.com 10.0-CURRENT FreeBSD 10.0-CURRENT #5: Thu Mar 14 20:28:24 EET 2013     root at xxx.com:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
I would like to submit a small patch for dmesg system utility which implements "-c" parameter like the other *nix systems support to clear current kernel message buffer instead of using "sysctl kern.msgbuf_clear=1" command for easier administration usage and similarity between other unix systems.

Here i wrote an article about this issue sometime ago.

http://lserinol.blogspot.com/2012/02/linux-like-dmesg-in-freebsd.html
>How-To-Repeat:

>Fix:


Patch attached with submission follows:

*** dmesg.c.org	Tue Jan  3 19:04:44 2012
--- dmesg.c	Mon Mar 12 15:48:34 2012
***************
*** 82,95 ****
  	size_t buflen, bufpos;
  	long pri;
! 	int all, ch;
  
  	all = 0;
  	(void) setlocale(LC_CTYPE, "");
  	memf = nlistf = NULL;
! 	while ((ch = getopt(argc, argv, "aM:N:")) != -1)
  		switch(ch) {
  		case 'a':
  			all++;
  			break;
  		case 'M':
  			memf = optarg;
--- 82,99 ----
  	size_t buflen, bufpos;
  	long pri;
! 	int all, ch, clear;
  
  	all = 0;
+ 	clear = 0;
  	(void) setlocale(LC_CTYPE, "");
  	memf = nlistf = NULL;
! 	while ((ch = getopt(argc, argv, "acM:N:")) != -1)
  		switch(ch) {
  		case 'a':
  			all++;
  			break;
+ 		case 'c':
+ 			clear++;
+ 			break;
  		case 'M':
  			memf = optarg;
***************
*** 192,195 ****
--- 196,202 ----
  		(void)strvisx(visbp, p, nextp - p, 0);
  		(void)printf("%s", visbp);
+ 		if (clear)
+ 			if (sysctlbyname("kern.msgbuf_clear", NULL, NULL, &clear, sizeof(int)) == -1)
+ 				err(1, "sysctl kern.msgbuf_clear");
  	}
  	exit(0);
***************
*** 199,203 ****
  usage(void)
  {
! 	(void)fprintf(stderr, "usage: dmesg [-a] [-M core [-N system]]\n");
  	exit(1);
  }
--- 206,210 ----
  usage(void)
  {
! 	(void)fprintf(stderr, "usage: dmesg [-a] [-c] [-M core [-N system]]\n");
  	exit(1);
  }


>Release-Note:
>Audit-Trail:
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