From owner-freebsd-questions  Fri Feb  5 08:14:57 1999
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id IAA06503
          for freebsd-questions-outgoing; Fri, 5 Feb 1999 08:14:57 -0800 (PST)
          (envelope-from owner-freebsd-questions@FreeBSD.ORG)
Received: from freefall.freebsd.org (freefall.FreeBSD.ORG [204.216.27.21])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id IAA06498
          for <freebsd-questions@freefall.cdrom.com>; Fri, 5 Feb 1999 08:14:56 -0800 (PST)
          (envelope-from ik26+@andrew.cmu.edu)
Received: from po9.andrew.cmu.edu (PO9.ANDREW.CMU.EDU [128.2.10.109])
	by freefall.freebsd.org (8.9.2/8.9.2) with ESMTP id IAA04816
	for <freebsd-questions@freefall.cdrom.com>; Fri, 5 Feb 1999 08:14:50 -0800 (PST)
	(envelope-from ik26+@andrew.cmu.edu)
Received: (from postman@localhost) by po9.andrew.cmu.edu (8.8.5/8.8.2) id LAA25191 for freebsd-questions@freefall.cdrom.com; Fri, 5 Feb 1999 11:14:44 -0500 (EST)
Received: via switchmail; Fri,  5 Feb 1999 11:14:44 -0500 (EST)
Received: from pcs6.andrew.cmu.edu via qmail
          ID </afs/andrew.cmu.edu/service/mailqs/q003/QF.wqilXfm00Ui501DrU0>;
          Fri,  5 Feb 1999 11:14:35 -0500 (EST)
Received: from pcs6.andrew.cmu.edu via qmail
          ID </afs/andrew.cmu.edu/usr21/ik26/.Outgoing/QF.wqilXfW00Ui503yF00>;
          Fri,  5 Feb 1999 11:14:35 -0500 (EST)
Received: from mms.4.60.Jun.27.1996.03.02.53.sun4.51.EzMail.PC.3.2.CUILIB.3.45.SNAP.NOT.LINKED.pcs6.andrew.cmu.edu.sun4m.54
          via MS.5.6.pcs6.andrew.cmu.edu.sun4_51;
          Fri,  5 Feb 1999 11:14:35 -0500 (EST)
Message-ID: <QqilXfW00Ui503yEs0@andrew.cmu.edu>
Date: Fri,  5 Feb 1999 11:14:35 -0500 (EST)
From: Ilhwan Kwon <ik26+@andrew.cmu.edu>
To: freebsd-questions@freefall.cdrom.com
Subject: [help] making my system calls
Sender: owner-freebsd-questions@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

Hi.

I am trying to write my own system call functions for BSD.
I am trying to calculate the maximum amount of memory a PC needs
when it is used as a router.
First, I declare "u_long max_memused" in /usr/src/sys/sys/mbuf.h.

Second, I add following code in m_devget function in
/usr/src/sys/kern/uipc_mbuf.c.

	u_long mem_used = size of memory currently used by mbufs and clusters.
	if(mem_used > max_memused) max_memused = mem_used;

Third, I make prototype for my system calls in mbuf.h like following.
	
	long get_mem_stat __P((void));
	void clear_mem_stat __P((void));

Fourth, I declare above system calls in uipc_mbuf.c like following.

	long get_mem_stat(){
		return (long) max_memused;
	}
	void clear_mem_stat(){
		max_memused = 0;
	}

Fifth, I put entries in init_sysent.c like following.

	struct sysent sysent[] = {
		/*......*/
		{0, (*sy_call)get_mem_stat},	/*241 = get_mem_stat */
		{0, (*sy_call)clear_mem_stat},  /*242 = clear_mem_stat */
		/* ..... */
	};
	
	the 241th and 242th wer originally looked like {0, (*sy_call)no_sys},

finally, I put entries in syscalls.c

	"get_mem_stat"		/*241 = get_mem_stat*/
	"clear_mem_stat" 	/*242 = clear_mem_stat*/
	
	they were originally "no_sys".

Now, I recompile the kernel and reboot.  but kernel library is not updated.
I copy /usr/src/sys/sys/mbuf.h to /usr/include/sys/mbuf.h.
I write a small program which includes <sys/mbuf.h> and calls get_mem_stat
and clear_mem_stat system calls.

Whe I compile, I get
"get_mem_stat" : undefined reference from the text segent"
"clear_mem_stat" : undefined reference from the text segent"

What did I do wrong?
Any help on this matter will be greatly appreciated.

Thanks
-James Kwon 

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message