Date: Wed, 7 Feb 1996 22:28:37 +0900 From: Hong Hunsoo <hunsoo@thebard.kci.co.kr> To: questions@freebsd.org Message-ID: <199602071328.WAA11822@thebard.kci.co.kr>
next in thread | raw e-mail | index | archive | help
Hi! all.
Currently I am using FreeBSD 2.0.5-RELEASE pleasantly.
I have some questions about kernel source codes. The followings are
my stupid questions.
1) Is it possible for me to insert a new system call without resulting
any trouble? That is, I want to know whether it is possible to insert a line
in /usr/src/sys/sys/syscall.h in my pleasure.
#define SYS_my_new_system_call 8
/*
* Here I selected 8 by the reason that /usr/src/sys/sys/syscall.h has a
* comment that ... 8 is old creat...
*/
I was always curious about the number, like 8 above, of a system call. I think
the only occurance of the number of a system call was through the syscall(2).
Is there anybody to explain me the significant role of the number?(in the case
of exit, 1; in the case of fork, 2; in the case of read, 3....)
2) If above is possible, what files should I re-edit?
I want to know how many times the each system call has been called from the
time the system start to operate.
I want to program something like this.
main()
{
printf("The open(2) system call has been called %d times.\n",
my_new_system_call());
}
My new system call, my_new_system_call(2) maybe be something like this.
[FreeBSD]
[FreeBSD] cat /usr/src/sys/kern/a_file.h
/*
* this file should be #include'd a lot of times, if I want to know
* the occurence of all the system calls. Maybe structure is more appropriate.
*/
int open_count;
/*
int exit_count;
int fork_count;
int read_count;
int write_count;
... something like that..
*/
[FreeBSD]
[FreeBSD] cat /usr/src/sys/kern/b_file.c
#include <a_file.h>
int
my_new_system_call(p, dummy, retval)
struct proc *p;
int dummy;
int *retval;
{
*retval = open_count;
return (0);
}
[FreeBSD]
[FreeBSD] cat /usr/src/kern/vfs_syscalls.c
.......
int
open(p, uap, retval)
struct proc *p;
register struct open_args *uap;
int *retval;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
register struct vnode *vp;
int flags, cmode;
struct file *nfp;
int type, indx, error;
struct flock lf;
struct nameidata nd;
extern struct fileops vnops;
open_count++; /* !!!!!!!!!! */
error = falloc(p, &nfp, &indx);
if (error)
return (error);
fp = nfp;
...........................
}
Is the above revision correct?
Thank you..
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199602071328.WAA11822>