Subject: Re: Intercepting system calls
To: John Clark <>
From: Antti Kantee <>
List: tech-kern
Date: 04/23/2002 11:30:38
On Mon Apr 22 2002 at 21:09:42 -0700, John Clark wrote:
> Am Montag den, 22. April 2002, um 20:32, schrieb Jason R Thorpe:
> >
> >Can you describe *precisely* what PT_SYSCALL does?
> There is a tool in linux, 'strace' which allows one to
> trace system calls. I've used it on rare occasions, when
> I though some particular system call was causing a
> kernel panic.
> From the linux man page, it is derived from
> a tool that was originally written for SunOS, of some ancient
> vintage.
> I presumed there was something similar for NetBSD until
> the poster asked...

There is, see ktrace(1)/ktrace(2). It also does a few bits more than
plain system call tracing if you want it to.

PT_SYSCALL is not the same thing, it is related to the ptrace(2) call.
See explanation in other mail.

Antti Kantee <>                     Of course he runs NetBSD                
                        "The dish washer returns!"