writing ktrace output to serial port

Daniel O'Connor doconnor at gsoft.com.au
Mon Jun 21 18:01:59 PDT 2004

Hash: SHA1

On Sun, 20 Jun 2004 23:29, Eugene Grosbein wrote:
> So I want to see what is happening just before my mplayer crashes the
> kernel. The problem is that ktracing mplayer does not help as filesystem
> can't keep ktrace.out being written just before crash. I tried 'sync'
> mount,
> it does not help too.
> I decided to divert ktrace.out to /dev/cuaa0 so another FreeBSD will keep
> it. However, ktrace() in src/sys/kern/kern_trace.c does not permit writing
> to non-regular file. Why?

The actual syscall passes a filename, not a file descriptor so you'd have to 
change that (or make a new syscall) if you wanted to change it at all :(

It would be nice to be able to ktrace() to an fd (eg socket or pipe) though :)

See ktrace() in /usr/src/sys/kern/kern_ktrace.c:494

As for your problem..
Can you NFS mount? If you have no ethernet you could NFS mount over 
(or PLIP if you have a parallel port)

- -- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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