writing ktrace output to serial port

[Julian Elischer]

On Tue, 22 Jun 2004, Daniel O'Connor wrote:

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> 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 
> PPP/SLIP :)
> (or PLIP if you have a parallel port)
> 

it would be relatively easy to sent it to a netgraph ng_ksocket node and
have the record sent out as a udp packet :-)