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Date: Tue, 18 Jun 1996 02:41:58 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199606171641.CAA10807@godzilla.zeta.org.au>
To: fcurrent@jraynard.demon.co.uk, wollman@lcs.mit.edu
Subject: Re: ktrace [Was: 2.2-960612-SNAP resolver problems]
Cc: bde@zeta.org.au, freebsd-current@freebsd.org, j@uriah.heep.sax.de,
        nate@sri.MT.net
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>1) The ktrace(2) system call takes a filename as its argument, not a
>descriptor.

I tried `mkfifo p; ktrace -f p ls'.  This hung in open() until p was
opened for reading by another process.  Then the ktrace() syscall
returned EPERM and ktrace(8) printed a garbage message (error() is
miscalled with 0 args when ktrace() fails).  This ktrace() error
wouldn't be handled be either SIGSYS or James' checking for ENOSYS.

I doubt that the kernel writes for ktrace() would work for either
named or nameless pipes.  They don't quite work for ufs either.

Bruce