Patch: add two accessors to Syscall

[Tom Tromey <tromey at redhat dot com>]

I was reading a thread on the valgrind list about finding where a bad
close() was called

    http://article.gmane.org/gmane.comp.debugging.valgrind/5996

and I thought this would be a simple thing for frysk to do.

First I wanted the appended patch to let my code inspect a Syscall.
Could someone check this in?  (I didn't add all the accessors, just
the ones I needed.)

I hacked up ftrace.java to do what I wanted (it was *very* easy this
way -- nice :-), but on my FC5 box I always get an I/O error when
trying to get the stack trace of a task (failure attached).  Any
ideas?

Also I noticed a few other oddities here and there.  For instance,
SyscallEventInfo.returnCode returns a long -- but apparently does not
sign-extend the syscall's actual return value.  This leads to the
unobvious test:

    (int) syscallEventInfo.returnCode(task) < 0

I wasn't sure whether you'd prefer email about little things like this
or whether I should just drop stuff directly in bugzilla... let me
know.

Tom

Attachment: P
Description: patch

Attachment: S
Description: stack trace