dtrace discuss - Jun 2009 - user dtrace over/beyond fork

This topic seems to come up, in one way or another,
every now and then but I cannot seem to find a good
answer for it.

What I want to do is either
- set dtrace probes in a parent and have them continue
  to be triggered in the child, up until it does an exec or
- set dtrace probes that are only executed in the child,
  up until it does an exec (.e.g pid$child rather than
  pid$target).

The practical application of this is that I want to use
dtrace on svc.startd, but only on the code path that is
after its call to fork1() and before it calls execve().

For now, I''m going to have to resort to printf''s but
it''s not really very desirable...

Darren

My best solution was not pretty but worked:

cjg at brompton:~/lang/d$ cat followfork.d 
proc:::start
/ppid == $target/
{
	stop();
	trace(pid);
	system("dtrace -ws child.d -p %d", pid);
}
cjg at brompton:~/lang/d$ cat child.d
pid$target::malloc:entry
{
	trace(ustackdepth)
}
cjg at brompton:~/lang/d$ pfexec /usr/sbin/dtrace -ws followfork.d -s child.d -p
26758

--chris
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