On Wed, May 19, 2010 at 4:51 PM, Alfred Perlstein <alf...@freebsd.org> wrote:
> * Dan McNulty <dkmcnu...@gmail.com> [100519 07:13] wrote:
>> Thanks for all the great suggestions!
>>
>> It looks like the kevent system call is the closest to what I need.
>> However, I didn't mention this, but I would like the process being
>> traced to be stopped on entrance to fork, exec, etc. This would be
>> similar to Linux's ptrace interface which sends a SIGTRAP to the
>> traced process on exec, fork, etc. From what I could tell so far,
>> kevent doesn't provide this functionality.
>>
>> Am I missing something? Is there a way to get kevent to stop the
>> process when events occur?
>
> Not that I know of off the top of my head.
>
> Although if you want to contrib the code I can help get it in. :)
>
> -Alfred

Unfortunately, writing a patch for the FreeBSD kernel may be beyond
the scope of my current work.

Although I wouldn't mind working on it in my spare time outside of my
job. Maybe in some free time this summer. I think the ideal fix for my
problem would be to implement a mechanism similar to the Linux ptrace
interface that sends a SIGTRAP for events such as fork, exec, thread
create, etc. Maybe I will poke around in the FreeBSD kernel source and
see what I can figure out.

Thanks for the help!
-Dan

>>
>> Thanks again for your help,
>> -Dan
>>
>> On Tue, May 18, 2010 at 2:40 AM, Alfred Perlstein <alf...@freebsd.org> wrote:
>> > * Dan McNulty <dkmcnu...@gmail.com> [100517 08:02] wrote:
>> >> Hi all,
>> >>
>> >> I have been experimenting with ptrace to determine when a child
>> >> process forks or calls exec. Particularly, I have explored tracing
>> >> every system call entry and exit similar to what the truss utility
>> >> does, and for my case, the performance impact of tracing every system
>> >> call is too great.
>> >>
>> >> Is there a more efficient way than tracing every system call entry and
>> >> exit to determine when a child process forks, calls exec, or creates a
>> >> new LWP?
>> >>
>> >> Thanks a lot for your help!
>> >
>> > kevent has some hooks, have you looked at that?
>> >
>> > --
>> > - Alfred Perlstein
>> > .- AMA, VMOA #5191, 03 vmax, 92 gs500, 85 ch250, 07 zx10
>> > .- FreeBSD committer
>> >
>
> --
> - Alfred Perlstein
> .- AMA, VMOA #5191, 03 vmax, 92 gs500, 85 ch250, 07 zx10
> .- FreeBSD committer
>
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