dtrace discuss - Aug 2008 - variables in dtrace scripts

Greetings,

is there a way to specify probes and other dtrace operations via command 
line parameters, like
"

BEGIN
{
     usr_exec=$$1;
     usr_syscall=$$2;
}

syscall::usr_syscall:entry
/execname == usr_exec && guard++ == 0/
{
...
"
[this does not work]

This would make it possible to create "generic" dtrace scripts.

Otherwise, some shellscript with sed-magic would need to be used.

  thanks Joachim

-- 
Joachim Worringen, Software Architect, Dolphin Interconnect Solutions
phone ++49/(0)228/324 08 17 - http://www.dolphinics.com

On Tue, Aug 19, 2008 at 04:59:31PM +0200, Joachim Worringen
wrote:
> Greetings,
> 
> is there a way to specify probes and other dtrace operations via command 
> line parameters, like
> "
> 
> BEGIN
> {
>      usr_exec=$$1;
>      usr_syscall=$$2;
> }
> 
> syscall::usr_syscall:entry
> /execname == usr_exec && guard++ == 0/
> {
> ...
> "
> [this does not work]
> 
> This would make it possible to create "generic" dtrace scripts.
> 
> Otherwise, some shellscript with sed-magic would need to be used.
> 
>   thanks Joachim
You have both asked and answered your own question :)

See http://wikis.sun.com/display/DTrace/Scripting

-Mike

-- 
Mike Shapiro, Sun Microsystems Fishworks. blogs.sun.com/mws/

Hi Joachim,

You can''t use variables, but you can use parameters from the
command-line:

---8<--- arg.d ---8<---

#!/usr/sbin/dtrace -s

pid$target::$1:entry
{
        @[$$1] = count();
}

---8<--- arg.d ---8<---

# ./arg.d -p `pgrep -n firefox` malloc
dtrace: script ''./arg.d'' matched 4 probes
^C
  malloc                                                        50262

Adam

On Tue, Aug 19, 2008 at 04:59:31PM +0200, Joachim Worringen
wrote:
> Greetings,
> 
> is there a way to specify probes and other dtrace operations via command 
> line parameters, like
> "
> 
> BEGIN
> {
>      usr_exec=$$1;
>      usr_syscall=$$2;
> }
> 
> syscall::usr_syscall:entry
> /execname == usr_exec && guard++ == 0/
> {
> ...
> "
> [this does not work]
> 
> This would make it possible to create "generic" dtrace scripts.
> 
> Otherwise, some shellscript with sed-magic would need to be used.
> 
>   thanks Joachim
> 
> -- 
> Joachim Worringen, Software Architect, Dolphin Interconnect Solutions
> phone ++49/(0)228/324 08 17 - http://www.dolphinics.com
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
-- 
Adam Leventhal, Fishworks                     http://blogs.sun.com/ahl

Adam Leventhal wrote:
> Hi Joachim,
> 
> You can''t use variables, but you can use parameters from the
command-line:
> 
> ---8<--- arg.d ---8<---
> 
> #!/usr/sbin/dtrace -s
> 
> pid$target::$1:entry
> {
>         @[$$1] = count();
> }
> 
> ---8<--- arg.d ---8<---
> 
> # ./arg.d -p `pgrep -n firefox` malloc
> dtrace: script ''./arg.d'' matched 4 probes
> ^C
>   malloc                                                        50262
Thanks, this will be fine as well. Don''t need variables, although they 
might make things clearer in longer scripts.

Still, it would be nice to have some sort of builtin getopt() to build 
more robust native dtrace scripts - with more than one macro argument, 
confusion is guaranteed now. And sed-preprocssing is addional overhead 
when writing and maintaining a script.

Before asking this question, I checked the dtrace user guide and failed 
to find this information - now it''s obvious... sorry.

  Joachim

-- 
Joachim Worringen, Software Architect, Dolphin Interconnect Solutions
phone ++49/(0)228/324 08 17 - http://www.dolphinics.com