On Tue, Apr 07, 2009 at 10:39:02AM -0700, Brett Monroe wrote:
> Hey all,
>
> This is probably a dumb newbie question but I seem to be misunderstanding
> what the copyin function can do. When I run the following one-liner:
>
> dtrace -n 'fbt::sprintf:return {printf("%s %s",execname,copyinstr(arg0))}'
>
> I get the following errors:
>
> ...
> dtrace: error on enabled probe ID 1 (ID 15240: fbt:genunix:sprintf:return):
> invalid address (0x1b2) in action #2 at DIF offset 28
> dtrace: error on enabled probe ID 1 (ID 15240: fbt:genunix:sprintf:return):
> invalid address (0x1b2) in action #2 at DIF offset 28
> dtrace: error on enabled probe ID 1 (ID 15240: fbt:genunix:sprintf:return):
> invalid address (0x1b2) in action #2 at DIF offset 28
> ...
>
> Shouldn't copyin output the string pointed to by *buf? Or does this only
> work for userspace functions?
copyin() is only used for user addresses. Kernel addresses can be used
directly (though for 'char *'s, you may need to use stringof()).
You've got another error, too; the returned value is in arg1, not arg0 (which
holds the offset of the ret instruction). Also, you should use the args[]
array, since fbt probes have type information:
% dtrace -n 'fbt::sprintf:return {printf("%s %s",execname,stringof(args[1]))}'
Cheers,
- jonathan
_______________________________________________
dtrace-discuss mailing list
dtrace-discuss@opensolaris.org
