Looking in siginfo to find who sent this signal

Question

Hello,
I am trying to trace the source of all signals received by a process.
As I read the documentation, the proc:::signal-handle probe will fire when a thread is about to receive a signal and will have args[1] either NULL or containing a siginfo_t structure.
I can print out the signal code using
dtrace -n "proc:::signal-handle
/pid==$MYPID && args[1]!=NULL/
printf(\"Thread %d about to handle signal %d code %d\n\",
tid,arg0,args[1]->si_code);
But when I try to print the pid of the sender from args[1]->si_pid, (which should be available when si_code<=0)
using
dtrace -n "proc:::signal-handle
/pid==$MYPID && args[1]!=NULL && args[1]->si_code<=0/
printf(\"Thread %d about to handle signal %d pid %d\n\",
tid,arg0,args[1]->si_pid);
I get
dtrace: invalid probe specifier proc:::signal-handle
/pid==18568 && args[1]!=NULL && args[1]->si_code<=0/
printf("Thread %d about to handle signal %d pid %d\n",
tid,arg0,args[1]->si_pid);
}: in action list: si_pid is not a member of struct siginfo
Is Dtraces' struct siginfo differant from the siginfo_t on Solaris 10?
Can anybody tell me the right way to find who sent a signal?
Thanks
-- Steve

Answer 1

Got it.
The siginfo structure does not really have a si_pid member.
It is defined in /usr/include/sys/siginfo.h as
#define si_pid __data.__proc.__pid
which Dtrace doesn't know about. So I just need to say
dtrace -n "proc:::signal-handle
/pid==$MYPID && args[1]!=NULL && args[1]->si_code<=0/
printf(\"Thread %d about to handle signal %d pid %d\n\",
tid,arg0,args[1]->__data.__proc.__pid);
and all is well.
-- Steve