UNIX for Advanced & Expert Users

My problem is this:

I need to have a catch-all for my processes. An example would be, using a trap, in the parent, to catch any non-0 exit or invalid command (a way to catch core dumps would be cool, too) in not only the parent, but it's children and they're children. Not only that, but I also have to be able to have the same functionalith on anything that the parent or children dot in (functions containted in seperate files). Currently I can only get the trap to operate correctly on one level - parent/child. Also, it doesn't seem like I can create some sort of trap function in a seperate trapfuncs file and have it work. I dot it in and it never sees anything go wrong.

I'd really appreciate any help I could get on this. I'm stuck and can't figure this out for the life of me. I know one of gurus out there must have the answer. P.S. I'm open to any alternatives that don't mean putting blocks of code in every sinlge script and file.

Thanks!

A bit more information would help...

What flavor of UNIX?
Is this a shell script or C program?
If shell script, what shell (sh, ksh, bash, csh)?

In shell's such as bash and ksh, if you execute another
shell script, a new shell is spawned to execute it and
your "trap"s are set to their original values when a child process
is created.

In general, child processes that dump core should return
the value of 127+signal

I don't know if any of this helps but if you can provide more
details of what you have, maybe I (and others) can be of more
help.

I'm running on AIX, model 000111924C00 (if it helps at all), and when I do a uname -v I get 4. I think we may be running an IBM version or something because 4 seems really low. I'm primarily concerned with shell scripts (all are ksh and dtksh) with minor concerns for C, C++ and COBOL. The minor concers are very minor, though.

I'm not sure how I would trap a value of 127. I thought I could only trap 1-15 and ERR. Would ERR catch the 127?

I hope that this info helps. Please let me know if I can help clear anything up. I really appreciate the help.

OK. AIX and ksh helps my understanding.
If you run... kill -l
...on AIX 4.3.3 you get some 40 distinct signals
you can trap.
The ERR trap will fire whenever a command has
a non-zero return value. Note that this trap
is not inheritied by functions. And of course,
if you execute another shell script, a new shell is spawned to execute it and your "trap"s are set to their original values when a child process
is created.

The 128+signal stuff only applies to the
return value variable "$?" which when a program
is terminated by a signal (i.e. SEGV, BUS, etc)
and dumps core, the value of this signal + 128
is returned in $?

The short of it is... if you want to assure
proper signal handling in your shells, you
should have traps in all your scripts.

in ksh you could do something like this:

Code:

#!/usr/bin/ksh
# Functions
function trap_cmd {
echo "Ack, I've been whacked!"
exit 2
}
function trap_segv {
echo "Uh oh, segmentation fault... we may have just dumped core."
exit 127
}
# Error handling
trap 'trap_cmd' 1 2 3 4 5 6 7 8 9 10 12 13 14 15 19 20
trap 'trap_segv' 11
# Dummy command... interrupt with ^C, ^\, ^Z or kill it...
while `true`
do
sleep 5
done

I hope that helps with the handling of multiple different signals, and with placing a function with the trap...

Oh, BTW, these signals are from Linux's kill... yours may vary...

Thanks! It looks like this will help. I'm going to try a few things and post back.

Thanks, again, for your help.

Thanks a lot! I put the stuff into some functions and everything is working well. The only caveat is that I have to dot the function file into every script (children included) so that it woks correctly.

Thanks again for your help.