[PATCH] exit/kill ourself with straced child's exitcode/signal

[Denys Vlasenko]

This patch is intended to implement this RFE:

https://bugzilla.redhat.com/show_bug.cgi?id=105371

There are some patches for this, but apparently discussion
on mailing list died out with no results. At least that bug
is still open. Moreover, the patches are somewhat buggy.

I propose this patch.

I think in real-world usage people do not check strace usage in scripts. They
just use it correctly, so that it doesn't exit(1) with usage info and whatnot.

But I know that when I try to debug something by replacing "cmd [args]"
with "strace cmd [args]" the fact that it's sometimes a problem
that parent does not see exit code of cmd but sees zero.

IOW: I do not think that there are users who will be adversely affected by this
change in behavior. Therefore I do not think adding a switch to enable this is
worth it. It will be just a case of featuritis.

Problems this patch fixes compared to previous patches:

* strace returns exit code of straced process, *never its children*.
* If child died from a signal, strace will (try to) die from the same signal.
* strace -p <pid> is not affected (will exit 0 as before).

--
vda