Re: [PATCH] Fix signull test case

[Andrew Cagney <cagney at gnu dot org>]

> Hello,
>
> the signull.exp test case fails when running under a 2.6 kernel,
> because it uses longjmp to leave a SIGSEGV handler.  This results
> in the signal remaining blocked for the rest of program execution,
> and the second segmentation violation triggered by the test case
> simply terminates the program.  The fix is to use siglongjmp.

Hmm, checking POSIX, it was left unspecified.  I choose to read the 
wrong man page :-(

> Also, the test case uses 'signal' to install the signal handler;
> according to POSIX it is undefined whether this routine installs
> the handler with the 'one-shot' property or not.  (Apparently,
> on BSD-like systems 'one-shot' is the default.)

Very very old systems.  Modern BSD systems leave the signal in place.

> Thus, I've also changed the test case to use sigaction instead,
> to make sure the handler remains active across multiple invocations.
> (This isn't currently an actual problem on Linux systems -- if you
> prefer I can remove this part.)
>
> Tested on s390-ibm-linux and s390x-ibm-linux, fixes one test suite
> failure.

Andrew