Quoth Brian Bloniarz
IMHO the simplest fix is the patch below: simply avoid SIG_IGN, instead install a handler which does nothing. This way, an exec() restores the handler to SIG_DFL. I've included a testcase too.
I don't know enough to make a case for or against this, but the side effects are different: whether the handler does anything or not, it will interrupt some system calls. Since there are already may be a regular barrage of SIGALRMs from the GHC runtime, maybe one more such interruption can't hurt anything ... but note that we recently heard from someone in Australia with a problem on OpenSolaris where evidently these SIGALRMs were in fact interrupting hGetContents from a pipe, and no one seemed to have any notion why. At any rate, the affected system calls would set EAGAIN, possibly including the write(2) that's supposed to set EPIPE (though I think that would be an unusual implementation.) Donn Cave, donn@avvanta.com