RFR (M): JDK-8200298 Unify all unix versions of libjsig/jsig.c

[David Holmes]

Hi Magnus,

I will take a look at this tomorrow. There are some open bugs on jsig 
regarding the number of signals it can handle on different platforms 
IIRC. Also the Solaris differences may not be needed as the pthread 
functions can be used without any concern in most cases.

Thanks,
David

On 27/03/2018 7:42 PM, Magnus Ihse Bursie wrote:
> When I was about to update jsig.c, I noticed that the four copies for 
> aix, linux, macosx and solaris were basically the same, with only small 
> differences. Some of the differences were not even well motivated, but 
> were likely the result of this code duplication causing the code to 
> diverge.
> 
> A better solution is to unify them all into a single unix version, with 
> the few platform-specific changes handled on a per-platform basis.
> 
> I've made the following notable changes:
> 
> * I have removed the version check for Solaris. All other platforms seem 
> to do fine without it, and in general, we don't mistrust other JDK 
> libraries. An alternative is to add this version check to all other 
> platforms instead. If you think this is the correct course of action, 
> let me know and I'll fix it.
> 
> * Solaris used to have a dynamically allocated sact, instead of a 
> statically allocated array as all other platforms have. It's not likely 
> to be large, and the size is known at compile time, so there seems to be 
> no good reason for this.
> 
> * Linux and macosx used a uint32_t/uint64_t instead of sigset_t for 
> jvmsigs, as aix and solaris do. This is a less robust solution, and the 
> added checks show that it has failed in the past. Now all platforms use 
> sigset_t/sigismember().
> 
> Also worth noting:
> 
> * Solaris is not using pthreads, but it's own thread library, which 
> accounts for most of the #ifdef SOLARIS.
> 
> * In general, if an implementation was needed on one platform, but has 
> no effect or is harmless on others, I've kept it on all platforms 
> instead of sprinkling the code with #ifdefs.
> 
> To facilitate code review, here is a specially crafted webrev that shows 
> the differences compared to each of the individual, original per-OS 
> versions of jsig.c:
> http://cr.openjdk.java.net/~ihse/JDK-8200298-unify-libjsig/webrev.01
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8200298
> WebRev: 
> http://cr.openjdk.java.net/~ihse/JDK-8200298-unify-libjsig/webrev.03
> 
> /Magnus