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

[Thomas Stüfe]

Hi Magnus,

just a cursory look, will look in greater detail tomorrow.

This is good, thanks for doing this.

As I wrote offlist, please remove the painfully wrong AIX "workarounds". I
do not know why we did this - the original code is quite old - my
assumption is that dlsym(RTLD_NEXT) was not working as expected on older
AIX versions. Well, it should work now according to IBMs manpages. Will
test later.

__thread is not Posix. I would prefer pthread_get/set_specific instead,
which is more portable.

Thanks!

Thomas





On Tue, Mar 27, 2018 at 11:42 AM, Magnus Ihse Bursie <
magnus.ihse.bursie at oracle.com> 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
>