[PATCH] 8170639: [Linux] jsig is limited to a maximum of 64 signals

[David Holmes]

Hi,

Was the issue of NSIG not being defined resolved?

Thanks,
David

On 14/12/2018 10:23 pm, Ao Qi wrote:
> Hi all,
> 
> Zero does not build on Linux MIPS (actually all Linux of NSIG > 64)
> since OpenJDK 9, because NISG is 128 on MIPS and can not be encoded in
> uint64_t sigs. James Cowgill from Debian tried to push a patch fixing
> this[1] but it seems he failed. I would like to try again to request
> fixing this in http://hg.openjdk.java.net/jdk/jdk. This was fixed in
> AIX implementation.
> 
> After applying this patch, zero can be built on MIPS (Debian testing).
> I've run the jtreg tests [2] on x86 Linux.
> 
> [1] http://mail.openjdk.java.net/pipermail/hotspot-dev/2016-November/025399.html
> [2] https://download.java.net/openjdk/testresults/12/docs/howtoruntests.html
> 
> Cheers,
> Ao Qi
> 
> $ hg export -r 52869
> # HG changeset patch
> # User aoqi
> # Date 1544089853 0
> #      Thu Dec 06 09:50:53 2018 +0000
> # Node ID 3eea22b79dc3a4bf26616bde1acb587e3f56e6fe
> # Parent  b4982a22926b4ddf1a7b1f770e4d42ce8c1dd575
> 8170639: [Linux] jsig is limited to a maximum of 64 signals
> 
> diff -r b4982a22926b -r 3eea22b79dc3 src/hotspot/os/linux/os_linux.cpp
> --- a/src/hotspot/os/linux/os_linux.cpp Thu Dec 06 11:54:39 2018 +0530
> +++ b/src/hotspot/os/linux/os_linux.cpp Thu Dec 06 09:50:53 2018 +0000
> @@ -4434,10 +4434,7 @@
> 
>   // For signal-chaining
>   struct sigaction sigact[NSIG];
> -uint64_t sigs = 0;
> -#if (64 < NSIG-1)
> -#error "Not all signals can be encoded in sigs. Adapt its type!"
> -#endif
> +sigset_t sigs;
>   bool os::Linux::libjsig_is_loaded = false;
>   typedef struct sigaction *(*get_signal_t)(int);
>   get_signal_t os::Linux::get_signal_action = NULL;
> @@ -4516,7 +4513,7 @@
>   }
> 
>   struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
> -  if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
> +  if (sigismember(&sigs, sig)) {
>       return &sigact[sig];
>     }
>     return NULL;
> @@ -4525,7 +4522,7 @@
>   void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
>     assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
>     sigact[sig] = oldAct;
> -  sigs |= (uint64_t)1 << (sig-1);
> +  sigaddset(&sigs, sig);
>   }
> 
>   // for diagnostic
> @@ -4616,6 +4613,7 @@
>         (*begin_signal_setting)();
>       }
> 
> +    ::sigemptyset(&sigs);
>       set_signal_handler(SIGSEGV, true);
>       set_signal_handler(SIGPIPE, true);
>       set_signal_handler(SIGBUS, true);
>