syscall: support sparc64 (and maybe other big-endian systems)

Thanks to the GCC compile farm project, we can wire up syscalls
for sparc64 and set system-specific SFD_* constants properly.

I've FINALLY figured out how to use POSIX::SigSet to generate
a usable buffer for the syscall perlfunc.  This is required
for endian-neutral behavior and relevant to sparc64, at least.

There's no need for signalfd-related stuff to be constants,
either.  signalfd initialization is never a hot path and a stub
subroutine for constants uses several KB of memory in the
interpreter.

We'll drop the needless SEEK_CUR import while we're importing
O_NONBLOCK, too.

6 files changed, 28 insertions, 23 deletions

diff --git a/lib/PublicInbox/DSKQXS.pm b/lib/PublicInbox/DSKQXS.pm
index 35cdecda..d1d3fe60 100644
--- a/lib/PublicInbox/DSKQXS.pm
+++ b/lib/PublicInbox/DSKQXS.pm
@@ -18,7 +18,7 @@ use Symbol qw(gensym);
 use IO::KQueue;
 use Errno qw(EAGAIN);
 use PublicInbox::Syscall qw(EPOLLONESHOT EPOLLIN EPOLLOUT EPOLLET
-        EPOLL_CTL_ADD EPOLL_CTL_MOD EPOLL_CTL_DEL SFD_NONBLOCK);
+        EPOLL_CTL_ADD EPOLL_CTL_MOD EPOLL_CTL_DEL $SFD_NONBLOCK);
 our @EXPORT_OK = qw(epoll_ctl epoll_wait);
 
 sub EV_DISPATCH () { 0x0080 }
@@ -57,7 +57,7 @@ sub signalfd {
 sub TIEHANDLE { # similar to signalfd()
         my ($class, $signo, $flags) = @_;
         my $self = $class->new;
-        $self->{timeout} = ($flags & SFD_NONBLOCK) ? 0 : -1;
+        $self->{timeout} = ($flags & $SFD_NONBLOCK) ? 0 : -1;
         my $kq = $self->{kq};
         $kq->EV_SET($_, EVFILT_SIGNAL, EV_ADD) for @$signo;
         $self;
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index ab0c2226..45475183 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -15,7 +15,7 @@ use Cwd qw/abs_path/;
 STDOUT->autoflush(1);
 STDERR->autoflush(1);
 use PublicInbox::DS qw(now);
-use PublicInbox::Syscall qw(SFD_NONBLOCK);
+use PublicInbox::Syscall qw($SFD_NONBLOCK);
 require PublicInbox::Listener;
 require PublicInbox::ParentPipe;
 use PublicInbox::Sigfd;
@@ -622,7 +622,7 @@ sub daemon_loop ($$$$) {
                 # this calls epoll_create:
                 PublicInbox::Listener->new($_, $tls_cb || $post_accept)
         } @listeners;
-        my $sigfd = PublicInbox::Sigfd->new($sig, SFD_NONBLOCK);
+        my $sigfd = PublicInbox::Sigfd->new($sig, $SFD_NONBLOCK);
         local %SIG = (%SIG, %$sig) if !$sigfd;
         if (!$sigfd) {
                 # wake up every second to accept signals if we don't
diff --git a/lib/PublicInbox/Sigfd.pm b/lib/PublicInbox/Sigfd.pm
index bf91bb37..5d61e630 100644
--- a/lib/PublicInbox/Sigfd.pm
+++ b/lib/PublicInbox/Sigfd.pm
@@ -6,7 +6,7 @@
 package PublicInbox::Sigfd;
 use strict;
 use parent qw(PublicInbox::DS);
-use PublicInbox::Syscall qw(signalfd EPOLLIN EPOLLET SFD_NONBLOCK);
+use PublicInbox::Syscall qw(signalfd EPOLLIN EPOLLET $SFD_NONBLOCK);
 use POSIX qw(:signal_h);
 use IO::Handle ();
 
@@ -33,7 +33,7 @@ sub new {
         } else {
                 return; # wake up every second to check for signals
         }
-        if ($flags & SFD_NONBLOCK) { # it can go into the event loop
+        if ($flags & $SFD_NONBLOCK) { # it can go into the event loop
                 $self->SUPER::new($io, EPOLLIN | EPOLLET);
         } else { # master main loop
                 $self->{sock} = $io;
diff --git a/lib/PublicInbox/Syscall.pm b/lib/PublicInbox/Syscall.pm
index ce6b0f3a..e4f00a2a 100644
--- a/lib/PublicInbox/Syscall.pm
+++ b/lib/PublicInbox/Syscall.pm
@@ -14,7 +14,7 @@
 package PublicInbox::Syscall;
 use strict;
 use parent qw(Exporter);
-use POSIX qw(ENOSYS SEEK_CUR);
+use POSIX qw(ENOSYS O_NONBLOCK);
 use Config;
 
 # $VERSION = '0.25'; # Sys::Syscall version
@@ -22,7 +22,7 @@ our @EXPORT_OK = qw(epoll_ctl epoll_create epoll_wait
                   EPOLLIN EPOLLOUT EPOLLET
                   EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
                   EPOLLONESHOT EPOLLEXCLUSIVE
-                  signalfd SFD_NONBLOCK);
+                  signalfd $SFD_NONBLOCK);
 our %EXPORT_TAGS = (epoll => [qw(epoll_ctl epoll_create epoll_wait
                              EPOLLIN EPOLLOUT
                              EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
@@ -41,9 +41,6 @@ use constant {
         EPOLL_CTL_ADD => 1,
         EPOLL_CTL_DEL => 2,
         EPOLL_CTL_MOD => 3,
-
-        SFD_CLOEXEC => 02000000,
-        SFD_NONBLOCK => 00004000,
 };
 
 our $loaded_syscall = 0;
@@ -69,6 +66,8 @@ our (
      $SYS_signalfd4,
      );
 
+my $SFD_CLOEXEC = 02000000; # Perl does not expose O_CLOEXEC
+our $SFD_NONBLOCK = O_NONBLOCK;
 our $no_deprecated = 0;
 
 if ($^O eq "linux") {
@@ -103,6 +102,13 @@ if ($^O eq "linux") {
         $SYS_epoll_ctl = 1073742057;
         $SYS_epoll_wait = 1073742056;
         $SYS_signalfd4 = 1073742113;
+    } elsif ($machine eq 'sparc64') {
+        $SYS_epoll_create = 193;
+        $SYS_epoll_ctl = 194;
+        $SYS_epoll_wait = 195;
+        $u64_mod_8 = 1;
+        $SYS_signalfd4 = 317;
+        $SFD_CLOEXEC = 020000000;
     } elsif ($machine =~ m/^parisc/) {
         $SYS_epoll_create = 224;
         $SYS_epoll_ctl    = 225;
@@ -140,6 +146,7 @@ if ($^O eq "linux") {
         $SYS_epoll_wait   = 409;
         $u64_mod_8        = 1;
         $SYS_signalfd4 = 484;
+        $SFD_CLOEXEC = 010000000;
     } elsif ($machine eq "aarch64") {
         $SYS_epoll_create = 20;  # (sys_epoll_create1)
         $SYS_epoll_ctl    = 21;
@@ -257,13 +264,11 @@ sub epoll_wait_mod8 {
 sub signalfd ($$$) {
         my ($fd, $signos, $flags) = @_;
         if ($SYS_signalfd4) {
-                # Not sure if there's a way to get pack/unpack to get the
-                # contents of POSIX::SigSet to a buffer, but prepping the
-                # bitmap like one would for select() works:
-                my $buf = "\0" x 8;
-                vec($buf, $_ - 1, 1) = 1 for @$signos;
-
-                syscall($SYS_signalfd4, $fd, $buf, 8, $flags|SFD_CLOEXEC);
+                my $set = POSIX::SigSet->new(@$signos);
+                syscall($SYS_signalfd4, $fd, "$$set",
+                        # $Config{sig_count} is NSIG, so this is NSIG/8:
+                        int($Config{sig_count}/8),
+                        $flags|$SFD_CLOEXEC);
         } else {
                 $! = ENOSYS;
                 undef;
diff --git a/script/public-inbox-watch b/script/public-inbox-watch
index c07d45d7..20534bf2 100755
--- a/script/public-inbox-watch
+++ b/script/public-inbox-watch
@@ -7,7 +7,7 @@ use PublicInbox::WatchMaildir;
 use PublicInbox::Config;
 use PublicInbox::DS;
 use PublicInbox::Sigfd;
-use PublicInbox::Syscall qw(SFD_NONBLOCK);
+use PublicInbox::Syscall qw($SFD_NONBLOCK);
 my $oldset = PublicInbox::Sigfd::block_signals();
 STDOUT->autoflush(1);
 STDERR->autoflush(1);
@@ -35,7 +35,7 @@ if ($watch_md) {
         unless (grep(/\A--no-scan\z/, @ARGV)) {
                 PublicInbox::DS::requeue($scan);
         }
-        my $sigfd = PublicInbox::Sigfd->new($sig, SFD_NONBLOCK);
+        my $sigfd = PublicInbox::Sigfd->new($sig, $SFD_NONBLOCK);
         local %SIG = (%SIG, %$sig) if !$sigfd;
         if (!$sigfd) {
                 PublicInbox::Sigfd::set_sigmask($oldset);
diff --git a/t/sigfd.t b/t/sigfd.t
index 07120b64..8daf3137 100644
--- a/t/sigfd.t
+++ b/t/sigfd.t
@@ -4,7 +4,7 @@ use Test::More;
 use IO::Handle;
 use POSIX qw(:signal_h);
 use Errno qw(ENOSYS);
-use PublicInbox::Syscall qw(SFD_NONBLOCK);
+use PublicInbox::Syscall qw($SFD_NONBLOCK);
 require_ok 'PublicInbox::Sigfd';
 
 SKIP: {
@@ -42,8 +42,8 @@ SKIP: {
                 }
                 $sigfd = undef;
 
-                my $nbsig = PublicInbox::Sigfd->new($sig, SFD_NONBLOCK);
-                ok($nbsig, 'Sigfd->new SFD_NONBLOCK works');
+                my $nbsig = PublicInbox::Sigfd->new($sig, $SFD_NONBLOCK);
+                ok($nbsig, 'Sigfd->new $SFD_NONBLOCK works');
                 is($nbsig->wait_once, undef, 'nonblocking ->wait_once');
                 ok($! == Errno::EAGAIN, 'got EAGAIN');
                 kill('HUP', $$) or die "kill $!";