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From: Eric Wong <e@yhbt.net>
To: meta@public-inbox.org
Subject: [PATCH] syscall: support sparc64 (and maybe other big-endian systems)
Date: Fri,  7 Aug 2020 10:15:04 +0000	[thread overview]
Message-ID: <20200807101504.9703-1-e@yhbt.net> (raw)

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.
---
 lib/PublicInbox/DSKQXS.pm  |  4 ++--
 lib/PublicInbox/Daemon.pm  |  4 ++--
 lib/PublicInbox/Sigfd.pm   |  4 ++--
 lib/PublicInbox/Syscall.pm | 29 +++++++++++++++++------------
 script/public-inbox-watch  |  4 ++--
 t/sigfd.t                  |  6 +++---
 6 files changed, 28 insertions(+), 23 deletions(-)

diff --git a/lib/PublicInbox/DSKQXS.pm b/lib/PublicInbox/DSKQXS.pm
index 35cdecda8..d1d3fe60d 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;
 	$self;
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index ab0c2226e..454751834 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -15,7 +15,7 @@ use Cwd qw/abs_path/;
 STDOUT->autoflush(1);
 STDERR->autoflush(1);
 use PublicInbox::DS qw(now);
-use PublicInbox::Syscall qw(SFD_NONBLOCK);
+use PublicInbox::Syscall qw($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 bf91bb377..5d61e6308 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 ce6b0f3af..e4f00a2a2 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 {
 		$! = ENOSYS;
 		undef;
diff --git a/script/public-inbox-watch b/script/public-inbox-watch
index c07d45d74..20534bf2a 100755
--- a/script/public-inbox-watch
+++ b/script/public-inbox-watch
@@ -7,7 +7,7 @@ use PublicInbox::WatchMaildir;
 use PublicInbox::Config;
 use PublicInbox::DS;
 use PublicInbox::Sigfd;
-use PublicInbox::Syscall qw(SFD_NONBLOCK);
+use PublicInbox::Syscall qw($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($oldset);
diff --git a/t/sigfd.t b/t/sigfd.t
index 07120b64c..8daf31374 100644
--- a/t/sigfd.t
+++ b/t/sigfd.t
@@ -4,7 +4,7 @@ use Test::More;
 use IO::Handle;
 use POSIX qw(:signal_h);
 use Errno qw(ENOSYS);
-use PublicInbox::Syscall qw(SFD_NONBLOCK);
+use PublicInbox::Syscall qw($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 $!";

                 reply	other threads:[~2020-08-07 10:15 UTC|newest]

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