Initial import of Perl5. The king is dead; long live the king!

1 files changed, 50 insertions, 0 deletions

diff --git a/contrib/perl5/ext/Thread/Thread/Signal.pm b/contrib/perl5/ext/Thread/Thread/Signal.pm
new file mode 100644
index 0000000..f5f03db
--- /dev/null
+++ b/contrib/perl5/ext/Thread/Thread/Signal.pm
@@ -0,0 +1,50 @@
+package Thread::Signal;
+use Thread qw(async);
+
+=head1 NAME
+
+Thread::Signal - Start a thread which runs signal handlers reliably
+
+=head1 SYNOPSIS
+
+    use Thread::Signal;
+
+    $SIG{HUP} = \&some_handler;
+
+=head1 DESCRIPTION
+
+The C<Thread::Signal> module starts up a special signal handler thread.
+All signals to the process are delivered to it and it runs the
+associated C<$SIG{FOO}> handlers for them. Without this module,
+signals arriving at inopportune moments (such as when perl's internals
+are in the middle of updating critical structures) cause the perl
+code of the handler to be run unsafely which can cause memory corruption
+or worse.
+
+=head1 BUGS
+
+This module changes the semantics of signal handling slightly in that
+the signal handler is run separately from the main thread (and in
+parallel with it). This means that tricks such as calling C<die> from
+a signal handler behave differently (and, in particular, can't be
+used to exit directly from a system call).
+
+=cut
+
+if (!init_thread_signals()) {
+    require Carp;
+    Carp::croak("init_thread_signals failed: $!");
+}
+
+async {
+    my $sig;
+    while ($sig = await_signal()) {
+	&$sig();
+    }
+};
+
+END {
+    kill_sighandler_thread();
+}
+
+1;