hup.diff

diff --git a/lib/Mojo/Server/Prefork.pm b/lib/Mojo/Server/Prefork.pm
index 42db1ed..853eb08 100644
--- a/lib/Mojo/Server/Prefork.pm
+++ b/lib/Mojo/Server/Prefork.pm
@@ -80,12 +80,14 @@ sub run {
   $self->{poll}->mask($self->{reader}, POLLIN | POLLPRI);
 
   # Clean manager environment
-  local $SIG{INT} = local $SIG{TERM} = sub { $self->_term };
   local $SIG{CHLD} = sub {
     while ((my $pid = waitpid -1, WNOHANG) > 0) {
       $self->emit(reap => $pid)->_stopped($pid);
     }
   };
+  local $SIG{HUP}
+    = sub { $_->{graceful} ||= steady_time for values %{$self->{pool}} };
+  local $SIG{INT} = local $SIG{TERM} = sub { $self->_term };
   local $SIG{QUIT} = sub { $self->_term(1) };
   local $SIG{TTIN} = sub { $self->workers($self->workers + 1) };
   local $SIG{TTOU} = sub {
@@ -189,7 +191,7 @@ sub _spawn {
   $loop->recurring($self->heartbeat_interval => $cb);
 
   # Clean worker environment
-  $SIG{$_} = 'DEFAULT' for qw(INT TERM CHLD TTIN TTOU);
+  $SIG{$_} = 'DEFAULT' for qw(CHLD HUP INT TERM TTIN TTOU);
   $SIG{QUIT} = sub { $loop->max_connections(0) };
   delete @$self{qw(poll reader)};
   srand;
@@ -287,6 +289,10 @@ See L<Mojolicious::Guides::Cookbook/"DEPLOYMENT"> for more.
 The L<Mojo::Server::Prefork> manager process can be controlled at runtime with
 the following signals.
 
+=head2 HUP
+
+Restart all workers gracefully.
+
 =head2 INT, TERM
 
 Shut down server immediately.