File Coverage

blib/lib/Sys/SigAction.pm

Criterion	Covered	Total	%
statement	78	89	87.6
branch	22	40	55.0
condition	4	12	33.3
subroutine	18	18	100.0
pod	5	8	62.5
total	127	167	76.0

#
#   Copyright (c) 2004-2016 Lincoln A. Baxter
#
#   You may distribute under the terms of either the GNU General Public
#   License or the Artistic License, as specified in the Perl README file,

package Sys::SigAction;
require 5.005;
use strict;
use warnings;
use POSIX qw( :signal_h ceil INT_MAX ) ;
require Exporter;
use vars qw( $VERSION @ISA @EXPORT_OK %EXPORT_TAGS );

#support high resolution time transparently in timeout_call by defining
#the function sig_alarm() which calls Time::HiRes::alarm if available
#or core alarm with the ceil of the value passed otherwise.
#timeout_call uses sig_alarm()

#replacement for alarm, factional second arg in floating point format:
use Sys::SigAction::Alarm qw( ssa_alarm );
sub sig_alarm
{
   my $secs = shift;
   ssa_alarm( $secs );
}

#use Data::Dumper;

@ISA = qw( Exporter );
@EXPORT_OK = qw( set_sig_handler timeout_call sig_name sig_number sig_alarm );
$VERSION = '0.23';

use Config;
my %signame = ();
my %signo = ();
{
   defined $Config{sig_name} or die "This OS does not support signals?";
   my $i = 0;     # Config prepends fake 0 signal called "ZERO".
   my @numbers = split( ' ' ,$Config{sig_num} );
   foreach my $name (split(' ', $Config{sig_name}))
   {
      $signo{$name} = $numbers[$i];
      $signame{$signo{$name}} = $name;
      #print "name=$name num=" .$numbers[$i] ."\n" ;
      $i++;
   }
}

sub sig_name {
   my ($sig) = @_;
   return $sig if $sig !~ m/^\d+$/ ;
   return $signame{$sig} ;
}
sub sig_number {
   my ($sig) = @_;
   return $sig if $sig =~ m/^\d+$/;
   return $signo{$sig} ;
}
#if ( $] < 5008 ) {
#   #over write definitions of sig_name and sig_number
#   sub sig_name { warn "sig_name() not supported on perl versions < 5.8.0"; }
#   sub sig_number { warn "sig_number() not supported on perl versions < 5.8.0"; }
#}

my $use_sigaction = ( $] >= 5.008 and $Config{d_sigaction} );

sub _attrs_warning($)
{
   my ( $attrs ) =  @_ ;
   #my $act =  POSIX::SigAction->new( $handler ,$mask ,$attrs->{flags} ,$attrs->{safe} );
   #steve ( [e-mail] submitted  http://rt.cpan.org/Ticket/Display.html?id=19916
   #  puts out the above line is a mis-interpretation of the API for POSIX::SigAcation
   #  so here is the fix (per his suggestion)... lab:
   #
   #http://rt.cpan.org/Public/Bug/Display.html?id=21777
   #2006-09-29: in perl 5.8.0 (RH) $act->safe() is broken
   #            safe is not available until 5.8.2
   #            DAMN... it was in my docs too...
   if ( exists( $attrs->{safe} ) )
   {
      if ( ( $] < 5.008002 ) && defined($attrs->{safe}) && $attrs->{safe} )
      {
         warn "safe mode is not supported in perl versions less than 5.8.2";
         delete $attrs->{safe};
      }
   }

}
sub set_sig_handler( $$;$$ )
{
   my ( $sig ,$handler ,$attrs ) = @_;
   $attrs = {} if not defined $attrs;
   _attrs_warning($attrs);
   if ( not $use_sigaction )
   {
      #warn '$flags not supported in perl versions < 5.8' if $] < 5.008 and defined $flags;
      $sig = sig_name( $sig );
      my $ohandler = $SIG{$sig};
      $SIG{$sig} = $handler;
      return if not defined wantarray;
      return Sys::SigAction->new( $sig ,$ohandler );
   }
   my $act = mk_sig_action( $handler ,$attrs );
   return set_sigaction( sig_number($sig) ,$act );
}
sub mk_sig_action($$)
{
   my ( $handler ,$attrs ) = @_;
   die 'mk_sig_action requires perl 5.8.0 or later' if $] < 5.008;
   $attrs->{flags} = 0 if not defined $attrs->{flags};
   $attrs->{mask} = [] if not defined $attrs->{mask};
   #die '$sig is not defined' if not defined $sig;
   #$sig = sig_number( $sig );
   my @siglist = ();
   foreach (@{$attrs->{mask}}) { push( @siglist ,sig_number($_)); };
   my $mask = POSIX::SigSet->new( @siglist );

   my $act =  POSIX::SigAction->new( $handler ,$mask ,$attrs->{flags} );

   #apply patch suggested by CPAN bugs
   #  http://rt.cpan.org/Ticket/Display.html?id=39599
   #  http://rt.cpan.org/Ticket/Display.html?id=39946 (these are dups)
   #using safe mode with masking signals still breaks the masking of signals!
   $act->safe($attrs->{safe}) if defined $attrs->{safe};
   return $act;
}


sub set_sigaction($$)
{
   my ( $sig ,$action  ) = @_;
   die 'set_sigaction() requires perl 5.8.0 or later' if $] < 5.008;
   die '$sig is not defined' if not defined $sig;
   die '$action is not a POSIX::SigAction' if not UNIVERSAL::isa( $action ,'POSIX::SigAction' );
   $sig = sig_number( $sig );
   if ( defined wantarray )
   {
      my $oact = POSIX::SigAction->new();
      sigaction( $sig ,$action ,$oact );
      return Sys::SigAction->new( $sig ,$oact );
   }
   else
   {
      sigaction( $sig ,$action );
   }
}

use constant TIMEDOUT => {};
sub timeout_call( $$@ )
{
   my ( $timeout, $code, @args ) = @_;

   if (!$timeout) {
      &$code(@args);
      return 0;
   }

   my $timed_out = 0;
   eval {
      my $sa = set_sig_handler( SIGALRM ,sub { $timed_out = 1; die TIMEDOUT; } );
      eval {
         sig_alarm( $timeout );
         &$code(@args);
      };
      sig_alarm(0);
      die $@ if $@;
   };
   die $@ if $@ and (not ref $@ or $@ != TIMEDOUT);

   return $timed_out;
}
sub new {
   my ($class,$sig,$act) = @_;
   bless { SIG=>$sig ,ACT => $act } ,$class ;
}
sub DESTROY
{
   if ( $use_sigaction )
   {
      set_sigaction( $_[0]->{'SIG'} ,$_[0]->{'ACT'} );
   }
   else
   {
      #set it to default if not defined (suppress undefined warning)
      $SIG{$_[0]->{'SIG'}} = defined $_[0]->{'ACT'} ? $_[0]->{'ACT'} : 'DEFAULT' ;
   }
   return;
}

1;

__END__