my $cmd;

eval {
  local $SIG{'ALRM'} = sub { die "DIED\n" };
  local $SIG{'CHLD'} = sub { die "DIED\n" };

  $cmd = <STDIN>;
};

if ($@) {
  die $@ eq "DIED\n" ? "We died from a sig handler\n" :
    "Other death: $@\n";
}