my $pid = open2($rfh, $wfh, "ssh $opts $hostspec $cmd");

##</code><code>##

### Self-pipe init.
pipe(SIGRD, SIGWR);
# Make SIGRD non-blocking.
vec($rin, fileno SIGRD, 1) = 1;

##</code><code>##

my $byte = 1;
syswrite(SIGWR, $byte, 1);

##</code><code>##

my $nfound = select($rout = $rin, $wout = $win, undef, undef);
# Check $nfound for errors.
if(vec($rout, fileno SIGRD, 1)) {
  my $byte;
  while(sysread(SIGRD, $byte, 1)) {
  if($term) {
    # INT/TERM arrived, kill sshs, modify some data, ...
    $term = 0;
  }
  else {
    # CHLD arrived, do waitpid(), modify some data, ...
  }
}