use 4-argument select() rather than SIGALRM for readability

1 files changed, 9 insertions, 15 deletions

diff --git a/perl5/Local/Interactive.pm b/perl5/Local/Interactive.pm
index 0cd6e912..fa66d18e 100644
--- a/perl5/Local/Interactive.pm
+++ b/perl5/Local/Interactive.pm
@@ -221,23 +221,17 @@ sub _sysptycap_tty {
     # SSH control socket is still alive (seems to happen when using
     # Debian's SSH jump host to SSH to salsa)
     while (kill 0, $pid) {
-        my ($chars, $nchars);
-        local $@;
-        eval {
-            local $SIG{ALRM} = sub { die "sysread timeout\n" };
-            alarm 1;
-            $nchars = sysread $slave, $chars, 8192;
-            alarm 0;
-        };
-        if (my $exception = $@) {
-            die $exception unless $exception eq "sysread timeout\n";
-            # since it's stopped emitting output, see if child needs
-            # reaping
+        my $rin = "";
+        vec($rin, fileno $slave, 1) = 1;
+        if (select $rin, undef, undef, 1) {
+            my $nchars = sysread $slave, my $chars, 8192;
+            last if defined $nchars and $nchars == 0;
+            print $chars;
+            $output .= $chars;
+        } else {
+            # since there was no new output, see if child needs reaping
             waitpid -1, &WNOHANG;
         }
-        last if defined $nchars and $nchars == 0;
-        print $chars;
-        $output .= $chars;
     }
     $slave->close;
     exit 2 if $interrupted;