vncserver: Display check should use named variables

Several calculated values such as file paths and port numbers were
hard coded within strings or expressions, sometimes multiple
times. These values should be extracted into named variables to
improve self-documentation and avoid accidental divergence.

diff --git a/unix/vncserver/vncserver.in b/unix/vncserver/vncserver.in
index 27288fd28fab961acb9d275ab101f94e1886557b..670bcf1bf8da80049030e0e776c9a0fdd2d55d6e 100755 (executable)
--- a/unix/vncserver/vncserver.in
+++ b/unix/vncserver/vncserver.in
@@ -363,15 +363,20 @@ sub CheckDisplayNumber
 {
     local ($n) = @_;
 
-    if (-e "/tmp/.X$n-lock") {
-       warn "\nWarning: $host:$n is taken because of /tmp/.X$n-lock\n";
+    my $x11_lock_path = "/tmp/.X$n-lock";
+
+    if (-e $x11_lock_path) {
+       warn "\nWarning: $host:$n is taken because of $x11_lock_path\n";
        warn "Remove this file if there is no X server $host:$n\n";
        return 0;
     }
 
+    my $rfb_port = 5900 + $n;
+    my $x11_port = 6000 + $n;
+
     socket(S, $AF_INET, $SOCK_STREAM, 0) || die "$prog: socket failed: $!\n";
     eval 'setsockopt(S, &SOL_SOCKET, &SO_REUSEADDR, pack("l", 1))';
-    if (!bind(S, pack('S n x12', $AF_INET, 6000 + $n))) {
+    if (!bind(S, pack('S n x12', $AF_INET, $x11_port))) {
        close(S);
        return 0;
     }
@@ -379,14 +384,16 @@ sub CheckDisplayNumber
 
     socket(S, $AF_INET, $SOCK_STREAM, 0) || die "$prog: socket failed: $!\n";
     eval 'setsockopt(S, &SOL_SOCKET, &SO_REUSEADDR, pack("l", 1))';
-    if (!bind(S, pack('S n x12', $AF_INET, 5900 + $n))) {
+    if (!bind(S, pack('S n x12', $AF_INET, $rfb_port))) {
        close(S);
        return 0;
     }
     close(S);
 
-    if (-e "/tmp/.X11-unix/X$n") {
-       warn "\nWarning: $host:$n is taken because of /tmp/.X11-unix/X$n\n";
+    my $x11_unix_domain = "/tmp/.X11-unix/X$n";
+
+    if (-e $x11_unix_domain) {
+       warn "\nWarning: $host:$n is taken because of $x11_unix_domain\n";
        warn "Remove this file if there is no X server $host:$n\n";
        return 0;
     }