fix bug #381: use persistent reservation file for ports

diff --git a/data/PVE/Tools.pm b/data/PVE/Tools.pm
index 235178a68cd68b4bebe08db263243905a46a48df..0ec74d85d12ea216c162b5acbb999700a4e7f154 100644 (file)
--- a/data/PVE/Tools.pm
+++ b/data/PVE/Tools.pm
@@ -632,24 +632,78 @@ sub wait_for_vnc_port {
     return undef;
 }
 
-sub next_vnc_port {
+sub next_unused_port {
+    my ($range_start, $range_end) = @_;
+
+    # We use a file to register allocated ports.
+    # Those registrations expires after $expiretime.
+    # We use this to avoid race conditions between
+    # allocation and use of ports.
+
+    my $filename = "/var/tmp/pve-reserved-ports";
 
-    for (my $p = 5900; $p < 6000; $p++) {
+    my $code = sub {
 
-       my $sock = IO::Socket::INET->new (Listen => 5,
-                                         LocalAddr => 'localhost',
-                                         LocalPort => $p,
-                                         ReuseAddr => 1,
-                                         Proto     => 0);
+       my $expiretime = 5;
+       my $ctime = time();
 
-       if ($sock) {
-           close ($sock);
-           return $p;
+       my $ports = {};
+
+       if (my $fh = IO::File->new ($filename, "r")) {
+           while (my $line = <$fh>) {
+               if ($line =~ m/^(\d+)\s(\d+)$/) {
+                   my ($port, $timestamp) = ($1, $2);
+                   if (($timestamp + $expiretime) > $ctime) {
+                       $ports->{$port} = $timestamp; # not expired
+                   }           
+               }
+           }
        }
-    }
+    
+       my $newport;
+
+       for (my $p = $range_start; $p < $range_end; $p++) {
+           next if $ports->{$p}; # reserved
+
+           my $sock = IO::Socket::INET->new(Listen => 5,
+                                            LocalAddr => 'localhost',
+                                            LocalPort => $p,
+                                            ReuseAddr => 1,
+                                            Proto     => 0);
+
+           if ($sock) {
+               close($sock);
+               $newport = $p;
+               $ports->{$p} = $ctime;
+               last;
+           }
+       }
+ 
+       my $data = "";
+       foreach my $p (keys %$ports) {
+           $data .= "$p $ports->{$p}\n";
+       }
+    
+       file_set_contents($filename, $data);
 
-    die "unable to find free vnc port";
-};
+       return $newport;
+    };
+
+    my $p = lock_file($filename, 10, $code);
+    die $@ if $@;
+   
+    die "unable to find free port (${range_start}-${range_end})\n" if !$p;
+
+    return $p;
+}
+
+sub next_migrate_port {
+    return next_unused_port(60000, 60010);
+}
+
+sub next_vnc_port {
+    return next_unused_port(5900, 6000);
+}
 
 # NOTE: NFS syscall can't be interrupted, so alarm does 
 # not work to provide timeouts.