feat: `-h` and `--help` options

kms.php

@@ -29,6 +29,19 @@ $VLMCSD = array( // vlmcsd process
     'pidFile' => '/run/vlmcsd.pid',
 );
 
+$HELP_MSG = "
+  kms-server ($VERSION)
+
+  Project: https://github.com/dnomd343/kms-server.git
+
+    --debug         Enable debug mode
+    --kms-port      Specify kms listen port
+    --http-port     Specify http listen port
+    --disable-http  Disable http service
+    --version       Show version info
+    --help          Show help message
+\n";
+
 function load_nginx_config(int $kms_port, int $http_port): void {
     global $VERSION;
     $nginx_config = "server {
@@ -177,6 +190,11 @@ if (in_array('-v', $argv) || in_array('--version', $argv)) {
     exit;
 }
 
+if (in_array('-h', $argv) || in_array('--help', $argv)) {
+    echo $HELP_MSG; // show help message
+    exit;
+}
+
 logging::info('Loading kms-server (' . $VERSION . ')');
 load_params();
 load_vlmcsd_command($KMS_PORT);