[Console] Don't register signal handlers if pcntl is disabled

Author: chalasr

Application.php

@@ -24,6 +24,7 @@
 use Symfony\Component\Console\Exception\ExceptionInterface;
 use Symfony\Component\Console\Exception\LogicException;
 use Symfony\Component\Console\Exception\NamespaceNotFoundException;
+use Symfony\Component\Console\Exception\RuntimeException;
 use Symfony\Component\Console\Formatter\OutputFormatter;
 use Symfony\Component\Console\Helper\DebugFormatterHelper;
 use Symfony\Component\Console\Helper\FormatterHelper;
@@ -88,8 +89,8 @@ public function __construct(string $name = 'UNKNOWN', string $version = 'UNKNOWN
         $this->version = $version;
         $this->terminal = new Terminal();
         $this->defaultCommand = 'list';
-        $this->signalRegistry = new SignalRegistry();
-        if (\defined('SIGINT')) {
+        if (\defined('SIGINT') && SignalRegistry::isSupported()) {
+            $this->signalRegistry = new SignalRegistry();
             $this->signalsToDispatchEvent = [\SIGINT, \SIGTERM, \SIGUSR1, \SIGUSR2];
         }
     }
@@ -953,6 +954,9 @@ protected function doRunCommand(Command $command, InputInterface $input, OutputI
         }
 
         if ($command instanceof SignalableCommandInterface) {
+            if (!$this->signalsToDispatchEvent) {
+                throw new RuntimeException('Unable to subscribe to signal events. Make sure that the `pcntl` extension is installed and that "pcntl_*" functions are not disabled by your php.ini\'s "disable_functions" directive.');
+            }
             foreach ($command->getSubscribedSignals() as $signal) {
                 $this->signalRegistry->register($signal, [$command, 'handleSignal']);
             }

SignalRegistry/SignalRegistry.php

@@ -37,6 +37,19 @@ public function register(int $signal, callable $signalHandler): void
         pcntl_signal($signal, [$this, 'handle']);
     }
 
+    public static function isSupported(): bool
+    {
+        if (!\function_exists('pcntl_signal')) {
+            return false;
+        }
+
+        if (\in_array('pcntl_signal', explode(',', ini_get('disable_functions')))) {
+            return false;
+        }
+
+        return true;
+    }
+
     /**
      * @internal
      */