ext/pcntl: fix pcntl_signal_dispatch() stale tail pointer and excepti…

ext/pcntl/pcntl.c

@@ -1342,6 +1342,7 @@ void pcntl_signal_dispatch(void)
 
 	queue = PCNTL_G(head);
 	PCNTL_G(head) = NULL; /* simple stores are atomic */
+	PCNTL_G(tail) = NULL;
 
 	/* Allocate */
 	while (queue) {
@@ -1363,6 +1364,9 @@ void pcntl_signal_dispatch(void)
 #ifdef HAVE_STRUCT_SIGINFO_T
 				zval_ptr_dtor(&params[1]);
 #endif
+				if (EG(exception)) {
+					break;
+				}
 			}
 		}
 
@@ -1372,6 +1376,14 @@ void pcntl_signal_dispatch(void)
 		queue = next;
 	}
 
+	/* drain the remaining in case of exception thrown */
+	while (queue) {
+		next = queue->next;
+		queue->next = PCNTL_G(spares);
+		PCNTL_G(spares) = queue;
+		queue = next;
+	}
+
 	PCNTL_G(pending_signals) = 0;
 
 	/* Re-enable queue */

ext/pcntl/tests/pcntl_signal_dispatch_exception.phpt

@@ -0,0 +1,34 @@
+--TEST--
+pcntl_signal_dispatch() stops dispatching after handler throws exception
+--EXTENSIONS--
+pcntl
+posix
+--FILE--
+<?php
+
+$called = [];
+
+pcntl_signal(SIGUSR1, function ($signo) use (&$called) {
+    $called[] = 'SIGUSR1';
+    throw new \Exception('Exception in signal handler');
+});
+
+pcntl_signal(SIGUSR2, function ($signo) use (&$called) {
+    $called[] = 'SIGUSR2';
+});
+
+posix_kill(posix_getpid(), SIGUSR1);
+posix_kill(posix_getpid(), SIGUSR2);
+
+try {
+    pcntl_signal_dispatch();
+} catch (\Exception $e) {
+    echo $e->getMessage() . "\n";
+}
+
+echo "Handlers called: " . implode(', ', $called) . "\n";
+
+?>
+--EXPECT--
+Exception in signal handler
+Handlers called: SIGUSR1