MFB: Fix for #32974

Author: wez

ext/pcntl/pcntl.c

@@ -162,17 +162,13 @@ void php_register_signal_constants(INIT_FUNC_ARGS)
 
 static void php_pcntl_init_globals(zend_pcntl_globals *pcntl_globals)
 { 
-	/* Just in case ... */
-	memset(&pcntl_globals->php_signal_queue,0,sizeof(pcntl_globals->php_signal_queue));
-   
-	zend_llist_init(&pcntl_globals->php_signal_queue, sizeof (long),  NULL, 1);
-	pcntl_globals->signal_queue_ready = 0;
-	pcntl_globals->processing_signal_queue = 0;
+	memset(pcntl_globals, 0, sizeof(*pcntl_globals));
 }
 
 PHP_RINIT_FUNCTION(pcntl)
 {
-	zend_hash_init(&PCNTL_G(php_signal_table), 16, NULL, ZVAL_PTR_DTOR, 1);
+	zend_hash_init(&PCNTL_G(php_signal_table), 16, NULL, ZVAL_PTR_DTOR, 0);
+	PCNTL_G(head) = PCNTL_G(tail) = PCNTL_G(spares) = NULL;
 	return SUCCESS;
 }
 
@@ -187,13 +183,26 @@ PHP_MINIT_FUNCTION(pcntl)
 
 PHP_MSHUTDOWN_FUNCTION(pcntl)
 {
-	zend_llist_destroy(&PCNTL_G(php_signal_queue));
 	return SUCCESS;
 }
 
 PHP_RSHUTDOWN_FUNCTION(pcntl)
 {
+	struct php_pcntl_pending_signal *sig;
+
+	/* FIXME: if a signal is delivered after this point, things will go pear shaped;
+	 * need to remove signal handlers */
 	zend_hash_destroy(&PCNTL_G(php_signal_table));
+	while (PCNTL_G(head)) {
+		sig = PCNTL_G(head);
+		PCNTL_G(head) = sig->next;
+		efree(sig);
+	}
+	while (PCNTL_G(spares)) {
+		sig = PCNTL_G(spares);
+		PCNTL_G(spares) = sig->next;
+		efree(sig);
+	}
 	return SUCCESS;
 }
 
@@ -520,6 +529,19 @@ PHP_FUNCTION(pcntl_signal)
 		return;
 	}
 
+	if (!PCNTL_G(spares)) {
+		/* since calling malloc() from within a signal handler is not portable,
+		 * pre-allocate a few records for recording signals */
+		int i;
+		for (i = 0; i < 32; i++) {
+			struct php_pcntl_pending_signal *psig;
+
+			psig = emalloc(sizeof(*psig));
+			psig->next = PCNTL_G(spares);
+			PCNTL_G(spares) = psig;
+		}
+	}
+
 	/* Special long value case for SIG_DFL and SIG_IGN */
 	if (Z_TYPE_P(handle)==IS_LONG) {
 		if (Z_LVAL_P(handle)!= (long) SIG_DFL && Z_LVAL_P(handle) != (long) SIG_IGN) {
@@ -631,57 +653,63 @@ PHP_FUNCTION(pcntl_setpriority)
 /* Our custom signal handler that calls the appropriate php_function */
 static void pcntl_signal_handler(int signo)
 {
-	long signal_num = signo;
+	struct php_pcntl_pending_signal *psig;
 	TSRMLS_FETCH();
 
-	IF_DEBUG(DEBUG_OUT("Caught signo %d\n", signo));
-	if (! PCNTL_G(processing_signal_queue)) {
-		zend_llist_add_element(&PCNTL_G(php_signal_queue), &signal_num);
-		PCNTL_G(signal_queue_ready) = 1;
-		IF_DEBUG(DEBUG_OUT("Added queue entry\n"));
+	psig = PCNTL_G(spares);
+	if (!psig) {
+		/* oops, too many signals for us to track, so we'll forget about this one */
+		return;
+	}
+	PCNTL_G(spares) = psig->next;
+
+	psig->signo = signo;
+	psig->next = NULL;
+
+	/* the head check is important, as the tick handler cannot atomically clear both
+	 * the head and tail */
+	if (PCNTL_G(head) && PCNTL_G(tail)) {
+		PCNTL_G(tail)->next = psig;
+	} else {
+		PCNTL_G(head) = psig;
 	}
-	return;
+	PCNTL_G(tail) = psig;
 }
 
 void pcntl_tick_handler()
 {
-	zend_llist_element *element;
 	zval *param, **handle, *retval;
+	struct php_pcntl_pending_signal *queue, *next;
 	TSRMLS_FETCH();
 
 	/* Bail if the queue is empty or if we are already playing the queue*/
-	if (! PCNTL_G(signal_queue_ready) || PCNTL_G(processing_signal_queue))
+	if (! PCNTL_G(head) || PCNTL_G(processing_signal_queue))
 		return;
 
-	/* Mark our queue empty */
-	PCNTL_G(signal_queue_ready) = 0;
-	
-	/* If for some reason our signal queue is empty then return */
-	if (zend_llist_count(&PCNTL_G(php_signal_queue)) <= 0) {
-		return;
-	}
-	
 	/* Prevent reentrant handler calls */
 	PCNTL_G(processing_signal_queue) = 1;
 
+	queue = PCNTL_G(head);
+	PCNTL_G(head) = NULL; /* simple stores are atomic */
+	
 	/* Allocate */
 	MAKE_STD_ZVAL(param);
 	MAKE_STD_ZVAL(retval);
 
-	/* Traverse through our signal queue and call the appropriate php functions */
-	for (element = (&PCNTL_G(php_signal_queue))->head; element; element = element->next) {
-		long *signal_num = (long *)&element->data;
-		if (zend_hash_index_find(&PCNTL_G(php_signal_table), *signal_num, (void **) &handle)==FAILURE) {
-			continue;
+	while (queue) {
+		if (zend_hash_index_find(&PCNTL_G(php_signal_table), queue->signo, (void **) &handle)==SUCCESS) {
+			ZVAL_LONG(param, queue->signo);
+
+			/* Call php signal handler - Note that we do not report errors, and we ignore the return value */
+			/* FIXME: this is probably broken when multiple signals are handled in this while loop (retval) */
+			call_user_function(EG(function_table), NULL, *handle, retval, 1, &param TSRMLS_CC);
 		}
 
-		ZVAL_LONG(param, *signal_num);
-		
-		/* Call php signal handler - Note that we do not report errors, and we ignore the return value */
-		call_user_function(EG(function_table), NULL, *handle, retval, 1, &param TSRMLS_CC);
+		next = queue->next;
+		queue->next = PCNTL_G(spares);
+		PCNTL_G(spares) = queue;
+		queue = next;
 	}
-	/* Clear */
-	zend_llist_clean(&PCNTL_G(php_signal_queue));
 
 	/* Re-enable queue */
 	PCNTL_G(processing_signal_queue) = 0;
@@ -691,6 +719,8 @@ void pcntl_tick_handler()
 	efree(retval);
 }
 
+
+
 /*
  * Local variables:
  * tab-width: 4

ext/pcntl/php_pcntl.h

@@ -58,12 +58,17 @@ PHP_FUNCTION(pcntl_getpriority);
 PHP_FUNCTION(pcntl_setpriority);
 #endif
 
+struct php_pcntl_pending_signal {
+	struct php_pcntl_pending_signal *next;
+	long signo;
+};
+
 ZEND_BEGIN_MODULE_GLOBALS(pcntl)
 	HashTable php_signal_table;
-	zend_llist php_signal_queue;
-	int signal_queue_ready;
 	int processing_signal_queue;
+	struct php_pcntl_pending_signal *head, *tail, *spares;
 ZEND_END_MODULE_GLOBALS(pcntl)
+
 #ifdef ZTS
 #define PCNTL_G(v) TSRMG(pcntl_globals_id, zend_pcntl_globals *, v)
 #else

ext/pcntl/test-pcntl.php

@@ -4,11 +4,11 @@
 declare(ticks=1);
 
 function alarm_handle($signal){
-	 if ($signal==SIGALRM) print "Caught SIGALRM!!!\n";
+	 if ($signal==SIGALRM) print "Child: Caught SIGALRM!!!\n";
 }
 
 function usr1_handle($signal){
-	if ($signal==SIGUSR1) print "Caught SIGUSR1!!!\n";
+	if ($signal==SIGUSR1) print "Child: Caught SIGUSR1!!!\n";
 }
 
 print "This test will demonstrate a fork followed by ipc via signals.\n";
@@ -23,6 +23,7 @@ function usr1_handle($signal){
 	sleep(100);
 	print "Child: Resetting Alarm handler to Ignore....\n";
 	pcntl_signal(SIGALRM, SIG_IGN);
+	print "Child: sleeping for 10 seconds....\n";
 	sleep(10);
 	print "Done\n";
 } else {
@@ -33,7 +34,7 @@ function usr1_handle($signal){
 	sleep(1);
 	print "Parent: Senging SIGUSR1 to Child\n";
 	posix_kill($pid,SIGUSR1);
-	sleep(1);
+	sleep(2);
 	print "Parent: Sending SIGALRM to Child\n";
 	pcntl_waitpid($pid, &$status, $options);
 }