FR #67990 - Added nowait argument to sem_acquire

Author: mbeccati

NEWS

@@ -45,6 +45,10 @@ PHP                                                                        NEWS
 - Session:
   . Fixed bug #67972 (SessionHandler Invalid memory read create_sid()). (Adam)
 
+- Sysvsem:
+  . Implemented FR #67990 (Add optional nowait argument to sem_acquire).
+    (Matteo)
+
 28 Aug 2014, PHP 5.6.0
 
 - Apache2 Handler SAPI:

ext/sysvsem/sysvsem.c

@@ -66,6 +66,7 @@ ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_sem_acquire, 0, 0, 1)
 	ZEND_ARG_INFO(0, sem_identifier)
+	ZEND_ARG_INFO(0, nowait)
 ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_sem_release, 0, 0, 1)
@@ -298,11 +299,18 @@ PHP_FUNCTION(sem_get)
 static void php_sysvsem_semop(INTERNAL_FUNCTION_PARAMETERS, int acquire)
 {
 	zval *arg_id;
+	zend_bool nowait = 0;
 	sysvsem_sem *sem_ptr;
 	struct sembuf sop;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r", &arg_id) == FAILURE) {
-		return;
+	if (acquire) {
+		if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r|b", &arg_id, &nowait) == FAILURE) {
+			return;
+		}
+	} else {
+		if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r", &arg_id) == FAILURE) {
+			return;
+		}
 	}
 
 	ZEND_FETCH_RESOURCE(sem_ptr, sysvsem_sem *, &arg_id, -1, "SysV semaphore", php_sysvsem_module.le_sem);
@@ -314,11 +322,13 @@ static void php_sysvsem_semop(INTERNAL_FUNCTION_PARAMETERS, int acquire)
 
 	sop.sem_num = SYSVSEM_SEM;
 	sop.sem_op  = acquire ? -1 : 1;
-	sop.sem_flg = SEM_UNDO;
+	sop.sem_flg = SEM_UNDO | (nowait ? IPC_NOWAIT : 0);
 
 	while (semop(sem_ptr->semid, &sop, 1) == -1) {
 		if (errno != EINTR) {
-			php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed to %s key 0x%x: %s", acquire ? "acquire" : "release", sem_ptr->key, strerror(errno));
+			if (errno != EAGAIN) {
+				php_error_docref(NULL TSRMLS_CC, E_WARNING, "failed to %s key 0x%x: %s", acquire ? "acquire" : "release", sem_ptr->key, strerror(errno));
+			}
 			RETURN_FALSE;
 		}
 	}

ext/sysvsem/tests/nowait.phpt

@@ -0,0 +1,103 @@
+--TEST--
+sem_acquire with nowait
+--SKIPIF--
+<?php // vim600: ts=4 sw=4 syn=php fdm=marker
+if(!extension_loaded('sysvsem') || !extension_loaded('pcntl')) {
+	die("skip sysvsem and pcntl required");
+}
+?>
+--FILE--
+<?php
+$SEMKEY	= ftok(__FILE__, 'P');  //  Semaphore key
+
+$pid = pcntl_fork();
+
+if ($pid) {
+	echo "Parent.\n";
+
+	pcntl_signal(SIGCHLD, SIG_IGN);
+
+	// Get semaphore
+	$sem_id = sem_get($SEMKEY, 1);
+	if ($sem_id === FALSE) {
+		echo "P: fail to get semaphore";
+		exit;
+	}
+	echo "P: got semaphore $sem_id.\n";
+
+	register_shutdown_function(function () use ($sem_id) {
+		echo "P: cleanup.\n";
+		sem_remove($sem_id);
+	});
+  
+	// Acquire semaphore
+	if (! sem_acquire($sem_id)) {
+		echo "P: fail to acquire semaphore $sem_id.\n";
+		sem_remove($sem_id);
+		exit;
+	}
+	echo "P: success acquire semaphore $sem_id.\n";
+
+	usleep(20000);
+
+	echo "P: releases.\n";
+	sem_release($sem_id);
+
+	usleep(5000);
+
+	// Acquire semaphore
+	if (! sem_acquire($sem_id)) {
+		echo "P: fail to acquire semaphore $sem_id.\n";
+		sem_remove($sem_id);
+		exit;
+	}
+	echo "P: success acquire semaphore $sem_id.\n";
+
+	$status = null;
+	pcntl_waitpid($pid, $status);
+
+} else {
+	usleep(10000);
+	echo "Child.\n";
+
+	// Get semaphore
+	$sem_id = sem_get($SEMKEY, 1);
+	if ($sem_id === FALSE) {
+		echo "C: fail to get semaphore";
+		exit;
+	}
+	echo "C: got semaphore $sem_id.\n";
+  
+	// Acquire semaphore
+	if (! sem_acquire($sem_id)) {
+		echo "C: fail to acquire semaphore $sem_id.\n";
+		exit;
+	}
+	echo "C: success acquire semaphore $sem_id.\n";
+
+	echo "C: releases.\n";
+	sem_release($sem_id);
+
+	usleep(10000);
+
+	// Acquire semaphore
+	if (! sem_acquire($sem_id, true)) {
+		echo "C: fail to acquire semaphore $sem_id.\n";
+		exit;
+	}
+	echo "C: success acquire semaphore $sem_id.\n";
+}
+
+?>
+--EXPECTF--
+Parent.
+P: got semaphore Resource id #%i.
+P: success acquire semaphore Resource id #%i.
+Child.
+C: got semaphore Resource id #%i.
+P: releases.
+C: success acquire semaphore Resource id #%i.
+C: releases.
+P: success acquire semaphore Resource id #%i.
+C: fail to acquire semaphore Resource id #%i.
+P: cleanup.

ext/sysvsem/tests/sysv.phpt

@@ -9,8 +9,8 @@ if(!extension_loaded('sysvsem') || !extension_loaded('sysvshm')) {
 --FILE--
 <?php
 $MEMSIZE = 512;  //  size of shared memory to allocate
-$SEMKEY	 =   1;  //  Semaphore key
-$SHMKEY	 =   2;  //  Shared memory key
+$SEMKEY	 =   ftok(__FILE__, 'P');  //  Semaphore key
+$SHMKEY	 =   ftok(__FILE__, 'Q');  //  Shared memory key
 
 echo "Start.\n";
 // Get semaphore