Adapted code to work with PHP7

LICENSE

@@ -1,14 +1,13 @@
-DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+Copyright 2019 Denis "ftc" Denisov
 
-Version 2, December 2004
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
 
-Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
+    http://www.apache.org/licenses/LICENSE-2.0
 
-Everyone is permitted to copy and distribute verbatim or modified copies of
-this license document, and changing it is allowed as long as the name is changed.
-
-DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
-
-TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
-   0. You just DO WHAT THE FUCK YOU WANT TO.
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

README.md

@@ -1,3 +1,135 @@
-# php_semaphores
+# posix_semaphores - POSIX semaphores extension for PHP
 
-POSIX semaphores extension for PHP
+## Introduction
+
+This a thin wrapper around [POSIX semaphores API](http://man7.org/linux/man-pages/man7/sem_overview.7.html). 
+There is built-in PHP extension for [semaphores and other IPC](https://www.php.net/manual/en/book.sem.php), 
+but it supports only System V semaphores, when POSIX version has much more convenient API.
+
+Also System V semaphore support in PHP does not match exactly with C API (in fact it constructs three semaphores
+in set under the hood and uses them for initialization and other bookkeeping tasks). That's very convenient
+when one uses semaphores solely from PHP code, but prevents some mixed use cases when one wants to sync PHP code
+and other code with semaphores. 
+
+For example it's not possible to create locked semaphore in C++ application, wait for it in PHP (with locking 
+of course) and then unlock in C++ application (this case could be used for shared memory IPC syncronization, for instance).
+
+So the goal here is to make C API wrapper as thin as possible to allow simultaneous usage of semaphores in 
+applications written in PHP or other programming languages.
+
+## Installation
+
+Make sure you have `php-devel` package installed in your system. You need to be able to build PHP extensions.
+
+After that run commands:
+```
+phpize
+./configure --enable-posix_semaphores
+make
+```
+
+If everything goes well, you will have file `./modules/posix_semaphores.so`. The last step is to include this file
+into your `php.ini`. Add line `extension=/<PATH>/posix_semaphores.so` (replace `<PATH>` with actual path to this
+extension) and you're done. Don't forget to restart php-fpm or apache if you're using PHP from there.
+
+## Reference
+
+Extension consists of several functions which are clearly mapped to POSIX semaphores API. 
+
+### posix_sem_open($name, $flags, $mode = 0666, $value = 0)
+
+This is equivalent of [sem_open](http://man7.org/linux/man-pages/man3/sem_open.3.html). 
+
+Parameters:
+* $name - name of semaphore to open,
+* $flags - opening flags (such as O_CREAT or O_EXCL),
+* $mode - opening mode (default value is 0666),
+* $value - initial value for semaphore (default is 0).
+
+Function returns semaphore resource on success or `null` on failure.
+
+### posix_sem_close($semaphore)
+
+Function closes semaphore resource (in fact it's just a proxy to [sem_close](http://man7.org/linux/man-pages/man3/sem_close.3.html)).
+
+Parameters:
+* $semaphore - semaphore resource acquired via `posix_sem_open`.
+
+Returns `true` on success, `false` otherwise.
+
+### posix_sem_unlink($name)
+
+Unlinks named semaphore from system. The semaphore name is removed immediately. The semaphore itself is removed when 
+all processed having the semaphore opened, close it.
+
+Parameters:
+* $name - name of semaphore to remove.
+
+Returns `true` on success, `false` otherwise.
+
+### posix_sem_post($semaphore)
+
+Unlocks semaphore. If the semaphore's value consequently becomes greater than zero, then
+another process or thread blocked in a sem_wait call will be woken
+up and proceed to lock the semaphore.
+
+Parameters:
+* $semaphore - semaphore resource to unlock (acquired via `posix_sem_open`).
+
+Returns `true` on success, `false` otherwise.
+
+
+### posix_sem_wait($semaphore)
+
+Locks a semaphore. If
+the semaphore's value is greater than zero, then the decrement
+proceeds, and the function returns, immediately.  If the semaphore
+currently has the value zero, then the call blocks until either it
+becomes possible to perform the decrement (i.e., the semaphore value
+rises above zero), or a signal handler interrupts the call.
+
+Parameters:
+* $semaphore - semaphore resource to unlock (acquired via `posix_sem_open`).
+
+Returns `true` on success, `false` otherwise.
+
+### posix_sem_trywait($semaphore)
+
+The same as `posix_sem_wait`, except that if the decrement
+cannot be immediately performed, then call returns an error (last error
+set to EAGAIN) instead of blocking.
+
+### posix_sem_timedwait($semaphore, $timeout_sec, $timeout_nsec = 0)
+
+Tries to lock a semaphore (as `posix_sem_wait`), but if lock could not 
+be performed in a specified timeout, returns and sets last error to ETIMEDOUT.
+
+Parameters:
+* $semaphore - semaphore resource to unlock (acquired via `posix_sem_open`).
+* $timeout_sec - part of the timeout in seconds.
+* $timeout_nsec - part of the timeout in nanoseconds.
+
+Total timeout is computed as `$timeout_sec * 1000000000 + $timeout_nsec` and is
+measured in nanoseconds.
+
+### posix_sem_getvalue($semaphore)
+
+Gets value of specified semaphore.
+
+Parameters:
+* $semaphore - semaphore resource which value to get (acquired via `posix_sem_open`).
+
+Returns semaphore value on success and `null` on error.
+
+Please note that underlying function `sem_getvalue` can behave differently according to
+POSIX specification, so please read your OS documentation on that.
+
+### posix_sem_error()
+
+Returns value of last error occured during call of another semaphore-related function.
+
+## Notes for PHP users
+
+All semaphore resources are closed automatically when PHP exits. But underlying semaphores are not unlinked by default. You 
+should use `register_shutdown_function` to unlink all semaphores which you don't need after program exit. 
+Alternative way for that is to manage semaphore creation and deletion outside of PHP.

posix_semaphores.c

@@ -17,6 +17,9 @@ static zend_function_entry posix_semaphores_functions[] = {
 	PHP_FE(posix_sem_getvalue, NULL)
 	PHP_FE(posix_sem_post, NULL)
 	PHP_FE(posix_sem_wait, NULL)
+	PHP_FE(posix_sem_trywait, NULL)
+	PHP_FE(posix_sem_timedwait, NULL)
+	PHP_FE(posix_sem_error, NULL)
 	{NULL, NULL, NULL}
 };
     
@@ -48,7 +51,7 @@ typedef struct _php_posix_semaphore {
 } php_posix_semaphore;
 
 
-static void php_posix_semaphore_dtor(zend_rsrc_list_entry *rsrc TSRMLS_DC)
+static void php_posix_semaphore_dtor(zend_resource *rsrc TSRMLS_DC)
 {
 	php_posix_semaphore *s = (php_posix_semaphore*)rsrc->ptr;
 	if (s) 
@@ -58,6 +61,7 @@ static void php_posix_semaphore_dtor(zend_rsrc_list_entry *rsrc TSRMLS_DC)
 			sem_close(s->sem);
 			s->sem = NULL;
 		}
+		efree(s);
 	}
 }
 
@@ -66,9 +70,13 @@ static void php_posix_semaphore_dtor(zend_rsrc_list_entry *rsrc TSRMLS_DC)
 // list entry identifier
 int le_posix_semaphore;
 
+// error which occured during last function call
+int last_errno;
+
 PHP_MINIT_FUNCTION(posix_semaphores)
 {
 	le_posix_semaphore = zend_register_list_destructors_ex(php_posix_semaphore_dtor, NULL, PHP_POSIX_SEMAPHORES_RES_NAME, module_number);
+	last_errno = 0;
 	return SUCCESS;
 }
 
@@ -84,10 +92,10 @@ PHP_MSHUTDOWN_FUNCTION(posix_semaphores)
 PHP_FUNCTION(posix_sem_open)
 {
 	char *name;
-	int name_length;
-	long flags;
-	long mode = 0666;
-	long value = 0;
+	size_t name_length;
+	zend_long flags;
+	zend_long mode = 0666;
+	zend_long value = 0;
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|ll", &name, &name_length, &flags, &mode, &value) == FAILURE) 
 	{
 		RETURN_NULL();
@@ -95,12 +103,12 @@ PHP_FUNCTION(posix_sem_open)
 	sem_t* sem = sem_open(name, flags, mode, value);
 	if (sem == SEM_FAILED)
 	{
-		printf("sem_open failed, errno = %d flags = %d O_CREAT = %d", errno, flags, O_CREAT);
+		last_errno = errno;
 		RETURN_NULL();
 	}
 	php_posix_semaphore *semaphore = emalloc(sizeof(php_posix_semaphore));
 	semaphore->sem = sem;
-	ZEND_REGISTER_RESOURCE(return_value, semaphore, le_posix_semaphore);
+	ZVAL_RES(return_value, zend_register_resource(semaphore, le_posix_semaphore));
 }
 
 PHP_FUNCTION(posix_sem_close)
@@ -111,12 +119,12 @@ PHP_FUNCTION(posix_sem_close)
 	{
 		RETURN_FALSE;
 	}
-	
-	ZEND_FETCH_RESOURCE(semaphore, php_posix_semaphore*, &zsemaphore, -1, PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
+	semaphore = (php_posix_semaphore*)zend_fetch_resource(Z_RES_P(zsemaphore), PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
 	if (semaphore->sem)
 	{
 		if (sem_close(semaphore->sem) == -1)
 		{
+		    last_errno = errno;
 		    RETURN_FALSE;
 		}
 		semaphore->sem = NULL;
@@ -128,14 +136,15 @@ PHP_FUNCTION(posix_sem_close)
 PHP_FUNCTION(posix_sem_unlink)
 {
 	char *name;
-	int name_length;
+	size_t name_length;
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &name, &name_length) == FAILURE) 
 	{
 		RETURN_NULL();
 	}
 	if (sem_unlink(name) == -1)
 	{
-	    RETURN_FALSE;
+		last_errno = errno;
+		RETURN_FALSE;
 	}
 	RETURN_TRUE;
 }
@@ -149,12 +158,13 @@ PHP_FUNCTION(posix_sem_getvalue)
 		RETURN_NULL();
 	}
 	
-	ZEND_FETCH_RESOURCE(semaphore, php_posix_semaphore*, &zsemaphore, -1, PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
+	semaphore = (php_posix_semaphore*)zend_fetch_resource(Z_RES_P(zsemaphore), PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
 	if (semaphore->sem)
 	{
 		int value;
 		if (sem_getvalue(semaphore->sem, &value) == -1)
 		{
+			last_errno = errno;
 			RETURN_NULL();
 		}
 		else
@@ -177,11 +187,12 @@ PHP_FUNCTION(posix_sem_post)
 		RETURN_FALSE;
 	}
 	
-	ZEND_FETCH_RESOURCE(semaphore, php_posix_semaphore*, &zsemaphore, -1, PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
+	semaphore = (php_posix_semaphore*)zend_fetch_resource(Z_RES_P(zsemaphore), PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
 	if (semaphore->sem)
 	{
 		if (sem_post(semaphore->sem) == -1)
 		{
+			last_errno = errno;
 			RETURN_FALSE;
 		}
 		else
@@ -204,11 +215,12 @@ PHP_FUNCTION(posix_sem_wait)
 		RETURN_FALSE;
 	}
 	
-	ZEND_FETCH_RESOURCE(semaphore, php_posix_semaphore*, &zsemaphore, -1, PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
+	semaphore = (php_posix_semaphore*)zend_fetch_resource(Z_RES_P(zsemaphore), PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
 	if (semaphore->sem)
 	{
 		if (sem_wait(semaphore->sem) == -1)
 		{
+			last_errno = errno;
 			RETURN_FALSE;
 		}
 		else
@@ -222,3 +234,69 @@ PHP_FUNCTION(posix_sem_wait)
 	}
 }
 
+PHP_FUNCTION(posix_sem_trywait)
+{
+	php_posix_semaphore *semaphore;
+	zval *zsemaphore;
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r", &zsemaphore) == FAILURE)
+	{
+		RETURN_FALSE;
+	}
+	
+	semaphore = (php_posix_semaphore*)zend_fetch_resource(Z_RES_P(zsemaphore), PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
+	if (semaphore->sem)
+	{
+		if (sem_trywait(semaphore->sem) == -1)
+		{
+			last_errno = errno;
+			RETURN_FALSE;
+		}
+		else
+		{
+			RETURN_TRUE;
+		}
+	}
+	else
+	{
+		RETURN_FALSE;
+	}
+}
+
+PHP_FUNCTION(posix_sem_timedwait)
+{
+	php_posix_semaphore *semaphore;
+	zval *zsemaphore;
+	zend_long timeout_sec;
+	zend_long timeout_nsec = 0;
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "rl|l", &zsemaphore, &timeout_sec, &timeout_nsec) == FAILURE)
+	{
+		RETURN_FALSE;
+	}
+	
+	semaphore = (php_posix_semaphore*)zend_fetch_resource(Z_RES_P(zsemaphore), PHP_POSIX_SEMAPHORES_RES_NAME, le_posix_semaphore);
+	if (semaphore->sem)
+	{
+		struct timespec tm;
+		tm.tv_sec = (int)timeout_sec;
+		tm.tv_nsec = (int)timeout_nsec;
+		if (sem_timedwait(semaphore->sem, &tm) == -1)
+		{
+			last_errno = errno;
+			RETURN_FALSE;
+		}
+		else
+		{
+			RETURN_TRUE;
+		}
+	}
+	else
+	{
+		RETURN_FALSE;
+	}
+}
+
+
+PHP_FUNCTION(posix_sem_error)
+{
+	RETURN_LONG(last_errno);
+}

posix_semaphores.h

@@ -13,6 +13,9 @@ PHP_FUNCTION(posix_sem_unlink);
 PHP_FUNCTION(posix_sem_getvalue);
 PHP_FUNCTION(posix_sem_post);
 PHP_FUNCTION(posix_sem_wait);
+PHP_FUNCTION(posix_sem_trywait);
+PHP_FUNCTION(posix_sem_timedwait);
+PHP_FUNCTION(posix_sem_error);
 
 extern zend_module_entry posix_semaphores_module_entry;
 #define phpext_posix_semaphores_ptr &posix_semaphores_module_entry;