Create class for shared memory blocks [wip]

3 files changed, 254 insertions, 0 deletions

diff --git a/drivers/unix/os_unix.cpp b/drivers/unix/os_unix.cpp
index e7550903a8..292e2d2219 100644
--- a/drivers/unix/os_unix.cpp
+++ b/drivers/unix/os_unix.cpp
@@ -40,6 +40,7 @@
 #include "drivers/unix/net_socket_posix.h"
 #include "drivers/unix/rw_lock_posix.h"
 #include "drivers/unix/semaphore_posix.h"
+#include "drivers/unix/shared_mem_access_posix.h"
 #include "drivers/unix/thread_posix.h"
 #include "servers/visual_server.h"
 
@@ -140,6 +141,7 @@ void OS_Unix::initialize_core() {
 	MutexPosix::make_default();
 	RWLockPosix::make_default();
 #endif
+	SharedMemAccessPosix::make_default();
 	FileAccess::make_default<FileAccessUnix>(FileAccess::ACCESS_RESOURCES);
 	FileAccess::make_default<FileAccessUnix>(FileAccess::ACCESS_USERDATA);
 	FileAccess::make_default<FileAccessUnix>(FileAccess::ACCESS_FILESYSTEM);
diff --git a/drivers/unix/shared_mem_access_posix.cpp b/drivers/unix/shared_mem_access_posix.cpp
new file mode 100644
index 0000000000..f50e177a8b
--- /dev/null
+++ b/drivers/unix/shared_mem_access_posix.cpp
@@ -0,0 +1,184 @@
+/*************************************************************************/
+/*  shared_mem_access_posix.cpp                                          */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "shared_mem_access_posix.h"
+
+#if defined(UNIX_ENABLED)
+
+//#include "core/os/memory.h"
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+//#include <stdio.h>
+#include <fcntl.h>
+//#include <sys/mman.h>
+//#include <sys/stat.h>
+
+SharedMemAccess *SharedMemAccessPosix::create_func_posix(const String &p_name) {
+
+	return memnew(SharedMemAccessPosix(p_name));
+}
+
+void SharedMemAccessPosix::make_default() {
+
+	create_func = create_func_posix;
+}
+
+Error SharedMemAccessPosix::open() {
+
+	ERR_EXPLAIN("Already open.");
+	ERR_FAIL_COND_V(fd != -1, ERR_ALREADY_IN_USE);
+
+	fd = shm_open(("/" + name).utf8().get_data(), O_CREAT | O_RDWR, 0600);
+	if (fd == -1) {
+		ERR_EXPLAIN("Cannot create/open.");
+		ERR_FAIL_V(ERR_CANT_OPEN);
+	}
+
+	return OK;
+}
+
+Error SharedMemAccessPosix::close() {
+
+	ERR_EXPLAIN("Not open.");
+	ERR_FAIL_COND_V(!is_open(), ERR_UNCONFIGURED);
+
+	if (!lock()) {
+		ERR_EXPLAIN("Cannot lock.");
+		ERR_FAIL_V(ERR_BUSY);
+	}
+
+	if (is_allocator) {
+		shm_unlink(("/" + name).utf8().get_data());
+		is_allocator = false;
+	}
+
+	::close(fd);
+	fd = -1;
+
+	unlock();
+
+	return OK;
+}
+
+_FORCE_INLINE_ bool SharedMemAccessPosix::is_open() {
+
+	return fd != -1;
+}
+
+void *SharedMemAccessPosix::lock() {
+
+	ERR_EXPLAIN("Not open.");
+	ERR_FAIL_COND_V(!is_open(), NULL);
+
+	ERR_EXPLAIN("Lock already held.");
+	ERR_FAIL_COND_V(is_locking(), NULL);
+
+	size = lseek(fd, 0, SEEK_END);
+
+	lock_addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (lock_addr == MAP_FAILED) {
+		ERR_EXPLAIN("Cannot map memory.");
+		ERR_FAIL_V(NULL);
+	}
+
+	return lock_addr;
+}
+
+void SharedMemAccessPosix::unlock() {
+
+	ERR_EXPLAIN("Lock not held.");
+	ERR_FAIL_COND(!is_locking());
+
+	munmap(lock_addr, size);
+	lock_addr = NULL;
+	size = 0;
+}
+
+_FORCE_INLINE_ bool SharedMemAccessPosix::is_locking() {
+
+	return lock_addr;
+}
+
+void *SharedMemAccessPosix::set_size(uint64_t p_size) {
+
+	ERR_EXPLAIN("Lock must be held to set the size.");
+	ERR_FAIL_COND_V(!is_locking(), NULL);
+
+	if (ftruncate(fd, p_size) == -1) {
+		ERR_EXPLAIN("Cannot set new size. (Out of memory?)");
+		ERR_FAIL_V(NULL);
+	}
+
+	munmap(lock_addr, size);
+
+	// Try to remap at former address
+	lock_addr = mmap(lock_addr, p_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (lock_addr == MAP_FAILED) {
+		unlock();
+
+		ERR_EXPLAIN("Cannot remap memory. Lock released.");
+		ERR_FAIL_V(NULL);
+	}
+
+	return lock_addr;
+}
+
+uint64_t SharedMemAccessPosix::get_size() {
+
+	ERR_EXPLAIN("Lock must be held to get the size.");
+	ERR_FAIL_COND_V(!is_locking(), 0);
+
+	return size;
+}
+
+SharedMemAccessPosix::SharedMemAccessPosix(const String &p_name) :
+		name(p_name),
+		is_allocator(false),
+		size(0),
+		fd(-1),
+		lock_addr(NULL) {
+}
+
+SharedMemAccessPosix::~SharedMemAccessPosix() {
+
+	if (is_open()) {
+
+		if (is_locking()) {
+			unlock();
+		}
+
+		if (close() != OK && is_allocator) {
+			ERR_PRINTS("Leaking shared memory '" + name + "'.");
+		}
+	}
+}
+
+#endif
diff --git a/drivers/unix/shared_mem_access_posix.h b/drivers/unix/shared_mem_access_posix.h
new file mode 100644
index 0000000000..df955e1add
--- /dev/null
+++ b/drivers/unix/shared_mem_access_posix.h
@@ -0,0 +1,68 @@
+/*************************************************************************/
+/*  shared_mem_access_posix.h                                            */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef SHARED_MEM_ACCESS_POSIX_H
+#define SHARED_MEM_ACCESS_POSIX_H
+
+#include "core/os/shared_mem_access.h"
+#include "core/ustring.h"
+
+#if defined(UNIX_ENABLED)
+
+class SharedMemAccessPosix : public SharedMemAccess {
+
+	String name;
+	bool is_allocator;
+	uint64_t size;
+	int fd;
+	void *lock_addr;
+
+	static SharedMemAccess *create_func_posix(const String &p_name);
+
+public:
+	static void make_default();
+
+	virtual Error open();
+	virtual Error close();
+	virtual bool is_open();
+
+	virtual void *lock();
+	virtual void unlock();
+	virtual bool is_locking();
+
+	virtual void *set_size(uint64_t p_size);
+	virtual uint64_t get_size();
+
+	SharedMemAccessPosix(const String &p_name);
+	virtual ~SharedMemAccessPosix();
+};
+
+#endif
+#endif