Kernel: Implement RamdiskDevice

Kernel/Storage/RamdiskDevice.cpp

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Memory.h>
+#include <AK/StringView.h>
+#include <Kernel/FileSystem/FileDescription.h>
+#include <Kernel/Storage/RamdiskController.h>
+#include <Kernel/Storage/RamdiskDevice.h>
+
+namespace Kernel {
+
+NonnullRefPtr<RamdiskDevice> RamdiskDevice::create(const RamdiskController& controller, OwnPtr<Region>&& region, int major, int minor)
+{
+    return adopt(*new RamdiskDevice(controller, move(region), major, minor));
+}
+
+RamdiskDevice::RamdiskDevice(const RamdiskController& controller, OwnPtr<Region>&& region, int major, int minor)
+    : StorageDevice(controller, major, minor, 512, 0)
+    , m_region(move(region))
+{
+    klog() << "Ramdisk: Device #" << minor << " @ " << m_region->vaddr() << " length " << m_region->size();
+}
+
+RamdiskDevice::~RamdiskDevice()
+{
+}
+
+const char* RamdiskDevice::class_name() const
+{
+    return "RamdiskDevice";
+}
+
+size_t RamdiskDevice::max_addressable_block() const
+{
+    return m_region->size() / 512;
+}
+
+void RamdiskDevice::start_request(AsyncBlockDeviceRequest& request)
+{
+    LOCKER(m_lock);
+
+    u8* base = m_region->vaddr().as_ptr();
+    size_t size = m_region->size();
+    u8* offset = base + request.block_index() * 512;
+    size_t length = request.block_count() * 512;
+
+    if ((offset + length > base + size) || (offset + length < base)) {
+        request.complete(AsyncDeviceRequest::Failure);
+    } else {
+        bool success;
+
+        if (request.request_type() == AsyncBlockDeviceRequest::Read) {
+            success = request.buffer().write(offset, length);
+        } else {
+            success = request.buffer().read(offset, length);
+        }
+
+        request.complete(success ? AsyncDeviceRequest::Success : AsyncDeviceRequest::MemoryFault);
+    }
+}
+
+}