Kernel+Userland: Replace the beep syscall with the new /dev/beep device

There's no need to have separate syscall for this kind of functionality,
as we can just have a device node in /dev, called "beep", that allows
writing tone generation packets to emulate the same behavior.

In addition to that, we remove LibC sysbeep function, as this function
was never being used by any C program nor it was standardized in any
way.
Instead, we move the userspace implementation to LibCore.

Kernel/Devices/Generic/PCSpeakerDevice.cpp

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2023, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/API/BeepInstruction.h>
+#if ARCH(X86_64)
+#    include <Kernel/Arch/x86_64/PCSpeaker.h>
+#endif
+#include <Kernel/Boot/CommandLine.h>
+#include <Kernel/Devices/DeviceManagement.h>
+#include <Kernel/Devices/Generic/PCSpeakerDevice.h>
+#include <Kernel/Sections.h>
+
+namespace Kernel {
+
+UNMAP_AFTER_INIT NonnullRefPtr<PCSpeakerDevice> PCSpeakerDevice::must_create()
+{
+    auto device = MUST(DeviceManagement::try_create_device<PCSpeakerDevice>());
+    return *device;
+}
+
+UNMAP_AFTER_INIT PCSpeakerDevice::PCSpeakerDevice()
+    : CharacterDevice(1, 10)
+{
+}
+
+UNMAP_AFTER_INIT PCSpeakerDevice::~PCSpeakerDevice() = default;
+
+bool PCSpeakerDevice::can_read(OpenFileDescription const&, u64) const
+{
+    return true;
+}
+
+ErrorOr<size_t> PCSpeakerDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t)
+{
+    return Error::from_errno(ENOTIMPL);
+}
+
+ErrorOr<size_t> PCSpeakerDevice::write(OpenFileDescription&, u64, UserOrKernelBuffer const& buffer, size_t buffer_size)
+{
+    if (!kernel_command_line().is_pc_speaker_enabled())
+        return Error::from_errno(ENOTSUP);
+    if (buffer_size % sizeof(BeepInstruction) != 0)
+        return Error::from_errno(EINVAL);
+    BeepInstruction instruction {};
+    TRY(buffer.read(&instruction, sizeof(BeepInstruction)));
+    if (instruction.tone < 20 || instruction.tone > 20000)
+        return Error::from_errno(EINVAL);
+#if ARCH(X86_64)
+    PCSpeaker::tone_on(instruction.tone);
+    auto result = Thread::current()->sleep(Duration::from_nanoseconds(200'000'000));
+    PCSpeaker::tone_off();
+    if (result.was_interrupted())
+        return Error::from_errno(EINTR);
+    return sizeof(BeepInstruction);
+#else
+    return Error::from_errno(ENOTIMPL);
+#endif
+}
+
+}

Kernel/Devices/Generic/PCSpeakerDevice.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2023, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/Devices/CharacterDevice.h>
+
+namespace Kernel {
+
+class PCSpeakerDevice final : public CharacterDevice {
+    friend class DeviceManagement;
+
+public:
+    virtual ~PCSpeakerDevice() override;
+
+    static NonnullRefPtr<PCSpeakerDevice> must_create();
+
+private:
+    PCSpeakerDevice();
+
+    // ^Device
+    virtual bool is_openable_by_jailed_processes() const override { return true; }
+
+    // ^CharacterDevice
+    virtual ErrorOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override;
+    virtual ErrorOr<size_t> write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t) override;
+    virtual bool can_write(OpenFileDescription const&, u64) const override { return true; }
+    virtual bool can_read(OpenFileDescription const&, u64) const override;
+    virtual StringView class_name() const override { return "PCSpeakerDevice"sv; }
+    virtual bool is_seekable() const override { return true; }
+};
+
+}