Start working on virtual consoles/TTYs.

This is a mess right now, but I'd rather commit as I go.

VirtualFileSystem/CharacterDevice.cpp

@@ -4,4 +4,7 @@ CharacterDevice::~CharacterDevice()
 {
 }
 
-
+OwnPtr<FileHandle> CharacterDevice::open(int options)
+{
+    //VirtualFileSystem::the().open()
+}

VirtualFileSystem/CharacterDevice.h

@@ -2,16 +2,26 @@
 
 #include <AK/Types.h>
 #include "Limits.h"
+#include "FileHandle.h"
 
 class CharacterDevice {
 public:
     virtual ~CharacterDevice();
 
+    virtual OwnPtr<FileHandle> open(int options);
+
     virtual bool hasDataAvailableForRead() const = 0;
 
     virtual Unix::ssize_t read(byte* buffer, Unix::size_t bufferSize) = 0;
     virtual Unix::ssize_t write(const byte* buffer, Unix::size_t bufferSize) = 0;
 
+    unsigned major() const { return m_major; }
+    unsigned minor() const { return m_minor; }
+
 protected:
-    CharacterDevice() { }
+    CharacterDevice(unsigned major, unsigned minor) : m_major(major), m_minor(minor) { }
+
+private:
+    unsigned m_major { 0 };
+    unsigned m_minor{ 0 };
 };

VirtualFileSystem/FullDevice.cpp

@@ -5,6 +5,7 @@
 #include <AK/kstdio.h>
 
 FullDevice::FullDevice()
+    : CharacterDevice(1, 7)
 {
 }
 

VirtualFileSystem/NullDevice.cpp

@@ -4,6 +4,7 @@
 #include <AK/kstdio.h>
 
 NullDevice::NullDevice()
+    : CharacterDevice(1, 3)
 {
 }
 

VirtualFileSystem/RandomDevice.cpp

@@ -3,6 +3,7 @@
 #include <AK/StdLib.h>
 
 RandomDevice::RandomDevice()
+    : CharacterDevice(1, 8)
 {
 }
 

VirtualFileSystem/VirtualFileSystem.cpp

@@ -5,15 +5,11 @@
 #include <AK/kmalloc.h>
 #include <AK/kstdio.h>
 #include <AK/ktime.h>
+#include "CharacterDevice.h"
 #include "sys-errno.h"
 
 //#define VFS_DEBUG
 
-static dword encodedDevice(unsigned major, unsigned minor)
-{
-    return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
-}
-
 static VirtualFileSystem* s_the;
 
 VirtualFileSystem& VirtualFileSystem::the()
@@ -542,9 +538,9 @@ VirtualFileSystem::Mount::Mount(InodeIdentifier host, RetainPtr<FileSystem>&& gu
 {
 }
 
-void VirtualFileSystem::registerCharacterDevice(unsigned major, unsigned minor, CharacterDevice& device)
+void VirtualFileSystem::registerCharacterDevice(CharacterDevice& device)
 {
-    m_characterDevices.set(encodedDevice(major, minor), &device);
+    m_characterDevices.set(encodedDevice(device.major(), device.minor()), &device);
 }
 
 void VirtualFileSystem::forEachMount(Function<void(const Mount&)> callback) const

VirtualFileSystem/VirtualFileSystem.h

@@ -22,6 +22,11 @@
 class CharacterDevice;
 class FileHandle;
 
+inline constexpr dword encodedDevice(unsigned major, unsigned minor)
+{
+    return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
+}
+
 class VirtualFileSystem {
 public:
     static void initializeGlobals();
@@ -94,7 +99,7 @@ public:
 
     bool touch(const String&path);
 
-    void registerCharacterDevice(unsigned major, unsigned minor, CharacterDevice&);
+    void registerCharacterDevice(CharacterDevice&);
 
     size_t mountCount() const { return m_mounts.size(); }
     void forEachMount(Function<void(const Mount&)>) const;

VirtualFileSystem/ZeroDevice.cpp

@@ -4,6 +4,7 @@
 #include <AK/kstdio.h>
 
 ZeroDevice::ZeroDevice()
+    : CharacterDevice(1, 5)
 {
 }