kernel: Make DeviceRegistry store the created devices instead of creating them when requested

kernel/src/fs/devices/ConsoleDevice.cpp

@@ -1,6 +1,7 @@
 #include "fs/devices/ConsoleDevice.h"
 #include "Log.h"
 #include "arch/Keyboard.h"
+#include "fs/devices/DeviceRegistry.h"
 #include "memory/MemoryManager.h"
 #include "thread/Scheduler.h"
 #include "video/TextConsole.h"
@@ -14,9 +15,10 @@ static Buffer g_console_input;
 static bool g_eof { false };
 static bool g_echo { true };
 
-Result<SharedPtr<Device>> ConsoleDevice::create()
+Result<void> ConsoleDevice::create()
 {
-    return (SharedPtr<Device>)TRY(make_shared<ConsoleDevice>());
+    auto device = (SharedPtr<Device>)TRY(make_shared<ConsoleDevice>());
+    return DeviceRegistry::register_special_device(DeviceRegistry::Console, 0, device);
 }
 
 Result<usize> ConsoleDevice::read(u8* buf, usize, usize length) const

kernel/src/fs/devices/ConsoleDevice.h

@@ -5,7 +5,7 @@ class ConsoleDevice : public Device
 {
   public:
     // Initializer for DeviceRegistry.
-    static Result<SharedPtr<Device>> create();
+    static Result<void> create();
 
     Result<usize> read(u8*, usize, usize) const override;
 

kernel/src/fs/devices/DeviceRegistry.cpp

@@ -8,7 +8,7 @@
 
 struct DeviceDescriptor
 {
-    device_create_func_t initializer;
+    SharedPtr<Device> device;
     u32 major;
     u32 minor;
 };
@@ -17,17 +17,17 @@ Vector<DeviceDescriptor> g_available_devices = {};
 
 namespace DeviceRegistry
 {
-    Result<SharedPtr<Device>> create_special_device(u32 major, u32 minor)
+    Result<SharedPtr<Device>> fetch_special_device(u32 major, u32 minor)
     {
         for (const auto& descriptor : g_available_devices)
         {
-            if (descriptor.major == major && descriptor.minor == minor) return descriptor.initializer();
+            if (descriptor.major == major && descriptor.minor == minor) return descriptor.device;
         }
 
         return err(ENODEV);
     }
 
-    Result<void> register_special_device(u32 major, u32 minor, device_create_func_t initializer)
+    Result<void> register_special_device(u32 major, u32 minor, SharedPtr<Device> device)
     {
         for (const auto& descriptor : g_available_devices)
         {
@@ -36,17 +36,15 @@ namespace DeviceRegistry
 
         kdbgln("DeviceRegistry: registered new device type %u:%u", major, minor);
 
-        return g_available_devices.try_append(
-            DeviceDescriptor { .initializer = initializer, .major = major, .minor = minor });
+        return g_available_devices.try_append(DeviceDescriptor { .device = device, .major = major, .minor = minor });
     }
 
     Result<void> init()
     {
-        // Hardcode default devices.
-        TRY(register_special_device(DeviceMajorTypes::Memory, 0, NullDevice::create));
-        TRY(register_special_device(DeviceMajorTypes::Memory, 1, ZeroDevice::create));
-        TRY(register_special_device(DeviceMajorTypes::Console, 0, ConsoleDevice::create));
-        TRY(register_special_device(DeviceMajorTypes::Framebuffer, 0, FramebufferDevice::create));
+        NullDevice::create();
+        ZeroDevice::create();
+        ConsoleDevice::create();
+        FramebufferDevice::create();
 
         return {};
     }

kernel/src/fs/devices/DeviceRegistry.h

@@ -3,8 +3,6 @@
 #include "fs/devices/Device.h"
 #include <luna/SharedPtr.h>
 
-typedef Result<SharedPtr<Device>> (*device_create_func_t)(void);
-
 namespace DeviceRegistry
 {
     enum DeviceMajorTypes : u32
@@ -15,9 +13,9 @@ namespace DeviceRegistry
         Framebuffer = 3,
     };
 
-    Result<SharedPtr<Device>> create_special_device(u32 major, u32 minor);
+    Result<SharedPtr<Device>> fetch_special_device(u32 major, u32 minor);
 
-    Result<void> register_special_device(u32 major, u32 minor, device_create_func_t initializer);
+    Result<void> register_special_device(u32 major, u32 minor, SharedPtr<Device> device);
 
     Result<void> init();
 }

kernel/src/fs/devices/FramebufferDevice.cpp

@@ -3,9 +3,10 @@
 #include <bits/ioctl-defs.h>
 #include <luna/CString.h>
 
-Result<SharedPtr<Device>> FramebufferDevice::create()
+Result<void> FramebufferDevice::create()
 {
-    return (SharedPtr<Device>)TRY(make_shared<FramebufferDevice>());
+    auto device = (SharedPtr<Device>)TRY(make_shared<FramebufferDevice>());
+    return DeviceRegistry::register_special_device(DeviceRegistry::Framebuffer, 0, device);
 }
 
 Result<usize> FramebufferDevice::read(u8*, usize, usize) const

kernel/src/fs/devices/FramebufferDevice.h

@@ -5,7 +5,7 @@ class FramebufferDevice : public Device
 {
   public:
     // Initializer for DeviceRegistry.
-    static Result<SharedPtr<Device>> create();
+    static Result<void> create();
 
     Result<usize> read(u8*, usize, usize) const override;
 

kernel/src/fs/devices/NullDevice.cpp

@@ -1,6 +1,7 @@
 #include "fs/devices/NullDevice.h"
 
-Result<SharedPtr<Device>> NullDevice::create()
+Result<void> NullDevice::create()
 {
-    return (SharedPtr<Device>)TRY(make_shared<NullDevice>());
+    auto device = (SharedPtr<Device>)TRY(make_shared<NullDevice>());
+    return DeviceRegistry::register_special_device(DeviceRegistry::Memory, 0, device);
 }

kernel/src/fs/devices/NullDevice.h

@@ -5,7 +5,7 @@ class NullDevice : public Device
 {
   public:
     // Initializer for DeviceRegistry.
-    static Result<SharedPtr<Device>> create();
+    static Result<void> create();
 
     Result<usize> read(u8*, usize, usize) const override
     {

kernel/src/fs/devices/ZeroDevice.cpp

@@ -1,6 +1,7 @@
 #include "fs/devices/ZeroDevice.h"
 
-Result<SharedPtr<Device>> ZeroDevice::create()
+Result<void> ZeroDevice::create()
 {
-    return (SharedPtr<Device>)TRY(make_shared<ZeroDevice>());
+    auto device = (SharedPtr<Device>)TRY(make_shared<ZeroDevice>());
+    return DeviceRegistry::register_special_device(DeviceRegistry::Memory, 1, device);
 }

kernel/src/fs/devices/ZeroDevice.h

@@ -5,7 +5,7 @@ class ZeroDevice : public Device
 {
   public:
     // Initializer for DeviceRegistry.
-    static Result<SharedPtr<Device>> create();
+    static Result<void> create();
 
     Result<usize> read(u8* buf, usize, usize length) const override
     {

kernel/src/fs/tmpfs/FileSystem.cpp

@@ -39,7 +39,7 @@ namespace TmpFS
 
     Result<SharedPtr<VFS::Inode>> FileSystem::create_device_inode(u32 major, u32 minor)
     {
-        SharedPtr<Device> device = TRY(DeviceRegistry::create_special_device(major, minor));
+        SharedPtr<Device> device = TRY(DeviceRegistry::fetch_special_device(major, minor));
 
         SharedPtr<DeviceInode> inode = TRY(make_shared<DeviceInode>());
         inode->set_fs(*this, {});