Kernel: Rework filesystem reading

We now read from a filesystem to user provided buffer.

Read sizes are determined by read call.

You should now get file descriptors and do reading through Process::current()

kernel/include/kernel/FS/Ext2.h

@@ -131,12 +131,13 @@ namespace Kernel
 
 		virtual BAN::StringView name() const override { return m_name; }
 
-		virtual BAN::ErrorOr<BAN::Vector<uint8_t>> read_all() override;
+		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override;
 		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes() override;
 		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView) override;
 
 	private:
-		BAN::ErrorOr<void> for_each_block(BAN::Function<BAN::ErrorOr<bool>(const BAN::Vector<uint8_t>&)>&);
+		using block_callback_t = BAN::ErrorOr<bool>(*)(const BAN::Vector<uint8_t>&, void*);
+		BAN::ErrorOr<void> for_each_block(block_callback_t, void*);
 
 	private:
 		Ext2Inode() {}

kernel/include/kernel/FS/Inode.h

@@ -36,6 +36,8 @@ namespace Kernel
 		};
 
 	public:
+		virtual ~Inode() {}
+
 		bool ifdir() const { return mode().IFDIR; }
 		bool ifreg() const { return mode().IFREG; }
 
@@ -47,7 +49,7 @@ namespace Kernel
 
 		virtual BAN::StringView name() const = 0;
 
-		virtual BAN::ErrorOr<BAN::Vector<uint8_t>> read_all() = 0;
+		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) = 0;
 		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes() = 0;
 		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView) = 0;
 	};

kernel/include/kernel/FS/VirtualFileSystem.h

@@ -15,19 +15,22 @@ namespace Kernel
 		static VirtualFileSystem& get();
 		virtual ~VirtualFileSystem() {};
 
-		virtual const BAN::RefPtr<Inode> root_inode() const override;
+		virtual const BAN::RefPtr<Inode> root_inode() const override  { return m_root_inode; }
 
-		void close_inode(BAN::StringView);
-
-		BAN::ErrorOr<BAN::RefPtr<Inode>> from_absolute_path(BAN::StringView);
+		struct File
+		{
+			BAN::RefPtr<Inode> inode;
+			BAN::String canonical_path;
+		};
+		BAN::ErrorOr<File> file_from_absolute_path(BAN::StringView);
 
 	private:
 		VirtualFileSystem() = default;
 		BAN::ErrorOr<void> initialize_impl();
 
 	private:
-		BAN::HashMap<BAN::String, BAN::RefPtr<Inode>>	m_open_inodes;
-		BAN::Vector<StorageController*>					m_storage_controllers;
+		BAN::RefPtr<Inode>				m_root_inode;
+		BAN::Vector<StorageController*>	m_storage_controllers;
 	};
 
 }

kernel/include/kernel/Process.h

@@ -1,7 +1,9 @@
 #pragma once
 
 #include <BAN/String.h>
+#include <BAN/StringView.h>
 #include <BAN/Vector.h>
+#include <kernel/FS/Inode.h>
 #include <kernel/Thread.h>
 
 namespace Kernel
@@ -24,12 +26,39 @@ namespace Kernel
 
 		pid_t pid() const { return m_pid; }
 
+		BAN::ErrorOr<int> open(BAN::StringView, int);
+		BAN::ErrorOr<void> close(int);
+		BAN::ErrorOr<size_t> read(int, void*, size_t);
+
+		BAN::StringView working_directory() const { return m_working_directory; }
+		BAN::ErrorOr<void> set_working_directory(BAN::StringView);
+
+		Inode& inode_for_fd(int);
+
 		static BAN::RefPtr<Process> current() { return Thread::current()->process(); }
 
 	private:
 		Process(pid_t pid) : m_pid(pid) {}
 
+		BAN::ErrorOr<BAN::String> absolute_path_of(BAN::StringView) const;
+
 	private:
+		struct OpenFileDescription
+		{
+			BAN::RefPtr<Inode> inode;
+			BAN::String path;
+			size_t offset = 0;
+			uint8_t flags = 0;
+
+			BAN::ErrorOr<size_t> read(void*, size_t);
+		};
+
+		BAN::ErrorOr<void> validate_fd(int);
+		OpenFileDescription& open_file_description(int);
+		BAN::ErrorOr<int> get_free_fd();
+
+		BAN::Vector<OpenFileDescription> m_open_files;
+
 		pid_t m_pid = 0;
 		BAN::String m_working_directory;
 		BAN::Vector<BAN::RefPtr<Thread>> m_threads;

kernel/include/kernel/Shell.h

@@ -13,7 +13,7 @@ namespace Kernel
 	public:
 		Shell(TTY*);
 		Shell(const Shell&) = delete;
-		void set_prompt(BAN::StringView);
+		BAN::ErrorOr<void> set_prompt(BAN::StringView);
 		void run();
 
 	private:
@@ -21,11 +21,13 @@ namespace Kernel
 		BAN::Vector<BAN::String> parse_arguments(BAN::StringView) const;
 		BAN::ErrorOr<void> process_command(const BAN::Vector<BAN::String>&);
 		void key_event_callback(Input::KeyEvent);
+		BAN::ErrorOr<void> update_prompt();
 
 	private:
 		TTY*						m_tty;
 		BAN::Vector<BAN::String>	m_old_buffer;
 		BAN::Vector<BAN::String>	m_buffer;
+		BAN::String					m_prompt_string;
 		BAN::String					m_prompt;
 		uint32_t					m_prompt_length = 0;