Kernel: Add basic Credentials for the system

Now filesystem access/open, etc confirm that you have access for rwxs

kernel/include/kernel/Credentials.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <sys/types.h>
+
+namespace Kernel
+{
+
+	class Credentials
+	{
+	public:
+		Credentials(uid_t ruid, uid_t euid, gid_t rgid, gid_t egid)
+			: m_ruid(ruid), m_euid(euid), m_suid(0)
+			, m_rgid(rgid), m_egid(egid), m_sgid(0)
+		{ }
+
+		uid_t ruid() const { return m_ruid; }
+		uid_t euid() const { return m_euid; }
+		uid_t suid() const { return m_suid; }
+
+		gid_t rgid() const { return m_rgid; }
+		gid_t egid() const { return m_egid; }
+		gid_t sgid() const { return m_sgid; }
+
+	private:
+		uid_t m_ruid, m_euid, m_suid;
+		gid_t m_rgid, m_egid, m_sgid;
+	};
+
+}
+
+namespace BAN::Formatter
+{
+
+	template<typename F>
+	void print_argument(F putc, const Kernel::Credentials& credentials, const ValueFormat&)
+	{
+		print(putc, "(ruid {}, euid {})", credentials.ruid(), credentials.euid());
+	}
+
+}

kernel/include/kernel/FS/Inode.h

@@ -6,6 +6,7 @@
 #include <BAN/Vector.h>
 
 #include <kernel/API/DirectoryEntry.h>
+#include <kernel/Credentials.h>
 
 #include <sys/types.h>
 #include <time.h>
@@ -56,6 +57,8 @@ namespace Kernel
 	public:
 		virtual ~Inode() {}
 
+		bool can_access(const Credentials&, int);
+
 		bool operator==(const Inode& other) const { return dev() == other.dev() && rdev() == other.rdev() && ino() == other.ino(); }
 
 		virtual ino_t ino() const = 0;

kernel/include/kernel/FS/VirtualFileSystem.h

@@ -11,21 +11,21 @@ namespace Kernel
 	class VirtualFileSystem : public FileSystem
 	{
 	public:
-		static BAN::ErrorOr<void> initialize(BAN::StringView);
+		static void initialize(BAN::StringView);
 		static VirtualFileSystem& get();
 		virtual ~VirtualFileSystem() {};
 
 		virtual BAN::RefPtr<Inode> root_inode() override { return m_root_fs->root_inode(); }
 
-		BAN::ErrorOr<void> mount(BAN::StringView, BAN::StringView);
-		BAN::ErrorOr<void> mount(FileSystem*, BAN::StringView);
+		BAN::ErrorOr<void> mount(const Credentials&, BAN::StringView, BAN::StringView);
+		BAN::ErrorOr<void> mount(const Credentials&, FileSystem*, BAN::StringView);
 
 		struct File
 		{
 			BAN::RefPtr<Inode> inode;
 			BAN::String canonical_path;
 		};
-		BAN::ErrorOr<File> file_from_absolute_path(BAN::StringView, bool follow_link);
+		BAN::ErrorOr<File> file_from_absolute_path(const Credentials&, BAN::StringView, int);
 
 	private:
 		VirtualFileSystem() = default;

kernel/include/kernel/Process.h

@@ -3,6 +3,7 @@
 #include <BAN/String.h>
 #include <BAN/StringView.h>
 #include <BAN/Vector.h>
+#include <kernel/Credentials.h>
 #include <kernel/FS/Inode.h>
 #include <kernel/Memory/FixedWidthAllocator.h>
 #include <kernel/Memory/GeneralAllocator.h>
@@ -37,7 +38,7 @@ namespace Kernel
 
 	public:
 		static Process* create_kernel(entry_t, void*);
-		static BAN::ErrorOr<Process*> create_userspace(BAN::StringView);
+		static BAN::ErrorOr<Process*> create_userspace(const Credentials&, BAN::StringView);
 		~Process();
 
 		[[noreturn]] void exit(int status);
@@ -91,12 +92,12 @@ namespace Kernel
 		const userspace_info_t& userspace_info() const { return m_userspace_info; }
 
 	private:
-		Process(pid_t);
-		static Process* create_process();
+		Process(const Credentials&, pid_t);
+		static Process* create_process(const Credentials&);
 		static void register_process(Process*);
 
 		// Load an elf file to virtual address space of the current page table
-		static BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> load_elf_for_exec(BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env);
+		static BAN::ErrorOr<BAN::UniqPtr<LibELF::ELF>> load_elf_for_exec(const Credentials&, BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env);
 		
 		// Copy an elf file from the current page table to the processes own
 		void load_elf_to_memory(LibELF::ELF&);
@@ -125,6 +126,8 @@ namespace Kernel
 			int waiting { 0 };
 		};
 
+		Credentials m_credentials;
+
 		BAN::Vector<OpenFileDescription> m_open_files;
 		BAN::Vector<VirtualRange*> m_mapped_ranges;
 

kernel/include/kernel/Terminal/TTY.h

@@ -108,7 +108,8 @@ namespace Kernel
 		TerminalDriver* m_terminal_driver { nullptr };
 
 	public:
-		virtual Mode mode() const override { return { Mode::IFCHR | Mode::IRUSR }; }
+		// FIXME: these should be crw------- with the owner being user
+		virtual Mode mode() const override { return { Mode::IFCHR | Mode::IRUSR | Mode::IWUSR | Mode::IRGRP | Mode::IWGRP | Mode::IROTH | Mode::IWOTH }; }
 		virtual uid_t uid() const override { return 0; }
 		virtual gid_t gid() const override { return 0; }
 		virtual dev_t rdev() const override { return m_rdev; }