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());
+	}
+
+}