Kernel/LibC: move file offset back to kernel

This makes keeping track of offsets easier and more proper

kernel/include/kernel/Process.h

@@ -42,10 +42,13 @@ namespace Kernel
 
 		BAN::ErrorOr<int> open(BAN::StringView, int);
 		BAN::ErrorOr<void> close(int fd);
-		BAN::ErrorOr<size_t> read(int fd, void* buffer, size_t offset, size_t count);
-		BAN::ErrorOr<size_t> write(int fd, const void* buffer, size_t offset, size_t count);
+		BAN::ErrorOr<size_t> read(int fd, void* buffer, size_t count);
+		BAN::ErrorOr<size_t> write(int fd, const void* buffer, size_t count);
 		BAN::ErrorOr<void> creat(BAN::StringView name, mode_t);
 
+		BAN::ErrorOr<void> seek(int fd, off_t offset, int whence);
+		BAN::ErrorOr<off_t> tell(int fd);
+
 		BAN::ErrorOr<void> fstat(int fd, struct stat*);
 		BAN::ErrorOr<void> stat(BAN::StringView path, struct stat*);
 
@@ -77,7 +80,8 @@ namespace Kernel
 		{
 			BAN::RefPtr<Inode> inode;
 			BAN::String path;
-			uint8_t flags = 0;
+			off_t offset { 0 };
+			uint8_t flags { 0 };
 		};
 
 		BAN::ErrorOr<void> validate_fd(int);

kernel/include/kernel/Syscall.h

@@ -8,6 +8,8 @@
 #define SYS_OPEN 6
 #define SYS_ALLOC 7
 #define SYS_FREE 8
+#define SYS_SEEK 9
+#define SYS_TELL 10
 
 #include <kernel/Attributes.h>
 #include <stdint.h>