---
title: "ustar.h"
summary: "specific driver for USTAR"
---

**Warning:** This is a filesystem specific driver, by this it should only be accessed by the [vfs](https://nerdcult.net/projects/noxos/docs/codebase/drivers/fs/vfs.h/).

The USTAR '_filesystem_' is probably more common known as **tar**-archive.
It is a really simple concept, where a file consists of a header block followed by data blocks.
These blocks are aligned at 512 bytes.

OSDev Wiki: [USTAR](https://wiki.osdev.org/USTAR)

# `ustar_type_E` - enum
The types an entry can have:
- **File**
- **Hardlink**
- **Symlink**
- **Char Device**
- **Block Device**
- **Directory**
- **Pipe**

# `ustar_header_T` - struct [packed / 512B aligned]

| Name              | Type      | Description                                                                                                                                                      |
|-------------------|-----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| name              | char[100] | The name of the entry                                                                                                                                            |
| mode              | uint64_t  | file mode (permissions, etc)                                                                                                                                     |
| owner_id          | uint64_t  | The owners ID                                                                                                                                                    |
| group_id          | uint64_t  | The groups ID                                                                                                                                                    |
| size              | char[12]  | The size of the entry, represented as a string of an octal number (dafuq)                                                                                        |
| last_modification | char[12]  | The unix-timestamp, when the entry was modified the last time                                                                                                    |
| checksum          | uint64_t  | I think this is a weird checksum of the header                                                                                                                   |
| type              | uint8_t   | The [ustar_type_E](https://nerdcult.net/projects/noxos/docs/codebase/drivers/fs/ustar.h/#ustar_type_e---enum) of the entry, represented as ascii numbers (dafuq) |
| name_linked       | char[100] | The path to the linked entry, if this is a link-entry                                                                                                            |
| indicator         | char[6]   | This needs to be `ustar`                                                                                                                                         |
| version           | uint16_t  | The version of the **tar** command, that created the archive                                                                                                     |
| owner_user_name   | char[32]  | The name of the file owner                                                                                                                                       |
| owner_group_name  | char[32]  | The name of the file group                                                                                                                                       |
| device_major      | uint64_t  | The devices major number                                                                                                                                         |
| device_minor      | uint64_t  | The devices minor number                                                                                                                                         |
| name_prefix       | char[155] | If this is not null, this acts as a prefix for _name_                                                                                                            |