Module cpio

CPIO (Copy In/Out) filesystem implementation for the kernel.

This module provides a read-only implementation of the CPIO archive format, typically used for the initial ramdisk (initramfs). The CPIO format is a simple archive format that stores files sequentially with headers containing metadata.

Features

• Parsing of CPIO archives in the “new ASCII” format (magic “070701”)
• Read-only access to files stored in the archive
• Directory traversal and metadata retrieval

Limitations

• Write operations are not supported as the filesystem is read-only
• Block operations are not implemented since CPIO is not a block-based filesystem

Components

• CpiofsEntry: Represents an individual file or directory within the archive
• Cpiofs: The main filesystem implementation handling mounting and file operations
• CpiofsFileHandle: Handles file read operations and seeking
• CpiofsDriver: Driver that creates CPIO filesystems from memory areas

Usage

The CPIO filesystem is typically created from a memory region containing the archive data, such as an initramfs loaded by the bootloader:

let cpio_driver = CpiofsDriver;
let fs = cpio_driver.create_from_memory(&initramfs_memory_area)?;
vfs_manager.register_filesystem(fs)?;

Structs

Cpiofs

Structure representing the entire Initramfs

CpiofsDriver

Driver for CPIO-format filesystems (initramfs)

CpiofsEntry

Structure representing an Initramfs entry

CpiofsFileHandle 🔒

Statics

__DRIVER_INITCALL__ 🔒

Functions

register_driver 🔒