gen-initrd

A simple utility to generate an init ram disk (initrd) for the aurora kernel

The initrd contains several different programs:

• early-init: mounts the root filesystem and starts the init process
• part-list: specifies which partitions have which filesystems and where to mount them
• fs-server: filesystem server that filesystem drivers talk to
• ahci-server: ahci driver that filesystem drivers use to communicate with drives
• one or more filesystem drivers

format

the format is very simple, and consists of one header and many entries

header layout

struct InitrdHeader {
	magic: u64,
	len: u64,
}

the header is always at the very beginning of the initrd

magic will always be initialized to 0x39f298aa4b92e836

len spicifies how many entries there are

entry layout

struct InitrdEntry {
	type: u64,
	name: u64,
	name_len: u64,
	data: u64,
	data_len: u64,
}

the entry list starts directly after the header

type spcifies the type of entry there are several different valid types:

• 0: any file
• 1: early-init
• 2: part-list
• 3: fs-server
• 4: ahci-server

name specifies the offset into the initrd of the name of the entry, and name_len specifies the length of this string

the name string will be a valid utf-8 string

data specifies the offset into the initrd of the data of the entry, and data_len specifies the length, in bytes, of the data

name and data will always be 8 byte aligned