OVERVIEW

This directory contains mkinitramfs, a tool used to create a Linux boot image (initramfs).

This distribution is a fork of illiliti's tinyramfs as of commit 8abfcc9 (Fri May 21 2021) with the following differences:

• bash completion
• GNU-style options/help/usage
• switch to the GNU getopt(1) for command-line parsing
• "local"s to prevent namespace violations
• support "rootdelay" kernel's command-line parameter
• experimental smdev hook
• luks hook: ask for password if header/keyfile is not specified
• manual pages in mdoc(7) format
• new "extrafiles" directive to copy additional files
• "resume" hook to resume machines from hibernation

See git log for complete/further differences.

The original sources can be downloaded from:

1. https://github.com/illiliti/tinyramfs
2. https://github.com/illiliti/tinyramfs/archive/8abfcc9/tinyramfs-8abfcc9.zip

FEATURES

The following advantages can be distinguished:

• no bashisms, only POSIX shell (with "local"s exception)
• portable, no distro specific
• easy to use configuration
• build time and init time hooks
• LUKS (detached header, key, password), LVM
• smdev, mdev, mdevd, eudev, systemd-udevd

REQUIREMENTS

Kernel

You need a kernel built with the following features (statically or as modules):

  General setup
    [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
        CONFIG_BLK_DEV_INITRD=y

  Device Drivers
    Generic Driver Options
      [*] Maintain a devtmpfs filesystem to mount at /dev
          CONFIG_DEVTMPFS=y

To use mkinitramfs with encrypted root is needed to include the following features too:

  Device Drivers --->
    Multiple devices driver support (RAID and LVM) --->
      [*] Device mapper support
      [*] Crypt target support

  Cryptographic API --->
    <*> XTS support
    <*> SHA224 and SHA256 digest algorithm
    <*> AES cipher algorithms
    <*> AES cipher algorithms (x86_64)
    <*> User-space interface for hash algorithms
    <*> User-space interface for symmetric key cipher algorithms

Build time

• POSIX sh(1p), make(1p) and "mandatory utilities"

Runtime

• POSIX sh(1p) and standard POSIX utilities
• GNU getopt(1), switch_root(8), mount(8), cpio(1)

The following runtime dependencies are optional:

• ldd(1): for copying binary dependencies
• strip(1p): for reducing image size by stripping binaries
• blkid(8): for UUID, LABEL, PARTUUID support
• smdev OR mdev OR mdevd OR eudev OR systemd-udevd or CONFIG_UEVENT_HELPER: for modular kernel, /dev/mapper/* and /dev/disk/*
• lvm(8): for LVM support
• cryptsetup(8): for LUKS support
• busybox' loadkmap: for keymap support
• kmod OR busybox' modutils+patch: for non-monolithic kernel

INSTALL

The shell command make install should install this package. The command make install_bashcomp should install bash completion script.

See config.mk file for configuration parameters.

USAGE

To use mkinitramfs, read mkinitramfs.config(5) and setup /etc/mkinitramfs/config file conform your needs. Next, run the following command:

sudo mkinitramfs -o "/boot/initramfs-$(uname -r).img"

Then update your bootloader config (i.e. grub):

sudo grub-mkconfig -o /boot/grub/grub.cfg

Reboot.

CREDITS

• illiliti https://github.com/illiliti
• E5ten https://github.com/E5ten
• dylanaraps https://github.com/dylanaraps

You can donate if you like this project to the original author:

• illiliti / (BTC) 1BwrcsgtWZeLVvNeEQSg4A28a3yrGN3FpK
• https://patreon.com/illiliti

LICENSE

mkinitramfs is licensed through the GNU General Public License v3 or later https://gnu.org/licenses/gpl.html. Read the COPYING file for copying conditions. Read the COPYRIGHT file for copyright notices.