plymouth

arch wiki - plymouth

• install plymouth (recommended to use development version, but unstable)

paru -S plymouth

• add plymouth hook to /etc/mkinitcpio.conf

  HOOKS=(base udev autodetect keyboard keymap consolefont modconf block encrypt lvm2 filesystems fsck)

  HOOKS=(base udev plymouth autodetect keyboard keymap consolefont modconf block plymouth-encrypt lvm2 filesystems fsck)

• make sure to replace encrypt with plymouth-encrypt!
  • (now: plymouth-encrypt no longer necessary as of version 22.02.122-7)
• add amdgpu to MODULES

MODULES=(amdgpu ...)

• arch wiki - silent boot
• add kernel parameters:

quiet loglevel=3 udev.log_level=3 splash vt.global_cursor_default=0 fbcon=nodefer

• splash necessary, fbcon=nodefer: don't try to defer vendor logo
• switch display manager service for smoother transition

sudo systemctl disable sddm.service
sudo systemctl enable sddm-plymouth.service

• can't quite get totally smooth transition (goes to black then sddm) but good enough for me :p
  • (now: plymouth-encrypt no longer necessary as of version 22.02.122-7)

theming

• list themes (can install additional from AUR)

plymouth-set-default-theme -l

• use -R to rebuild initramfs

plymouth-set-default-theme -R theme

• or edit /etc/plymouth/plymouthd.conf

[Daemon]
Theme=simple

• and regenerate initramfs with sudo mkinitcpio -P
• for themes using ModuleName two-step, e.g. spinner (check /usr/share/plymouth/themes/ folder, .plymouth file for module)
• add background to /usr/share/plymouth/themes/theme/background-tile.png
• can only tile! (seems hardcoded)

script module

• problem: many modules compiled into .so, hard to modify
• solution: use script module, write code in domain-specific language
• language documented on Plymouth page but out of date
• easiest to read C source directly
• and examples:
  • default script theme /usr/share/plymouth/themes/script
  • spinner script theme
• language is sort of weird
  • everything is an object...
  • ...except functions, they seem not to be first-class objects
  • no runtime errors, NULL propagation
  • global easily pollutes namespace
• feels like what I would imagine JavaScript is
  • but to be honest I have written more .script than .js...

testing

• switch to virtual console with ctrl+alt+F6
• log in as root, run

plymouthd
plymouth show-splash
plymouth quit

• problem: once plymouth starts showing splash, cannot issue commands!
• solution: make shell file, say test.fish

plymouthd --debug --debug-file=/usr/share/plymouth/themes/simple/testing/log.txt
plymouth show-splash
sleep 5
plymouth quit

• run with test.fish, after 5 seconds automatically kills
• testing messages:

plymouthd
plymouth show-splash
set message "test message"
sleep 1
plymouth display-message --text=$message
sleep 2
# has to be the same message or callback isn't called
plymouth hide-message --text=$message
sleep 2

• testing passwords: need to inject key presses into /dev/tty1 (by default)
• easiest way (not necessarily best) with TIOCSTI
• see stackoverflow - inject.py:

import fcntl
import sys
import termios

with open(sys.argv[1], "w") as fd:
    chars = eval(f"'{sys.argv[2]}'")
    for c in chars:
        fcntl.ioctl(fd, termios.TIOCSTI, c)

• client script:

plymouthd
plymouth show-splash
sleep 1
plymouth ask-for-password --prompt="test" &
sleep 1
python inject.py /dev/tty1 "these keypresses are sent to /dev/tty1"
sleep 1
# backspaces
python inject.py /dev/tty1 "\x7f\x7f\x7f\x7f\x7f\x7f\x7f"
sleep 1
python inject.py /dev/tty1 "additional text"
sleep 1
# enter, send password
python inject.py /dev/tty1 "\n"
sleep 2
plymouth quit

• useful: tmux to have multiple consoles, vim settings:

set autoindent
set expandtab
set shiftwidth=4
set tabstop=4
set colorcolumn=80

multi-head

just works!

careful when scripting:

Window.GetX()
Window.GetY()

are not accurate (leads to black bars on multi-head setups with different resolutions). Basically assume the Window's top left corner is (0, 0) and everything will be ok.