plymouth - graphical boot animation and logger



Plymouth is an application that runs very early in the boot process (even before the

root filesystem is mounted!) that provides a graphical boot animation while the boot

process happens in the background.



It is designed to work on systems with DRM modesetting drivers.  The idea is

that early on in the boot process the native mode for the computer is set, plymouth

uses that mode, and that mode stays throughout the entire boot process up to and

after X starts.  Ideally, the goal is to get rid of all flicker during startup.



For systems that don't have DRM mode settings drivers, plymouth falls back to

text mode.



In either text or graphics mode, the boot messages are completely occluded.  After

the root file system is mounted read-write, the messages are dumped to

/var/log/bootmessages.log.  Also, the user can see the messages at any time during

boot up by hitting the escape key.



Plymouth isn't really designed to be built from source by end users.  For it to work

correctly, it needs integration with the distribution.  Because it starts so early,

it needs to be packed into the distribution's initial ram disk, and the distribution

needs to poke plymouth to tell it how boot is progressing.



In the scripts/ directory there is a shell script that attempts to unpack an existing

initrd, add plymouth, and pack it back up.  It's not a complete solution, though, it's

more for debugging/testing and will probably only work on Fedora based systems.



plymouth ships with two binaries: /usr/libexec/plymouth/plymouthd and /usr/bin/plymouth



The first one, plymouthd, does all the heavy lifting. It logs the session and shows the

splash screen. The second one, /usr/bin/plymouth, is the control interface to plymouthd.



It supports things like plymouth --show-splash, or plymouth --ask-for-password, which

trigger the associated action in plymouthd.



plymouth supports various "splash" plugins which are analagous to screensavers, but

happen at boot time.  Currently there are two graphical splash plugins: fade-in,

and spinfinity.  There are also two non-graphical plugins which are for text

mode and the details view.



The graphical plugins need a logo image and background color to function.

Distributions are expected to set these up in their packages at ./configure

time, but there are some placeholder values set up if ./configure doesn't get

those options.



Plymouth isn't done yet.  It's still under active development and isn't ready for

distros to use as-is.  That should change in the near future though.