Arch Linux

KairiTech

Member

From: Toronto, Canada

Registered: 2011-06-04

Posts: 275

[Solved] Silent LUKS boot

[Synopsis] Create a hook as shown below to silence the kernel.

I'd like to have a truly silent boot as in the Wiki but it only seems to address the login prompt.

I would also like to get rid of the (USB) boot messages pollution of the the LUKS password prompt for my encrypted root. Is there some configuration of the initramfs required to accomplish this? If so, what exactly would that be?

I should add that I boot the STUB EFI kernel so there's no bootloader as such.

Last edited by KairiTech (2013-12-14 01:27:52)

jasonwryan

Anarchist

From: .nz

Registered: 2009-05-09

Posts: 30,426

Website

Re: [Solved] Silent LUKS boot

Not an Installation issue, moving to Kernel and Hardware...

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Arch + dwm   •   Mercurial repos  •   Surfraw

Registered Linux User #482438

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: [Solved] Silent LUKS boot

The encrypt hook is just a shel script.  So you could either a) modify /usr/bin/initcpio/hooks/encrypt to address these changes you wish to make, or b) copy the encrypt "hook" and "install" files to a different name, and edit them instead (calling it something like myencrypt).

I would personally go with the second option just because you seriosuly risk losing any changes you make to the encrypt hook, as it is not a file that is in the backup array of the package.  So if you create a "new" hook outside of the package manager's control, this would put those risks to a minimum.

KairiTech

Member

From: Toronto, Canada

Registered: 2011-06-04

Posts: 275

Re: [Solved] Silent LUKS boot

I created the hook shown below to silence the kernel and now the LUKS prompt is clean.

/usr/lib/initcpio/hooks/hushkernel

#!/usr/bin/ash

# https://bbs.archlinux.org/viewtopic.php?pid=1312342#p1312342

run_hook() {

   # http://unix.stackexchange.com/questions/44999/how-can-i-hide-messages-of-udev/45525#45525

   # The four values in printk denote: console_loglevel, default_message_loglevel, minimum_console_loglevel and default_console_loglevel respectively.

   # These values influence printk() behavior when printing or logging error messages. See 'man 2 syslog' for more info on the different loglevels.

   # • console_loglevel: messages with a higher priority than this will be printed to the console
   # • default_message_level: messages without an explicit priority will be printed with this priority
   # • minimum_console_loglevel: minimum (highest) value to which console_loglevel can be set
   # • default_console_loglevel: default value for console_loglevel

   #define  KERN_EMERG    "<0>"  /* system is unusable               */
   #define  KERN_ALERT    "<1>"  /* action must be taken immediately */
   #define  KERN_CRIT     "<2>"  /* critical conditions              */
   #define  KERN_ERR      "<3>"  /* error conditions                 */
   #define  KERN_WARNING  "<4>"  /* warning conditions               */
   #define  KERN_NOTICE   "<5>"  /* normal but significant condition */
   #define  KERN_INFO     "<6>"  /* informational                    */
   #define  KERN_DEBUG    "<7>"  /* debug-level messages             */

   echo "3 3 3 3" > /proc/sys/kernel/printk

}

/usr/lib/initcpio/install/hushkernel

#!/bin/ash

build() {
   add_runscript
}

help() {
   cat <<HELPEOF

This hook will suppress kernel messages during the boot LUKS password prompt

HELPEOF
}