Sortix volatile manual
This manual documents Sortix volatile, a development build that has not been officially released. You can instead view this document in the latest official manual.
RELEASE-ISO-MODIFICATION(7) | Miscellaneous Information Manual | RELEASE-ISO-MODIFICATION(7) |
NAME
release-iso-modification
—
instructions on how to modify release .iso
filesystems
DESCRIPTION
This document describes how to modify Sortix .iso releases to meet your custom needs. The bootloader configuration in .iso releases is designed with an extensible hooks system that let's you override it with further configuration and to load additional files of your choice into the live environment. The live environment is configurable through the normal operating system configuration as described in section 5 of the manual.
The release modification procedure lets you customize aspects such as the default bootloader menu option and timeout, the default hostname, the default keyboard layout, the default graphics resolution, adding files of your choice to the live environment, control which drivers are loaded by default, control which live environment daemons are started by default, deploy ssh keys so secure shell connections are trusted on the first connection, configure automatic installation and upgrading, and so on.
Prerequisites
- A sortix-x.y-arch.iso release for your architecture.
- xorriso(1) needs to be installed.
Overview
The release modification process has three stages:
- Optionally, creating additional files that will be loaded onto the live environment (the liveconfig).
- Creating additional bootloader configuration (the bootconfig), which will contain an archived copy of the liveconfig (if any).
- Adding the bootconfig to the release .iso.
The bootloader menu Install and Upgrade selections will start the live environment and run the sysinstall(8) installer and sysupgrade(8) upgrader respectively and they are thus also customizable by this procedure.
Convenience Scripts
The release modification can be done manually by hand, or you can use the following convenience scripts that make the release modification easy:
- tix-iso-liveconfig(8) that generates additional configuration files for the live environment.
- tix-iso-bootconfig(8) that generates additional bootloader configuration and optionally configures the bootloader to load the liveconfig into the live environment.
- tix-iso-add(8) that adds the bootconfig (and thus the liveconfig if any) to the release .iso.
These convenience scripts come with the operating system and are installed in the /sbin directory. These scripts are entirely for convenience and you can perform their tasks yourself if they don't meet your needs. The scripts are readable shell scripts and you can learn how they work and extend them with your own features.
If you are not on a Sortix system or on a different version of Sortix than the one you are customizing, you can download the shell scripts matching the latest stable release:
- https://pub.sortix.org/sortix/release/nightly/scripts/tix-iso-liveconfig
- https://pub.sortix.org/sortix/release/nightly/scripts/tix-iso-bootconfig
- https://pub.sortix.org/sortix/release/nightly/scripts/tix-iso-add
If you are not customizing the latest stable release, you can find the matching versions of the scripts in the scripts/ subdirectory of the appropriate release directory, or you can check out the tix directory in the source code from https://sortix.org/source/ matching the release you are currently customizing.
Additional Live Configuration Configuration
The live environment is a normal instance of the operating system and can be configured by adding additional files or overwriting existing files. Section 5 of the manual documents the system and software configuration files. Additional files can also be added for their own sake.
To do so, create a directory that will contain this additional live environment configuration (liveconfig), whose contents will be extracted on top of the live environment's root filesystem. A compressed archive of this directory will be made in the next subsection and needs to be registered with the bootloader configuration.
The tix-iso-liveconfig(8) convenience script is useful as it offers a lot of commonly useful customizations to the live environment and can populate an initial liveconfig directory for you.
Additional Bootloader Configuration
The GRUB bootloader configuration of an release .iso is extensible and allows additional configuration to hook into it by writing a /boot/grub/hooks.cfg configuration file as described in release-iso-bootconfig(7).
To do so, create a directory that will contain this additional bootloader configuration (bootconfig), whose contents will be added onto the release .iso. The liveconfig (if any) is normally added to the bootconfig as a compressed archive and the additional bootloader configuration loads it as an initrd onto the live environment. The bootconfig will be overlaid to the release .iso in the next subsection.
The
tix-iso-bootconfig(8)
convenience script makes it easy to generate common additional bootloader
configuration and its documentation has examples of what it can do. It is
commonly used with the --liveconfig
option to
generate the bootloader configuration that loads the additional files from
the liveconfig into the live environment.
Adding Files To The Release
Releases are modified by adding the bootconfig (which contains a compressed copy of the liveconfig, if any) files to the release .iso.
The tix-iso-add(8) convenience script makes it easy to add files to a release .iso while taking care to keep the release .iso bootable after the modification. You need xorriso(1) installed to use this script. Alternatively you can add the files to the release .iso by running xorriso(1) yourself:
xorriso \ -indev "$input_file" \ -outdev "$output_file" \ -boot_image grub keep \ -pathspecs on \ -add \ ="$input_directory"
Your modified release can then be used in place of the original release. See the EXAMPLES section below for inspiration on what customizations to make, as well as the manual pages for the tix-iso-liveconfig(8) and tix-iso-bootconfig(8) convenience scripts.
EXAMPLES
This section contains examples of how one can modify a release .iso.
No Change
To customize a release with no customizations except for the bootloader to say the release was modified by the current user on the current host:
tix-iso-bootconfig bootconfig tix-iso-add sortix.iso bootconfig
Add Files to the Live Environment
To customize a release with additional files and directories in the live environment:
mkdir -p liveconfig mkdir -p liveconfig/root echo foo > liveconfig/root/foofile echo bar > liveconfig/root/barfile tix-iso-bootconfig --liveconfig=liveconfig bootconfig tix-iso-add sortix.iso bootconfig
Provide Random Seed
To customize a release with a random seed (/boot/random.seed) (which must be kept confidential and not reused, see the warnings in tix-iso-bootconfig(8)):
tix-iso-bootconfig --random-seed bootconfig tix-iso-add sortix.iso bootconfig rm bootconfig/boot/random.seed # When no longer useful. rm sortix.iso # When no longer useful. # And erase any media made from sortix.iso when no longer useful.
Hostname, Keyboard Layout, and Graphics Resolution
To customize the live environment of a release with a custom hostname, custom keyboard layout, and custom graphics resolution:
tix-iso-liveconfig \ --hostname=dragon \ --kblayout=dk \ --videomode=1920x1080x32 \ liveconfig tix-iso-bootconfig --liveconfig=liveconfig bootconfig tix-iso-add sortix.iso bootconfig
Load Only Basic Ports by Default
To customize a release to only loads basic ports by default:
mkdir -p bootconfig/boot/grub cat > bootconfig/boot/grub/hooks.cfg << EOF select_ports_set_basic EOF tix-iso-add sortix.iso bootconfig
Default Bootloader Menu Option and Timeout
To customize a release so the default bootloader menu option is to run the installer (bootloader menu option 1, counting from 0) and to change the bootloader menu timeout to 2 seconds:
tix-iso-bootconfig --default=1 --timeout=2 bootconfig tix-iso-add sortix.iso bootconfig
Locked Down Multi-User Live Environment
To customize a release so the live environment boots to the login screen by default with the provided database of users and groups (passwd(5) and group(5)), password protect the bootloader so only the default live environment option can be chosen by unauthenticated users:
mkdir -p liveconfig/etc # Each user's password is their username hashed with crypt_newhash(3). (printf 'root:%s:0:0:root:/root:sh\n' \ '$2b$10$S/fJmYIJSkRdifk61xDYn.w62y.vNu35tZkznR6xa3Ntg0hsbI8tO' && printf 'alice:%s:1000:1000:alice:/home/alice:sh\n' \ '$2b$10$4xGAf5FyCYedWoNltWvbmOOreXcI5cH/f4Jz/pkWrWxwZ7TQ/WbRC' && printf 'bob:%s:1001:1001:bob:/home/bob:sh\n' \ '$2b$10$0.IukhbHNy63te6ozVJ7Pu/EvbCcr892981XbqRQ0w16UPhmDdUqa') | cat > liveconfig/etc/passwd cat > liveconfig/etc/group << EOF root::0:root alice::1000:alice bob::1001:bob EOF mkdir -p liveconfig/home mkdir -p -m 700 liveconfig/home/alice mkdir -p -m 700 liveconfig/home/bob grub-mkpasswd-pbkdf2 | # enter bootloader password tee /dev/tty | tail -n 1 | sed 's/PBKDF2 hash of your password is //' > liveconfig/etc/grubpw tix-iso-bootconfig --liveconfig=liveconfig bootconfig (echo 'insmod password_pbkdf2' echo 'set superusers="root"' echo "password_pbkdf2 root $(cat liveconfig/etc/grubpw)") | cat >> bootconfig/boot/grub/hooks.cfg cat > bootconfig/boot/grub/main.cfg << \EOF menu_title="$base_menu_title" hook_menu_pre menuentry "Sortix $version" --unrestricted { load_sortix -- /sbin/init --target=multi-user } hook_menu_post EOF tix-iso-add sortix.iso bootconfig
Add a new Port
To customize a release with a new port foo in the basic and all port sets and fully integrate it with the bootloader menus:
mkdir -p bootconfig/boot/grub cat > bootconfig/boot/grub/hooks.cfg << \EOF port_foo=true tix_foo=false export port_foo export tix_foo function hook_ports_menu { if $port_foo; then menuentry "foo = true" { port_foo=false configfile /boot/grub/ports.cfg } else menuentry "foo = false" { port_foo=true configfile /boot/grub/ports.cfg } fi } function hook_tix_menu { if $tix_foo; then menuentry "foo = true" { tix_foo=false configfile /boot/grub/tix.cfg } else menuentry "foo = false" { tix_foo=true configfile /boot/grub/tix.cfg } fi } function hook_ports_set_all { port_foo=true } function hook_tix_set_all { tix_foo=true } function hook_ports_set_basic { port_foo=true } function hook_tix_set_basic { tix_foo=true } function hook_ports_set_minimal { port_foo=false } function hook_tix_set_minimal { tix_foo=false } function hook_ports_set_no { port_foo=false } function hook_tix_set_no { tix_foo=false } function hook_ports_pre { if $tix_foo; then echo -n "Loading /repository/foo.tix.tar.xz (3.0M) ... " module --nounzip /repository/foo.tix.tar.xz \ --to /repository/foo.tix.tar.xz echo done fi if $port_foo; then echo -n "Loading /repository/foo.tix.tar.xz (3.0M) ... " module /repository/foo.tix.tar.xz echo done fi } EOF mkdir -p bootconfig/repository cp foo.tix.tar.xz bootconfig/repository/foo.tix.tar.xz tix-iso-add sortix.iso bootconfig
Add a new Ports Set
To customize a release with your own set of ports that are loaded by default and fully integrate it with the bootloader menus:
mkdir -p bootconfig/boot/grub cat > bootconfig/boot/grub/hooks.cfg << \EOF function hook_ports_menu_sets { menuentry "Load only recommended ports" { select_ports_set_recommended configfile /boot/grub/ports.cfg } } function hook_tix_menu_sets { menuentry "Load only basic binary packages" { select_tix_set_recommended configfile /boot/grub/tix.cfg } } select_ports_set_recommended { # The basic set can be extended by calling select_ports_set_basic here. port_foo=false port_bar=true } select_tix_set_recommended { # The basic set can be extended by calling select_tix_set_basic here. tix_foo=false tix_bar=true } # Load the recommended set of ports by default. hook_ports_menu_sets EOF tix-iso-add sortix.iso bootconfig
Disable Networking Drivers By Default
To customize a release so it doesn't load network drivers by default, useful for security reasons or to work around driver issues:
tix-iso-bootconfig --disable-network-drivers bootconfig tix-iso-add sortix.iso bootconfig
Disable DHCP Auto-Configuration By Default
To customize a release so dhclient(8) doesn't automatically configure network interfaces using DHCP, useful if one wants to manually configure network interfaces with ifconfig(8).
tix-iso-bootconfig --disable-dhclient bootconfig tix-iso-add sortix.iso bootconfig
Enable SSH Server By Default
To customize a release so it starts the SSH server sshd(8) automatically using the SSH configuration found in the liveconfig directory:
tix-iso-bootconfig --liveconfig=liveconfig --enable-sshd bootconfig tix-iso-add sortix.iso bootconfig
SSH Into Live Environment
To customize the live environment of a release so you can ssh into its root user, to have the hostname example.com, to start a ssh server with the keys generated now, authorize the local user to ssh into the live environment's root user, and register the sshd server's keys by their hostnames and network addresses so the connection is trusted on the first attempt (you can omit the network addresses if you don't know yet):
tix-iso-liveconfig \ --hostname=example.com \ --root-ssh-authorized-keys="$HOME/.ssh/id_rsa.pub" \ --sshd-keygen \ --sshd-key-known-hosts-file="$HOME/.ssh/known_hosts" \ --sshd-key-known-hosts-hosts="example.com example.com,192.0.2.1 192.0.2.1" \ liveconfig tix-iso-bootconfig --liveconfig=liveconfig --enable-sshd bootconfig tix-iso-add sortix.iso bootconfig rm -f liveconfig/etc/ssh_host_*_key # When no longer useful. rm -f bootconfig/boot/liveconfig.xz # When no longer useful. rm -f sortix.iso # When no longer useful. # And erase any media made from sortix.iso when no longer useful. ssh root@example.org # When the system is running.
This example generates sshd private keys (remember to delete them when no longer needed, see the warnings in tix-iso-liveconfig(8)) and shows them by running:
mkdir -p liveconfig/etc for keytype in rsa ecdsa ed25519; do ssh-keygen -t $keytype -f liveconfig/etc/ssh_host_${keytype}_key" -N "" \ -C "root@$hostname" done for keytype in rsa ecdsa ed25519; do ssh-keygen -l -f liveconfig/etc/ssh_host_${keytype}_key done
It then constructs a known_hosts file for each network address and hashes it.
(for host in $network_addresses; do for keytype in rsa ecdsa ed25519; do printf '%s ' "$host" && sed -E 's/^([^ ]* [^ ]*).*/\1/' \ liveconfig/etc/ssh_host_${keytype}_key.pub done done) > known_hosts ssh-keygen -H -f known_hosts rm -f known_hosts.old
ssh(1) will trust the server by the network addresses on the first connection if you append the contents of known_hosts to your ~/.ssh/known_hosts. liveconfig/root/.ssh/authorized_keys file is made by appending the appropriate public keys previously made with ssh-keygen(1).
SSH Back From Live Environment
To customize the live environment of a release so its root user can ssh back to your user, where the local hostname is example.com (the address to which the new installation will be connecting), by generating a private key for the root user (remember to delete it when no longer needed, see the warnings in tix-iso-liveconfig(8)) and adding its public key to your local ~/.ssh/authorized_keys:
tix-iso-liveconfig --root-ssh-keygen liveconfig ssh-keyscan -H example.com > liveconfig/root/.ssh/known_hosts cat liveconfig/root/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys tix-iso-bootconfig --liveconfig=liveconfig --enable-sshd bootconfig tix-iso-add sortix.iso bootconfig rm -f output-directory/root/.ssh/id_rsa # When no longer useful. rm -f bootconfig/boot/liveconfig.xz # When no longer useful. rm -f sortix.iso # When no longer useful. # And erase any media made from sortix.iso when no longer useful.
This example will generate a ssh key for the root user by running:
mkdir -p -m 700 liveconfig/root/.ssh ssh-keygen -t rsa -f liveconfig/root/.ssh/id_rsa -N "" -C "root@$hostname"
Consider omitting the -N
option and
password protect the private key to protect it in the case of a leak.
Boot to Console Instead of GUI By Default
To customize a release so it boots to a console instead of the GUI:
tix-iso-bootconfig --disable-gui bootconfig tix-iso-add sortix.iso bootconfig
Automatic Installation
To customize a release so it automatically installs itself per the autoinstall.conf(5):
tix-iso-liveconfig --autoinstall=autoinstall.conf liveconfig tix-iso-bootconfig --liveconfig=liveconfig --default=1 bootconfig tix-iso-add sortix.iso bootconfig
Automatic Upgrade
To customize a release so it automatically upgrades a local installation per the autoupgrade.conf(5):
tix-iso-liveconfig --autoinstall=autoupgrade.conf liveconfig tix-iso-bootconfig --liveconfig=liveconfig --default=2 bootconfig tix-iso-add sortix.iso bootconfig
Boot to Console Instead of GUI By Default
To customize a release so it boots to a console instead of the GUI:
tix-iso-bootconfig --disable-gui bootconfig tix-iso-add sortix.iso bootconfig
Boot to Serial Console using Qemu
To boot to a serial terminal with a custom serial settings and a
custom terminal window size of 118 columns by 256 rows and a specific
TERM
variable inside the qemu virtual machine:
tix-iso-bootconfig --serial="com1,9600n8,118x56 --term=xterm-256color" bootconfig tix-iso-add sortix.iso bootconfig qemu-system-x86_64 -serial mon:stdio -cdrom sortix.iso
SEE ALSO
xorriso(1), development(7), installation(7), release-iso-bootconfig(7), upgrade(7), user-guide(7), tix-iso-add(8), tix-iso-bootconfig(8), tix-iso-liveconfig(8)
February 5, 2018 | Sortix 1.1.0-dev |