nixpkgs/nixos/modules/installer/cd-dvd/iso-image.nix
Jonathan Ringer b5168a9900 nixos/iso-image: fix isoImage.grubTheme = null;
Fixes `error: cannot coerce null to a string`
2024-11-26 21:18:21 +02:00

895 lines
30 KiB
Nix

# This module creates a bootable ISO image containing the given NixOS
# configuration. The derivation for the ISO image will be placed in
# config.system.build.isoImage.
{ config, lib, pkgs, ... }:
let
/**
* Given a list of `options`, concats the result of mapping each options
* to a menuentry for use in grub.
*
* * defaults: {name, image, params, initrd}
* * options: [ option... ]
* * option: {name, params, class}
*/
menuBuilderGrub2 =
defaults: options: lib.concatStrings
(
map
(option: ''
menuentry '${defaults.name} ${
# Name appended to menuentry defaults to params if no specific name given.
option.name or (lib.optionalString (option ? params) "(${option.params})")
}' ${lib.optionalString (option ? class) " --class ${option.class}"} {
# Fallback to UEFI console for boot, efifb sometimes has difficulties.
terminal_output console
linux ${defaults.image} \''${isoboot} ${defaults.params} ${
option.params or ""
}
initrd ${defaults.initrd}
}
'')
options
)
;
/**
* Builds the default options.
*/
buildMenuGrub2 = buildMenuAdditionalParamsGrub2 "";
targetArch =
if config.boot.loader.grub.forcei686 then
"ia32"
else
pkgs.stdenv.hostPlatform.efiArch;
/**
* Given params to add to `params`, build a set of default options.
* Use this one when creating a variant (e.g. hidpi)
*/
buildMenuAdditionalParamsGrub2 = additional:
let
finalCfg = {
name = "${config.isoImage.prependToMenuLabel}${config.system.nixos.distroName} ${config.system.nixos.label}${config.isoImage.appendToMenuLabel}";
params = "init=${config.system.build.toplevel}/init ${additional} ${toString config.boot.kernelParams}";
image = "/boot/${config.system.boot.loader.kernelFile}";
initrd = "/boot/initrd";
};
in
menuBuilderGrub2
finalCfg
[
{ class = "installer"; }
{ class = "nomodeset"; params = "nomodeset"; }
{ class = "copytoram"; params = "copytoram"; }
{ class = "debug"; params = "debug"; }
]
;
# Timeout in syslinux is in units of 1/10 of a second.
# null means max timeout (35996, just under 1h in 1/10 seconds)
# 0 means disable timeout
syslinuxTimeout = if config.boot.loader.timeout == null then
35996
else
config.boot.loader.timeout * 10;
# Timeout in grub is in seconds.
# null means max timeout (infinity)
# 0 means disable timeout
grubEfiTimeout = if config.boot.loader.timeout == null then
-1
else
config.boot.loader.timeout;
# The configuration file for syslinux.
# Notes on syslinux configuration and UNetbootin compatibility:
# * Do not use '/syslinux/syslinux.cfg' as the path for this
# configuration. UNetbootin will not parse the file and use it as-is.
# This results in a broken configuration if the partition label does
# not match the specified config.isoImage.volumeID. For this reason
# we're using '/isolinux/isolinux.cfg'.
# * Use APPEND instead of adding command-line arguments directly after
# the LINUX entries.
# * COM32 entries (chainload, reboot, poweroff) are not recognized. They
# result in incorrect boot entries.
baseIsolinuxCfg = ''
SERIAL 0 115200
TIMEOUT ${builtins.toString syslinuxTimeout}
UI vesamenu.c32
MENU BACKGROUND /isolinux/background.png
${config.isoImage.syslinuxTheme}
DEFAULT boot
LABEL boot
MENU LABEL ${config.isoImage.prependToMenuLabel}${config.system.nixos.distroName} ${config.system.nixos.label}${config.isoImage.appendToMenuLabel}
LINUX /boot/${config.system.boot.loader.kernelFile}
APPEND init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}
INITRD /boot/${config.system.boot.loader.initrdFile}
# A variant to boot with 'nomodeset'
LABEL boot-nomodeset
MENU LABEL ${config.isoImage.prependToMenuLabel}${config.system.nixos.distroName} ${config.system.nixos.label}${config.isoImage.appendToMenuLabel} (nomodeset)
LINUX /boot/${config.system.boot.loader.kernelFile}
APPEND init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams} nomodeset
INITRD /boot/${config.system.boot.loader.initrdFile}
# A variant to boot with 'copytoram'
LABEL boot-copytoram
MENU LABEL ${config.isoImage.prependToMenuLabel}${config.system.nixos.distroName} ${config.system.nixos.label}${config.isoImage.appendToMenuLabel} (copytoram)
LINUX /boot/${config.system.boot.loader.kernelFile}
APPEND init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams} copytoram
INITRD /boot/${config.system.boot.loader.initrdFile}
# A variant to boot with verbose logging to the console
LABEL boot-debug
MENU LABEL ${config.isoImage.prependToMenuLabel}${config.system.nixos.distroName} ${config.system.nixos.label}${config.isoImage.appendToMenuLabel} (debug)
LINUX /boot/${config.system.boot.loader.kernelFile}
APPEND init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams} loglevel=7
INITRD /boot/${config.system.boot.loader.initrdFile}
# A variant to boot with a serial console enabled
LABEL boot-serial
MENU LABEL ${config.isoImage.prependToMenuLabel}${config.system.nixos.distroName} ${config.system.nixos.label}${config.isoImage.appendToMenuLabel} (serial console=ttyS0,115200n8)
LINUX /boot/${config.system.boot.loader.kernelFile}
APPEND init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams} console=ttyS0,115200n8
INITRD /boot/${config.system.boot.loader.initrdFile}
'';
isolinuxMemtest86Entry = ''
LABEL memtest
MENU LABEL Memtest86+
LINUX /boot/memtest.bin
APPEND ${toString config.boot.loader.grub.memtest86.params}
'';
isolinuxCfg = lib.concatStringsSep "\n"
([ baseIsolinuxCfg ] ++ lib.optional config.boot.loader.grub.memtest86.enable isolinuxMemtest86Entry);
refindBinary = if targetArch == "x64" || targetArch == "aa64" then "refind_${targetArch}.efi" else null;
# Setup instructions for rEFInd.
refind =
if refindBinary != null then
''
# Adds rEFInd to the ISO.
cp -v ${pkgs.refind}/share/refind/${refindBinary} $out/EFI/BOOT/
''
else
"# No refind for ${targetArch}"
;
grubPkgs = if config.boot.loader.grub.forcei686 then pkgs.pkgsi686Linux else pkgs;
grubMenuCfg = ''
#
# Menu configuration
#
# Search using a "marker file"
search --set=root --file /EFI/nixos-installer-image
insmod gfxterm
insmod png
set gfxpayload=keep
set gfxmode=${lib.concatStringsSep "," [
# GRUB will use the first valid mode listed here.
# `auto` will sometimes choose the smallest valid mode it detects.
# So instead we'll list a lot of possibly valid modes :/
#"3840x2160"
#"2560x1440"
"1920x1200"
"1920x1080"
"1366x768"
"1280x800"
"1280x720"
"1200x1920"
"1024x768"
"800x1280"
"800x600"
"auto"
]}
if [ "\$textmode" == "false" ]; then
terminal_output gfxterm
terminal_input console
else
terminal_output console
terminal_input console
# Sets colors for console term.
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
fi
${ # When there is a theme configured, use it, otherwise use the background image.
if config.isoImage.grubTheme != null then ''
# Sets theme.
set theme=(\$root)/EFI/BOOT/grub-theme/theme.txt
# Load theme fonts
$(find ${config.isoImage.grubTheme} -iname '*.pf2' -printf "loadfont (\$root)/EFI/BOOT/grub-theme/%P\n")
'' else ''
if background_image (\$root)/EFI/BOOT/efi-background.png; then
# Black background means transparent background when there
# is a background image set... This seems undocumented :(
set color_normal=black/black
set color_highlight=white/blue
else
# Falls back again to proper colors.
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
fi
''}
'';
# The EFI boot image.
# Notes about grub:
# * Yes, the grubMenuCfg has to be repeated in all submenus. Otherwise you
# will get white-on-black console-like text on sub-menus. *sigh*
efiDir = pkgs.runCommand "efi-directory" {
nativeBuildInputs = [ pkgs.buildPackages.grub2_efi ];
strictDeps = true;
} ''
mkdir -p $out/EFI/BOOT
# Add a marker so GRUB can find the filesystem.
touch $out/EFI/nixos-installer-image
# ALWAYS required modules.
MODULES=(
# Basic modules for filesystems and partition schemes
"fat"
"iso9660"
"part_gpt"
"part_msdos"
# Basic stuff
"normal"
"boot"
"linux"
"configfile"
"loopback"
"chain"
"halt"
# Allows rebooting into firmware setup interface
"efifwsetup"
# EFI Graphics Output Protocol
"efi_gop"
# User commands
"ls"
# System commands
"search"
"search_label"
"search_fs_uuid"
"search_fs_file"
"echo"
# We're not using it anymore, but we'll leave it in so it can be used
# by user, with the console using "C"
"serial"
# Graphical mode stuff
"gfxmenu"
"gfxterm"
"gfxterm_background"
"gfxterm_menu"
"test"
"loadenv"
"all_video"
"videoinfo"
# File types for graphical mode
"png"
)
echo "Building GRUB with modules:"
for mod in ''${MODULES[@]}; do
echo " - $mod"
done
# Modules that may or may not be available per-platform.
echo "Adding additional modules:"
for mod in efi_uga; do
if [ -f ${grubPkgs.grub2_efi}/lib/grub/${grubPkgs.grub2_efi.grubTarget}/$mod.mod ]; then
echo " - $mod"
MODULES+=("$mod")
fi
done
# Make our own efi program, we can't rely on "grub-install" since it seems to
# probe for devices, even with --skip-fs-probe.
grub-mkimage \
--directory=${grubPkgs.grub2_efi}/lib/grub/${grubPkgs.grub2_efi.grubTarget} \
-o $out/EFI/BOOT/BOOT${lib.toUpper targetArch}.EFI \
-p /EFI/BOOT \
-O ${grubPkgs.grub2_efi.grubTarget} \
''${MODULES[@]}
cp ${grubPkgs.grub2_efi}/share/grub/unicode.pf2 $out/EFI/BOOT/
cat <<EOF > $out/EFI/BOOT/grub.cfg
set textmode=${lib.boolToString (config.isoImage.forceTextMode)}
set timeout=${toString grubEfiTimeout}
clear
# This message will only be viewable on the default (UEFI) console.
echo ""
echo "Loading graphical boot menu..."
echo ""
echo "Press 't' to use the text boot menu on this console..."
echo ""
${grubMenuCfg}
hiddenentry 'Text mode' --hotkey 't' {
loadfont (\$root)/EFI/BOOT/unicode.pf2
set textmode=true
terminal_output console
}
${lib.optionalString (config.isoImage.grubTheme != null) ''
hiddenentry 'GUI mode' --hotkey 'g' {
$(find ${config.isoImage.grubTheme} -iname '*.pf2' -printf "loadfont (\$root)/EFI/BOOT/grub-theme/%P\n")
set textmode=false
terminal_output gfxterm
}
''}
# If the parameter iso_path is set, append the findiso parameter to the kernel
# line. We need this to allow the nixos iso to be booted from grub directly.
if [ \''${iso_path} ] ; then
set isoboot="findiso=\''${iso_path}"
fi
#
# Menu entries
#
${buildMenuGrub2}
submenu "HiDPI, Quirks and Accessibility" --class hidpi --class submenu {
${grubMenuCfg}
submenu "Suggests resolution @720p" --class hidpi-720p {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "video=1280x720@60"}
}
submenu "Suggests resolution @1080p" --class hidpi-1080p {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "video=1920x1080@60"}
}
# If we boot into a graphical environment where X is autoran
# and always crashes, it makes the media unusable. Allow the user
# to disable this.
submenu "Disable display-manager" --class quirk-disable-displaymanager {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "systemd.mask=display-manager.service"}
}
# Some laptop and convertibles have the panel installed in an
# inconvenient way, rotated away from the keyboard.
# Those entries makes it easier to use the installer.
submenu "" {return}
submenu "Rotate framebuffer Clockwise" --class rotate-90cw {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "fbcon=rotate:1"}
}
submenu "Rotate framebuffer Upside-Down" --class rotate-180 {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "fbcon=rotate:2"}
}
submenu "Rotate framebuffer Counter-Clockwise" --class rotate-90ccw {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "fbcon=rotate:3"}
}
# As a proof of concept, mainly. (Not sure it has accessibility merits.)
submenu "" {return}
submenu "Use black on white" --class accessibility-blakconwhite {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "vt.default_red=0xFF,0xBC,0x4F,0xB4,0x56,0xBC,0x4F,0x00,0xA1,0xCF,0x84,0xCA,0x8D,0xB4,0x84,0x68 vt.default_grn=0xFF,0x55,0xBA,0xBA,0x4D,0x4D,0xB3,0x00,0xA0,0x8F,0xB3,0xCA,0x88,0x93,0xA4,0x68 vt.default_blu=0xFF,0x58,0x5F,0x58,0xC5,0xBD,0xC5,0x00,0xA8,0xBB,0xAB,0x97,0xBD,0xC7,0xC5,0x68"}
}
# Serial access is a must!
submenu "" {return}
submenu "Serial console=ttyS0,115200n8" --class serial {
${grubMenuCfg}
${buildMenuAdditionalParamsGrub2 "console=ttyS0,115200n8"}
}
}
${lib.optionalString (refindBinary != null) ''
# GRUB apparently cannot do "chainloader" operations on "CD".
if [ "\$root" != "cd0" ]; then
menuentry 'rEFInd' --class refind {
# Force root to be the FAT partition
# Otherwise it breaks rEFInd's boot
search --set=root --no-floppy --fs-uuid 1234-5678
chainloader (\$root)/EFI/BOOT/${refindBinary}
}
fi
''}
menuentry 'Firmware Setup' --class settings {
fwsetup
clear
echo ""
echo "If you see this message, your EFI system doesn't support this feature."
echo ""
}
menuentry 'Shutdown' --class shutdown {
halt
}
EOF
grub-script-check $out/EFI/BOOT/grub.cfg
${refind}
'';
efiImg = pkgs.runCommand "efi-image_eltorito" {
nativeBuildInputs = [ pkgs.buildPackages.mtools pkgs.buildPackages.libfaketime pkgs.buildPackages.dosfstools ];
strictDeps = true;
}
# Be careful about determinism: du --apparent-size,
# dates (cp -p, touch, mcopy -m, faketime for label), IDs (mkfs.vfat -i)
''
mkdir ./contents && cd ./contents
mkdir -p ./EFI/BOOT
cp -rp "${efiDir}"/EFI/BOOT/{grub.cfg,*.EFI,*.efi} ./EFI/BOOT
# Rewrite dates for everything in the FS
find . -exec touch --date=2000-01-01 {} +
# Round up to the nearest multiple of 1MB, for more deterministic du output
usage_size=$(( $(du -s --block-size=1M --apparent-size . | tr -cd '[:digit:]') * 1024 * 1024 ))
# Make the image 110% as big as the files need to make up for FAT overhead
image_size=$(( ($usage_size * 110) / 100 ))
# Make the image fit blocks of 1M
block_size=$((1024*1024))
image_size=$(( ($image_size / $block_size + 1) * $block_size ))
echo "Usage size: $usage_size"
echo "Image size: $image_size"
truncate --size=$image_size "$out"
mkfs.vfat --invariant -i 12345678 -n EFIBOOT "$out"
# Force a fixed order in mcopy for better determinism, and avoid file globbing
for d in $(find EFI -type d | sort); do
faketime "2000-01-01 00:00:00" mmd -i "$out" "::/$d"
done
for f in $(find EFI -type f | sort); do
mcopy -pvm -i "$out" "$f" "::/$f"
done
# Verify the FAT partition.
fsck.vfat -vn "$out"
''; # */
in
{
options = {
isoImage.isoName = lib.mkOption {
default = "${config.isoImage.isoBaseName}.iso";
type = lib.types.str;
description = ''
Name of the generated ISO image file.
'';
};
isoImage.isoBaseName = lib.mkOption {
default = config.system.nixos.distroId;
type = lib.types.str;
description = ''
Prefix of the name of the generated ISO image file.
'';
};
isoImage.compressImage = lib.mkOption {
default = false;
type = lib.types.bool;
description = ''
Whether the ISO image should be compressed using
{command}`zstd`.
'';
};
isoImage.squashfsCompression = lib.mkOption {
default = "zstd -Xcompression-level 19";
type = lib.types.nullOr lib.types.str;
description = ''
Compression settings to use for the squashfs nix store.
`null` disables compression.
'';
example = "zstd -Xcompression-level 6";
};
isoImage.edition = lib.mkOption {
default = "";
type = lib.types.str;
description = ''
Specifies which edition string to use in the volume ID of the generated
ISO image.
'';
};
isoImage.volumeID = lib.mkOption {
# nixos-$EDITION-$RELEASE-$ARCH
default = "nixos${lib.optionalString (config.isoImage.edition != "") "-${config.isoImage.edition}"}-${config.system.nixos.release}-${pkgs.stdenv.hostPlatform.uname.processor}";
type = lib.types.str;
description = ''
Specifies the label or volume ID of the generated ISO image.
Note that the label is used by stage 1 of the boot process to
mount the CD, so it should be reasonably distinctive.
'';
};
isoImage.contents = lib.mkOption {
example = lib.literalExpression ''
[ { source = pkgs.memtest86 + "/memtest.bin";
target = "boot/memtest.bin";
}
]
'';
description = ''
This option lists files to be copied to fixed locations in the
generated ISO image.
'';
};
isoImage.storeContents = lib.mkOption {
example = lib.literalExpression "[ pkgs.stdenv ]";
description = ''
This option lists additional derivations to be included in the
Nix store in the generated ISO image.
'';
};
isoImage.includeSystemBuildDependencies = lib.mkOption {
default = false;
type = lib.types.bool;
description = ''
Set this option to include all the needed sources etc in the
image. It significantly increases image size. Use that when
you want to be able to keep all the sources needed to build your
system or when you are going to install the system on a computer
with slow or non-existent network connection.
'';
};
isoImage.makeBiosBootable = lib.mkOption {
# Before this option was introduced, images were BIOS-bootable if the
# hostPlatform was x86-based. This option is enabled by default for
# backwards compatibility.
#
# Also note that syslinux package currently cannot be cross-compiled from
# non-x86 platforms, so the default is false on non-x86 build platforms.
default = pkgs.stdenv.buildPlatform.isx86 && pkgs.stdenv.hostPlatform.isx86;
defaultText = lib.literalMD ''
`true` if both build and host platforms are x86-based architectures,
e.g. i686 and x86_64.
'';
type = lib.types.bool;
description = ''
Whether the ISO image should be a BIOS-bootable disk.
'';
};
isoImage.makeEfiBootable = lib.mkOption {
default = false;
type = lib.types.bool;
description = ''
Whether the ISO image should be an EFI-bootable volume.
'';
};
isoImage.makeUsbBootable = lib.mkOption {
default = false;
type = lib.types.bool;
description = ''
Whether the ISO image should be bootable from CD as well as USB.
'';
};
isoImage.efiSplashImage = lib.mkOption {
default = pkgs.fetchurl {
url = "https://raw.githubusercontent.com/NixOS/nixos-artwork/a9e05d7deb38a8e005a2b52575a3f59a63a4dba0/bootloader/efi-background.png";
sha256 = "18lfwmp8yq923322nlb9gxrh5qikj1wsk6g5qvdh31c4h5b1538x";
};
description = ''
The splash image to use in the EFI bootloader.
'';
};
isoImage.splashImage = lib.mkOption {
default = pkgs.fetchurl {
url = "https://raw.githubusercontent.com/NixOS/nixos-artwork/a9e05d7deb38a8e005a2b52575a3f59a63a4dba0/bootloader/isolinux/bios-boot.png";
sha256 = "1wp822zrhbg4fgfbwkr7cbkr4labx477209agzc0hr6k62fr6rxd";
};
description = ''
The splash image to use in the legacy-boot bootloader.
'';
};
isoImage.grubTheme = lib.mkOption {
default = pkgs.nixos-grub2-theme;
type = lib.types.nullOr (lib.types.either lib.types.path lib.types.package);
description = ''
The grub2 theme used for UEFI boot.
'';
};
isoImage.syslinuxTheme = lib.mkOption {
default = ''
MENU TITLE ${config.system.nixos.distroName}
MENU RESOLUTION 800 600
MENU CLEAR
MENU ROWS 6
MENU CMDLINEROW -4
MENU TIMEOUTROW -3
MENU TABMSGROW -2
MENU HELPMSGROW -1
MENU HELPMSGENDROW -1
MENU MARGIN 0
# FG:AARRGGBB BG:AARRGGBB shadow
MENU COLOR BORDER 30;44 #00000000 #00000000 none
MENU COLOR SCREEN 37;40 #FF000000 #00E2E8FF none
MENU COLOR TABMSG 31;40 #80000000 #00000000 none
MENU COLOR TIMEOUT 1;37;40 #FF000000 #00000000 none
MENU COLOR TIMEOUT_MSG 37;40 #FF000000 #00000000 none
MENU COLOR CMDMARK 1;36;40 #FF000000 #00000000 none
MENU COLOR CMDLINE 37;40 #FF000000 #00000000 none
MENU COLOR TITLE 1;36;44 #00000000 #00000000 none
MENU COLOR UNSEL 37;44 #FF000000 #00000000 none
MENU COLOR SEL 7;37;40 #FFFFFFFF #FF5277C3 std
'';
type = lib.types.str;
description = ''
The syslinux theme used for BIOS boot.
'';
};
isoImage.prependToMenuLabel = lib.mkOption {
default = "";
type = lib.types.str;
example = "Install ";
description = ''
The string to prepend before the menu label for the NixOS system.
This will be directly prepended (without whitespace) to the NixOS version
string, like for example if it is set to `XXX`:
`XXXNixOS 99.99-pre666`
'';
};
isoImage.appendToMenuLabel = lib.mkOption {
default = " Installer";
type = lib.types.str;
example = " Live System";
description = ''
The string to append after the menu label for the NixOS system.
This will be directly appended (without whitespace) to the NixOS version
string, like for example if it is set to `XXX`:
`NixOS 99.99-pre666XXX`
'';
};
isoImage.forceTextMode = lib.mkOption {
default = false;
type = lib.types.bool;
example = true;
description = ''
Whether to use text mode instead of graphical grub.
A value of `true` means graphical mode is not tried to be used.
This is useful for validating that graphics mode usage is not at the root cause of a problem with the iso image.
If text mode is required off-handedly (e.g. for serial use) you can use the `T` key, after being prompted, to use text mode for the current boot.
'';
};
};
# store them in lib so we can mkImageMediaOverride the
# entire file system layout in installation media (only)
config.lib.isoFileSystems = {
"/" = lib.mkImageMediaOverride
{
fsType = "tmpfs";
options = [ "mode=0755" ];
};
# Note that /dev/root is a symlink to the actual root device
# specified on the kernel command line, created in the stage 1
# init script.
"/iso" = lib.mkImageMediaOverride
{ device = "/dev/root";
neededForBoot = true;
noCheck = true;
};
# In stage 1, mount a tmpfs on top of /nix/store (the squashfs
# image) to make this a live CD.
"/nix/.ro-store" = lib.mkImageMediaOverride
{ fsType = "squashfs";
device = "/iso/nix-store.squashfs";
options = [ "loop" ] ++ lib.optional (config.boot.kernelPackages.kernel.kernelAtLeast "6.2") "threads=multi";
neededForBoot = true;
};
"/nix/.rw-store" = lib.mkImageMediaOverride
{ fsType = "tmpfs";
options = [ "mode=0755" ];
neededForBoot = true;
};
"/nix/store" = lib.mkImageMediaOverride
{ fsType = "overlay";
device = "overlay";
options = [
"lowerdir=/nix/.ro-store"
"upperdir=/nix/.rw-store/store"
"workdir=/nix/.rw-store/work"
];
depends = [
"/nix/.ro-store"
"/nix/.rw-store/store"
"/nix/.rw-store/work"
];
};
};
config = {
assertions = [
{
# Syslinux (and isolinux) only supports x86-based architectures.
assertion = config.isoImage.makeBiosBootable -> pkgs.stdenv.hostPlatform.isx86;
message = "BIOS boot is only supported on x86-based architectures.";
}
{
assertion = !(lib.stringLength config.isoImage.volumeID > 32);
# https://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor
# Volume Identifier can only be 32 bytes
message = let
length = lib.stringLength config.isoImage.volumeID;
howmany = toString length;
toomany = toString (length - 32);
in
"isoImage.volumeID ${config.isoImage.volumeID} is ${howmany} characters. That is ${toomany} characters longer than the limit of 32.";
}
];
# Don't build the GRUB menu builder script, since we don't need it
# here and it causes a cyclic dependency.
boot.loader.grub.enable = false;
environment.systemPackages = [ grubPkgs.grub2 ]
++ lib.optional (config.isoImage.makeBiosBootable) pkgs.syslinux
;
system.extraDependencies = [ grubPkgs.grub2_efi ];
# In stage 1 of the boot, mount the CD as the root FS by label so
# that we don't need to know its device. We pass the label of the
# root filesystem on the kernel command line, rather than in
# `fileSystems' below. This allows CD-to-USB converters such as
# UNetbootin to rewrite the kernel command line to pass the label or
# UUID of the USB stick. It would be nicer to write
# `root=/dev/disk/by-label/...' here, but UNetbootin doesn't
# recognise that.
boot.kernelParams =
[ "root=LABEL=${config.isoImage.volumeID}"
"boot.shell_on_fail"
];
fileSystems = config.lib.isoFileSystems;
boot.initrd.availableKernelModules = [ "squashfs" "iso9660" "uas" "overlay" ];
boot.initrd.kernelModules = [ "loop" "overlay" ];
# Closures to be copied to the Nix store on the CD, namely the init
# script and the top-level system configuration directory.
isoImage.storeContents =
[ config.system.build.toplevel ] ++
lib.optional config.isoImage.includeSystemBuildDependencies
config.system.build.toplevel.drvPath;
# Individual files to be included on the CD, outside of the Nix
# store on the CD.
isoImage.contents =
[
{ source = config.boot.kernelPackages.kernel + "/" + config.system.boot.loader.kernelFile;
target = "/boot/" + config.system.boot.loader.kernelFile;
}
{ source = config.system.build.initialRamdisk + "/" + config.system.boot.loader.initrdFile;
target = "/boot/" + config.system.boot.loader.initrdFile;
}
{ source = pkgs.writeText "version" config.system.nixos.label;
target = "/version.txt";
}
] ++ lib.optionals (config.isoImage.makeBiosBootable) [
{ source = config.isoImage.splashImage;
target = "/isolinux/background.png";
}
{ source = pkgs.substituteAll {
name = "isolinux.cfg";
src = pkgs.writeText "isolinux.cfg-in" isolinuxCfg;
bootRoot = "/boot";
};
target = "/isolinux/isolinux.cfg";
}
{ source = "${pkgs.syslinux}/share/syslinux";
target = "/isolinux";
}
] ++ lib.optionals config.isoImage.makeEfiBootable [
{ source = efiImg;
target = "/boot/efi.img";
}
{ source = "${efiDir}/EFI";
target = "/EFI";
}
{ source = (pkgs.writeTextDir "grub/loopback.cfg" "source /EFI/BOOT/grub.cfg") + "/grub";
target = "/boot/grub";
}
{ source = config.isoImage.efiSplashImage;
target = "/EFI/BOOT/efi-background.png";
}
] ++ lib.optionals (config.boot.loader.grub.memtest86.enable && config.isoImage.makeBiosBootable) [
{ source = "${pkgs.memtest86plus}/memtest.bin";
target = "/boot/memtest.bin";
}
] ++ lib.optionals (config.isoImage.grubTheme != null) [
{ source = config.isoImage.grubTheme;
target = "/EFI/BOOT/grub-theme";
}
];
boot.loader.timeout = 10;
# Create the ISO image.
system.build.isoImage = pkgs.callPackage ../../../lib/make-iso9660-image.nix ({
inherit (config.isoImage) isoName compressImage volumeID contents;
bootable = config.isoImage.makeBiosBootable;
bootImage = "/isolinux/isolinux.bin";
syslinux = if config.isoImage.makeBiosBootable then pkgs.syslinux else null;
squashfsContents = config.isoImage.storeContents;
squashfsCompression = config.isoImage.squashfsCompression;
} // lib.optionalAttrs (config.isoImage.makeUsbBootable && config.isoImage.makeBiosBootable) {
usbBootable = true;
isohybridMbrImage = "${pkgs.syslinux}/share/syslinux/isohdpfx.bin";
} // lib.optionalAttrs config.isoImage.makeEfiBootable {
efiBootable = true;
efiBootImage = "boot/efi.img";
});
boot.postBootCommands =
''
# After booting, register the contents of the Nix store on the
# CD in the Nix database in the tmpfs.
${config.nix.package.out}/bin/nix-store --load-db < /nix/store/nix-path-registration
# nixos-rebuild also requires a "system" profile and an
# /etc/NIXOS tag.
touch /etc/NIXOS
${config.nix.package.out}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
'';
# Add vfat support to the initrd to enable people to copy the
# contents of the CD to a bootable USB stick.
boot.initrd.supportedFilesystems = [ "vfat" ];
};
}