120 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			120 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
{ pkgs
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, lib
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, # The NixOS configuration to be installed onto the disk image.
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  config
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, # The size of the disk, in megabytes.
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  diskSize
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, # Whether the disk should be partitioned (with a single partition
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  # containing the root filesystem) or contain the root filesystem
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  # directly.
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  partitioned ? true
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, # The root file system type.
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  fsType ? "ext4"
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, # The initial NixOS configuration file to be copied to
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  # /etc/nixos/configuration.nix.
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  configFile ? null
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, # Shell code executed after the VM has finished.
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  postVM ? ""
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, name ? "nixos-disk-image"
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, format ? "raw"
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}:
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with lib;
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pkgs.vmTools.runInLinuxVM (
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  pkgs.runCommand name
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    { preVM =
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        ''
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          mkdir $out
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          diskImage=$out/nixos.${if format == "qcow2" then "qcow2" else "img"}
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          ${pkgs.vmTools.qemu}/bin/qemu-img create -f ${format} $diskImage "${toString diskSize}M"
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          mv closure xchg/
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        '';
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      buildInputs = [ pkgs.utillinux pkgs.perl pkgs.e2fsprogs pkgs.parted ];
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      exportReferencesGraph =
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        [ "closure" config.system.build.toplevel ];
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      inherit postVM;
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      memSize = 1024;
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    }
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    ''
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      ${if partitioned then ''
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        # Create a single / partition.
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        parted /dev/vda mklabel msdos
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        parted /dev/vda -- mkpart primary ext2 1M -1s
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        . /sys/class/block/vda1/uevent
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        mknod /dev/vda1 b $MAJOR $MINOR
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        rootDisk=/dev/vda1
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      '' else ''
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        rootDisk=/dev/vda
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      ''}
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      # Create an empty filesystem and mount it.
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      mkfs.${fsType} -L nixos $rootDisk
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      ${optionalString (fsType == "ext4") ''
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        tune2fs -c 0 -i 0 $rootDisk
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      ''}
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      mkdir /mnt
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      mount $rootDisk /mnt
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      # The initrd expects these directories to exist.
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      mkdir /mnt/dev /mnt/proc /mnt/sys
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      mount -o bind /proc /mnt/proc
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      mount -o bind /dev /mnt/dev
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      mount -o bind /sys /mnt/sys
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      # Copy all paths in the closure to the filesystem.
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      storePaths=$(perl ${pkgs.pathsFromGraph} /tmp/xchg/closure)
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      mkdir -p /mnt/nix/store
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      echo "copying everything (will take a while)..."
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      set -f
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      cp -prd $storePaths /mnt/nix/store/
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      # Register the paths in the Nix database.
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      printRegistration=1 perl ${pkgs.pathsFromGraph} /tmp/xchg/closure | \
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          chroot /mnt ${config.nix.package.out}/bin/nix-store --load-db --option build-users-group ""
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      # Add missing size/hash fields to the database. FIXME:
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      # exportReferencesGraph should provide these directly.
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      chroot /mnt ${config.nix.package.out}/bin/nix-store --verify --check-contents
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      # Create the system profile to allow nixos-rebuild to work.
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      chroot /mnt ${config.nix.package.out}/bin/nix-env --option build-users-group "" \
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          -p /nix/var/nix/profiles/system --set ${config.system.build.toplevel}
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      # `nixos-rebuild' requires an /etc/NIXOS.
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      mkdir -p /mnt/etc
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      touch /mnt/etc/NIXOS
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      # `switch-to-configuration' requires a /bin/sh
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      mkdir -p /mnt/bin
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      ln -s ${config.system.build.binsh}/bin/sh /mnt/bin/sh
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      # Install a configuration.nix.
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      mkdir -p /mnt/etc/nixos
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      ${optionalString (configFile != null) ''
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        cp ${configFile} /mnt/etc/nixos/configuration.nix
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      ''}
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      # Generate the GRUB menu.
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      ln -s vda /dev/xvda
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      ln -s vda /dev/sda
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      chroot /mnt ${config.system.build.toplevel}/bin/switch-to-configuration boot
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      umount /mnt/proc /mnt/dev /mnt/sys
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      umount /mnt
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      # Do a fsck to make sure resize2fs works.
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      fsck.${fsType} -f -y $rootDisk
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    ''
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)
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