boot: full silent boot up to plymouth

.gitignore

@@ -1,2 +1,2 @@
 configuration.nix
-dotfiles/weechat/*
+assets/weechat/*

common/default.nix

@@ -42,7 +42,6 @@
 
     environment.variables.NIX_AUTO_RUN = "1";
     programs.command-not-found.enable = true;
-    console.earlySetup = true;
 
     # no UDP when through tor, so we use http date to synchronize the system
     # clock
@@ -52,12 +51,12 @@
     "en.wikipedia.org" "google.com" "govanify.com" "lkml.org" "www.apache.org" 
     "www.duckduckgo.com" "www.kernel.org" "www.mozilla.org" "www.xkcd.com"];
 
-    boot.consoleLogLevel = 0;
-    boot.kernelParams = [ "vt.global_cursor_default=0" "intel_iommu=on"
-    "quiet" "udev.log_priority=3" "i915.enable_guc=0" "i915.enable_gvt=1" ]; # i915 iGVT-g
+    boot.kernelParams = [ "intel_iommu=on"
+    "i915.enable_guc=0" "i915.enable_gvt=1" ]; # i915 iGVT-g
 
     modules.navi.bootloader = {
       enable = true;
+      no_mercy = false;
     };
   }
 

common/desktop.nix

@@ -9,9 +9,9 @@
               ./../component/virtualization.nix
             ];
   home-manager.users.govanify = {
-    home.file.".config/sway/config".source = ./../dotfiles/graphical/sway/config;
-    home.file.".config/sway/locale.sh".source = ./../dotfiles/graphical/sway/locale.sh;
-    home.file.".config/sway/status.sh".source = ./../dotfiles/graphical/sway/status.sh;
+    home.file.".config/sway/config".source = ./../assets/graphical/sway/config;
+    home.file.".config/sway/locale.sh".source = ./../assets/graphical/sway/locale.sh;
+    home.file.".config/sway/status.sh".source = ./../assets/graphical/sway/status.sh;
   };
 
 }

common/graphical.nix

@@ -276,11 +276,11 @@ in
   home-manager.users.govanify = {
     # initial pass setup
     # should i make this global?
-    home.file.".cache/clone-pass.sh".source  = ./../dotfiles/clone-pass.sh;
+    home.file.".cache/clone-pass.sh".source  = ./../assets/clone-pass.sh;
 
    # QT theme
-   home.file.".config/qt5ct/qt5ct.conf".source  = ./../dotfiles/graphical/qt5ct/qt5ct.conf;
-   home.file.".config/qt5ct/colors/breeze-dark.conf".source  = ./../dotfiles/graphical/qt5ct/breeze-dark.conf;
+   home.file.".config/qt5ct/qt5ct.conf".source  = ./../assets/graphical/qt5ct/qt5ct.conf;
+   home.file.".config/qt5ct/colors/breeze-dark.conf".source  = ./../assets/graphical/qt5ct/breeze-dark.conf;
 
 
    # GTK theme

common/headfull.nix

@@ -46,7 +46,7 @@
   home-manager.users.govanify = {
     home.file.".config/gnupg/key.gpg".source  = ./../secrets/key.gpg;
     home.file.".config/gnupg/trust.txt".source  = ./../secrets/gpg-trust.txt;
-    home.file.".config/gnupg/gpg.conf".source  = ./../dotfiles/gpg/gpg.conf;
+    home.file.".config/gnupg/gpg.conf".source  = ./../assets/gpg/gpg.conf;
     home.file.".config/gdb/init".text  = "source ~/.config/gdb/gdbinit-gef.py";
     home.file.".config/gdb/gdbinit-gef.py".text  = builtins.readFile (pkgs.fetchFromGitHub {
       owner = "hugsy";
@@ -60,7 +60,7 @@
       signByDefault = true;
       key = "52142D39A7CEF8FA872BCA7FDE62E1E2A6145556";
     };
-    #home.file.".config/weechat".source  = ./../dotfiles/weechat;
+    #home.file.".config/weechat".source  = ./../assets/weechat;
 
   };
 

common/laptop.nix

@@ -27,9 +27,9 @@
   };
 
   home-manager.users.govanify = {
-    home.file.".config/sway/config".source = ./../dotfiles/graphical/sway-laptop/config;
-    home.file.".config/sway/locale.sh".source = ./../dotfiles/graphical/sway-laptop/locale.sh;
-    home.file.".config/sway/status.sh".source = ./../dotfiles/graphical/sway-laptop/status.sh;
+    home.file.".config/sway/config".source = ./../assets/graphical/sway-laptop/config;
+    home.file.".config/sway/locale.sh".source = ./../assets/graphical/sway-laptop/locale.sh;
+    home.file.".config/sway/status.sh".source = ./../assets/graphical/sway-laptop/status.sh;
   };
 
   nix.distributedBuilds = true;

common/mail.nix

@@ -7,10 +7,10 @@
   # XDG_CONFIG_HOME does not get parsed correctly so we do it manually
   # you need to create the caching folder otherwise this fails
   home-manager.users.govanify = {
-    home.file.".config/msmtp/config".source  = ./../dotfiles/mail/msmtp/config;
-    home.file.".config/mbsync/config".source  = ./../dotfiles/mail/mbsync/config;
-    home.file.".config/mutt".source  = ./../dotfiles/mail/mutt;
-    home.file.".config/notmuch".source  = ./../dotfiles/mail/notmuch;
+    home.file.".config/msmtp/config".source  = ./../assets/mail/msmtp/config;
+    home.file.".config/mbsync/config".source  = ./../assets/mail/mbsync/config;
+    home.file.".config/mutt".source  = ./../assets/mail/mutt;
+    home.file.".config/notmuch".source  = ./../assets/mail/notmuch;
   };
   #environment.shellAliases = { neomutt = "mutt"; };
 

common/xdg.nix

@@ -111,9 +111,9 @@
   };
 
   home-manager.users.govanify = {
-    home.file.".config/wgetrc".source  = ./../dotfiles/xdg/wgetrc;
-    home.file.".config/python/startup.py".source  = ./../dotfiles/xdg/python/startup.py;
-    home.file.".config/npm/npmrc".source  = ./../dotfiles/xdg/npmrc;
+    home.file.".config/wgetrc".source  = ./../assets/xdg/wgetrc;
+    home.file.".config/python/startup.py".source  = ./../assets/xdg/python/startup.py;
+    home.file.".config/npm/npmrc".source  = ./../assets/xdg/npmrc;
   };
   programs.fish.shellAliases = {
     gdb = "gdb -nh -x \"$XDG_CONFIG_HOME\"/gdb/init";

component/bootloader.nix

@@ -16,8 +16,10 @@ let
   secrets_path = ./. + "/../secrets/bootloader/${config.networking.hostName}/pub.gpg";
 in
 {
-  disabledModules = [ "system/boot/loader/grub/grub.nix" ];
-  imports = [ ./../overlays/grub/grub.nix ];
+  disabledModules = [ "system/boot/loader/grub/grub.nix"
+                      "system/boot/stage-1.nix" ];
+  imports = [ ./../overlays/grub/grub.nix 
+              ./../overlays/stage-1/stage-1.nix ];
 
   options.modules.navi.bootloader = {
     enable = mkEnableOption "Enable navi's bootloader";
@@ -32,6 +34,10 @@ in
     };
   };
   config = mkIf cfg.enable {
+    # verbosity
+    console.earlySetup = true;
+    boot.consoleLogLevel = 0;
+    boot.kernelParams = [ "vt.global_cursor_default=0" "quiet" "udev.log_priority=3" ];
     # required so we can write the .sig
     boot.loader.grub.copyKernels = true;
 
@@ -40,19 +46,22 @@ in
     "--modules=verifiers gcry_sha256 gcry_sha512 gcry_dsa gcry_rsa" ];
     boot.loader.grub.configurationName = "navi";
 
-  # we wait one second for esc keyboard mashing, otherwise we boot normally
-  boot.loader.grub.extraConfig = ''
-    set timeout=1
-    set timeout_style='hidden'
-  '';
-  # no need for another display change + half a second background image flicker
-  boot.loader.grub.splashImage = null;
+    # we wait one second for esc keyboard mashing, otherwise we boot normally
+    # unset background_color if you want to see the boot framebuffer by default
+    boot.loader.grub.extraConfig = ''
+      set timeout=1
+      set timeout_style='hidden'
+    '';
 
-  nixpkgs.overlays = [
-    (self: super: {
-      grub2 = super.grub2.overrideAttrs (oldAttrs: rec {
-        postPatch = grubPatch;
-      });
-    })];
-  };
+    # this shows the UEFI framebuffer if it isn't cleaned, get a UEFI that likes
+    # you or configure grub to clear that
+    boot.loader.grub.splashImage = null;
+
+    nixpkgs.overlays = [
+      (self: super: {
+        grub2 = super.grub2.overrideAttrs (oldAttrs: rec {
+          postPatch = grubPatch;
+        });
+      })];
+    };
 }

overlays/grub/README.md

@@ -7,3 +7,5 @@ c14f14eeaf919c914e4dec2ce485a5bdc8dd4fec
 of nixpkgs master. 
 
 PLEASE UPDATE ME TO BE ABLE TO EASILY DIFF OUT THE CHANGES WHEN YOU REBASE ME.
+This overlay will be removed once https://github.com/NixOS/nixpkgs/pull/108242
+is merged.

overlays/stage-1/README.md

@@ -0,0 +1,11 @@
+This is based on commit 
+
+
+c14f14eeaf919c914e4dec2ce485a5bdc8dd4fec
+
+
+of nixpkgs master. 
+
+PLEASE UPDATE ME TO BE ABLE TO EASILY DIFF OUT THE CHANGES WHEN YOU REBASE ME.
+This overlay will be removed once https://github.com/NixOS/nixpkgs/issues/32555
+is solved.

overlays/stage-1/stage-1-init.sh

@@ -0,0 +1,637 @@
+#! @shell@
+
+targetRoot=/mnt-root
+console=tty1
+verbose=${verbose:-0}
+
+extraUtils="@extraUtils@"
+export LD_LIBRARY_PATH=@extraUtils@/lib
+export PATH=@extraUtils@/bin
+ln -s @extraUtils@/bin /bin
+
+# Copy the secrets to their needed location
+if [ -d "@extraUtils@/secrets" ]; then
+    for secret in $(cd "@extraUtils@/secrets"; find . -type f); do
+        mkdir -p $(dirname "/$secret")
+        ln -s "@extraUtils@/secrets/$secret" "$secret"
+    done
+fi
+
+# Stop LVM complaining about fd3
+export LVM_SUPPRESS_FD_WARNINGS=true
+
+fail() {
+    if [ -n "$panicOnFail" ]; then exit 1; fi
+
+    @preFailCommands@
+
+    # If starting stage 2 failed, allow the user to repair the problem
+    # in an interactive shell.
+    cat <<EOF
+
+An error occurred in stage 1 of the boot process, which must mount the
+root filesystem on \`$targetRoot' and then start stage 2.  Press one
+of the following keys:
+
+EOF
+    if [ -n "$allowShell" ]; then cat <<EOF
+  i) to launch an interactive shell
+  f) to start an interactive shell having pid 1 (needed if you want to
+     start stage 2's init manually)
+EOF
+    fi
+    cat <<EOF
+  r) to reboot immediately
+  *) to ignore the error and continue
+EOF
+
+    read -n 1 reply
+
+    if [ -n "$allowShell" -a "$reply" = f ]; then
+        exec setsid @shell@ -c "exec @shell@ < /dev/$console >/dev/$console 2>/dev/$console"
+    elif [ -n "$allowShell" -a "$reply" = i ]; then
+        echo "Starting interactive shell..."
+        setsid @shell@ -c "exec @shell@ < /dev/$console >/dev/$console 2>/dev/$console" || fail
+    elif [ "$reply" = r ]; then
+        echo "Rebooting..."
+        reboot -f
+    else
+        echo "Continuing..."
+    fi
+}
+
+trap 'fail' 0
+
+
+# Print a greeting.
+if [ $verbose -eq 1 ]; then
+    echo
+    echo "<<< NixOS Stage 1 >>>"
+    echo
+fi
+
+# Make several required directories.
+mkdir -p /etc/udev
+touch /etc/fstab # to shut up mount
+ln -s /proc/mounts /etc/mtab # to shut up mke2fs
+touch /etc/udev/hwdb.bin # to shut up udev
+touch /etc/initrd-release
+
+# Function for waiting a device to appear.
+waitDevice() {
+    local device="$1"
+
+    # USB storage devices tend to appear with some delay.  It would be
+    # great if we had a way to synchronously wait for them, but
+    # alas...  So just wait for a few seconds for the device to
+    # appear.
+    if test ! -e $device; then
+        echo -n "waiting for device $device to appear..."
+        try=20
+        while [ $try -gt 0 ]; do
+            sleep 1
+            # also re-try lvm activation now that new block devices might have appeared
+            lvm vgchange -ay
+            # and tell udev to create nodes for the new LVs
+            udevadm trigger --action=add
+            if test -e $device; then break; fi
+            echo -n "."
+            try=$((try - 1))
+        done
+        echo
+        [ $try -ne 0 ]
+    fi
+}
+
+# Mount special file systems.
+specialMount() {
+  local device="$1"
+  local mountPoint="$2"
+  local options="$3"
+  local fsType="$4"
+
+  mkdir -m 0755 -p "$mountPoint"
+  mount -n -t "$fsType" -o "$options" "$device" "$mountPoint"
+}
+source @earlyMountScript@
+
+# Log the script output to /dev/kmsg or /run/log/stage-1-init.log.
+mkdir -p /tmp
+mkfifo /tmp/stage-1-init.log.fifo
+logOutFd=8 && logErrFd=9
+eval "exec $logOutFd>&1 $logErrFd>&2"
+if test -w /dev/kmsg; then
+    tee -i < /tmp/stage-1-init.log.fifo /proc/self/fd/"$logOutFd" | while read -r line; do
+        if test -n "$line"; then
+            echo "<7>stage-1-init: [$(date)] $line" > /dev/kmsg
+        fi
+    done &
+else
+    mkdir -p /run/log
+    tee -i < /tmp/stage-1-init.log.fifo /run/log/stage-1-init.log &
+fi
+exec > /tmp/stage-1-init.log.fifo 2>&1
+
+
+# Process the kernel command line.
+export stage2Init=/init
+for o in $(cat /proc/cmdline); do
+    case $o in
+        console=*)
+            set -- $(IFS==; echo $o)
+            params=$2
+            set -- $(IFS=,; echo $params)
+            console=$1
+            ;;
+        init=*)
+            set -- $(IFS==; echo $o)
+            stage2Init=$2
+            ;;
+        boot.persistence=*)
+            set -- $(IFS==; echo $o)
+            persistence=$2
+            ;;
+        boot.persistence.opt=*)
+            set -- $(IFS==; echo $o)
+            persistence_opt=$2
+            ;;
+        boot.trace|debugtrace)
+            # Show each command.
+            set -x
+            ;;
+        boot.shell_on_fail)
+            allowShell=1
+            ;;
+        boot.debug1|debug1) # stop right away
+            allowShell=1
+            fail
+            ;;
+        boot.debug1devices) # stop after loading modules and creating device nodes
+            allowShell=1
+            debug1devices=1
+            ;;
+        boot.debug1mounts) # stop after mounting file systems
+            allowShell=1
+            debug1mounts=1
+            ;;
+        boot.panic_on_fail|stage1panic=1)
+            panicOnFail=1
+            ;;
+        root=*)
+            # If a root device is specified on the kernel command
+            # line, make it available through the symlink /dev/root.
+            # Recognise LABEL= and UUID= to support UNetbootin.
+            set -- $(IFS==; echo $o)
+            if [ $2 = "LABEL" ]; then
+                root="/dev/disk/by-label/$3"
+            elif [ $2 = "UUID" ]; then
+                root="/dev/disk/by-uuid/$3"
+            else
+                root=$2
+            fi
+            ln -s "$root" /dev/root
+            ;;
+        copytoram)
+            copytoram=1
+            ;;
+        findiso=*)
+            # if an iso name is supplied, try to find the device where
+            # the iso resides on
+            set -- $(IFS==; echo $o)
+            isoPath=$2
+            ;;
+    esac
+done
+
+# Set hostid before modules are loaded.
+# This is needed by the spl/zfs modules.
+@setHostId@
+
+# Load the required kernel modules.
+mkdir -p /lib
+ln -s @modulesClosure@/lib/modules /lib/modules
+ln -s @modulesClosure@/lib/firmware /lib/firmware
+echo @extraUtils@/bin/modprobe > /proc/sys/kernel/modprobe
+for i in @kernelModules@; do
+    if [ $verbose -eq 1 ]; then
+        echo "loading module $(basename $i)..."
+    fi
+    modprobe $i
+done
+
+
+# Create device nodes in /dev.
+@preDeviceCommands@
+if [ $verbose -eq 1 ]; then
+    echo "running udev..."
+fi
+ln -sfn /proc/self/fd /dev/fd
+ln -sfn /proc/self/fd/0 /dev/stdin
+ln -sfn /proc/self/fd/1 /dev/stdout
+ln -sfn /proc/self/fd/2 /dev/stderr
+mkdir -p /etc/systemd
+ln -sfn @linkUnits@ /etc/systemd/network
+mkdir -p /etc/udev
+ln -sfn @udevRules@ /etc/udev/rules.d
+mkdir -p /dev/.mdadm
+systemd-udevd --daemon
+udevadm trigger --action=add
+udevadm settle
+
+
+# XXX: Use case usb->lvm will still fail, usb->luks->lvm is covered
+@preLVMCommands@
+
+if [ $verbose -eq 1 ]; then
+    echo "starting device mapper and LVM..."
+fi
+lvm vgchange -ay
+
+if test -n "$debug1devices"; then fail; fi
+
+
+@postDeviceCommands@
+
+
+# Return true if the machine is on AC power, or if we can't determine
+# whether it's on AC power.
+onACPower() {
+    ! test -d "/proc/acpi/battery" ||
+    ! ls /proc/acpi/battery/BAT[0-9]* > /dev/null 2>&1 ||
+    ! cat /proc/acpi/battery/BAT*/state | grep "^charging state" | grep -q "discharg"
+}
+
+
+# Check the specified file system, if appropriate.
+checkFS() {
+    local device="$1"
+    local fsType="$2"
+
+    # Only check block devices.
+    if [ ! -b "$device" ]; then return 0; fi
+
+    # Don't check ROM filesystems.
+    if [ "$fsType" = iso9660 -o "$fsType" = udf ]; then return 0; fi
+
+    # Don't check resilient COWs as they validate the fs structures at mount time
+    if [ "$fsType" = btrfs -o "$fsType" = zfs -o "$fsType" = bcachefs ]; then return 0; fi
+
+    # Skip fsck for nilfs2 - not needed by design and no fsck tool for this filesystem.
+    if [ "$fsType" = nilfs2 ]; then return 0; fi
+
+    # Skip fsck for inherently readonly filesystems.
+    if [ "$fsType" = squashfs ]; then return 0; fi
+
+    # If we couldn't figure out the FS type, then skip fsck.
+    if [ "$fsType" = auto ]; then
+        echo 'cannot check filesystem with type "auto"!'
+        return 0
+    fi
+
+    # Device might be already mounted manually
+    # e.g. NBD-device or the host filesystem of the file which contains encrypted root fs
+    if mount | grep -q "^$device on "; then
+        echo "skip checking already mounted $device"
+        return 0
+    fi
+
+    # Optionally, skip fsck on journaling filesystems.  This option is
+    # a hack - it's mostly because e2fsck on ext3 takes much longer to
+    # recover the journal than the ext3 implementation in the kernel
+    # does (minutes versus seconds).
+    if test -z "@checkJournalingFS@" -a \
+        \( "$fsType" = ext3 -o "$fsType" = ext4 -o "$fsType" = reiserfs \
+        -o "$fsType" = xfs -o "$fsType" = jfs -o "$fsType" = f2fs \)
+    then
+        return 0
+    fi
+
+    # Don't run `fsck' if the machine is on battery power.  !!! Is
+    # this a good idea?
+    if ! onACPower; then
+        echo "on battery power, so no \`fsck' will be performed on \`$device'"
+        return 0
+    fi
+
+    echo "checking $device..."
+
+    fsckFlags=
+    if test "$fsType" != "btrfs"; then
+        fsckFlags="-V -a"
+    fi
+    fsck $fsckFlags "$device"
+    fsckResult=$?
+
+    if test $(($fsckResult | 2)) = $fsckResult; then
+        echo "fsck finished, rebooting..."
+        sleep 3
+        reboot -f
+    fi
+
+    if test $(($fsckResult | 4)) = $fsckResult; then
+        echo "$device has unrepaired errors, please fix them manually."
+        fail
+    fi
+
+    if test $fsckResult -ge 8; then
+        echo "fsck on $device failed."
+        fail
+    fi
+
+    return 0
+}
+
+
+# Function for mounting a file system.
+mountFS() {
+    local device="$1"
+    local mountPoint="$2"
+    local options="$3"
+    local fsType="$4"
+
+    if [ "$fsType" = auto ]; then
+        fsType=$(blkid -o value -s TYPE "$device")
+        if [ -z "$fsType" ]; then fsType=auto; fi
+    fi
+
+    # Filter out x- options, which busybox doesn't do yet.
+    local optionsFiltered="$(IFS=,; for i in $options; do if [ "${i:0:2}" != "x-" ]; then echo -n $i,; fi; done)"
+    # Prefix (lower|upper|work)dir with /mnt-root (overlayfs)
+    local optionsPrefixed="$( echo "$optionsFiltered" | sed -E 's#\<(lowerdir|upperdir|workdir)=#\1=/mnt-root#g' )"
+
+    echo "$device /mnt-root$mountPoint $fsType $optionsPrefixed" >> /etc/fstab
+
+    checkFS "$device" "$fsType"
+
+    # Optionally resize the filesystem.
+    case $options in
+        *x-nixos.autoresize*)
+            if [ "$fsType" = ext2 -o "$fsType" = ext3 -o "$fsType" = ext4 ]; then
+                modprobe "$fsType"
+                echo "resizing $device..."
+                e2fsck -fp "$device"
+                resize2fs "$device"
+            elif [ "$fsType" = f2fs ]; then
+                echo "resizing $device..."
+                fsck.f2fs -fp "$device"
+                resize.f2fs "$device"
+            fi
+            ;;
+    esac
+
+    # Create backing directories for overlayfs
+    if [ "$fsType" = overlay ]; then
+        for i in upper work; do
+             dir="$( echo "$optionsPrefixed" | grep -o "${i}dir=[^,]*" )"
+             mkdir -m 0700 -p "${dir##*=}"
+        done
+    fi
+
+    if [ $verbose -eq 1 ]; then
+        echo "mounting $device on $mountPoint..."
+    fi
+
+    mkdir -p "/mnt-root$mountPoint"
+
+    # For ZFS and CIFS mounts, retry a few times before giving up.
+    # We do this for ZFS as a workaround for issue NixOS/nixpkgs#25383.
+    local n=0
+    while true; do
+        mount "/mnt-root$mountPoint" && break
+        if [ \( "$fsType" != cifs -a "$fsType" != zfs \) -o "$n" -ge 10 ]; then fail; break; fi
+        echo "retrying..."
+        sleep 1
+        n=$((n + 1))
+    done
+
+    [ "$mountPoint" == "/" ] &&
+        [ -f "/mnt-root/etc/NIXOS_LUSTRATE" ] &&
+        lustrateRoot "/mnt-root"
+
+    true
+}
+
+lustrateRoot () {
+    local root="$1"
+
+    echo
+    echo -e "\e[1;33m<<< NixOS is now lustrating the root filesystem (cruft goes to /old-root) >>>\e[0m"
+    echo
+
+    mkdir -m 0755 -p "$root/old-root.tmp"
+
+    echo
+    echo "Moving impurities out of the way:"
+    for d in "$root"/*
+    do
+        [ "$d" == "$root/nix"          ] && continue
+        [ "$d" == "$root/boot"         ] && continue # Don't render the system unbootable
+        [ "$d" == "$root/old-root.tmp" ] && continue
+
+        mv -v "$d" "$root/old-root.tmp"
+    done
+
+    # Use .tmp to make sure subsequent invokations don't clash
+    mv -v "$root/old-root.tmp" "$root/old-root"
+
+    mkdir -m 0755 -p "$root/etc"
+    touch "$root/etc/NIXOS"
+
+    exec 4< "$root/old-root/etc/NIXOS_LUSTRATE"
+
+    echo
+    echo "Restoring selected impurities:"
+    while read -u 4 keeper; do
+        dirname="$(dirname "$keeper")"
+        mkdir -m 0755 -p "$root/$dirname"
+        cp -av "$root/old-root/$keeper" "$root/$keeper"
+    done
+
+    exec 4>&-
+}
+
+
+
+if test -e /sys/power/resume -a -e /sys/power/disk; then
+    if test -n "@resumeDevice@" && waitDevice "@resumeDevice@"; then
+        resumeDev="@resumeDevice@"
+        resumeInfo="$(udevadm info -q property "$resumeDev" )"
+    else
+        for sd in @resumeDevices@; do
+            # Try to detect resume device. According to Ubuntu bug:
+            # https://bugs.launchpad.net/ubuntu/+source/pm-utils/+bug/923326/comments/1
+            # when there are multiple swap devices, we can't know where the hibernate
+            # image will reside. We can check all of them for swsuspend blkid.
+            if waitDevice "$sd"; then
+                resumeInfo="$(udevadm info -q property "$sd")"
+                if [ "$(echo "$resumeInfo" | sed -n 's/^ID_FS_TYPE=//p')" = "swsuspend" ]; then
+                    resumeDev="$sd"
+                    break
+                fi
+            fi
+        done
+    fi
+    if test -n "$resumeDev"; then
+        resumeMajor="$(echo "$resumeInfo" | sed -n 's/^MAJOR=//p')"
+        resumeMinor="$(echo "$resumeInfo" | sed -n 's/^MINOR=//p')"
+        echo "$resumeMajor:$resumeMinor" > /sys/power/resume 2> /dev/null || echo "failed to resume..."
+    fi
+fi
+
+# If we have a path to an iso file, find the iso and link it to /dev/root
+if [ -n "$isoPath" ]; then
+  mkdir -p /findiso
+
+  for delay in 5 10; do
+    blkid | while read -r line; do
+      device=$(echo "$line" | sed 's/:.*//')
+      type=$(echo "$line" | sed 's/.*TYPE="\([^"]*\)".*/\1/')
+
+      mount -t "$type" "$device" /findiso
+      if [ -e "/findiso$isoPath" ]; then
+        ln -sf "/findiso$isoPath" /dev/root
+        break 2
+      else
+        umount /findiso
+      fi
+    done
+
+    sleep "$delay"
+  done
+fi
+
+# Try to find and mount the root device.
+mkdir -p $targetRoot
+
+exec 3< @fsInfo@
+
+while read -u 3 mountPoint; do
+    read -u 3 device
+    read -u 3 fsType
+    read -u 3 options
+
+    # !!! Really quick hack to support bind mounts, i.e., where the
+    # "device" should be taken relative to /mnt-root, not /.  Assume
+    # that every device that starts with / but doesn't start with /dev
+    # is a bind mount.
+    pseudoDevice=
+    case $device in
+        /dev/*)
+            ;;
+        //*)
+            # Don't touch SMB/CIFS paths.
+            pseudoDevice=1
+            ;;
+        /*)
+            device=/mnt-root$device
+            ;;
+        *)
+            # Not an absolute path; assume that it's a pseudo-device
+            # like an NFS path (e.g. "server:/path").
+            pseudoDevice=1
+            ;;
+    esac
+
+    if test -z "$pseudoDevice" && ! waitDevice "$device"; then
+        # If it doesn't appear, try to mount it anyway (and
+        # probably fail).  This is a fallback for non-device "devices"
+        # that we don't properly recognise.
+        echo "Timed out waiting for device $device, trying to mount anyway."
+    fi
+
+    # Wait once more for the udev queue to empty, just in case it's
+    # doing something with $device right now.
+    udevadm settle
+
+    # If copytoram is enabled: skip mounting the ISO and copy its content to a tmpfs.
+    if [ -n "$copytoram" ] && [ "$device" = /dev/root ] && [ "$mountPoint" = /iso ]; then
+      fsType=$(blkid -o value -s TYPE "$device")
+      fsSize=$(blockdev --getsize64 "$device")
+
+      mkdir -p /tmp-iso
+      mount -t "$fsType" /dev/root /tmp-iso
+      mountFS tmpfs /iso size="$fsSize" tmpfs
+
+      cp -r /tmp-iso/* /mnt-root/iso/
+
+      umount /tmp-iso
+      rmdir /tmp-iso
+      continue
+    fi
+
+    if [ "$mountPoint" = / ] && [ "$device" = tmpfs ] && [ ! -z "$persistence" ]; then
+        echo persistence...
+        waitDevice "$persistence"
+        echo enabling persistence...
+        mountFS "$persistence" "$mountPoint" "$persistence_opt" "auto"
+        continue
+    fi
+
+    mountFS "$device" "$mountPoint" "$options" "$fsType"
+done
+
+exec 3>&-
+
+
+@postMountCommands@
+
+
+# Emit a udev rule for /dev/root to prevent systemd from complaining.
+if [ -e /mnt-root/iso ]; then
+    eval $(udevadm info --export --export-prefix=ROOT_ --device-id-of-file=/mnt-root/iso)
+else
+    eval $(udevadm info --export --export-prefix=ROOT_ --device-id-of-file=$targetRoot)
+fi
+if [ "$ROOT_MAJOR" -a "$ROOT_MINOR" -a "$ROOT_MAJOR" != 0 ]; then
+    mkdir -p /run/udev/rules.d
+    echo 'ACTION=="add|change", SUBSYSTEM=="block", ENV{MAJOR}=="'$ROOT_MAJOR'", ENV{MINOR}=="'$ROOT_MINOR'", SYMLINK+="root"' > /run/udev/rules.d/61-dev-root-link.rules
+fi
+
+
+# Stop udevd.
+udevadm control --exit
+
+# Reset the logging file descriptors.
+# Do this just before pkill, which will kill the tee process.
+exec 1>&$logOutFd 2>&$logErrFd
+eval "exec $logOutFd>&- $logErrFd>&-"
+
+# Kill any remaining processes, just to be sure we're not taking any
+# with us into stage 2. But keep storage daemons like unionfs-fuse.
+#
+# Storage daemons are distinguished by an @ in front of their command line:
+# https://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons/
+for pid in $(pgrep -v -f '^@'); do
+    # Make sure we don't kill kernel processes, see #15226 and:
+    # http://stackoverflow.com/questions/12213445/identifying-kernel-threads
+    readlink "/proc/$pid/exe" &> /dev/null || continue
+    # Try to avoid killing ourselves.
+    [ $pid -eq $$ ] && continue
+    kill -9 "$pid"
+done
+
+if test -n "$debug1mounts"; then fail; fi
+
+
+# Restore /proc/sys/kernel/modprobe to its original value.
+echo /sbin/modprobe > /proc/sys/kernel/modprobe
+
+
+# Start stage 2.  `switch_root' deletes all files in the ramfs on the
+# current root.  Note that $stage2Init might be an absolute symlink,
+# in which case "-e" won't work because we're not in the chroot yet.
+if [ ! -e "$targetRoot/$stage2Init" ] && [ ! -L "$targetRoot/$stage2Init" ] ; then
+    echo "stage 2 init script ($targetRoot/$stage2Init) not found"
+    fail
+fi
+
+mkdir -m 0755 -p $targetRoot/proc $targetRoot/sys $targetRoot/dev $targetRoot/run
+
+mount --move /proc $targetRoot/proc
+mount --move /sys $targetRoot/sys
+mount --move /dev $targetRoot/dev
+mount --move /run $targetRoot/run
+
+exec env -i $(type -P switch_root) "$targetRoot" "$stage2Init"
+
+fail # should never be reached

overlays/stage-1/stage-1.nix

@@ -0,0 +1,636 @@
+# This module builds the initial ramdisk, which contains an init
+# script that performs the first stage of booting the system: it loads
+# the modules necessary to mount the root file system, then calls the
+# init in the root file system to start the second boot stage.
+
+{ config, lib, utils, pkgs, ... }:
+
+with lib;
+
+let
+
+  udev = config.systemd.package;
+
+  kernel-name = config.boot.kernelPackages.kernel.name or "kernel";
+
+  modulesTree = config.system.modulesTree.override { name = kernel-name + "-modules"; };
+  firmware = config.hardware.firmware;
+
+
+  # Determine the set of modules that we need to mount the root FS.
+  modulesClosure = pkgs.makeModulesClosure {
+    rootModules = config.boot.initrd.availableKernelModules ++ config.boot.initrd.kernelModules;
+    kernel = modulesTree;
+    firmware = firmware;
+    allowMissing = true;
+  };
+
+
+  # The initrd only has to mount `/` or any FS marked as necessary for
+  # booting (such as the FS containing `/nix/store`, or an FS needed for
+  # mounting `/`, like `/` on a loopback).
+  fileSystems = filter utils.fsNeededForBoot config.system.build.fileSystems;
+
+  # A utility for enumerating the shared-library dependencies of a program
+  findLibs = pkgs.buildPackages.writeShellScriptBin "find-libs" ''
+    set -euo pipefail
+
+    declare -A seen
+    left=()
+
+    patchelf="${pkgs.buildPackages.patchelf}/bin/patchelf"
+
+    function add_needed {
+      rpath="$($patchelf --print-rpath $1)"
+      dir="$(dirname $1)"
+      for lib in $($patchelf --print-needed $1); do
+        left+=("$lib" "$rpath" "$dir")
+      done
+    }
+
+    add_needed "$1"
+
+    while [ ''${#left[@]} -ne 0 ]; do
+      next=''${left[0]}
+      rpath=''${left[1]}
+      ORIGIN=''${left[2]}
+      left=("''${left[@]:3}")
+      if [ -z ''${seen[$next]+x} ]; then
+        seen[$next]=1
+
+        # Ignore the dynamic linker which for some reason appears as a DT_NEEDED of glibc but isn't in glibc's RPATH.
+        case "$next" in
+          ld*.so.?) continue;;
+        esac
+
+        IFS=: read -ra paths <<< $rpath
+        res=
+        for path in "''${paths[@]}"; do
+          path=$(eval "echo $path")
+          if [ -f "$path/$next" ]; then
+              res="$path/$next"
+              echo "$res"
+              add_needed "$res"
+              break
+          fi
+        done
+        if [ -z "$res" ]; then
+          echo "Couldn't satisfy dependency $next" >&2
+          exit 1
+        fi
+      fi
+    done
+  '';
+
+  # Some additional utilities needed in stage 1, like mount, lvm, fsck
+  # etc.  We don't want to bring in all of those packages, so we just
+  # copy what we need.  Instead of using statically linked binaries,
+  # we just copy what we need from Glibc and use patchelf to make it
+  # work.
+  extraUtils = pkgs.runCommandCC "extra-utils"
+    { nativeBuildInputs = [pkgs.buildPackages.nukeReferences];
+      allowedReferences = [ "out" ]; # prevent accidents like glibc being included in the initrd
+    }
+    ''
+      set +o pipefail
+
+      mkdir -p $out/bin $out/lib
+      ln -s $out/bin $out/sbin
+
+      copy_bin_and_libs () {
+        [ -f "$out/bin/$(basename $1)" ] && rm "$out/bin/$(basename $1)"
+        cp -pdv $1 $out/bin
+      }
+
+      # Copy BusyBox.
+      for BIN in ${pkgs.busybox}/{s,}bin/*; do
+        copy_bin_and_libs $BIN
+      done
+
+      # Copy some util-linux stuff.
+      copy_bin_and_libs ${pkgs.util-linux}/sbin/blkid
+
+      # Copy dmsetup and lvm.
+      copy_bin_and_libs ${getBin pkgs.lvm2}/bin/dmsetup
+      copy_bin_and_libs ${getBin pkgs.lvm2}/bin/lvm
+
+      # Add RAID mdadm tool.
+      copy_bin_and_libs ${pkgs.mdadm}/sbin/mdadm
+      copy_bin_and_libs ${pkgs.mdadm}/sbin/mdmon
+
+      # Copy udev.
+      copy_bin_and_libs ${udev}/bin/udevadm
+      copy_bin_and_libs ${udev}/lib/systemd/systemd-sysctl
+      for BIN in ${udev}/lib/udev/*_id; do
+        copy_bin_and_libs $BIN
+      done
+      # systemd-udevd is only a symlink to udevadm these days
+      ln -sf udevadm $out/bin/systemd-udevd
+
+      # Copy modprobe.
+      copy_bin_and_libs ${pkgs.kmod}/bin/kmod
+      ln -sf kmod $out/bin/modprobe
+
+      # Copy resize2fs if any ext* filesystems are to be resized
+      ${optionalString (any (fs: fs.autoResize && (lib.hasPrefix "ext" fs.fsType)) fileSystems) ''
+        # We need mke2fs in the initrd.
+        copy_bin_and_libs ${pkgs.e2fsprogs}/sbin/resize2fs
+      ''}
+
+      # Copy secrets if needed.
+      #
+      # TODO: move out to a separate script; see #85000.
+      ${optionalString (!config.boot.loader.supportsInitrdSecrets)
+          (concatStringsSep "\n" (mapAttrsToList (dest: source:
+             let source' = if source == null then dest else source; in
+               ''
+                  mkdir -p $(dirname "$out/secrets/${dest}")
+                  # Some programs (e.g. ssh) doesn't like secrets to be
+                  # symlinks, so we use `cp -L` here to match the
+                  # behaviour when secrets are natively supported.
+                  cp -Lr ${source'} "$out/secrets/${dest}"
+                ''
+          ) config.boot.initrd.secrets))
+       }
+
+      ${config.boot.initrd.extraUtilsCommands}
+
+      # Copy ld manually since it isn't detected correctly
+      cp -pv ${pkgs.stdenv.cc.libc.out}/lib/ld*.so.? $out/lib
+
+      # Copy all of the needed libraries
+      find $out/bin $out/lib -type f | while read BIN; do
+        echo "Copying libs for executable $BIN"
+        for LIB in $(${findLibs}/bin/find-libs $BIN); do
+          TGT="$out/lib/$(basename $LIB)"
+          if [ ! -f "$TGT" ]; then
+            SRC="$(readlink -e $LIB)"
+            cp -pdv "$SRC" "$TGT"
+          fi
+        done
+      done
+
+      # Strip binaries further than normal.
+      chmod -R u+w $out
+      stripDirs "$STRIP" "lib bin" "-s"
+
+      # Run patchelf to make the programs refer to the copied libraries.
+      find $out/bin $out/lib -type f | while read i; do
+        if ! test -L $i; then
+          nuke-refs -e $out $i
+        fi
+      done
+
+      find $out/bin -type f | while read i; do
+        if ! test -L $i; then
+          echo "patching $i..."
+          patchelf --set-interpreter $out/lib/ld*.so.? --set-rpath $out/lib $i || true
+        fi
+      done
+
+      if [ -z "${toString (pkgs.stdenv.hostPlatform != pkgs.stdenv.buildPlatform)}" ]; then
+      # Make sure that the patchelf'ed binaries still work.
+      echo "testing patched programs..."
+      $out/bin/ash -c 'echo hello world' | grep "hello world"
+      export LD_LIBRARY_PATH=$out/lib
+      $out/bin/mount --help 2>&1 | grep -q "BusyBox"
+      $out/bin/blkid -V 2>&1 | grep -q 'libblkid'
+      $out/bin/udevadm --version
+      $out/bin/dmsetup --version 2>&1 | tee -a log | grep -q "version:"
+      LVM_SYSTEM_DIR=$out $out/bin/lvm version 2>&1 | tee -a log | grep -q "LVM"
+      $out/bin/mdadm --version
+
+      ${config.boot.initrd.extraUtilsCommandsTest}
+      fi
+    ''; # */
+
+
+  linkUnits = pkgs.runCommand "link-units" {
+      allowedReferences = [ extraUtils ];
+      preferLocalBuild = true;
+    } ''
+      mkdir -p $out
+      cp -v ${udev}/lib/systemd/network/*.link $out/
+    '';
+
+  udevRules = pkgs.runCommand "udev-rules" {
+      allowedReferences = [ extraUtils ];
+      preferLocalBuild = true;
+    } ''
+      mkdir -p $out
+
+      echo 'ENV{LD_LIBRARY_PATH}="${extraUtils}/lib"' > $out/00-env.rules
+
+      cp -v ${udev}/lib/udev/rules.d/60-cdrom_id.rules $out/
+      cp -v ${udev}/lib/udev/rules.d/60-persistent-storage.rules $out/
+      cp -v ${udev}/lib/udev/rules.d/75-net-description.rules $out/
+      cp -v ${udev}/lib/udev/rules.d/80-drivers.rules $out/
+      cp -v ${udev}/lib/udev/rules.d/80-net-setup-link.rules $out/
+      cp -v ${pkgs.lvm2}/lib/udev/rules.d/*.rules $out/
+      ${config.boot.initrd.extraUdevRulesCommands}
+
+      for i in $out/*.rules; do
+          substituteInPlace $i \
+            --replace ata_id ${extraUtils}/bin/ata_id \
+            --replace scsi_id ${extraUtils}/bin/scsi_id \
+            --replace cdrom_id ${extraUtils}/bin/cdrom_id \
+            --replace ${pkgs.coreutils}/bin/basename ${extraUtils}/bin/basename \
+            --replace ${pkgs.util-linux}/bin/blkid ${extraUtils}/bin/blkid \
+            --replace ${getBin pkgs.lvm2}/bin ${extraUtils}/bin \
+            --replace ${pkgs.mdadm}/sbin ${extraUtils}/sbin \
+            --replace ${pkgs.bash}/bin/sh ${extraUtils}/bin/sh \
+            --replace ${udev} ${extraUtils}
+      done
+
+      # Work around a bug in QEMU, which doesn't implement the "READ
+      # DISC INFORMATION" SCSI command:
+      #   https://bugzilla.redhat.com/show_bug.cgi?id=609049
+      # As a result, `cdrom_id' doesn't print
+      # ID_CDROM_MEDIA_TRACK_COUNT_DATA, which in turn prevents the
+      # /dev/disk/by-label symlinks from being created.  We need these
+      # in the NixOS installation CD, so use ID_CDROM_MEDIA in the
+      # corresponding udev rules for now.  This was the behaviour in
+      # udev <= 154.  See also
+      #   http://www.spinics.net/lists/hotplug/msg03935.html
+      substituteInPlace $out/60-persistent-storage.rules \
+        --replace ID_CDROM_MEDIA_TRACK_COUNT_DATA ID_CDROM_MEDIA
+    ''; # */
+
+
+  # The init script of boot stage 1 (loading kernel modules for
+  # mounting the root FS).
+  bootStage1 = pkgs.substituteAll {
+    src = ./stage-1-init.sh;
+
+    shell = "${extraUtils}/bin/ash";
+
+    isExecutable = true;
+
+    postInstall = ''
+      echo checking syntax
+      # check both with bash
+      ${pkgs.buildPackages.bash}/bin/sh -n $target
+      # and with ash shell, just in case
+      ${pkgs.buildPackages.busybox}/bin/ash -n $target
+    '';
+
+    inherit linkUnits udevRules extraUtils modulesClosure;
+
+    inherit (config.boot) resumeDevice;
+
+    inherit (config.system.build) earlyMountScript;
+
+    inherit (config.boot.initrd) checkJournalingFS
+      preLVMCommands preDeviceCommands postDeviceCommands postMountCommands preFailCommands kernelModules;
+
+    resumeDevices = map (sd: if sd ? device then sd.device else "/dev/disk/by-label/${sd.label}")
+                    (filter (sd: hasPrefix "/dev/" sd.device && !sd.randomEncryption.enable
+                             # Don't include zram devices
+                             && !(hasPrefix "/dev/zram" sd.device)
+                            ) config.swapDevices);
+
+    fsInfo =
+      let f = fs: [ fs.mountPoint (if fs.device != null then fs.device else "/dev/disk/by-label/${fs.label}") fs.fsType (builtins.concatStringsSep "," fs.options) ];
+      in pkgs.writeText "initrd-fsinfo" (concatStringsSep "\n" (concatMap f fileSystems));
+
+    setHostId = optionalString (config.networking.hostId != null) ''
+      hi="${config.networking.hostId}"
+      ${if pkgs.stdenv.isBigEndian then ''
+        echo -ne "\x''${hi:0:2}\x''${hi:2:2}\x''${hi:4:2}\x''${hi:6:2}" > /etc/hostid
+      '' else ''
+        echo -ne "\x''${hi:6:2}\x''${hi:4:2}\x''${hi:2:2}\x''${hi:0:2}" > /etc/hostid
+      ''}
+    '';
+  };
+
+
+  # The closure of the init script of boot stage 1 is what we put in
+  # the initial RAM disk.
+  initialRamdisk = pkgs.makeInitrd {
+    name = "initrd-${kernel-name}";
+    inherit (config.boot.initrd) compressor compressorArgs prepend;
+
+    contents =
+      [ { object = bootStage1;
+          symlink = "/init";
+        }
+        { object = pkgs.writeText "mdadm.conf" config.boot.initrd.mdadmConf;
+          symlink = "/etc/mdadm.conf";
+        }
+        { object = pkgs.runCommand "initrd-kmod-blacklist-ubuntu" {
+              src = "${pkgs.kmod-blacklist-ubuntu}/modprobe.conf";
+              preferLocalBuild = true;
+            } ''
+              target=$out
+              ${pkgs.buildPackages.perl}/bin/perl -0pe 's/## file: iwlwifi.conf(.+?)##/##/s;' $src > $out
+            '';
+          symlink = "/etc/modprobe.d/ubuntu.conf";
+        }
+        { object = pkgs.kmod-debian-aliases;
+          symlink = "/etc/modprobe.d/debian.conf";
+        }
+      ];
+  };
+
+  # Script to add secret files to the initrd at bootloader update time
+  initialRamdiskSecretAppender =
+    let
+      compressorExe = initialRamdisk.compressorExecutableFunction pkgs;
+    in pkgs.writeScriptBin "append-initrd-secrets"
+      ''
+        #!${pkgs.bash}/bin/bash -e
+        function usage {
+          echo "USAGE: $0 INITRD_FILE" >&2
+          echo "Appends this configuration's secrets to INITRD_FILE" >&2
+        }
+
+        if [ $# -ne 1 ]; then
+          usage
+          exit 1
+        fi
+
+        if [ "$1"x = "--helpx" ]; then
+          usage
+          exit 0
+        fi
+
+        ${lib.optionalString (config.boot.initrd.secrets == {})
+            "exit 0"}
+
+        export PATH=${pkgs.coreutils}/bin:${pkgs.cpio}/bin:${pkgs.gzip}/bin:${pkgs.findutils}/bin
+
+        function cleanup {
+          if [ -n "$tmp" -a -d "$tmp" ]; then
+            rm -fR "$tmp"
+          fi
+        }
+        trap cleanup EXIT
+
+        tmp=$(mktemp -d initrd-secrets.XXXXXXXXXX)
+
+        ${lib.concatStringsSep "\n" (mapAttrsToList (dest: source:
+            let source' = if source == null then dest else toString source; in
+              ''
+                mkdir -p $(dirname "$tmp/${dest}")
+                cp -a ${source'} "$tmp/${dest}"
+              ''
+          ) config.boot.initrd.secrets)
+         }
+
+        (cd "$tmp" && find . -print0 | sort -z | cpio -o -H newc -R +0:+0 --reproducible --null) | \
+          ${compressorExe} ${lib.escapeShellArgs initialRamdisk.compressorArgs} >> "$1"
+      '';
+
+in
+
+{
+  options = {
+
+    boot.resumeDevice = mkOption {
+      type = types.str;
+      default = "";
+      example = "/dev/sda3";
+      description = ''
+        Device for manual resume attempt during boot. This should be used primarily
+        if you want to resume from file. If left empty, the swap partitions are used.
+        Specify here the device where the file resides.
+        You should also use <varname>boot.kernelParams</varname> to specify
+        <literal><replaceable>resume_offset</replaceable></literal>.
+      '';
+    };
+
+    boot.initrd.enable = mkOption {
+      type = types.bool;
+      default = !config.boot.isContainer;
+      defaultText = "!config.boot.isContainer";
+      description = ''
+        Whether to enable the NixOS initial RAM disk (initrd). This may be
+        needed to perform some initialisation tasks (like mounting
+        network/encrypted file systems) before continuing the boot process.
+      '';
+    };
+
+    boot.initrd.prepend = mkOption {
+      default = [ ];
+      type = types.listOf types.str;
+      description = ''
+        Other initrd files to prepend to the final initrd we are building.
+      '';
+    };
+
+    boot.initrd.checkJournalingFS = mkOption {
+      default = true;
+      type = types.bool;
+      description = ''
+        Whether to run <command>fsck</command> on journaling filesystems such as ext3.
+      '';
+    };
+
+    boot.initrd.mdadmConf = mkOption {
+      default = "";
+      type = types.lines;
+      description = ''
+        Contents of <filename>/etc/mdadm.conf</filename> in stage 1.
+      '';
+    };
+
+    boot.initrd.preLVMCommands = mkOption {
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed immediately before LVM discovery.
+      '';
+    };
+
+    boot.initrd.preDeviceCommands = mkOption {
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed before udev is started to create
+        device nodes.
+      '';
+    };
+
+    boot.initrd.postDeviceCommands = mkOption {
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed immediately after stage 1 of the
+        boot has loaded kernel modules and created device nodes in
+        <filename>/dev</filename>.
+      '';
+    };
+
+    boot.initrd.postMountCommands = mkOption {
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed immediately after the stage 1
+        filesystems have been mounted.
+      '';
+    };
+
+    boot.initrd.preFailCommands = mkOption {
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed before the failure prompt is shown.
+      '';
+    };
+
+    boot.initrd.extraUtilsCommands = mkOption {
+      internal = true;
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed in the builder of the
+        extra-utils derivation.  This can be used to provide
+        additional utilities in the initial ramdisk.
+      '';
+    };
+
+    boot.initrd.extraUtilsCommandsTest = mkOption {
+      internal = true;
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed in the builder of the
+        extra-utils derivation after patchelf has done its
+        job.  This can be used to test additional utilities
+        copied in extraUtilsCommands.
+      '';
+    };
+
+    boot.initrd.extraUdevRulesCommands = mkOption {
+      internal = true;
+      default = "";
+      type = types.lines;
+      description = ''
+        Shell commands to be executed in the builder of the
+        udev-rules derivation.  This can be used to add
+        additional udev rules in the initial ramdisk.
+      '';
+    };
+
+    boot.initrd.compressor = mkOption {
+      default = "gzip";
+      type = types.unspecified; # We don't have a function type...
+      description = ''
+        The compressor to use on the initrd image. May be any of:
+
+        <itemizedlist>
+         <listitem><para>The name of one of the predefined compressors, see <filename>pkgs/build-support/kernel/initrd-compressor-meta.nix</filename> for the definitions.</para></listitem>
+         <listitem><para>A function which, given the nixpkgs package set, returns the path to a compressor tool, e.g. <literal>pkgs: "''${pkgs.pigz}/bin/pigz"</literal></para></listitem>
+         <listitem><para>(not recommended, because it does not work when cross-compiling) the full path to a compressor tool, e.g. <literal>"''${pkgs.pigz}/bin/pigz"</literal></para></listitem>
+        </itemizedlist>
+
+        The given program should read data from stdin and write it to stdout compressed.
+      '';
+      example = "xz";
+    };
+
+    boot.initrd.compressorArgs = mkOption {
+      default = null;
+      type = types.nullOr (types.listOf types.str);
+      description = "Arguments to pass to the compressor for the initrd image, or null to use the compressor's defaults.";
+    };
+
+    boot.initrd.secrets = mkOption
+      { default = {};
+        type = types.attrsOf (types.nullOr types.path);
+        description =
+          ''
+            Secrets to append to the initrd. The attribute name is the
+            path the secret should have inside the initrd, the value
+            is the path it should be copied from (or null for the same
+            path inside and out).
+          '';
+        example = literalExample
+          ''
+            { "/etc/dropbear/dropbear_rsa_host_key" =
+                ./secret-dropbear-key;
+            }
+          '';
+      };
+
+    boot.initrd.supportedFilesystems = mkOption {
+      default = [ ];
+      example = [ "btrfs" ];
+      type = types.listOf types.str;
+      description = "Names of supported filesystem types in the initial ramdisk.";
+    };
+
+    boot.loader.supportsInitrdSecrets = mkOption
+      { internal = true;
+        default = false;
+        type = types.bool;
+        description =
+          ''
+            Whether the bootloader setup runs append-initrd-secrets.
+            If not, any needed secrets must be copied into the initrd
+            and thus added to the store.
+          '';
+      };
+
+    fileSystems = mkOption {
+      type = with lib.types; attrsOf (submodule {
+        options.neededForBoot = mkOption {
+          default = false;
+          type = types.bool;
+          description = ''
+            If set, this file system will be mounted in the initial ramdisk.
+            Note that the file system will always be mounted in the initial
+            ramdisk if its mount point is one of the following:
+            ${concatStringsSep ", " (
+              forEach utils.pathsNeededForBoot (i: "<filename>${i}</filename>")
+            )}.
+          '';
+        };
+      });
+    };
+
+  };
+
+  config = mkIf config.boot.initrd.enable {
+    assertions = [
+      { assertion = any (fs: fs.mountPoint == "/") fileSystems;
+        message = "The ‘fileSystems’ option does not specify your root file system.";
+      }
+      { assertion = let inherit (config.boot) resumeDevice; in
+          resumeDevice == "" || builtins.substring 0 1 resumeDevice == "/";
+        message = "boot.resumeDevice has to be an absolute path."
+          + " Old \"x:y\" style is no longer supported.";
+      }
+      # TODO: remove when #85000 is fixed
+      { assertion = !config.boot.loader.supportsInitrdSecrets ->
+          all (source:
+            builtins.isPath source ||
+            (builtins.isString source && hasPrefix builtins.storeDir source))
+          (attrValues config.boot.initrd.secrets);
+        message = ''
+          boot.loader.initrd.secrets values must be unquoted paths when
+          using a bootloader that doesn't natively support initrd
+          secrets, e.g.:
+
+            boot.initrd.secrets = {
+              "/etc/secret" = /path/to/secret;
+            };
+
+          Note that this will result in all secrets being stored
+          world-readable in the Nix store!
+        '';
+      }
+    ];
+
+    system.build =
+      { inherit bootStage1 initialRamdisk initialRamdiskSecretAppender extraUtils; };
+
+    system.requiredKernelConfig = with config.lib.kernelConfig; [
+      (isYes "TMPFS")
+      (isYes "BLK_DEV_INITRD")
+    ];
+
+    boot.initrd.supportedFilesystems = map (fs: fs.fsType) fileSystems;
+
+  };
+}