Split the initrd sshd support into a separate module

Also, drop boot.initrd.postEarlyDeviceCommands since preLVMCommands
should work fine.

nixos/modules/module-list.nix

@@ -460,10 +460,10 @@
   ./system/boot/coredump.nix
   ./system/boot/emergency-mode.nix
   ./system/boot/initrd-network.nix
+  ./system/boot/initrd-ssh.nix
   ./system/boot/kernel.nix
   ./system/boot/kexec.nix
   ./system/boot/loader/efi.nix
-  ./system/boot/loader/loader.nix
   ./system/boot/loader/generations-dir/generations-dir.nix
   ./system/boot/loader/generic-extlinux-compatible
   ./system/boot/loader/grub/grub.nix
@@ -471,15 +471,16 @@
   ./system/boot/loader/grub/memtest.nix
   ./system/boot/loader/gummiboot/gummiboot.nix
   ./system/boot/loader/init-script/init-script.nix
+  ./system/boot/loader/loader.nix
   ./system/boot/loader/raspberrypi/raspberrypi.nix
   ./system/boot/luksroot.nix
   ./system/boot/modprobe.nix
+  ./system/boot/networkd.nix
+  ./system/boot/resolved.nix
   ./system/boot/shutdown.nix
   ./system/boot/stage-1.nix
   ./system/boot/stage-2.nix
   ./system/boot/systemd.nix
-  ./system/boot/networkd.nix
-  ./system/boot/resolved.nix
   ./system/boot/timesyncd.nix
   ./system/boot/tmp.nix
   ./system/etc/etc.nix

nixos/modules/system/boot/initrd-network.nix

@@ -3,9 +3,11 @@
 with lib;
 
 let
+
   cfg = config.boot.initrd.network;
 
 in
+
 {
 
   options = {
@@ -21,75 +23,15 @@ in
       '';
     };
 
-    boot.initrd.network.ssh.enable = mkOption {
-      type = types.bool;
-      default = false;
+    boot.initrd.network.postCommands = mkOption {
+      default = "";
+      type = types.lines;
       description = ''
-        Start SSH service during initrd boot. It can be used to debug failing
-        boot on a remote server, enter pasphrase for an encrypted partition etc.
-        Service is killed when stage-1 boot is finished.
+        Shell commands to be executed after stage 1 of the
+        boot has initialised the network.
       '';
     };
 
-    boot.initrd.network.ssh.port = mkOption {
-      type = types.int;
-      default = 22;
-      description = ''
-        Port on which SSH initrd service should listen.
-      '';
-    };
-
-    boot.initrd.network.ssh.shell = mkOption {
-      type = types.str;
-      default = "/bin/ash";
-      description = ''
-        Login shell of the remote user. Can be used to limit actions user can do.
-      '';
-    };
-
-    boot.initrd.network.ssh.hostRSAKey = mkOption {
-      type = types.nullOr types.path;
-      default = null;
-      description = ''
-        RSA SSH private key file in the Dropbear format.
-
-        WARNING: This key is contained insecurely in the global Nix store. Do NOT
-        use your regular SSH host private keys for this purpose or you'll expose
-        them to regular users!
-      '';
-    };
-
-    boot.initrd.network.ssh.hostDSSKey = mkOption {
-      type = types.nullOr types.path;
-      default = null;
-      description = ''
-        DSS SSH private key file in the Dropbear format.
-
-        WARNING: This key is contained insecurely in the global Nix store. Do NOT
-        use your regular SSH host private keys for this purpose or you'll expose
-        them to regular users!
-      '';
-    };
-
-    boot.initrd.network.ssh.hostECDSAKey = mkOption {
-      type = types.nullOr types.path;
-      default = null;
-      description = ''
-        ECDSA SSH private key file in the Dropbear format.
-
-        WARNING: This key is contained insecurely in the global Nix store. Do NOT
-        use your regular SSH host private keys for this purpose or you'll expose
-        them to regular users!
-      '';
-    };
-
-    boot.initrd.network.ssh.authorizedKeys = mkOption {
-      type = types.listOf types.str;
-      default = config.users.extraUsers.root.openssh.authorizedKeys.keys;
-      description = ''
-        Authorized keys for the root user on initrd.
-      '';
-    };
 
   };
 
@@ -99,17 +41,9 @@ in
 
     boot.initrd.extraUtilsCommands = ''
       copy_bin_and_libs ${pkgs.mkinitcpio-nfs-utils}/bin/ipconfig
-    '' + optionalString cfg.ssh.enable ''
-      copy_bin_and_libs ${pkgs.dropbear}/bin/dropbear
-
-      cp -pv ${pkgs.glibc}/lib/libnss_files.so.* $out/lib
     '';
 
-    boot.initrd.extraUtilsCommandsTest = optionalString cfg.ssh.enable ''
-      $out/bin/dropbear -V
-    '';
-
-    boot.initrd.postEarlyDeviceCommands = ''
+    boot.initrd.preLVMCommands = ''
       # Search for interface definitions in command line
       for o in $(cat /proc/cmdline); do
         case $o in
@@ -118,32 +52,10 @@ in
             ;;
         esac
       done
-    '' + optionalString cfg.ssh.enable ''
-      if [ -n "$hasNetwork" ]; then
-        mkdir /dev/pts
-        mount -t devpts devpts /dev/pts
 
-        mkdir -p /etc
-        echo 'root:x:0:0:root:/root:${cfg.ssh.shell}' > /etc/passwd
-        echo '${cfg.ssh.shell}' > /etc/shells
-        echo 'passwd: files' > /etc/nsswitch.conf
-
-        mkdir -p /var/log
-        touch /var/log/lastlog
-
-        mkdir -p /etc/dropbear
-        ${optionalString (cfg.ssh.hostRSAKey != null) "ln -s ${cfg.ssh.hostRSAKey} /etc/dropbear/dropbear_rsa_host_key"}
-        ${optionalString (cfg.ssh.hostDSSKey != null) "ln -s ${cfg.ssh.hostDSSKey} /etc/dropbear/dropbear_dss_host_key"}
-        ${optionalString (cfg.ssh.hostECDSAKey != null) "ln -s ${cfg.ssh.hostECDSAKey} /etc/dropbear/dropbear_ecdsa_host_key"}
-
-        mkdir -p /root/.ssh
-        ${concatStrings (map (key: ''
-          echo -n ${escapeShellArg key} >> /root/.ssh/authorized_keys
-        '') cfg.ssh.authorizedKeys)}
-
-        dropbear -s -j -k -E -m -p ${toString cfg.ssh.port}
-      fi
+      ${cfg.postCommands}
     '';
 
   };
+
 }

nixos/modules/system/boot/initrd-ssh.nix

@@ -0,0 +1,124 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.boot.initrd.network.ssh;
+
+in
+
+{
+
+  options = {
+
+    boot.initrd.network.ssh.enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Start SSH service during initrd boot. It can be used to debug failing
+        boot on a remote server, enter pasphrase for an encrypted partition etc.
+        Service is killed when stage-1 boot is finished.
+      '';
+    };
+
+    boot.initrd.network.ssh.port = mkOption {
+      type = types.int;
+      default = 22;
+      description = ''
+        Port on which SSH initrd service should listen.
+      '';
+    };
+
+    boot.initrd.network.ssh.shell = mkOption {
+      type = types.str;
+      default = "/bin/ash";
+      description = ''
+        Login shell of the remote user. Can be used to limit actions user can do.
+      '';
+    };
+
+    boot.initrd.network.ssh.hostRSAKey = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      description = ''
+        RSA SSH private key file in the Dropbear format.
+
+        WARNING: This key is contained insecurely in the global Nix store. Do NOT
+        use your regular SSH host private keys for this purpose or you'll expose
+        them to regular users!
+      '';
+    };
+
+    boot.initrd.network.ssh.hostDSSKey = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      description = ''
+        DSS SSH private key file in the Dropbear format.
+
+        WARNING: This key is contained insecurely in the global Nix store. Do NOT
+        use your regular SSH host private keys for this purpose or you'll expose
+        them to regular users!
+      '';
+    };
+
+    boot.initrd.network.ssh.hostECDSAKey = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      description = ''
+        ECDSA SSH private key file in the Dropbear format.
+
+        WARNING: This key is contained insecurely in the global Nix store. Do NOT
+        use your regular SSH host private keys for this purpose or you'll expose
+        them to regular users!
+      '';
+    };
+
+    boot.initrd.network.ssh.authorizedKeys = mkOption {
+      type = types.listOf types.str;
+      default = config.users.extraUsers.root.openssh.authorizedKeys.keys;
+      description = ''
+        Authorized keys for the root user on initrd.
+      '';
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    boot.initrd.extraUtilsCommands = ''
+      copy_bin_and_libs ${pkgs.dropbear}/bin/dropbear
+      cp -pv ${pkgs.glibc}/lib/libnss_files.so.* $out/lib
+    '';
+
+    boot.initrd.extraUtilsCommandsTest = ''
+      $out/bin/dropbear -V
+    '';
+
+    boot.initrd.network.postCommands = ''
+      if [ -n "$hasNetwork" ]; then
+        mkdir /dev/pts
+        mount -t devpts devpts /dev/pts
+
+        echo '${cfg.shell}' > /etc/shells
+
+        mkdir -p /var/log
+        touch /var/log/lastlog
+
+        mkdir -p /etc/dropbear
+        ${optionalString (cfg.hostRSAKey != null) "ln -s ${cfg.hostRSAKey} /etc/dropbear/dropbear_rsa_host_key"}
+        ${optionalString (cfg.hostDSSKey != null) "ln -s ${cfg.hostDSSKey} /etc/dropbear/dropbear_dss_host_key"}
+        ${optionalString (cfg.hostECDSAKey != null) "ln -s ${cfg.hostECDSAKey} /etc/dropbear/dropbear_ecdsa_host_key"}
+
+        mkdir -p /root/.ssh
+        ${concatStrings (map (key: ''
+          echo -n ${escapeShellArg key} >> /root/.ssh/authorized_keys
+        '') cfg.authorizedKeys)}
+
+        dropbear -s -j -k -E -m -p ${toString cfg.port}
+      fi
+    '';
+
+  };
+
+}

nixos/modules/system/boot/stage-1-init.sh

@@ -72,6 +72,11 @@ mkdir -p /run
 mount -t tmpfs -o "mode=0755,size=@runSize@" tmpfs /run
 
 
+# Initialise /etc.
+echo 'root:x:0:0:root:/root:${cfg.shell}' > /etc/passwd
+echo 'passwd: files' > /etc/nsswitch.conf
+
+
 # Process the kernel command line.
 export stage2Init=/init
 for o in $(cat /proc/cmdline); do
@@ -150,10 +155,6 @@ udevadm trigger --action=add
 udevadm settle
 
 
-# Additional devices initialization.
-@postEarlyDeviceCommands@
-
-
 # Load boot-time keymap before any LVM/LUKS initialization
 @extraUtils@/bin/busybox loadkmap < "@busyboxKeymap@"
 

nixos/modules/system/boot/stage-1.nix

@@ -199,7 +199,7 @@ let
     inherit (config.boot) resumeDevice devSize runSize;
 
     inherit (config.boot.initrd) checkJournalingFS
-      preLVMCommands preDeviceCommands postEarlyDeviceCommands postDeviceCommands postMountCommands kernelModules;
+      preLVMCommands preDeviceCommands postDeviceCommands postMountCommands kernelModules;
 
     resumeDevices = map (sd: if sd ? device then sd.device else "/dev/disk/by-label/${sd.label}")
                     (filter (sd: (sd ? label || hasPrefix "/dev/" sd.device) && !sd.randomEncryption) config.swapDevices);
@@ -318,14 +318,6 @@ in
       '';
     };
 
-    boot.initrd.postEarlyDeviceCommands = mkOption {
-      default = "";
-      type = types.lines;
-      description = ''
-        Shell commands to be executed early after creation of device nodes.
-      '';
-    };
-
     boot.initrd.postMountCommands = mkOption {
       default = "";
       type = types.lines;