Add --install option for nixos-option which is used to handle options of

the target system (when installing) and also to generate a template
configuration file for users.

svn path=/nixos/trunk/; revision=23923

modules/installer/tools/nixos-option.sh

@@ -2,15 +2,17 @@
 
 # Allow the location of NixOS sources and the system configuration
 # file to be overridden.
+
+: ${mountPoint=/mnt}
 : ${NIXOS_PATH=/etc/nixos/nixos}
-: ${NIXOS=/etc/nixos/nixos}
-: ${NIXPKGS=/etc/nixos/nixpkgs}
 : ${NIXOS_CONFIG=/etc/nixos/configuration.nix}
+: ${NIXPKGS=/etc/nixos/nixpkgs}
 export NIXOS_PATH
 
 usage () {
   echo 1>&2 "
-Usage: $0 OPTION_NAME [-v] [-d] [-l]
+Usage: $0 [--install] [-v] [-d] [-l] OPTION_NAME
+       $0 [--install]
 
 This program is used to explore NixOS options by looking at their values or
 by looking at their description.  It is helpful for understanding the how
@@ -18,6 +20,11 @@ your configuration is working.
 
 Options:
 
+  -i | --install        Use the configuration on
+                        ${mountPoint:+$mountPoint/}$NIXOS_CONFIG instead of
+                        the current system configuration.  Generate a
+                        template configuration if no option name is
+                        specified.
   -v | --value          Display the current value, based on your
                         configuration.
   -d | --default        Display the default value, the example and the
@@ -26,8 +33,9 @@ Options:
                         is declared.
   --help                Show this message.
 
-Environment variables affecting nixos-option:
+Environment variables affecting $0:
 
+  \$mountPoint          Path to the target file system.
   \$NIXOS_PATH          Path where the NixOS repository is located.
   \$NIXOS_CONFIG        Path to your configuration file.
   \$NIXPKGS             Path to Nix packages.
@@ -44,6 +52,7 @@ Environment variables affecting nixos-option:
 desc=false
 defs=false
 value=false
+install=false
 verbose=false
 
 option=""
@@ -52,18 +61,39 @@ argfun=""
 for arg; do
   if test -z "$argfun"; then
     case $arg in
-      -d|--description) desc=true;;
+      -*)
-      -v|--value) value=true;;
+        longarg=""
-      -l|--lookup) defs=true;;
+        sarg="$arg"
+        while test "$sarg" != "-"; do
+          case $sarg in
+            --*) longarg=$arg;;
+            -d*) longarg="$longarg --description";;
+            -v*) longarg="$longarg --value";;
+            -l*) longarg="$longarg --lookup";;
+            -i*) longarg="$longarg --install";;
+            -*) usage;;
+          esac
+          sarg="-${sarg#??}"
+        done
+        ;;
+      *) longarg=$arg;;
+    esac
+    for larg in $longarg; do
+      case $larg in
+        --description) desc=true;;
+        --value) value=true;;
+        --lookup) defs=true;;
+        --install) install=true;;
         --verbose) verbose=true;;
         --help) usage;;
         -*) usage;;
         *) if test -z "$option"; then
-           option="$arg"
+             option="$larg"
            else
              usage
            fi;;
       esac
+    done
   else
     case $argfun in
       set_*)
@@ -75,6 +105,16 @@ for arg; do
   fi
 done
 
+# --install cannot be used with -d -v -l without option name.
+if $value || $desc || $defs && $install && test -z "$option"; then
+  usage
+fi
+
+generate=false
+if ! $defs && ! $desc && ! $value && $install && test -z "$option"; then
+  generate=true
+fi
+
 if ! $defs && ! $desc; then
   value=true
 fi
@@ -111,7 +151,130 @@ findSources(){
     nix-instantiate - --eval-only --strict
 }
 
+if $install; then
+  if test -e "$mountPoint$NIXOS_PATH"; then
+    export NIXOS_PATH="$mountPoint$NIXOS_PATH"
+  fi
+  if test -e "$mountPoint$NIXPKGS"; then
+    export NIXPKGS="$mountPoint$NIXPKGS"
+  fi
+  export NIXOS_CONFIG="$mountPoint$NIXOS_CONFIG"
+fi
 
+if $generate; then
+  mkdir -p $(dirname "$NIXOS_CONFIG")
+
+  # Scan the hardware and add the result to /etc/nixos/hardware-scan.nix.
+  hardware_config="${NIXOS_CONFIG%/configuration.nix}/hardware-configuration.nix"
+  if test -e "$hardware_config"; then
+    echo "A hardware configuration file exists, generation skipped."
+  else
+    echo "Scan your hardware to generate a hardware configuration file."
+    nixos-hardware-scan > "$hardware_config"
+  fi
+
+  if test -e "$NIXOS_CONFIG"; then
+    echo 1>&2 "error: Cannot generate a template configuration because a configuration file exists."
+    exit 1
+  fi
+
+  echo "Generate a template configuration that you should edit."
+
+  # Generate a template configuration file where the user has to
+  # fill the gaps.
+  echo > "$NIXOS_CONFIG" \
+'# Edit this configuration file which defines what would be installed on the
+# system.  To Help while choosing option value, you can watch at the manual
+# page of configuration.nix or at the last chapter of the manual available
+# on the virtual console 8 (Alt+F8).
+
+{config, pkgs, ...}:
+
+{
+  require = [
+    # Include the configuration for part of your system which have been
+    # detected automatically.  In addition, it includes the same
+    # configuration as the installation device that you used.
+    ./hardware-configuration.nix
+  ];
+
+  boot.initrd.kernelModules = [
+    # Specify all kernel modules that are necessary for mounting the root
+    # file system.
+    #
+    # "ext4" "ata_piix"
+  ];
+
+  boot.loader.grub = {
+    # Use grub 2 as boot loader.
+    enable = true;
+    version = 2;
+
+    # Define on which hard drive you want to install Grub.
+    # device = "/dev/sda";
+  };
+
+  networking = {
+    # hostName = "nixos"; # Define your hostname.
+    interfaceMonitor.enable = true; # Watch for plugged cable.
+    enableWLAN = true;  # Enables Wireless.
+  };
+
+  # Add file system entries for each partition that you want to see mounted
+  # at boot time.  You can add filesystems which are not mounted at boot by
+  # adding the noauto option.
+  fileSystems = [
+    # Mount the root file system
+    #
+    # { mountPoint = "/";
+    #   device = "/dev/sda2";
+    # }
+
+    # Copy & Paste & Uncomment & Modify to add any other file system.
+    #
+    # { mountPoint = "/data"; # where you want to mount the device
+    #   device = "/dev/sdb"; # the device or the label of the device
+    #   # label = "data";
+    #   fsType = "ext3";      # the type of the partition.
+    #   options = "data=journal";
+    # }
+  ];
+
+  swapDevices = [
+    # List swap partitions that are mounted at boot time.
+    #
+    # { device = "/dev/sda1"; }
+  ];
+
+  # Select internationalisation properties.
+  # i18n = {
+  #   consoleFont = "lat9w-16";
+  #   consoleKeyMap = "us";
+  #   defaultLocale = "en_US.UTF-8";
+  # };
+
+  # List services that you want to enable:
+
+  # Add an OpenSSH daemon.
+  # services.openssh.enable = true;
+
+  # Add CUPS to print documents.
+  # services.printing.enable = true;
+
+  # Add XServer (default if you have used a graphical iso)
+  # service.xserver = {
+  #   enable = true;
+  #   layout = "us";
+  #   xkbOptions = "eurosign:e";
+  # };
+
+  # Add the NixOS Manual on virtual console 8
+  services.nixosManual.showManual = true;
+}
+'
+
+  exit 0
+fi;
 
 if test "$(evalOpt "_type" 2> /dev/null)" = '"option"'; then
   $value && evalCfg;