1 files changed, 43 insertions, 0 deletions
diff --git a/nixos/modules/installer/cd-dvd/channel.nix b/nixos/modules/installer/cd-dvd/channel.nix
new file mode 100644
index 00000000000..8126ce46dd9
--- /dev/null
+++ b/nixos/modules/installer/cd-dvd/channel.nix
@@ -0,0 +1,43 @@
+# Provide an initial copy of the NixOS channel so that the user
+# doesn't need to run "nix-channel --update" first.
+
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  # We need a copy of the Nix expressions for Nixpkgs and NixOS on the
+  # CD.  These are installed into the "nixos" channel of the root
+  # user, as expected by nixos-rebuild/nixos-install.
+  channelSources = pkgs.runCommand "nixos-${config.system.nixosVersion}"
+    { expr = builtins.readFile ../../../lib/channel-expr.nix; }
+    ''
+      mkdir -p $out/nixos
+      cp -prd ${cleanSource ../../..} $out/nixos/nixos
+      cp -prd ${cleanSource <nixpkgs>} $out/nixos/nixpkgs
+      chmod -R u+w $out/nixos/nixos
+      echo -n ${config.system.nixosVersion} > $out/nixos/nixos/.version
+      echo -n "" > $out/nixos/nixos/.version-suffix
+      echo "$expr" > $out/nixos/default.nix
+    '';
+
+in
+
+{
+  # Provide the NixOS/Nixpkgs sources in /etc/nixos.  This is required
+  # for nixos-install.
+  boot.postBootCommands =
+    ''
+      if ! [ -e /var/lib/nixos/did-channel-init ]; then
+        echo "unpacking the NixOS/Nixpkgs sources..."
+        mkdir -p /nix/var/nix/profiles/per-user/root
+        ${config.environment.nix}/bin/nix-env -p /nix/var/nix/profiles/per-user/root/channels \
+          -i ${channelSources} --quiet --option use-substitutes false
+        mkdir -m 0700 -p /root/.nix-defexpr
+        ln -s /nix/var/nix/profiles/per-user/root/channels /root/.nix-defexpr/channels
+        mkdir -m 0755 -p /var/lib/nixos
+        touch /var/lib/nixos/did-channel-init
+      fi
+    '';
+}