Add nix installer.

Add self extracting nix installer.

default.nix

@@ -6,6 +6,7 @@ let
 
   makeself = callPackage ./makeself.nix {};
   makedir = callPackage ./makedir.nix {};
+  nix-installer = callPackage ./nix-installer.nix {};
 
   makebootstrap = callPackage ./makebootstrap.nix {
     inherit makedir makeself;
@@ -28,4 +29,9 @@ in {
     run = "/stage1.sh";
   };
 
+  nixInstaller = makebootstrap {
+    name = "nix-installer.sh";
+    target = nix-installer;
+    run = "/install";
+  };
 }

install-nix-from-closure.sh

@@ -0,0 +1,128 @@
+#!/bin/sh
+
+set -e
+
+dest="/nix"
+self="."
+nix="@nix@"
+cacert="@cacert@"
+
+if ! [ -e $self/.reginfo ]; then
+    echo "$0: incomplete installer (.reginfo is missing)" >&2
+    exit 1
+fi
+
+if [ -z "$USER" ]; then
+    echo "$0: \$USER is not set" >&2
+    exit 1
+fi
+
+if [ "$(id -u)" -eq 0 ]; then
+    printf '\e[1;31mwarning: installing Nix as root is not supported by this script!\e[0m\n'
+fi
+
+echo "performing a single-user installation of Nix..." >&2
+
+if ! [ -e $dest ]; then
+    cmd="mkdir -m 0755 $dest && chown $USER $dest"
+    echo "directory $dest does not exist; creating it by running '$cmd' using sudo" >&2
+    if ! sudo sh -c "$cmd"; then
+        echo "$0: please manually run ‘$cmd’ as root to create $dest" >&2
+        exit 1
+    fi
+fi
+
+if ! [ -w $dest ]; then
+    echo "$0: directory $dest exists, but is not writable by you. This could indicate that another user has already performed a single-user installation of Nix on this system. If you wish to enable multi-user support see http://nixos.org/nix/manual/#ssec-multi-user. If you wish to continue with a single-user install for $USER please run ‘chown -R $USER $dest’ as root." >&2
+    exit 1
+fi
+
+mkdir -p $dest/store
+
+echo -n "copying Nix to $dest/store..." >&2
+
+for i in $(cd $self/store >/dev/null && echo *); do
+    echo -n "." >&2
+    i_tmp="$dest/store/$i.$$"
+    if [ -e "$i_tmp" ]; then
+        rm -rf "$i_tmp"
+    fi
+    if ! [ -e "$dest/store/$i" ]; then
+        cp -Rp "$self/store/$i" "$i_tmp"
+        chmod -R a-w "$i_tmp"
+        chmod +w "$i_tmp"
+        mv "$i_tmp" "$dest/store/$i"
+        chmod -w "$dest/store/$i"
+    fi
+done
+echo "" >&2
+
+echo "initialising Nix database..." >&2
+if ! $nix/bin/nix-store --init; then
+    echo "$0: failed to initialize the Nix database" >&2
+    exit 1
+fi
+
+if ! $nix/bin/nix-store --load-db < $self/.reginfo; then
+    echo "$0: unable to register valid paths" >&2
+    exit 1
+fi
+
+. $nix/etc/profile.d/nix.sh
+
+if ! $nix/bin/nix-env -i "$nix"; then
+    echo "$0: unable to install Nix into your default profile" >&2
+    exit 1
+fi
+
+# Install an SSL certificate bundle.
+if [ -z "$SSL_CERT_FILE" -o ! -f "$SSL_CERT_FILE" ]; then
+    $nix/bin/nix-env -i "$cacert"
+    export SSL_CERT_FILE="$HOME/.nix-profile/etc/ssl/certs/ca-bundle.crt"
+fi
+
+# Subscribe the user to the Nixpkgs channel and fetch it.
+if ! $nix/bin/nix-channel --list | grep -q "^nixpkgs "; then
+    $nix/bin/nix-channel --add https://nixos.org/channels/nixpkgs-unstable
+fi
+if [ -z "$_NIX_INSTALLER_TEST" ]; then
+    $nix/bin/nix-channel --update nixpkgs
+fi
+
+# Make the shell source nix.sh during login.
+p=$HOME/.nix-profile/etc/profile.d/nix.sh
+
+added=
+for i in .bash_profile .bash_login .profile; do
+    fn="$HOME/$i"
+    if [ -w "$fn" ]; then
+        if ! grep -q "$p" "$fn"; then
+            echo "modifying $fn..." >&2
+            echo "if [ -e $p ]; then . $p; fi # added by Nix installer" >> $fn
+        fi
+        added=1
+        break
+    fi
+done
+
+if [ -z "$added" ]; then
+    cat >&2 <<EOF
+
+Installation finished!  To ensure that the necessary environment
+variables are set, please add the line
+
+  . $p
+
+to your shell profile (e.g. ~/.profile).
+EOF
+else
+    cat >&2 <<EOF
+
+Installation finished!  To ensure that the necessary environment
+variables are set, either log in again, or type
+
+  . $p
+
+in your shell.
+EOF
+fi

nix-installer.nix

@@ -1,21 +1,15 @@
 { stdenv, fetchFromGitHub, writeText, nix, cacert }:
 
-let
-
-  run-from-closure = writeText "run-from-closure" (builtins.readFile ./run-from-closure.sh);
-
-in
-
   stdenv.mkDerivation {
-    name = "nix-bootstrap";
+    name = "nix-installer";
 
-    propagatedBuildInputs = [ nix cacert ];
+    propagatedBuildInputs = [ nix.out cacert ];
 
     buildCommand = ''
       mkdir -p $out/bin/
-      substitute ${run-from-closure} $out/bin/run-from-closure \
+      substitute ${./install-nix-from-closure.sh} $out/install \
         --subst-var-by nix ${nix.out} \
         --subst-var-by cacert ${cacert}
-      chmod +x $out/bin/run-from-closure
+      chmod +x $out/install
     '';
   }