* Show a splash screen during booting. The splash screen is displayed

by the program /sbin/splash_helper in the initrd and is called even
  before /init.
* make-initrd.nix: allow a list of FSOs to be placed in the initrd,
  with a symlink to each top-level FSO (e.g., /init,
  /sbin/splash_helper, /etc/splash).
* make-initrd.nix: pre-create /proc, /dev and /sys, because
  splash_helper needs them.

svn path=/nixu/trunk/; revision=7144

test/boot-environment.nix

@@ -28,6 +28,12 @@ rec {
   nix = pkgs.nixUnstable; # we need the exportReferencesGraph feature
 
 
+  # Splash configuration.
+  splashThemes = import ./splash-themes.nix {
+    inherit (pkgs) fetchurl;
+  };
+
+
   # Determine the set of modules that we need to mount the root FS.
   modulesClosure = import ./modules-closure.nix {
     inherit (pkgs) stdenv kernel module_init_tools;
@@ -45,10 +51,12 @@ rec {
       ensureDir $out/bin
       cp $utillinux/bin/mount $utillinux/bin/umount $utillinux/sbin/pivot_root $out/bin
       cp -p $e2fsprogs/sbin/fsck* $e2fsprogs/sbin/e2fsck $out/bin
+      cp $splashutils/bin/splash_helper $out/bin
       nuke-refs $out/bin/*
     ";
     buildInputs = [pkgs.nukeReferences];
     inherit (pkgsStatic) utillinux;
+    inherit (pkgs) splashutils;
     e2fsprogs = pkgs.e2fsprogsDiet;
   };
   
@@ -71,7 +79,21 @@ rec {
   # the initial RAM disk.
   initialRamdisk = import ./make-initrd.nix {
     inherit (pkgs) stdenv cpio;
-    init = bootStage1;
+    contents = [
+      { object = bootStage1;
+        symlink = "/init";
+      }
+      { object = extraUtils;
+        suffix = "/bin/splash_helper";
+        symlink = "/sbin/splash_helper";
+      }
+      { object = import ./helpers/unpack-theme.nix {
+          inherit (pkgs) stdenv;
+          theme = splashThemes.splashScreen;
+        };
+        symlink = "/etc/splash";
+      }
+    ];
   };
 
 
@@ -116,9 +138,7 @@ rec {
       # Transparent TTY backgrounds.
       (import ./upstart-jobs/tty-backgrounds.nix {
         inherit (pkgs) stdenv splashutils;
-        backgrounds = (import ./splash-themes.nix {
-          inherit (pkgs) fetchurl;
-        }).ttyBackgrounds;
+        backgrounds = splashThemes.ttyBackgrounds;
       })
 
       # Handles the maintenance/stalled event (single-user shell).

test/boot-stage-1-init.sh

@@ -24,11 +24,11 @@ done
 
 
 # Mount special file systems.
-mkdir /etc # to shut up mount
+mkdir -p /etc # to shut up mount
 touch /etc/fstab # idem
-mkdir /proc
+mkdir -p /proc
 mount -t proc none /proc
-mkdir /sys
+mkdir -p /sys
 mount -t sysfs none /sys
 
 

test/make-initrd.nix

@@ -1,5 +1,5 @@
 # Create an initial ramdisk containing the closure of the specified
-# `init' package.  An initial ramdisk is used during the initial
+# file system objects.  An initial ramdisk is used during the initial
 # stages of booting a Linux system.  It is loaded by the boot loader
 # along with the kernel image.  It's supposed to contain everything
 # (such as kernel modules) necessary to allow us to mount the root
@@ -8,18 +8,24 @@
 #
 # An initrd is really just a gzipped cpio archive.
 #
-# A symlink `/init' is made to the store path passed in the `init'
+# Symlinks are created for each top-level file system object.  E.g.,
+# `contents = {object = ...; symlink = /init;}' is a typical
 # argument.
 
-{stdenv, cpio, init}:
+{stdenv, cpio, contents}:
 
 stdenv.mkDerivation {
   name = "initrd";
   builder = ./make-initrd.sh;
   buildInputs = [cpio];
-  inherit init;
+
+  # !!! should use XML.
+  objects = map (x: x.object) contents;
+  symlinks = map (x: x.symlink) contents;
+  suffices = map (x: if x ? suffix then x.suffix else "none") contents;
   
-  # For obtaining the closure of `init'.
-  exportReferencesGraph = ["init-closure" init];
+  # For obtaining the closure of `contents'.
+  exportReferencesGraph =
+    map (x: [("closure-" + baseNameOf x.symlink) x.object]) contents;
   pathsFromGraph = ./paths-from-graph.sh;
 }

test/make-initrd.sh

@@ -2,20 +2,41 @@ source $stdenv/setup
 
 set -o pipefail
 
-# Get the paths in the closure of `init'.
-if ! test -e ./init-closure; then
-    echo 'Your Nix installation is too old! Upgrade to nix-0.11pre7038 or newer.'
-    exit 1
-fi
-storePaths=$($SHELL $pathsFromGraph ./init-closure)
+objects=($objects)
+symlinks=($symlinks)
+suffices=($suffices)
 
-# Paths in cpio archives *must* be relative, otherwise the kernel
-# won't unpack 'em.
 mkdir root
-cd root
-cp -prd --parents $storePaths .
+
+# Needed for splash_helper, which gets run before init.
+mkdir root/dev
+mkdir root/sys
+mkdir root/proc
+
+
+for ((n = 0; n < ${#objects[*]}; n++)); do
+    object=${objects[$n]}
+    symlink=${symlinks[$n]}
+    suffix=${suffices[$n]}
+    if test "$suffix" = none; then suffix=; fi
+
+    # Get the paths in the closure of `object'.
+    closure=closure-$(basename $symlink)
+    if ! test -e $closure; then
+        echo 'Your Nix installation is too old! Upgrade to nix-0.11pre7038 or newer.'
+        exit 1
+    fi
+    storePaths=$($SHELL $pathsFromGraph $closure)
+
+    # Paths in cpio archives *must* be relative, otherwise the kernel
+    # won't unpack 'em.
+    (cd root && cp -prd --parents $storePaths .)
+
+    mkdir -p $(dirname root/$symlink)
+    ln -s $object$suffix root/$symlink
+done
+    
 
 # Put the closure in a gzipped cpio archive.
 ensureDir $out
-ln -s $init init
-find * -print0 | cpio -ov -H newc --null | gzip -9 > $out/initrd
+(cd root && find * -print0 | cpio -ov -H newc --null | gzip -9 > $out/initrd)

test/splash-themes.nix

@@ -25,6 +25,11 @@ rec {
   };
 
 
+  # The splash screen.
+  
+  splashScreen = themeBabyTux;
+
+
   # The themes to use for each tty.  For each tty except the first
   # entry in the list, you can omit `theme' to get the same theme as
   # the first one.  If a tty does not appear, it doesn't get a