system: Add (guix build install) module.

* guix/build/vm.scm (install-grub, evaluate-populate-directive,
  reset-timestamps, register-closure): Move to...
* guix/build/install.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.
* gnu/system/vm.scm (expression->derivation-in-linux-vm): Add (guix
  build install) to #:modules.

Makefile.am

@@ -70,6 +70,7 @@ MODULES =					\
   guix/build/rpath.scm				\
   guix/build/svn.scm				\
   guix/build/vm.scm				\
+  guix/build/install.scm			\
   guix/build/activation.scm			\
   guix/build/syscalls.scm			\
   guix/packages.scm				\

gnu/system/vm.scm

@@ -109,6 +109,7 @@ input tuple.  The output file name is when building for SYSTEM."
                                              (env-vars '())
                                              (modules
                                               '((guix build vm)
+                                                (guix build install)
                                                 (guix build linux-initrd)
                                                 (guix build utils)))
                                              (guile-for-build
@@ -179,9 +180,7 @@ made available under the /xchg CIFS share."
                       ;; TODO: Require the "kvm" feature.
                       #:system system
                       #:env-vars env-vars
-                      #:modules `((guix build utils)
+                      #:modules modules
-                                  (guix build vm)
-                                  (guix build linux-initrd))
                       #:guile-for-build guile-for-build
                       #:references-graphs references-graphs)))
 

guix/build/install.scm

@@ -0,0 +1,82 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013, 2014 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix build install)
+  #:use-module (guix build utils)
+  #:use-module (guix build install)
+  #:use-module (ice-9 match)
+  #:export (install-grub
+            evaluate-populate-directive
+            reset-timestamps
+            register-closure))
+
+;;; Commentary:
+;;;
+;;; This module supports the installation of the GNU system on a hard disk.
+;;; It is meant to be used both in a build environment (in derivations that
+;;; build VM images), and on the bare metal (when really installing the
+;;; system.)
+;;;
+;;; Code:
+
+(define* (install-grub grub.cfg device mount-point)
+  "Install GRUB with GRUB.CFG on DEVICE, which is assumed to be mounted on
+MOUNT-POINT.  Return #t on success."
+  (mkdir-p (string-append mount-point "/boot/grub"))
+  (symlink grub.cfg (string-append mount-point "/boot/grub/grub.cfg"))
+  (zero? (system* "grub-install" "--no-floppy"
+                  "--boot-directory" (string-append mount-point "/boot")
+                  device)))
+
+(define (evaluate-populate-directive directive target)
+  "Evaluate DIRECTIVE, an sexp describing a file or directory to create under
+directory TARGET."
+  (match directive
+    (('directory name)
+     (mkdir-p (string-append target name)))
+    (('directory name uid gid)
+     (let ((dir (string-append target name)))
+       (mkdir-p dir)
+       (chown dir uid gid)))
+    ((new '-> old)
+     (symlink old (string-append target new)))))
+
+(define (reset-timestamps directory)
+  "Reset the timestamps of all the files under DIRECTORY, so that they appear
+as created and modified at the Epoch."
+  (display "clearing file timestamps...\n")
+  (for-each (lambda (file)
+              (let ((s (lstat file)))
+                ;; XXX: Guile uses libc's 'utime' function (not 'futime'), so
+                ;; the timestamp of symlinks cannot be changed, and there are
+                ;; symlinks here pointing to /gnu/store, which is the host,
+                ;; read-only store.
+                (unless (eq? (stat:type s) 'symlink)
+                  (utime file 0 0 0 0))))
+            (find-files directory "")))
+
+(define (register-closure store closure)
+  "Register CLOSURE in STORE, where STORE is the directory name of the target
+store and CLOSURE is the name of a file containing a reference graph as used
+by 'guix-register'."
+  (let ((status (system* "guix-register" "--prefix" store
+                         closure)))
+    (unless (zero? status)
+      (error "failed to register store items" closure))))
+
+;;; install.scm ends here

guix/build/vm.scm

@@ -19,6 +19,7 @@
 (define-module (guix build vm)
   #:use-module (guix build utils)
   #:use-module (guix build linux-initrd)
+  #:use-module (guix build install)
   #:use-module (ice-9 match)
   #:use-module (ice-9 rdelim)
   #:use-module (srfi srfi-1)
@@ -124,15 +125,6 @@ partition of PARTITION-SIZE MiB.  Return #t on success."
                   "mkpart" "primary" "ext2" "1MiB"
                   (format #f "~aB" partition-size))))
 
-(define* (install-grub grub.cfg device mount-point)
-  "Install GRUB with GRUB.CFG on DEVICE, which is assumed to be mounted on
-MOUNT-POINT.  Return #t on success."
-  (mkdir-p (string-append mount-point "/boot/grub"))
-  (symlink grub.cfg (string-append mount-point "/boot/grub/grub.cfg"))
-  (zero? (system* "grub-install" "--no-floppy"
-                  "--boot-directory" (string-append mount-point "/boot")
-                  device)))
-
 (define* (populate-store reference-graphs target)
   "Populate the store under directory TARGET with the items specified in
 REFERENCE-GRAPHS, a list of reference-graph files."
@@ -153,42 +145,6 @@ REFERENCE-GRAPHS, a list of reference-graph files."
                                 (string-append target thing)))
             (things-to-copy)))
 
-(define (evaluate-populate-directive directive target)
-  "Evaluate DIRECTIVE, an sexp describing a file or directory to create under
-directory TARGET."
-  (match directive
-    (('directory name)
-     (mkdir-p (string-append target name)))
-    (('directory name uid gid)
-     (let ((dir (string-append target name)))
-       (mkdir-p dir)
-       (chown dir uid gid)))
-    ((new '-> old)
-     (symlink old (string-append target new)))))
-
-(define (reset-timestamps directory)
-  "Reset the timestamps of all the files under DIRECTORY, so that they appear
-as created and modified at the Epoch."
-  (display "clearing file timestamps...\n")
-  (for-each (lambda (file)
-              (let ((s (lstat file)))
-                ;; XXX: Guile uses libc's 'utime' function (not 'futime'), so
-                ;; the timestamp of symlinks cannot be changed, and there are
-                ;; symlinks here pointing to /gnu/store, which is the host,
-                ;; read-only store.
-                (unless (eq? (stat:type s) 'symlink)
-                  (utime file 0 0 0 0))))
-            (find-files directory "")))
-
-(define (register-closure store closure)
-  "Register CLOSURE in STORE, where STORE is the directory name of the target
-store and CLOSURE is the name of a file containing a reference graph as used
-by 'guix-register'."
-  (let ((status (system* "guix-register" "--prefix" store
-                         closure)))
-    (unless (zero? status)
-      (error "failed to register store items" closure))))
-
 (define MS_BIND 4096)                             ; <sys/mounts.h> again!
 
 (define* (initialize-hard-disk #:key