Add (gnu system vm).

* gnu/system/vm.scm: New file.
* Makefile.am (MODULES): Add it.

Makefile.am

@@ -160,7 +160,8 @@ MODULES =					\
   gnu/packages/which.scm			\
   gnu/packages/xml.scm				\
   gnu/packages/zile.scm				\
-  gnu/packages/zip.scm
+  gnu/packages/zip.scm				\
+  gnu/system/vm.scm
 
 
 GOBJECTS = $(MODULES:%.scm=%.go) guix/config.go

gnu/system/vm.scm

@@ -0,0 +1,263 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013 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 (gnu system vm)
+  #:use-module (guix store)
+  #:use-module (guix derivations)
+  #:use-module (guix packages)
+  #:use-module ((gnu packages base) #:select (%final-inputs guile-final))
+  #:use-module (gnu packages qemu)
+  #:use-module (gnu packages parted)
+  #:use-module (gnu packages grub)
+  #:use-module (gnu packages linux)
+  #:use-module (gnu packages linux-initrd)
+  #:use-module ((gnu packages make-bootstrap)
+                #:select (%guile-static-stripped))
+  #:use-module (srfi srfi-26)
+  #:use-module (ice-9 match)
+  #:export (expression->derivation-in-linux-vm
+            qemu-image))
+
+
+;;; Commentary:
+;;;
+;;; Tools to evaluate build expressions within virtual machines.
+;;;
+;;; Code:
+
+(define* (expression->derivation-in-linux-vm store name system exp inputs
+                                             #:key
+                                             (linux linux-libre)
+                                             (initrd qemu-initrd)
+                                             (qemu qemu-kvm/smb-shares)
+                                             (env-vars '())
+                                             (modules '())
+                                             (guile-for-build
+                                              (%guile-for-build))
+
+                                             (make-disk-image? #f)
+                                             (disk-image-size
+                                              (* 100 (expt 2 20))))
+  "Evaluate EXP in a QEMU virtual machine running LINUX with INITRD.  In the
+virtual machine, EXP has access to all of INPUTS from the store; it should put
+its output files in the `/xchg' directory, which is copied to the derivation's
+output when the VM terminates.
+
+When MAKE-DISK-IMAGE? is true, then create a QEMU disk image of
+DISK-IMAGE-SIZE bytes and return it."
+  (define input-alist
+    (map (match-lambda
+          ((input package)
+           `(,input . ,(package-output store package "out" system)))
+          ((input package sub-drv)
+           `(,input . ,(package-output store package sub-drv system))))
+         inputs))
+
+  (define exp*
+    ;; EXP, but with INPUTS available.
+    `(let ((%build-inputs ',input-alist))
+       ,exp))
+
+  (define builder
+    ;; Code that launches the VM that evaluates EXP.
+    `(begin
+       (use-modules (guix build utils))
+
+       (let ((out     (assoc-ref %outputs "out"))
+             (cu      (string-append (assoc-ref %build-inputs "coreutils")
+                                     "/bin"))
+             (qemu    (string-append (assoc-ref %build-inputs "qemu")
+                                     "/bin/qemu-system-"
+                                     (car (string-split ,system #\-))))
+             (img     (string-append (assoc-ref %build-inputs "qemu")
+                                     "/bin/qemu-img"))
+             (linux   (string-append (assoc-ref %build-inputs "linux")
+                                     "/bzImage"))
+             (initrd  (string-append (assoc-ref %build-inputs "initrd")
+                                     "/initrd"))
+             (builder (assoc-ref %build-inputs "builder")))
+
+         ;; XXX: QEMU uses "rm -rf" when it's done to remove the temporary SMB
+         ;; directory, so it really needs `rm' in $PATH.
+         (setenv "PATH" cu)
+
+         ,(if make-disk-image?
+              `(zero? (system* img "create" "image.qcow2"
+                               ,(number->string disk-image-size)))
+              '(begin))
+
+         (mkdir "xchg")
+         (and (zero?
+               (system* qemu "-nographic" "-no-reboot"
+                        "-net" "nic,model=e1000"
+                        "-net" (string-append "user,smb=" (getcwd))
+                        "-kernel" linux
+                        "-initrd" initrd
+                        "-append" (string-append "console=ttyS0 --load="
+                                                 builder)
+                        ,@(if make-disk-image?
+                              '("-hda" "image.qcow2")
+                              '())))
+              ,(if make-disk-image?
+                   '(copy-file "image.qcow2"      ; XXX: who mkdir'd OUT?
+                               out)
+                   '(begin
+                      (mkdir out)
+                      (copy-recursively "xchg" out)))))))
+
+  (let ((user-builder (add-text-to-store store "builder-in-linux-vm"
+                                         (object->string exp*)
+                                         '()))
+        (->drv        (cut package-derivation store <> system))
+        (coreutils    (car (assoc-ref %final-inputs "coreutils"))))
+    (build-expression->derivation store name system builder
+                                  `(("qemu" ,(->drv qemu))
+                                    ("linux" ,(->drv linux))
+                                    ("initrd" ,(->drv initrd))
+                                    ("coreutils" ,(->drv coreutils))
+                                    ("builder" ,user-builder)
+                                    ,@(map (match-lambda
+                                            ((name package sub-drv ...)
+                                             `(,name ,(->drv package)
+                                                     ,@sub-drv)))
+                                           inputs))
+                                  #:env-vars env-vars
+                                  #:modules `((guix build utils)
+                                              ,@modules)
+                                  #:guile-for-build guile-for-build)))
+
+(define* (qemu-image store #:key
+                     (name "qemu-image")
+                     (system (%current-system))
+                     (disk-image-size (* 100 (expt 2 20)))
+                     (linux linux-libre)
+                     (initrd qemu-initrd)
+                     (inputs '()))
+  "Return a bootable, stand-alone QEMU image."
+  (expression->derivation-in-linux-vm
+   store "qemu-image" system
+   `(let ((parted  (string-append (assoc-ref %build-inputs "parted")
+                                  "/sbin/parted"))
+          (mkfs    (string-append (assoc-ref %build-inputs "e2fsprogs")
+                                  "/sbin/mkfs.ext3"))
+          (grub    (string-append (assoc-ref %build-inputs "grub")
+                                  "/sbin/grub-install"))
+          (umount  (string-append (assoc-ref %build-inputs "util-linux")
+                                  "/bin/umount")) ; XXX: add to Guile
+          (initrd  (string-append (assoc-ref %build-inputs "initrd")
+                                  "/initrd"))
+          (linux   (string-append (assoc-ref %build-inputs "linux")
+                                  "/bzImage"))
+          (makedev (lambda (major minor)
+                     (+ (* major 256) minor))))
+
+      ;; GRUB is full of shell scripts.
+      (setenv "PATH"
+              (string-append (dirname grub) ":"
+                             (assoc-ref %build-inputs "coreutils") "/bin:"
+                             (assoc-ref %build-inputs "findutils") "/bin:"
+                             (assoc-ref %build-inputs "sed") "/bin:"
+                             (assoc-ref %build-inputs "grep") "/bin:"
+                             (assoc-ref %build-inputs "gawk") "/bin"))
+
+      (display "creating partition table...\n")
+      (mknod "/dev/vda" 'block-special #o644 (makedev 8 0))
+      (and (zero? (system* parted "/dev/vda" "mklabel" "msdos"
+                           "mkpart" "primary" "ext2" "1MiB"
+                           ,(format #f "~aB"
+                                    (- disk-image-size
+                                       (* 5 (expt 2 20))))))
+           (begin
+             (display "creating ext3 partition...\n")
+             (mknod "/dev/vda1" 'block-special #o644 (makedev 8 1))
+             (and (zero? (system* mkfs "-F" "/dev/vda1"))
+                  (begin
+                    (display "mounting partition...\n")
+                    (mkdir "/fs")
+                    (mount "/dev/vda1" "/fs" "ext3")
+                    (mkdir "/fs/boot")
+                    (mkdir "/fs/boot/grub")
+                    (copy-file linux "/fs/boot/bzImage")
+                    (copy-file initrd "/fs/boot/initrd")
+                    (call-with-output-file "/fs/boot/grub/grub.cfg"
+                      (lambda (p)
+                        (display "
+set timeout=10
+search.file /boot/bzImage
+
+menuentry \"Boot-to-Guile! Happy Birthday Guile 2.0! (Guile, Guix & co.)\" {
+  linux /boot/bzImage --repl
+  initrd /boot/initrd
+}" p)))
+                    (and (zero?
+                          (system* grub "--no-floppy"
+                                   "--boot-directory" "/fs/boot"
+                                   "/dev/vda"))
+                         (zero?
+                          (system* umount "/fs"))))))))
+   `(("parted" ,parted)
+     ("grub" ,grub)
+     ("e2fsprogs" ,e2fsprogs)
+     ("linux" ,linux-libre)
+     ("initrd" ,qemu-initrd)
+
+     ;; For shell scripts.
+     ("sed" ,(car (assoc-ref %final-inputs "sed")))
+     ("grep" ,(car (assoc-ref %final-inputs "grep")))
+     ("coreutils" ,(car (assoc-ref %final-inputs "coreutils")))
+     ("findutils" ,(car (assoc-ref %final-inputs "findutils")))
+     ("gawk" ,(car (assoc-ref %final-inputs "gawk")))
+     ("util-linux" ,util-linux))
+   #:make-disk-image? #t
+   #:disk-image-size disk-image-size))
+
+
+;;;
+;;; Guile 2.0 potluck examples.
+;;;
+
+(define (example1)
+  (let ((store #f))
+    (dynamic-wind
+      (lambda ()
+        (set! store (open-connection)))
+      (lambda ()
+        (parameterize ((%guile-for-build (package-derivation store guile-final)))
+          (expression->derivation-in-linux-vm
+           store "vm-test" (%current-system)
+           '(begin
+              (display "hello from boot!\n")
+              (call-with-output-file "/xchg/hello"
+                (lambda (p)
+                  (display "world" p))))
+           '())))
+      (lambda ()
+        (close-connection store)))))
+
+(define (example2)
+  (let ((store #f))
+    (dynamic-wind
+      (lambda ()
+        (set! store (open-connection)))
+      (lambda ()
+        (parameterize ((%guile-for-build (package-derivation store guile-final)))
+          (qemu-image store #:disk-image-size (* 30 (expt 2 20)))))
+      (lambda ()
+        (close-connection store)))))
+
+;;; vm.scm ends here