guix/gnu/system/vm.scm

;;; 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 (gnu system vm)
  #:use-module (guix config)
  #:use-module (guix store)
  #:use-module (guix gexp)
  #:use-module (guix derivations)
  #:use-module (guix packages)
  #:use-module (guix monads)
  #:use-module ((gnu packages base)
                #:select (%final-inputs))
  #:use-module (gnu packages guile)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages less)
  #:use-module (gnu packages qemu)
  #:use-module (gnu packages parted)
  #:use-module (gnu packages zile)
  #:use-module (gnu packages grub)
  #:use-module (gnu packages linux)
  #:use-module (gnu packages package-management)
  #:use-module ((gnu packages make-bootstrap)
                #:select (%guile-static-stripped))
  #:use-module (gnu packages admin)

  #:use-module (gnu system shadow)
  #:use-module (gnu system linux)
  #:use-module (gnu system linux-initrd)
  #:use-module (gnu system grub)
  #:use-module (gnu system)
  #:use-module (gnu services)

  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (ice-9 match)

  #:export (expression->derivation-in-linux-vm
            qemu-image
            system-qemu-image
            system-qemu-image/shared-store
            system-qemu-image/shared-store-script))


;;; Commentary:
;;;
;;; Tools to evaluate build expressions within virtual machines.
;;;
;;; Code:

(define* (input->name+output tuple #:key (system (%current-system)))
  "Return as a monadic value a name/file-name pair corresponding to TUPLE, an
input tuple.  The output file name is when building for SYSTEM."
  (with-monad %store-monad
    (match tuple
      ((input (? package? package))
       (mlet %store-monad ((out (package-file package #:system system)))
         (return `(,input . ,out))))
      ((input (? package? package) sub-drv)
       (mlet %store-monad ((out (package-file package
                                              #:output sub-drv
                                              #:system system)))
         (return `(,input . ,out))))
      ((input (? derivation? drv))
       (return `(,input . ,(derivation->output-path drv))))
      ((input (? derivation? drv) sub-drv)
       (return `(,input . ,(derivation->output-path drv sub-drv))))
      ((input (and (? string?) (? store-path?) file))
       (return `(,input . ,file))))))

;; An alias to circumvent name clashes.
(define %imported-modules imported-modules)

(define* (expression->derivation-in-linux-vm name exp
                                             #:key
                                             (system (%current-system))
                                             (inputs '())
                                             (linux linux-libre)
                                             initrd
                                             (qemu qemu-headless)
                                             (env-vars '())
                                             (imported-modules
                                              '((guix build vm)
                                                (guix build linux-initrd)
                                                (guix build utils)))
                                             (guile-for-build
                                              (%guile-for-build))

                                             (make-disk-image? #f)
                                             (references-graphs #f)
                                             (memory-size 256)
                                             (disk-image-size
                                              (* 100 (expt 2 20))))
  "Evaluate EXP in a QEMU virtual machine running LINUX with INITRD (a
derivation).  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.  The virtual machine
runs with MEMORY-SIZE MiB of memory.

When MAKE-DISK-IMAGE? is true, then create a QEMU disk image of
DISK-IMAGE-SIZE bytes and return it.

IMPORTED-MODULES is the set of modules imported in the execution environment
of EXP.

When REFERENCES-GRAPHS is true, it must be a list of file name/store path
pairs, as for `derivation'.  The files containing the reference graphs are
made available under the /xchg CIFS share."
  ;; FIXME: Add #:modules parameter, for the 'use-modules' form.

  (define input-alist
    (map input->name+output inputs))

  (define builder
    ;; Code that launches the VM that evaluates EXP.
    `(let ()
       (use-modules (guix build utils)
                    (guix build vm))

       (let ((linux   (string-append (assoc-ref %build-inputs "linux")
                                     "/bzImage"))
             (initrd  (string-append (assoc-ref %build-inputs "initrd")
                                     "/initrd"))
             (loader  (assoc-ref %build-inputs "loader"))
             (graphs  ',(match references-graphs
                          (((graph-files . _) ...) graph-files)
                          (_ #f))))

         (set-path-environment-variable "PATH" '("bin")
                                        (map cdr %build-inputs))

         (load-in-linux-vm loader
                           #:output (assoc-ref %outputs "out")
                           #:linux linux #:initrd initrd
                           #:memory-size ,memory-size
                           #:make-disk-image? ,make-disk-image?
                           #:disk-image-size ,disk-image-size
                           #:references-graphs graphs))))

  (mlet* %store-monad
      ((input-alist  (sequence %store-monad input-alist))
       (module-dir   (%imported-modules imported-modules))
       (compiled     (compiled-modules imported-modules))
       (exp* ->      `(let ((%build-inputs ',input-alist))
                        ,exp))
       (user-builder (text-file "builder-in-linux-vm"
                                (object->string exp*)))
       (loader       (gexp->file "linux-vm-loader"
                                 #~(begin
                                     (set! %load-path
                                           (cons #$module-dir %load-path))
                                     (set! %load-compiled-path
                                           (cons #$compiled
                                                 %load-compiled-path))
                                     (primitive-load #$user-builder))))
       (coreutils -> (car (assoc-ref %final-inputs "coreutils")))
       (initrd       (if initrd                   ; use the default initrd?
                         (return initrd)
                         (qemu-initrd #:guile-modules-in-chroot? #t
                                      #:mounts `((9p "store" ,(%store-prefix))
                                                 (9p "xchg" "/xchg")))))
       (inputs       (lower-inputs `(("qemu" ,qemu)
                                     ("linux" ,linux)
                                     ("initrd" ,initrd)
                                     ("coreutils" ,coreutils)
                                     ("builder" ,user-builder)
                                     ("loader" ,loader)
                                     ,@inputs))))
    (derivation-expression name builder
                           ;; TODO: Require the "kvm" feature.
                           #:system system
                           #:inputs inputs
                           #:env-vars env-vars
                           #:modules (delete-duplicates
                                      `((guix build utils)
                                        (guix build vm)
                                        (guix build linux-initrd)
                                        ,@imported-modules))
                           #:guile-for-build guile-for-build
                           #:references-graphs references-graphs)))

(define* (qemu-image #:key
                     (name "qemu-image")
                     (system (%current-system))
                     (disk-image-size (* 100 (expt 2 20)))
                     grub-configuration
                     (initialize-store? #f)
                     (populate #f)
                     (inputs '())
                     (inputs-to-copy '()))
  "Return a bootable, stand-alone QEMU image.  The returned image is a full
disk image, with a GRUB installation that uses GRUB-CONFIGURATION as its
configuration file (GRUB-CONFIGURATION must be the name of a file in the VM.)

INPUTS-TO-COPY is a list of inputs (as for packages) whose closure is copied
into the image being built.  When INITIALIZE-STORE? is true, initialize the
store database in the image so that Guix can be used in the image.

POPULATE is a list of directives stating directories or symlinks to be created
in the disk image partition.  It is evaluated once the image has been
populated with INPUTS-TO-COPY.  It can be used to provide additional files,
such as /etc files."
  (mlet %store-monad
      ((graph (sequence %store-monad
                        (map input->name+output inputs-to-copy))))
   (expression->derivation-in-linux-vm
    "qemu-image"
    `(let ()
       (use-modules (guix build vm)
                    (guix build utils))

       (set-path-environment-variable "PATH" '("bin" "sbin")
                                      (map cdr %build-inputs))

       (let ((graphs ',(match inputs-to-copy
                         (((names . _) ...)
                          names))))
         (initialize-hard-disk #:grub.cfg ,grub-configuration
                               #:closures-to-copy graphs
                               #:disk-image-size ,disk-image-size
                               #:initialize-store? ,initialize-store?
                               #:directives ',populate)
         (reboot)))
    #:system system
    #:inputs `(("parted" ,parted)
               ("grub" ,grub)
               ("e2fsprogs" ,e2fsprogs)

               ;; 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)

               ,@(if initialize-store?
                     `(("guix" ,guix))
                     '())

               ,@inputs-to-copy)
    #:make-disk-image? #t
    #:disk-image-size disk-image-size
    #:references-graphs graph)))


;;;
;;; Stand-alone VM image.
;;;

(define (operating-system-build-gid os)
  "Return as a monadic value the group id for build users of OS, or #f."
  (anym %store-monad
        (lambda (service)
          (and (equal? '(guix-daemon)
                       (service-provision service))
               (match (service-user-groups service)
                 ((group)
                  (user-group-id group)))))
        (operating-system-services os)))

(define (operating-system-default-contents os)
  "Return a list of directives suitable for 'system-qemu-image' describing the
basic contents of the root file system of OS."
  (define (user-directories user)
    (let ((home (user-account-home-directory user))
          ;; XXX: Deal with automatically allocated ids.
          (uid  (or (user-account-uid user) 0))
          (gid  (or (user-account-gid user) 0))
          (root (string-append "/var/guix/profiles/per-user/"
                               (user-account-name user))))
      `((directory ,root ,uid ,gid)
        (directory ,home ,uid ,gid))))

  (mlet* %store-monad ((os-drv    (operating-system-derivation os))
                       (os-dir -> (derivation->output-path os-drv))
                       (build-gid (operating-system-build-gid os))
                       (profile   (operating-system-profile-directory os)))
    (return `((directory ,(%store-prefix) 0 ,(or build-gid 0))
              (directory "/etc")
              (directory "/var/log")                     ; for dmd
              (directory "/var/run/nscd")
              (directory "/var/guix/gcroots")
              ("/var/guix/gcroots/system" -> ,os-dir)
              (directory "/run")
              ("/run/current-system" -> ,profile)
              (directory "/bin")
              ("/bin/sh" -> "/run/current-system/bin/bash")
              (directory "/tmp")
              (directory "/var/guix/profiles/per-user/root" 0 0)

              (directory "/root" 0 0)             ; an exception
              ,@(append-map user-directories
                            (operating-system-users os))))))

(define* (system-qemu-image os
                            #:key (disk-image-size (* 900 (expt 2 20))))
  "Return the derivation of a QEMU image of DISK-IMAGE-SIZE bytes of the GNU
system as described by OS."
  (mlet* %store-monad
      ((os-drv      (operating-system-derivation os))
       (os-dir   -> (derivation->output-path os-drv))
       (grub.cfg -> (string-append os-dir "/grub.cfg"))
       (populate    (operating-system-default-contents os)))
    (qemu-image  #:grub-configuration grub.cfg
                 #:populate populate
                 #:disk-image-size disk-image-size
                 #:initialize-store? #t
                 #:inputs-to-copy `(("system" ,os-drv)))))

(define* (system-qemu-image/shared-store
          os
          #:key (disk-image-size (* 15 (expt 2 20))))
  "Return a derivation that builds a QEMU image of OS that shares its store
with the host."
  (mlet* %store-monad
      ((os-drv      (operating-system-derivation os))
       (os-dir   -> (derivation->output-path os-drv))
       (grub.cfg -> (string-append os-dir "/grub.cfg"))
       (populate    (operating-system-default-contents os)))
    ;; TODO: Initialize the database so Guix can be used in the guest.
    (qemu-image #:grub-configuration grub.cfg
                #:populate populate
                #:disk-image-size disk-image-size)))

(define* (system-qemu-image/shared-store-script
          os
          #:key
          (qemu qemu)
          (graphic? #t))
  "Return a derivation that builds a script to run a virtual machine image of
OS that shares its store with the host."
  (define initrd
    (qemu-initrd #:mounts `((9p "store" ,(%store-prefix)))
                 #:volatile-root? #t))

  (mlet* %store-monad
      ((os ->  (operating-system (inherit os) (initrd initrd)))
       (os-drv (operating-system-derivation os))
       (initrd initrd)
       (image  (system-qemu-image/shared-store os)))
    (define builder
      #~(call-with-output-file #$output
          (lambda (port)
            (display
             (string-append "#!" #$bash "/bin/sh
exec " #$qemu "/bin/qemu-system-x86_64 -enable-kvm -no-reboot -net nic,model=virtio \
  -virtfs local,path=" #$(%store-prefix) ",security_model=none,mount_tag=store \
  -net user \
  -kernel " #$(operating-system-kernel os) "/bzImage \
  -initrd " #$initrd "/initrd \
-append \"" #$(if graphic? "" "console=ttyS0 ")
  "--load=" #$os-drv "/boot --root=/dev/vda1\" \
  -drive file=" #$image
  ",if=virtio,cache=writeback,werror=report,readonly\n")
             port)
            (chmod port #o555))))

    (gexp->derivation "run-vm.sh" builder)))

;;; vm.scm ends here