;;; 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 config)
  #:use-module (guix store)
  #:use-module (guix derivations)
  #:use-module (guix packages)
  #:use-module (guix monads)
  #:use-module ((gnu packages base)
                #:select (%final-inputs
                          guile-final gcc-final glibc-final
                          coreutils findutils grep sed))
  #:use-module (gnu packages guile)
  #:use-module (gnu packages bash)
  #: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 linux-initrd)
  #:use-module (gnu packages package-management)
  #:use-module ((gnu packages make-bootstrap)
                #:select (%guile-static-stripped))
  #:use-module (gnu packages system)

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

  #: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))

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

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

                                             (make-disk-image? #f)
                                             (references-graphs #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.

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: Allow use of macros from other modules, as done in
  ;; `build-expression->derivation'.

  (define input-alist
    (with-monad %store-monad
      (map (match-lambda
            ((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))))
           inputs)))

  (define builder
    ;; Code that launches the VM that evaluates EXP.
    `(let ()
       (use-modules (guix build utils)
                    (srfi srfi-1)
                    (ice-9 rdelim))

       (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" "-f" "qcow2" "image.qcow2"
                               ,(number->string disk-image-size)))
              '(begin))

         (mkdir "xchg")

         ;; Copy the reference-graph files under xchg/ so EXP can access it.
         (begin
           ,@(match references-graphs
               (((graph-files . _) ...)
                (map (lambda (file)
                       `(copy-file ,file
                                   ,(string-append "xchg/" file)))
                     graph-files))
               (#f '())))

         (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)))))))


  (define (lower-inputs inputs)
    ;; Turn any package in INPUTS into a derivation.
    (with-monad %store-monad
      (sequence %store-monad
                (map (match-lambda
                      ((name (? package? package) sub-drv ...)
                       (mlet %store-monad ((drv (package->derivation package)))
                         (return `(,name ,drv ,@sub-drv))))
                      ((name (? string? file))
                       (return `(,name ,file)))
                      (tuple
                       (return tuple)))
                     inputs))))

  (mlet* %store-monad
      ((input-alist  (sequence %store-monad input-alist))
       (exp* ->      `(let ((%build-inputs ',input-alist))
                        ,exp))
       (user-builder (text-file "builder-in-linux-vm"
                                (object->string exp*)))
       (coreutils -> (car (assoc-ref %final-inputs "coreutils")))
       (inputs       (lower-inputs `(("qemu" ,qemu)
                                     ("linux" ,linux)
                                     ("initrd" ,initrd)
                                     ("coreutils" ,coreutils)
                                     ("builder" ,user-builder)
                                     ,@inputs))))
    (derivation-expression name system builder inputs
                           #:env-vars env-vars
                           #:modules (delete-duplicates
                                      `((guix build utils)
                                        ,@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.

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."
  (define (input->name+derivation tuple)
    (with-monad %store-monad
      (match tuple
        ((name (? package? package))
         (mlet %store-monad ((drv (package->derivation package system)))
           (return `(,name . ,(derivation->output-path drv)))))
        ((name (? package? package) sub-drv)
         (mlet %store-monad ((drv (package->derivation package system)))
           (return `(,name . ,(derivation->output-path drv sub-drv)))))
        ((name (? derivation? drv))
         (return `(,name . ,(derivation->output-path drv))))
        ((name (? derivation? drv) sub-drv)
         (return `(,name . ,(derivation->output-path drv sub-drv))))
        ((input (and (? string?) (? store-path?) file))
         (return `(,input . ,file))))))

  (mlet %store-monad
      ((graph (sequence %store-monad
                        (map input->name+derivation inputs-to-copy))))
   (expression->derivation-in-linux-vm
    "qemu-image"
    `(let ()
       (use-modules (ice-9 rdelim)
                    (srfi srfi-1)
                    (guix build utils)
                    (guix build linux-initrd))

       (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
             (grub.cfg (assoc-ref %build-inputs "grub.cfg")))

         (define (read-reference-graph port)
           ;; Return a list of store paths from the reference graph at PORT.
           ;; The data at PORT is the format produced by #:references-graphs.
           (let loop ((line   (read-line port))
                      (result '()))
             (cond ((eof-object? line)
                    (delete-duplicates result))
                   ((string-prefix? "/" line)
                    (loop (read-line port)
                          (cons line result)))
                   (else
                    (loop (read-line port)
                          result)))))

         (define (things-to-copy)
           ;; Return the list of store files to copy to the image.
           (define (graph-from-file file)
             (call-with-input-file file
               read-reference-graph))

           ,(match inputs-to-copy
              (((graph-files . _) ...)
               `(let* ((graph-files ',(map (cut string-append "/xchg/" <>)
                                           graph-files))
                       (paths       (append-map graph-from-file graph-files)))
                  (delete-duplicates paths)))
              (#f ''())))

         ;; 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")
         (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")
                (and (zero? (system* mkfs "-F" "/dev/vda1"))
                     (let ((store (string-append "/fs" ,%store-directory)))
                       (display "mounting partition...\n")
                       (mkdir "/fs")
                       (mount "/dev/vda1" "/fs" "ext3")
                       (mkdir-p "/fs/boot/grub")
                       (symlink grub.cfg "/fs/boot/grub/grub.cfg")

                       ;; Populate the image's store.
                       (mkdir-p store)
                       (chmod store #o1775)
                       (for-each (lambda (thing)
                                   (copy-recursively thing
                                                     (string-append "/fs"
                                                                    thing)))
                                 (cons grub.cfg (things-to-copy)))

                       ;; Populate /dev.
                       (make-essential-device-nodes #:root "/fs")

                       ;; Optionally, register the inputs in the image's store.
                       (let* ((guix     (assoc-ref %build-inputs "guix"))
                              (register (string-append guix
                                                       "/sbin/guix-register")))
                         ,@(if initialize-store?
                               (match inputs-to-copy
                                 (((graph-files . _) ...)
                                  (map (lambda (closure)
                                         `(system* register "--prefix" "/fs"
                                                   ,(string-append "/xchg/"
                                                                   closure)))
                                       graph-files)))
                               '(#f)))

                       ;; Evaluate the POPULATE directives.
                       ,@(let loop ((directives populate)
                                    (statements '()))
                           (match directives
                             (()
                              (reverse statements))
                             ((('directory name) rest ...)
                              (loop rest
                                    (cons `(mkdir-p ,(string-append "/fs" name))
                                          statements)))
                             ((('directory name uid gid) rest ...)
                              (let ((dir (string-append "/fs" name)))
                                (loop rest
                                      (cons* `(chown ,dir ,uid ,gid)
                                             `(mkdir-p ,dir)
                                             statements))))
                             (((new '-> old) rest ...)
                              (loop rest
                                    (cons `(symlink ,old
                                                    ,(string-append "/fs" new))
                                          statements)))))

                       (and=> (assoc-ref %build-inputs "populate")
                              (lambda (populate)
                                (chdir "/fs")
                                (primitive-load populate)
                                (chdir "/")))

                       (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
                                     ;; /nix/store, which is the host,
                                     ;; read-only store.
                                     (unless (eq? (stat:type s) 'symlink)
                                       (utime file 0 0 0 0))))
                                 (find-files "/fs" ".*"))

                       (and (zero?
                             (system* grub "--no-floppy"
                                      "--boot-directory" "/fs/boot"
                                      "/dev/vda"))
                            (zero? (system* umount "/fs"))
                            (reboot))))))))
    #:system system
    #:inputs `(("parted" ,parted)
               ("grub" ,grub)
               ("e2fsprogs" ,e2fsprogs)
               ("grub.cfg" ,grub-configuration)

               ;; 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
    #:modules '((guix build utils)
                (guix build linux-initrd)))))

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

(define* (union inputs
                #:key (guile (%guile-for-build)) (system (%current-system))
                (name "union"))
  "Return a derivation that builds the union of INPUTS.  INPUTS is a list of
input tuples."
  (define builder
    '(begin
       (use-modules (guix build union))

       (setvbuf (current-output-port) _IOLBF)
       (setvbuf (current-error-port) _IOLBF)

       (let ((output (assoc-ref %outputs "out"))
             (inputs (map cdr %build-inputs)))
         (format #t "building union `~a' with ~a packages...~%"
                 output (length inputs))
         (union-build output inputs))))

  (mlet %store-monad
      ((inputs (sequence %store-monad
                         (map (match-lambda
                               ((name (? package? p))
                                (mlet %store-monad
                                    ((drv (package->derivation p system)))
                                  (return `(,name ,drv))))
                               ((name (? package? p) output)
                                (mlet %store-monad
                                    ((drv (package->derivation p system)))
                                  (return `(,name ,drv ,output))))
                               (x
                                (return x)))
                              inputs))))
    (derivation-expression name system builder
                           inputs
                           #:modules '((guix build union))
                           #:guile-for-build guile)))

(define (system-qemu-image)
  "Return the derivation of a QEMU image of the GNU system."
  (define build-user-gid 30000)

  (mlet* %store-monad
      ((motd (text-file "motd" "
Happy birthday, GNU!                                http://www.gnu.org/gnu30

"))

       (%pam-services ->
                      ;; Services known to PAM.
                      (list %pam-other-services
                            (unix-pam-service "login"
                                              #:allow-empty-passwords? #t
                                              #:motd motd)))

       (services (listm %store-monad
                        (host-name-service "gnu")
                        (mingetty-service "tty1")
                        (mingetty-service "tty2")
                        (mingetty-service "tty3")
                        (mingetty-service "tty4")
                        (mingetty-service "tty5")
                        (mingetty-service "tty6")
                        (syslog-service)
                        (guix-service)
                        (nscd-service)

                        ;; QEMU networking settings.
                        (static-networking-service "eth0" "10.0.2.10"
                                                   #:gateway "10.0.2.2")))

       (build-accounts (guix-build-accounts 10 #:gid build-user-gid))

       (resolv.conf
        ;; Name resolution for default QEMU settings.
        (text-file "resolv.conf" "nameserver 10.0.2.3\n"))

       (etc-services  (package-file net-base "etc/services"))
       (etc-protocols (package-file net-base "etc/protocols"))
       (etc-rpc       (package-file net-base "etc/rpc"))

       (bash-file (package-file bash "bin/bash"))
       (dmd-file  (package-file dmd "bin/dmd"))
       (dmd-conf  (dmd-configuration-file services))
       (accounts -> (cons* (user-account
                            (name "root")
                            (password "")
                            (uid 0) (gid 0)
                            (comment "System administrator")
                            (home-directory "/")
                            (shell bash-file))
                           (user-account
                            (name "guest")
                            (password "")
                            (uid 1000) (gid 100)
                            (comment "Guest of GNU")
                            (home-directory "/home/guest")
                            (shell bash-file))
                           build-accounts))
       (passwd    (passwd-file accounts))
       (shadow    (passwd-file accounts #:shadow? #t))
       (group     (group-file (list (user-group
                                     (name "root")
                                     (id 0))
                                    (user-group
                                     (name "users")
                                     (id 100)
                                     (members '("guest")))
                                    (user-group
                                     (name "guixbuild")
                                     (id build-user-gid)
                                     (members (map user-account-name
                                                   build-accounts))))))
       (pam.d-drv (pam-services->directory %pam-services))
       (pam.d ->  (derivation->output-path pam.d-drv))

       (packages -> `(("coreutils" ,coreutils)
                      ("bash" ,bash)
                      ("guile" ,guile-2.0)
                      ("dmd" ,dmd)
                      ("gcc" ,gcc-final)
                      ("libc" ,glibc-final)
                      ("inetutils" ,inetutils)
                      ("findutils" ,findutils)
                      ("grep" ,grep)
                      ("sed" ,sed)
                      ("procps" ,procps)
                      ("psmisc" ,psmisc)
                      ("zile" ,zile)
                      ("guix" ,guix)))

       ;; TODO: Replace with a real profile with a manifest.
       ;; TODO: Generate bashrc from packages' search-paths.
       (profile-drv (union packages
                           #:name "default-profile"))
       (profile ->  (derivation->output-path profile-drv))
       (bashrc   (text-file "bashrc" (string-append "
export PS1='\\u@\\h\\$ '
export PATH=$HOME/.guix-profile/bin:" profile "/bin:" profile "/sbin
export CPATH=$HOME/.guix-profile/include:" profile "/include
export LIBRARY_PATH=$HOME/.guix-profile/lib:" profile "/lib
alias ls='ls -p --color'
alias ll='ls -l'
")))

       (issue    (text-file "issue" "
This is an alpha preview of the GNU system.  Welcome.

This image features the GNU Guix package manager, which was used to
build it (http://www.gnu.org/software/guix/).  The init system is
GNU dmd (http://www.gnu.org/software/dmd/).

You can log in as 'guest' or 'root' with no password.
"))

       (populate -> `((directory "/nix/store" 0 ,build-user-gid)
                      (directory "/etc")
                      (directory "/var/log")      ; for dmd
                      (directory "/var/run/nscd")
                      ("/etc/shadow" -> ,shadow)
                      ("/etc/passwd" -> ,passwd)
                      ("/etc/group" -> ,group)
                      ("/etc/login.defs" -> "/dev/null")
                      ("/etc/pam.d" -> ,pam.d)
                      ("/etc/resolv.conf" -> ,resolv.conf)
                      ("/etc/profile" -> ,bashrc)
                      ("/etc/issue" -> ,issue)
                      ("/etc/services" -> ,etc-services)
                      ("/etc/protocols" -> ,etc-protocols)
                      ("/etc/rpc" -> ,etc-rpc)
                      (directory "/var/nix/gcroots")
                      ("/var/nix/gcroots/default-profile" -> ,profile)
                      (directory "/tmp")
                      (directory "/var/nix/profiles/per-user/root" 0 0)
                      (directory "/var/nix/profiles/per-user/guest"
                                 1000 100)
                      (directory "/home/guest" 1000 100)))
       (boot     (text-file "boot" (object->string
                                    `(execl ,dmd-file "dmd"
                                            "--config" ,dmd-conf))))
       (entries -> (list (return (menu-entry
                                  (label (string-append
                                          "GNU system with Linux-Libre "
                                          (package-version linux-libre)
                                          " (technology preview)"))
                                  (linux linux-libre)
                                  (linux-arguments `("--root=/dev/vda1"
                                                     ,(string-append "--load=" boot)))
                                  (initrd gnu-system-initrd)))))
       (grub.cfg (grub-configuration-file entries)))
    (qemu-image  #:grub-configuration grub.cfg
                 #:populate populate
                 #:disk-image-size (* 550 (expt 2 20))
                 #:initialize-store? #t
                 #:inputs-to-copy `(("boot" ,boot)
                                    ("linux" ,linux-libre)
                                    ("initrd" ,gnu-system-initrd)
                                    ("pam.d" ,pam.d-drv)
                                    ("profile" ,profile-drv)

                                    ;; Configuration.
                                    ("dmd.conf" ,dmd-conf)
                                    ("etc-pam.d" ,pam.d-drv)
                                    ("etc-passwd" ,passwd)
                                    ("etc-shadow" ,shadow)
                                    ("etc-group" ,group)
                                    ("etc-resolv.conf" ,resolv.conf)
                                    ("etc-bashrc" ,bashrc)
                                    ("etc-issue" ,issue)
                                    ("etc-motd" ,motd)
                                    ("net-base" ,net-base)
                                    ,@(append-map service-inputs
                                                  services)))))

;;; vm.scm ends here
