aboutsummaryrefslogtreecommitdiff
path: root/gnu/system/linux-initrd.scm
blob: 93f751b75712ccedef241a8ad168b9782fcbbdbd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
;;; 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 linux-initrd)
  #:use-module (guix monads)
  #:use-module (guix gexp)
  #:use-module (guix utils)
  #:use-module ((guix store)
                #:select (%store-prefix))
  #:use-module ((guix derivations)
                #:select (derivation->output-path))
  #:use-module (gnu packages cpio)
  #:use-module (gnu packages compression)
  #:use-module (gnu packages linux)
  #:use-module (gnu packages guile)
  #:use-module ((gnu packages make-bootstrap)
                #:select (%guile-static-stripped))
  #:use-module (gnu system file-systems)
  #:use-module (ice-9 match)
  #:use-module (ice-9 regex)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:export (expression->initrd
            base-initrd))


;;; Commentary:
;;;
;;; Tools to build initial RAM disks (initrd's) for Linux-Libre, and in
;;; particular initrd's that run Guile.
;;;
;;; Code:


(define* (expression->initrd exp
                             #:key
                             (guile %guile-static-stripped)
                             (cpio cpio)
                             (gzip gzip)
                             (name "guile-initrd")
                             (system (%current-system))
                             (modules '()))
  "Return a derivation that builds a Linux initrd (a gzipped cpio archive)
containing GUILE and that evaluates EXP, a G-expression, upon booting.  All
the derivations referenced by EXP are automatically copied to the initrd.

MODULES is a list of Guile module names to be embedded in the initrd."

  ;; General Linux overview in `Documentation/early-userspace/README' and
  ;; `Documentation/filesystems/ramfs-rootfs-initramfs.txt'.

  (mlet %store-monad ((init (gexp->script "init" exp
                                          #:modules modules
                                          #:guile guile)))
    (define builder
      #~(begin
          (use-modules (gnu build linux-initrd))

          (mkdir #$output)
          (build-initrd (string-append #$output "/initrd")
                        #:guile #$guile
                        #:init #$init
                        ;; Copy everything INIT refers to into the initrd.
                        #:references-graphs '("closure")
                        #:cpio (string-append #$cpio "/bin/cpio")
                        #:gzip (string-append #$gzip "/bin/gzip"))))

   (gexp->derivation name builder
                     #:modules '((guix build utils)
                                 (guix build store-copy)
                                 (gnu build linux-initrd))
                     #:references-graphs `(("closure" ,init)))))

(define (flat-linux-module-directory linux modules)
  "Return a flat directory containing the Linux kernel modules listed in
MODULES and taken from LINUX."
  (define build-exp
    #~(begin
        (use-modules (ice-9 match) (ice-9 regex)
                     (guix build utils))

        (define (string->regexp str)
          ;; Return a regexp that matches STR exactly.
          (string-append "^" (regexp-quote str) "$"))

        (define module-dir
          (string-append #$linux "/lib/modules"))

        (mkdir #$output)
        (for-each (lambda (module)
                    (match (find-files module-dir (string->regexp module))
                      ((file)
                       (format #t "copying '~a'...~%" file)
                       (copy-file file (string-append #$output "/" module)))
                      (()
                       (error "module not found" module module-dir))
                      ((_ ...)
                       (error "several modules by that name"
                              module module-dir))))
                  '#$modules)))

  (gexp->derivation "linux-modules" build-exp
                    #:modules '((guix build utils))))

(define (file-system->spec fs)
  "Return a list corresponding to file-system FS that can be passed to the
initrd code."
  (match fs
    (($ <file-system> device title mount-point type flags options _ check?)
     (list device title mount-point type flags options check?))))

(define* (base-initrd file-systems
                      #:key
                      qemu-networking?
                      virtio?
                      volatile-root?
                      (extra-modules '())
                      guile-modules-in-chroot?)
  ;; TODO: Support boot-time device mappings.
  "Return a monadic derivation that builds a generic initrd.  FILE-SYSTEMS is
a list of file-systems to be mounted by the initrd, possibly in addition to
the root file system specified on the kernel command line via '--root'.

When QEMU-NETWORKING? is true, set up networking with the standard QEMU
parameters.  When VIRTIO? is true, load additional modules so the initrd can
be used as a QEMU guest with para-virtualized I/O drivers.

When VOLATILE-ROOT? is true, the root file system is writable but any changes
to it are lost.

The initrd is automatically populated with all the kernel modules necessary
for FILE-SYSTEMS and for the given options.  However, additional kernel
modules can be listed in EXTRA-MODULES.  They will be added to the initrd, and
loaded at boot time in the order in which they appear.

When GUILE-MODULES-IN-CHROOT? is true, make core Guile modules available in
the new root.  This is necessary is the file specified as '--load' needs
access to these modules (which is the case if it wants to even just print an
exception and backtrace!)."
  (define virtio-modules
    ;; Modules for Linux para-virtualized devices, for use in QEMU guests.
    '("virtio.ko" "virtio_ring.ko" "virtio_pci.ko"
      "virtio_balloon.ko" "virtio_blk.ko" "virtio_net.ko"))

  (define cifs-modules
    ;; Modules needed to mount CIFS file systems.
    '("md4.ko" "ecb.ko" "cifs.ko"))

  (define virtio-9p-modules
    ;; Modules for the 9p paravirtualized file system.
    '("fscache.ko" "9pnet.ko" "9p.ko" "9pnet_virtio.ko"))

  (define (file-system-type-predicate type)
    (lambda (fs)
      (string=? (file-system-type fs) type)))

  (define linux-modules
    ;; Modules added to the initrd and loaded from the initrd.
    `("libahci.ko" "ahci.ko" ; modules for SATA controllers
      ,@(if (or virtio? qemu-networking?)
            virtio-modules
            '())
      ,@(if (find (file-system-type-predicate "cifs") file-systems)
            cifs-modules
            '())
      ,@(if (find (file-system-type-predicate "9p") file-systems)
            virtio-9p-modules
            '())
      ,@(if volatile-root?
            '("fuse.ko")
            '())
      ,@extra-modules))

  (define helper-packages
    ;; Packages to be copied on the initrd.
    `(,@(if (find (lambda (fs)
                    (string-prefix? "ext" (file-system-type fs)))
                  file-systems)
            (list e2fsck/static)
            '())
      ,@(if volatile-root?
            (list unionfs-fuse/static)
            '())))

  (mlet %store-monad ((kodir (flat-linux-module-directory linux-libre
                                                          linux-modules)))
    (expression->initrd
     #~(begin
         (use-modules (gnu build linux-boot)
                      (guix build utils)
                      (srfi srfi-26))

         (with-output-to-port (%make-void-port "w")
           (lambda ()
             (set-path-environment-variable "PATH" '("bin" "sbin")
                                            '#$helper-packages)))

         (boot-system #:mounts '#$(map file-system->spec file-systems)
                      #:linux-modules (map (lambda (file)
                                             (string-append #$kodir "/" file))
                                           '#$linux-modules)
                      #:qemu-guest-networking? #$qemu-networking?
                      #:guile-modules-in-chroot? '#$guile-modules-in-chroot?
                      #:volatile-root? '#$volatile-root?))
     #:name "base-initrd"
     #:modules '((guix build utils)
                 (gnu build linux-boot)
                 (gnu build file-systems)))))

;;; linux-initrd.scm ends here