summaryrefslogtreecommitdiff
path: root/gnu/system/linux-initrd.scm
blob: 3edbf5046bdc223674dc08f46974059913a0885c (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
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
;;; 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)
  #:export (expression->initrd
            qemu-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 '())
                             (to-copy '())
                             (linux #f)
                             (linux-modules '()))
  "Return a package that contains a Linux initrd (a gzipped cpio archive)
containing GUILE and that evaluates EXP upon booting.  LINUX-MODULES is a list
of `.ko' file names to be copied from LINUX into the initrd.  TO-COPY is a
list of additional derivations or packages to copy 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'.

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

  (mlet* %store-monad ((source   (imported-modules modules))
                       (compiled (compiled-modules modules)))
    (define builder
      ;; TODO: Move most of this code to (guix build linux-initrd).
      #~(begin
          (use-modules (guix build utils)
                       (ice-9 pretty-print)
                       (ice-9 popen)
                       (ice-9 match)
                       (ice-9 ftw)
                       (srfi srfi-26)
                       (system base compile)
                       (rnrs bytevectors)
                       ((system foreign) #:select (sizeof)))

          (let ((cpio    (string-append #$cpio "/bin/cpio"))
                (gzip    (string-append #$gzip "/bin/gzip"))
                (modules #$source)
                (gos     #$compiled)
                (scm-dir (string-append "share/guile/" (effective-version)))
                (go-dir  (format #f ".cache/guile/ccache/~a-~a-~a-~a"
                                 (effective-version)
                                 (if (eq? (native-endianness) (endianness little))
                                     "LE"
                                     "BE")
                                 (sizeof '*)
                                 (effective-version))))
            (mkdir #$output)
            (mkdir "contents")
            (with-directory-excursion "contents"
              (copy-recursively #$guile ".")
              (call-with-output-file "init"
                (lambda (p)
                  (format p "#!/bin/guile -ds~%!#~%" #$guile)
                  (pretty-print '#$exp p)))
              (chmod "init" #o555)
              (chmod "bin/guile" #o555)

              ;; Copy Guile modules.
              (chmod scm-dir #o777)
              (copy-recursively modules scm-dir
                                #:follow-symlinks? #t)
              (copy-recursively gos (string-append "lib/guile/"
                                                   (effective-version) "/ccache")
                                #:follow-symlinks? #t)

              ;; Compile `init'.
              (mkdir-p go-dir)
              (set! %load-path (cons modules %load-path))
              (set! %load-compiled-path (cons gos %load-compiled-path))
              (compile-file "init"
                            #:opts %auto-compilation-options
                            #:output-file (string-append go-dir "/init.go"))

              ;; Copy Linux modules.
              (let* ((linux      #$linux)
                     (module-dir (and linux
                                      (string-append linux "/lib/modules"))))
                (mkdir "modules")
                #$@(map (lambda (module)
                          #~(match (find-files module-dir
                                               #$(string->regexp module))
                              ((file)
                               (format #t "copying '~a'...~%" file)
                               (copy-file file (string-append "modules/"
                                                              #$module)))
                              (()
                               (error "module not found" #$module module-dir))
                              ((_ ...)
                               (error "several modules by that name"
                                      #$module module-dir))))
                        linux-modules))

              (let ((store   #$(string-append "." (%store-prefix)))
                    (to-copy '#$to-copy))
                (unless (null? to-copy)
                  (mkdir-p store))
                ;; XXX: Should we do export-references-graph?
                (for-each (lambda (input)
                            (let ((target
                                   (string-append store "/"
                                                  (basename input))))
                              (copy-recursively input target)))
                          to-copy))

              ;; Reset the timestamps of all the files that will make it in the
              ;; initrd.
              (for-each (cut utime <> 0 0 0 0)
                        (find-files "." ".*"))

              (system* cpio "--version")
              (let ((pipe (open-pipe* OPEN_WRITE cpio "-o"
                                      "-O" (string-append #$output "/initrd")
                                      "-H" "newc" "--null")))
                (define print0
                  (let ((len (string-length "./")))
                    (lambda (file)
                      (format pipe "~a\0" (string-drop file len)))))

                ;; Note: as per `ramfs-rootfs-initramfs.txt', always add
                ;; directory entries before the files that are inside of it: "The
                ;; Linux kernel cpio extractor won't create files in a directory
                ;; that doesn't exist, so the directory entries must go before
                ;; the files that go in those directories."
                (file-system-fold (const #t)
                                  (lambda (file stat result) ; leaf
                                    (print0 file))
                                  (lambda (dir stat result) ; down
                                    (unless (string=? dir ".")
                                      (print0 dir)))
                                  (const #f)         ; up
                                  (const #f)         ; skip
                                  (const #f)
                                  #f
                                  ".")

                (and (zero? (close-pipe pipe))
                     (with-directory-excursion #$output
                       (and (zero? (system* gzip "--best" "initrd"))
                            (rename-file "initrd.gz" "initrd")))))))))

   (gexp->derivation name builder
                     #: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* (qemu-initrd file-systems
                      #:key
                      qemu-networking?
                      virtio?
                      volatile-root?
                      guile-modules-in-chroot?)
  "Return a monadic derivation that builds an initrd for use in a QEMU guest
where the store is shared with the host.  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.

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.
    '("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.
    `(,@(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")
            '())))

  (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)
            '())))

  (expression->initrd
   #~(begin
       (use-modules (guix build linux-initrd)
                    (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 '#$(map file-system->spec file-systems)
                    #:linux-modules '#$linux-modules
                    #:qemu-guest-networking? #$qemu-networking?
                    #:guile-modules-in-chroot? '#$guile-modules-in-chroot?
                    #:volatile-root? '#$volatile-root?))
   #:name "qemu-initrd"
   #:modules '((guix build utils)
               (guix build linux-initrd))
   #:to-copy helper-packages
   #:linux linux-libre
   #:linux-modules linux-modules))

;;; linux-initrd.scm ends here