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;;; 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
(mapped-devices '())
qemu-networking?
virtio?
volatile-root?
(extra-modules '()))
"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'.
MAPPED-DEVICES is a list of device mappings to realize before FILE-SYSTEMS are
mounted.
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."
(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)
'())))
(define device-mapping-commands
;; List of gexps to open the mapped devices.
(map (lambda (md)
(let* ((source (mapped-device-source md))
(target (mapped-device-target md))
(type (mapped-device-type md))
(open (mapped-device-kind-open type)))
(open source target)))
mapped-devices))
(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)
#:pre-mount (lambda ()
(and #$@device-mapping-commands))
#:linux-modules (map (lambda (file)
(string-append #$kodir "/" file))
'#$linux-modules)
#:qemu-guest-networking? #$qemu-networking?
#:volatile-root? '#$volatile-root?))
#:name "base-initrd"
#:modules '((guix build utils)
(gnu build linux-boot)
(gnu build file-systems)))))
;;; linux-initrd.scm ends here
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