Mirror of GNU Guix
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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015 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
;;; 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 build linux-initrd)
#:use-module ((guix cpio) #:prefix cpio:)
#:use-module (guix build utils)
#:use-module (guix build store-copy)
#:use-module (system base compile)
#:use-module (rnrs bytevectors)
#:use-module ((system foreign) #:select (sizeof))
#:use-module (ice-9 ftw)
#:export (write-cpio-archive
;;; Commentary:
;;; Tools to create Linux initial RAM disks ("initrds"). Initrds are
;;; essentially gzipped cpio archives, with a '/init' executable that the
;;; kernel runs at boot time.
;;; Code:
(define* (write-cpio-archive output directory
(compress? #t)
(gzip "gzip"))
"Write a cpio archive containing DIRECTORY to file OUTPUT. When
COMPRESS? is true, compress it using GZIP. On success, return OUTPUT."
;; 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."
(define files
;; Use 'sort' so that (1) the order of files is deterministic, and (2)
;; directories appear before the files they contain.
(sort (file-system-fold (const #t) ;enter?
(lambda (file stat result) ;leaf
(cons file result))
(lambda (dir stat result) ;down
(if (string=? dir directory)
(cons dir result)))
(lambda (file stat result)
(const #f) ;skip
(const #f) ;error
(call-with-output-file output
(lambda (port)
(cpio:write-cpio-archive files port
#:file->header cpio:file->cpio-header*)))
(or (not compress?)
;; Use '--no-name' so that gzip records neither a file name nor a time
;; stamp in its output.
(and (zero? (system* gzip "--best" "--no-name" output))
(rename-file (string-append output ".gz")
(define (cache-compiled-file-name file)
"Return the file name of the in-cache .go file for FILE, relative to the
current directory.
This is similar to what 'compiled-file-name' in (system base compile) does."
(let loop ((file file))
(let ((target (false-if-exception (readlink file))))
(if target
(loop target)
(format #f ".cache/guile/ccache/~a-~a-~a-~a/~a"
(if (eq? (native-endianness) (endianness little))
(sizeof '*)
(define (compile-to-cache file)
"Compile FILE to the cache."
(let ((compiled-file (cache-compiled-file-name file)))
(mkdir-p (dirname compiled-file))
(compile-file file
#:opts %auto-compilation-options
#:output-file compiled-file)))
(define* (build-initrd output
guile init
(references-graphs '())
(gzip "gzip"))
"Write an initial RAM disk (initrd) to OUTPUT. The initrd starts the script
at INIT, running GUILE. It contains all the items referred to by
(mkdir "contents")
;; Copy the closures of all the items referenced in REFERENCES-GRAPHS.
(populate-store references-graphs "contents")
(with-directory-excursion "contents"
;; Make '/init'.
(symlink init "init")
;; Compile it.
(compile-to-cache "init")
;; Allow Guile to find out where it is (XXX). See
;; 'guile-relocatable.patch'.
(mkdir-p "proc/self")
(symlink (string-append guile "/bin/guile") "proc/self/exe")
(readlink "proc/self/exe")
;; Reset the timestamps of all the files that will make it in the initrd.
(for-each (lambda (file)
(unless (eq? 'symlink (stat:type (lstat file)))
(utime file 0 0 0 0)))
(find-files "." ".*"))
(write-cpio-archive output "." #:gzip gzip))
(delete-file-recursively "contents"))
;;; linux-initrd.scm ends here