;;; 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 ;;; 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 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 build-initrd)) ;;; 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 #:key (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) result (cons dir result))) (lambda (file stat result) result) (const #f) ;skip (const #f) ;error '() directory) string<?)) (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") output)) output)) (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" (effective-version) (if (eq? (native-endianness) (endianness little)) "LE" "BE") (sizeof '*) (effective-version) file))))) (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 #:key 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 REFERENCES-GRAPHS." (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