mirror of
https://git.in.rschanz.org/ryan77627/guix.git
synced 2024-12-25 22:08:16 -05:00
c828969036
Overlayfs is part of the kernel, while unionfs needs FUSE. This also reduces the size of the initrd by ca. 4.3% (487K). * gnu/build/linux-boot.scm (mount-root-file-system): Remove optional parameter "unionfs"; mount using overlayfs instead of unionfs; new directory layout requied by overlayfs; update documentation. [mark-as-not-killable]: Remove now unused function * gnu/system/linux-initrd.scm (file-system-packages): Remove now unused packages "unionfs-fuse/static" and thus unused related 'if'. (linux-modules): Replace "fuse" by "overlay".
415 lines
15 KiB
Scheme
415 lines
15 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
|
||
;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
|
||
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
|
||
;;;
|
||
;;; 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-boot)
|
||
#:use-module (rnrs io ports)
|
||
#:use-module (system repl error-handling)
|
||
#:autoload (system repl repl) (start-repl)
|
||
#:autoload (system base compile) (compile-file)
|
||
#:use-module (srfi srfi-1)
|
||
#:use-module (srfi srfi-26)
|
||
#:use-module (ice-9 match)
|
||
#:use-module (ice-9 ftw)
|
||
#:use-module (guix build utils)
|
||
#:use-module ((guix build syscalls)
|
||
#:hide (file-system-type))
|
||
#:use-module (gnu build linux-modules)
|
||
#:use-module (gnu build file-systems)
|
||
#:use-module (gnu system file-systems)
|
||
#:export (mount-essential-file-systems
|
||
linux-command-line
|
||
find-long-option
|
||
make-essential-device-nodes
|
||
configure-qemu-networking
|
||
|
||
bind-mount
|
||
device-number
|
||
boot-system))
|
||
|
||
;;; Commentary:
|
||
;;;
|
||
;;; Utility procedures useful in a Linux initial RAM disk (initrd). Note that
|
||
;;; many of these use procedures not yet available in vanilla Guile (`mount',
|
||
;;; `load-linux-module', etc.); these are provided by a Guile patch used in
|
||
;;; the GNU distribution.
|
||
;;;
|
||
;;; Code:
|
||
|
||
(define* (mount-essential-file-systems #:key (root "/"))
|
||
"Mount /dev, /proc, and /sys under ROOT."
|
||
(define (scope dir)
|
||
(string-append root
|
||
(if (string-suffix? "/" root)
|
||
""
|
||
"/")
|
||
dir))
|
||
|
||
(unless (file-exists? (scope "proc"))
|
||
(mkdir (scope "proc")))
|
||
(mount "none" (scope "proc") "proc")
|
||
|
||
(unless (file-exists? (scope "dev"))
|
||
(mkdir (scope "dev")))
|
||
(mount "none" (scope "dev") "devtmpfs")
|
||
|
||
(unless (file-exists? (scope "sys"))
|
||
(mkdir (scope "sys")))
|
||
(mount "none" (scope "sys") "sysfs"))
|
||
|
||
(define (move-essential-file-systems root)
|
||
"Move currently mounted essential file systems to ROOT."
|
||
(for-each (lambda (dir)
|
||
(let ((target (string-append root dir)))
|
||
(unless (file-exists? target)
|
||
(mkdir target))
|
||
(mount dir target "" MS_MOVE)))
|
||
'("/dev" "/proc" "/sys")))
|
||
|
||
(define (linux-command-line)
|
||
"Return the Linux kernel command line as a list of strings."
|
||
(string-tokenize
|
||
(call-with-input-file "/proc/cmdline"
|
||
get-string-all)))
|
||
|
||
(define (find-long-option option arguments)
|
||
"Find OPTION among ARGUMENTS, where OPTION is something like \"--load\".
|
||
Return the value associated with OPTION, or #f on failure."
|
||
(let ((opt (string-append option "=")))
|
||
(and=> (find (cut string-prefix? opt <>)
|
||
arguments)
|
||
(lambda (arg)
|
||
(substring arg (+ 1 (string-index arg #\=)))))))
|
||
|
||
(define* (make-disk-device-nodes base major #:optional (minor 0))
|
||
"Make the block device nodes around BASE (something like \"/root/dev/sda\")
|
||
with the given MAJOR number, starting with MINOR."
|
||
(mknod base 'block-special #o644 (device-number major minor))
|
||
(let loop ((i 1))
|
||
(when (< i 16)
|
||
(mknod (string-append base (number->string i))
|
||
'block-special #o644 (device-number major (+ minor i)))
|
||
(loop (+ i 1)))))
|
||
|
||
(define* (make-essential-device-nodes #:key (root "/"))
|
||
"Make essential device nodes under ROOT/dev."
|
||
;; The hand-made devtmpfs/udev!
|
||
|
||
(define (scope dir)
|
||
(string-append root
|
||
(if (string-suffix? "/" root)
|
||
""
|
||
"/")
|
||
dir))
|
||
|
||
(unless (file-exists? (scope "dev"))
|
||
(mkdir (scope "dev")))
|
||
|
||
;; Make the device nodes for SCSI disks.
|
||
(make-disk-device-nodes (scope "dev/sda") 8)
|
||
(make-disk-device-nodes (scope "dev/sdb") 8 16)
|
||
(make-disk-device-nodes (scope "dev/sdc") 8 32)
|
||
(make-disk-device-nodes (scope "dev/sdd") 8 48)
|
||
|
||
;; SCSI CD-ROM devices (aka. "/dev/sr0" etc.).
|
||
(mknod (scope "dev/scd0") 'block-special #o644 (device-number 11 0))
|
||
(mknod (scope "dev/scd1") 'block-special #o644 (device-number 11 1))
|
||
|
||
;; The virtio (para-virtualized) block devices, as supported by QEMU/KVM.
|
||
(make-disk-device-nodes (scope "dev/vda") 252)
|
||
|
||
;; Memory (used by Xorg's VESA driver.)
|
||
(mknod (scope "dev/mem") 'char-special #o640 (device-number 1 1))
|
||
(mknod (scope "dev/kmem") 'char-special #o640 (device-number 1 2))
|
||
|
||
;; Inputs (used by Xorg.)
|
||
(unless (file-exists? (scope "dev/input"))
|
||
(mkdir (scope "dev/input")))
|
||
(mknod (scope "dev/input/mice") 'char-special #o640 (device-number 13 63))
|
||
(mknod (scope "dev/input/mouse0") 'char-special #o640 (device-number 13 32))
|
||
(mknod (scope "dev/input/event0") 'char-special #o640 (device-number 13 64))
|
||
|
||
;; System console. This node is magically created by the kernel on the
|
||
;; initrd's root, so don't try to create it in that case.
|
||
(unless (string=? root "/")
|
||
(mknod (scope "dev/console") 'char-special #o600
|
||
(device-number 5 1)))
|
||
|
||
;; TTYs.
|
||
(mknod (scope "dev/tty") 'char-special #o600
|
||
(device-number 5 0))
|
||
(chmod (scope "dev/tty") #o666)
|
||
(let loop ((n 0))
|
||
(and (< n 50)
|
||
(let ((name (format #f "dev/tty~a" n)))
|
||
(mknod (scope name) 'char-special #o600
|
||
(device-number 4 n))
|
||
(loop (+ 1 n)))))
|
||
|
||
;; Serial line.
|
||
(mknod (scope "dev/ttyS0") 'char-special #o660
|
||
(device-number 4 64))
|
||
|
||
;; Pseudo ttys.
|
||
(mknod (scope "dev/ptmx") 'char-special #o666
|
||
(device-number 5 2))
|
||
(chmod (scope "dev/ptmx") #o666)
|
||
|
||
;; Create /dev/pts; it will be mounted later, at boot time.
|
||
(unless (file-exists? (scope "dev/pts"))
|
||
(mkdir (scope "dev/pts")))
|
||
|
||
;; Rendez-vous point for syslogd.
|
||
(mknod (scope "dev/log") 'socket #o666 0)
|
||
(mknod (scope "dev/kmsg") 'char-special #o600 (device-number 1 11))
|
||
|
||
;; Other useful nodes, notably relied on by guix-daemon.
|
||
(for-each (match-lambda
|
||
((file major minor)
|
||
(mknod (scope file) 'char-special #o666
|
||
(device-number major minor))
|
||
(chmod (scope file) #o666)))
|
||
'(("dev/null" 1 3)
|
||
("dev/zero" 1 5)
|
||
("dev/full" 1 7)
|
||
("dev/random" 1 8)
|
||
("dev/urandom" 1 9)))
|
||
|
||
(symlink "/proc/self/fd" (scope "dev/fd"))
|
||
(symlink "/proc/self/fd/0" (scope "dev/stdin"))
|
||
(symlink "/proc/self/fd/1" (scope "dev/stdout"))
|
||
(symlink "/proc/self/fd/2" (scope "dev/stderr"))
|
||
|
||
;; Loopback devices.
|
||
(let loop ((i 0))
|
||
(when (< i 8)
|
||
(mknod (scope (string-append "dev/loop" (number->string i)))
|
||
'block-special #o660
|
||
(device-number 7 i))
|
||
(loop (+ 1 i))))
|
||
|
||
;; File systems in user space (FUSE).
|
||
(mknod (scope "dev/fuse") 'char-special #o666 (device-number 10 229)))
|
||
|
||
(define %host-qemu-ipv4-address
|
||
(inet-pton AF_INET "10.0.2.10"))
|
||
|
||
(define* (configure-qemu-networking #:optional (interface "eth0"))
|
||
"Setup the INTERFACE network interface and /etc/resolv.conf according to
|
||
QEMU's default networking settings (see net/slirp.c in QEMU for default
|
||
networking values.) Return #t if INTERFACE is up, #f otherwise."
|
||
(display "configuring QEMU networking...\n")
|
||
(let* ((sock (socket AF_INET SOCK_STREAM 0))
|
||
(address (make-socket-address AF_INET %host-qemu-ipv4-address 0))
|
||
(flags (network-interface-flags sock interface)))
|
||
(set-network-interface-address sock interface address)
|
||
(set-network-interface-flags sock interface (logior flags IFF_UP))
|
||
|
||
;; Hello! We used to create /etc/resolv.conf here, with "nameserver
|
||
;; 10.0.2.3\n". However, with Linux-libre 3.16, we're getting ENOSPC.
|
||
;; And since it's actually unnecessary, it's gone.
|
||
|
||
(logand (network-interface-flags sock interface) IFF_UP)))
|
||
|
||
(define (device-number major minor)
|
||
"Return the device number for the device with MAJOR and MINOR, for use as
|
||
the last argument of `mknod'."
|
||
(+ (* major 256) minor))
|
||
|
||
(define (pidof program)
|
||
"Return the PID of the first presumed instance of PROGRAM."
|
||
(let ((program (basename program)))
|
||
(find (lambda (pid)
|
||
(let ((exe (format #f "/proc/~a/exe" pid)))
|
||
(and=> (false-if-exception (readlink exe))
|
||
(compose (cut string=? program <>) basename))))
|
||
(filter-map string->number (scandir "/proc")))))
|
||
|
||
(define* (mount-root-file-system root type
|
||
#:key volatile-root?)
|
||
"Mount the root file system of type TYPE at device ROOT. If VOLATILE-ROOT?
|
||
is true, mount ROOT read-only and make it a overlay with a writable tmpfs
|
||
using the kernel build-in overlayfs."
|
||
(if volatile-root?
|
||
(begin
|
||
(mkdir-p "/real-root")
|
||
(mount root "/real-root" type MS_RDONLY)
|
||
(mkdir-p "/rw-root")
|
||
(mount "none" "/rw-root" "tmpfs")
|
||
|
||
;; Create the upperdir and the workdir of the overlayfs
|
||
(mkdir-p "/rw-root/upper")
|
||
(mkdir-p "/rw-root/work")
|
||
|
||
;; We want read-write /dev nodes.
|
||
(mkdir-p "/rw-root/upper/dev")
|
||
(mount "none" "/rw-root/upper/dev" "devtmpfs")
|
||
|
||
;; Make /root an overlay of the tmpfs and the actual root.
|
||
(mount "none" "/root" "overlay" 0
|
||
"lowerdir=/real-root,upperdir=/rw-root/upper,workdir=/rw-root/work"))
|
||
(begin
|
||
(check-file-system root type)
|
||
(mount root "/root" type)))
|
||
|
||
;; Make sure /root/etc/mtab is a symlink to /proc/self/mounts.
|
||
(false-if-exception
|
||
(delete-file "/root/etc/mtab"))
|
||
(symlink "/proc/self/mounts" "/root/etc/mtab"))
|
||
|
||
(define (switch-root root)
|
||
"Switch to ROOT as the root file system, in a way similar to what
|
||
util-linux' switch_root(8) does."
|
||
(move-essential-file-systems root)
|
||
(chdir root)
|
||
|
||
;; Since we're about to 'rm -rf /', try to make sure we're on an initrd.
|
||
;; TODO: Use 'statfs' to check the fs type, like klibc does.
|
||
(when (or (not (file-exists? "/init")) (directory-exists? "/home"))
|
||
(format (current-error-port)
|
||
"The root file system is probably not an initrd; \
|
||
bailing out.~%root contents: ~s~%" (scandir "/"))
|
||
(force-output (current-error-port))
|
||
(exit 1))
|
||
|
||
;; Delete files from the old root, without crossing mount points (assuming
|
||
;; there are no mount points in sub-directories.) That means we're leaving
|
||
;; the empty ROOT directory behind us, but that's OK.
|
||
(let ((root-device (stat:dev (stat "/"))))
|
||
(for-each (lambda (file)
|
||
(unless (member file '("." ".."))
|
||
(let* ((file (string-append "/" file))
|
||
(device (stat:dev (lstat file))))
|
||
(when (= device root-device)
|
||
(delete-file-recursively file)))))
|
||
(scandir "/")))
|
||
|
||
;; Make ROOT the new root.
|
||
(mount root "/" "" MS_MOVE)
|
||
(chroot ".")
|
||
(chdir "/")
|
||
|
||
(when (file-exists? "/dev/console")
|
||
;; Close the standard file descriptors since they refer to the old
|
||
;; /dev/console, and reopen them.
|
||
(let ((console (open-file "/dev/console" "r+b0")))
|
||
(for-each close-fdes '(0 1 2))
|
||
|
||
(dup2 (fileno console) 0)
|
||
(dup2 (fileno console) 1)
|
||
(dup2 (fileno console) 2)
|
||
|
||
(close-port console))))
|
||
|
||
|
||
(define* (boot-system #:key
|
||
(linux-modules '())
|
||
linux-module-directory
|
||
qemu-guest-networking?
|
||
volatile-root?
|
||
pre-mount
|
||
(mounts '()))
|
||
"This procedure is meant to be called from an initrd. Boot a system by
|
||
first loading LINUX-MODULES (a list of module names) from
|
||
LINUX-MODULE-DIRECTORY, then setting up QEMU guest networking if
|
||
QEMU-GUEST-NETWORKING? is true, calling PRE-MOUNT, mounting the file systems
|
||
specified in MOUNTS, and finally booting into the new root if any. The initrd
|
||
supports kernel command-line options '--load', '--root', and '--repl'.
|
||
|
||
Mount the root file system, specified by the '--root' command-line argument,
|
||
if any.
|
||
|
||
MOUNTS must be a list of <file-system> objects.
|
||
|
||
When VOLATILE-ROOT? is true, the root file system is writable but any changes
|
||
to it are lost."
|
||
(define (root-mount-point? fs)
|
||
(string=? (file-system-mount-point fs) "/"))
|
||
|
||
(define root-fs-type
|
||
(or (any (lambda (fs)
|
||
(and (root-mount-point? fs)
|
||
(file-system-type fs)))
|
||
mounts)
|
||
"ext4"))
|
||
|
||
(define (lookup-module name)
|
||
(string-append linux-module-directory "/"
|
||
(ensure-dot-ko name)))
|
||
|
||
(display "Welcome, this is GNU's early boot Guile.\n")
|
||
(display "Use '--repl' for an initrd REPL.\n\n")
|
||
|
||
(call-with-error-handling
|
||
(lambda ()
|
||
(mount-essential-file-systems)
|
||
(let* ((args (linux-command-line))
|
||
(to-load (find-long-option "--load" args))
|
||
(root (find-long-option "--root" args)))
|
||
|
||
(when (member "--repl" args)
|
||
(start-repl))
|
||
|
||
(display "loading kernel modules...\n")
|
||
(for-each (cut load-linux-module* <>
|
||
#:lookup-module lookup-module)
|
||
(map lookup-module linux-modules))
|
||
|
||
(when qemu-guest-networking?
|
||
(unless (configure-qemu-networking)
|
||
(display "network interface is DOWN\n")))
|
||
|
||
;; Prepare the real root file system under /root.
|
||
(unless (file-exists? "/root")
|
||
(mkdir "/root"))
|
||
|
||
(when (procedure? pre-mount)
|
||
;; Do whatever actions are needed before mounting the root file
|
||
;; system--e.g., installing device mappings. Error out when the
|
||
;; return value is false.
|
||
(unless (pre-mount)
|
||
(error "pre-mount actions failed")))
|
||
|
||
(if root
|
||
(mount-root-file-system (canonicalize-device-spec root)
|
||
root-fs-type
|
||
#:volatile-root? volatile-root?)
|
||
(mount "none" "/root" "tmpfs"))
|
||
|
||
;; Mount the specified file systems.
|
||
(for-each mount-file-system
|
||
(remove root-mount-point? mounts))
|
||
|
||
(if to-load
|
||
(begin
|
||
(switch-root "/root")
|
||
(format #t "loading '~a'...\n" to-load)
|
||
|
||
(primitive-load to-load)
|
||
|
||
(format (current-error-port)
|
||
"boot program '~a' terminated, rebooting~%"
|
||
to-load)
|
||
(sleep 2)
|
||
(reboot))
|
||
(begin
|
||
(display "no boot file passed via '--load'\n")
|
||
(display "entering a warm and cozy REPL\n")
|
||
(start-repl)))))))
|
||
|
||
;;; linux-initrd.scm ends here
|