ryan77627/guix
1
0
Fork 0
mirror of https://git.in.rschanz.org/ryan77627/guix.git synced 2024-12-26 22:38:07 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions
guix/gnu/build/linux-boot.scm
Alex Kost b8c02c18b4 Rename '/root/etc/dmd' directory and 'do-not-kill' file. 
* gnu/services/base.scm (%do-not-kill-file): Rename to
  "/etc/shepherd/do-not-kill".
* gnu/build/linux-boot.scm (mount-root-file-system): Rename
  "/root/etc/dmd" to "/root/etc/shepherd".
2016-01-29 20:20:19 +03:00

430 lines
15 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016 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-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 (gnu build linux-modules)
#:use-module (gnu build 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? (unionfs "unionfs"))
"Mount the root file system of type TYPE at device ROOT. If VOLATILE-ROOT?
is true, mount ROOT read-only and make it a union with a writable tmpfs using
UNIONFS."
(define (mark-as-not-killable pid)
;; Tell the 'user-processes' shepherd service that PID must be kept alive
;; when shutting down.
(mkdir-p "/root/etc/shepherd")
(let ((port (open-file "/root/etc/shepherd/do-not-kill" "a")))
(chmod port #o600)
(write pid port)
(newline port)
(close-port port)))
(if volatile-root?
(begin
(mkdir-p "/real-root")
(mount root "/real-root" type MS_RDONLY)
(mkdir-p "/rw-root")
(mount "none" "/rw-root" "tmpfs")
;; We want read-write /dev nodes.
(mkdir-p "/rw-root/dev")
(mount "none" "/rw-root/dev" "devtmpfs")
;; Make /root a union of the tmpfs and the actual root. Use
;; 'max_files' to set a high RLIMIT_NOFILE for the unionfs process
;; itself. Failing to do that, we quickly run out of file
;; descriptors; see <http://bugs.gnu.org/17827>.
(unless (zero? (system* unionfs "-o"
"cow,allow_other,use_ino,suid,dev,max_files=65536"
"/rw-root=RW:/real-root=RO"
"/root"))
(error "unionfs failed"))
;; Make sure unionfs remains alive till the end. Because
;; 'fuse_daemonize' doesn't tell the PID of the forked daemon, we
;; have to resort to 'pidof' here.
(mark-as-not-killable (pidof unionfs)))
(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 suitable for 'mount-file-system'.
When VOLATILE-ROOT? is true, the root file system is writable but any changes
to it are lost."
(define root-mount-point?
(match-lambda
((device _ "/" _ ...) #t)
(_ #f)))
(define root-fs-type
(or (any (match-lambda
((device _ "/" type _ ...) type)
(_ #f))
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
Reference in a new issue View git blame Copy permalink