;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
(define-module (guix build linux-initrd)
#:use-module (rnrs io ports)
#:use-module (system foreign)
+ #: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)
#:export (mount-essential-file-systems
linux-command-line
make-essential-device-nodes
configure-qemu-networking
- mount-qemu-smb-share
+ check-file-system
+ mount-file-system
bind-mount
load-linux-module*
- device-number))
+ device-number
+ boot-system))
;;; Commentary:
;;;
(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)))
+ '("/proc" "/sys")))
+
(define (linux-command-line)
"Return the Linux kernel command line as a list of strings."
(string-tokenize
(unless (file-exists? (scope "dev"))
(mkdir (scope "dev")))
- ;; Make the device nodes for QEMU's hard disk and partitions.
- (mknod (scope "dev/vda") 'block-special #o644 (device-number 8 0))
- (mknod (scope "dev/vda1") 'block-special #o644 (device-number 8 1))
- (mknod (scope "dev/vda2") 'block-special #o644 (device-number 8 2))
+ ;; Make the device nodes for SCSI disks.
+ (mknod (scope "dev/sda") 'block-special #o644 (device-number 8 0))
+ (mknod (scope "dev/sda1") 'block-special #o644 (device-number 8 1))
+ (mknod (scope "dev/sda2") 'block-special #o644 (device-number 8 2))
+
+ ;; The virtio (para-virtualized) block devices, as supported by QEMU/KVM.
+ (mknod (scope "dev/vda") 'block-special #o644 (device-number 252 0))
+ (mknod (scope "dev/vda1") 'block-special #o644 (device-number 252 1))
+ (mknod (scope "dev/vda2") 'block-special #o644 (device-number 252 2))
+
+ ;; 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))
;; 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)))
(device-number 4 n))
(loop (+ 1 n)))))
+ ;; 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.
- (mknod (scope "dev/null") 'char-special #o666 (device-number 1 3))
- (mknod (scope "dev/zero") 'char-special #o666 (device-number 1 5)))
+ ;; 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"))
+
+ ;; 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"))
(logand (network-interface-flags sock interface) IFF_UP)))
-(define (mount-qemu-smb-share share mount-point)
- "Mount QEMU's CIFS/SMB SHARE at MOUNT-POINT.
-
-Vanilla QEMU's `-smb' option just exports a /qemu share, whereas our
-`qemu-with-multiple-smb-shares' package exports the /xchg and /store shares
- (the latter allows the store to be shared between the host and guest.)"
-
- (format #t "mounting QEMU's SMB share `~a'...\n" share)
- (let ((server "10.0.2.4"))
- (mount (string-append "//" server share) mount-point "cifs" 0
- (string->pointer "guest,sec=none"))))
+;; Linux mount flags, from libc's <sys/mount.h>.
+(define MS_RDONLY 1)
+(define MS_BIND 4096)
+(define MS_MOVE 8192)
(define (bind-mount source target)
"Bind-mount SOURCE at TARGET."
- (define MS_BIND 4096) ; from libc's <sys/mount.h>
-
(mount source target "" MS_BIND))
(define (load-linux-module* file)
the last argument of `mknod'."
(+ (* major 256) minor))
+(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."
+ (catch #t
+ (lambda ()
+ (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.
+ (make-essential-device-nodes #:root "/rw-root")
+
+ ;; Make /root a union of the tmpfs and the actual root.
+ (unless (zero? (system* unionfs "-o"
+ "cow,allow_other,use_ino,suid,dev"
+ "/rw-root=RW:/real-root=RO"
+ "/root"))
+ (error "unionfs failed")))
+ (begin
+ (check-file-system root type)
+ (mount root "/root" type))))
+ (lambda args
+ (format (current-error-port) "exception while mounting '~a': ~s~%"
+ root args)
+ (start-repl)))
+
+ (copy-file "/proc/mounts" "/root/etc/mtab"))
+
+(define (check-file-system device type)
+ "Run a file system check of TYPE on DEVICE."
+ (define fsck
+ (string-append "fsck." type))
+
+ (let ((status (system* fsck "-v" "-p" device)))
+ (match (status:exit-val status)
+ (0
+ #t)
+ (1
+ (format (current-error-port) "'~a' corrected errors on ~a; continuing~%"
+ fsck device))
+ (2
+ (format (current-error-port) "'~a' corrected errors on ~a; rebooting~%"
+ fsck device)
+ (sleep 3)
+ (reboot))
+ (code
+ (format (current-error-port) "'~a' exited with code ~a on ~a; spawning REPL~%"
+ fsck code device)
+ (start-repl)))))
+
+(define* (mount-file-system spec #:key (root "/root"))
+ "Mount the file system described by SPEC under ROOT. SPEC must have the
+form:
+
+ (DEVICE MOUNT-POINT TYPE (FLAGS ...) OPTIONS CHECK?)
+
+DEVICE, MOUNT-POINT, and TYPE must be strings; OPTIONS can be a string or #f;
+FLAGS must be a list of symbols. CHECK? is a Boolean indicating whether to
+run a file system check."
+ (define flags->bit-mask
+ (match-lambda
+ (('read-only rest ...)
+ (or MS_RDONLY (flags->bit-mask rest)))
+ (('bind-mount rest ...)
+ (or MS_BIND (flags->bit-mask rest)))
+ (()
+ 0)))
+
+ (match spec
+ ((source mount-point type (flags ...) options check?)
+ (let ((mount-point (string-append root "/" mount-point)))
+ (when check?
+ (check-file-system source type))
+ (mkdir-p mount-point)
+ (mount source mount-point type (flags->bit-mask flags)
+ (if options
+ (string->pointer options)
+ %null-pointer))
+
+ ;; Update /etc/mtab.
+ (mkdir-p (string-append root "/etc"))
+ (let ((port (open-file (string-append root "/etc/mtab") "a")))
+ (format port "~a ~a ~a ~a 0 0~%"
+ source mount-point type options)
+ (close-port port))))))
+
+(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 '())
+ qemu-guest-networking?
+ guile-modules-in-chroot?
+ volatile-root?
+ (mounts '()))
+ "This procedure is meant to be called from an initrd. Boot a system by
+first loading LINUX-MODULES, then setting up QEMU guest networking if
+QEMU-GUEST-NETWORKING? is true, 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 GUILE-MODULES-IN-CHROOT? is true, make core Guile modules available in
+the new root.
+
+When VOLATILE-ROOT? is true, the root file system is writable but any changes
+to it are lost."
+ (define (resolve file)
+ ;; If FILE is a symlink to an absolute file name, resolve it as if we were
+ ;; under /root.
+ (let ((st (lstat file)))
+ (if (eq? 'symlink (stat:type st))
+ (let ((target (readlink file)))
+ (resolve (string-append "/root" target)))
+ file)))
+
+ (define root-mount-point?
+ (match-lambda
+ ((device "/" _ ...) #t)
+ (_ #f)))
+
+ (define root-fs-type
+ (or (any (match-lambda
+ ((device "/" type _ ...) type)
+ (_ #f))
+ mounts)
+ "ext4"))
+
+ (display "Welcome, this is GNU's early boot Guile.\n")
+ (display "Use '--repl' for an initrd REPL.\n\n")
+
+ (mount-essential-file-systems)
+ (let* ((args (linux-command-line))
+ (option (lambda (opt)
+ (let ((opt (string-append opt "=")))
+ (and=> (find (cut string-prefix? opt <>)
+ args)
+ (lambda (arg)
+ (substring arg (+ 1 (string-index arg #\=))))))))
+ (to-load (option "--load"))
+ (root (option "--root")))
+
+ (when (member "--repl" args)
+ (start-repl))
+
+ (display "loading kernel modules...\n")
+ (for-each (compose load-linux-module*
+ (cut string-append "/modules/" <>))
+ linux-modules)
+
+ (when qemu-guest-networking?
+ (unless (configure-qemu-networking)
+ (display "network interface is DOWN\n")))
+
+ ;; Make /dev nodes.
+ (make-essential-device-nodes)
+
+ ;; Prepare the real root file system under /root.
+ (unless (file-exists? "/root")
+ (mkdir "/root"))
+ (if root
+ (mount-root-file-system root root-fs-type
+ #:volatile-root? volatile-root?)
+ (mount "none" "/root" "tmpfs"))
+
+ (unless (file-exists? "/root/dev")
+ (mkdir "/root/dev")
+ (make-essential-device-nodes #:root "/root"))
+
+ ;; Mount the specified file systems.
+ (for-each mount-file-system
+ (remove root-mount-point? mounts))
+
+ (when guile-modules-in-chroot?
+ ;; Copy the directories that contain .scm and .go files so that the
+ ;; child process in the chroot can load modules (we would bind-mount
+ ;; them but for some reason that fails with EINVAL -- XXX).
+ (mkdir-p "/root/share")
+ (mkdir-p "/root/lib")
+ (mount "none" "/root/share" "tmpfs")
+ (mount "none" "/root/lib" "tmpfs")
+ (copy-recursively "/share" "/root/share"
+ #:log (%make-void-port "w"))
+ (copy-recursively "/lib" "/root/lib"
+ #:log (%make-void-port "w")))
+
+ (if to-load
+ (begin
+ (switch-root "/root")
+ (format #t "loading '~a'...\n" to-load)
+
+ ;; Obviously this has to be done each time we boot. Do it from here
+ ;; so that statfs(2) returns DEVPTS_SUPER_MAGIC like libc's getpt(3)
+ ;; expects (and thus openpty(3) and its users, such as xterm.)
+ (mount "none" "/dev/pts" "devpts")
+
+ ;; TODO: Remove /lib, /share, and /loader.go.
+ (catch #t
+ (lambda ()
+ (primitive-load to-load))
+ (lambda args
+ (format (current-error-port) "'~a' raised an exception: ~s~%"
+ to-load args)
+ (start-repl)))
+ (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
HCoop / jackhill / guix / guix.git / blobdiff