linux-command-line
make-essential-device-nodes
configure-qemu-networking
+ check-file-system
mount-file-system
bind-mount
load-linux-module*
(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
;; 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."
(+ (* major 256) minor))
(define* (mount-root-file-system root type
- #:key volatile-root? unionfs)
+ #: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."
"/rw-root=RW:/real-root=RO"
"/root"))
(error "unionfs failed")))
- (mount root "/root" type)))
+ (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))))
+ (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)
+ (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."
+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 ...)
0)))
(match spec
- ((source mount-point type (flags ...) options)
+ ((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))))))
+ %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? unionfs
- (root-fs-type "ext4")
+ 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
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, of type ROOT-FS-TYPE, specified by the '--root'
-command-line argument, if any.
+Mount the root file system, specified by the '--root' command-line argument,
+if any.
MOUNTS must be a list suitable for 'mount-file-system'.
(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")
(mkdir "/root"))
(if root
(mount-root-file-system root root-fs-type
- #:volatile-root? volatile-root?
- #:unionfs unionfs)
+ #:volatile-root? volatile-root?)
(mount "none" "/root" "tmpfs"))
- (mount-essential-file-systems #:root "/root")
-
(unless (file-exists? "/root/dev")
(mkdir "/root/dev")
(make-essential-device-nodes #:root "/root"))
;; Mount the specified file systems.
- (for-each mount-file-system mounts)
+ (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
(if to-load
(begin
+ (switch-root "/root")
(format #t "loading '~a'...\n" to-load)
- (chdir "/root")
- (chroot "/root")
;; 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)
HCoop / jackhill / guix / guix.git / blobdiff