linux-command-line
make-essential-device-nodes
configure-qemu-networking
- mount-qemu-smb-share
- mount-qemu-9p
+ check-file-system
+ mount-file-system
bind-mount
load-linux-module*
device-number
(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
(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"))))
-
-(define (mount-qemu-9p source mount-point)
- "Mount QEMU's 9p file system from SOURCE at MOUNT-POINT.
-
-This uses the 'virtio' transport, which requires the various virtio Linux
-modules to be loaded."
-
- (format #t "mounting QEMU's 9p share '~a'...\n" source)
- (let ((server "10.0.2.4"))
- (mount source mount-point "9p" 0
- (string->pointer "trans=virtio"))))
+;; 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? unionfs
+ 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'.
-MOUNTS must be a list of elements of the form:
+Mount the root file system, specified by the '--root' command-line argument,
+if any.
- (FILE-SYSTEM-TYPE SOURCE TARGET)
+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.
(resolve (string-append "/root" target)))
file)))
- (define MS_RDONLY 1)
+ (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")
(unless (file-exists? "/root")
(mkdir "/root"))
(if root
- (catch #t
- (lambda ()
- (if volatile-root?
- (begin
- (mkdir-p "/real-root")
- (mount root "/real-root" "ext3" 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")))
- (mount root "/root" "ext3")))
- (lambda args
- (format (current-error-port) "exception while mounting '~a': ~s~%"
- root args)
- (start-repl)))
+ (mount-root-file-system root root-fs-type
+ #: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 (match-lambda
- (('cifs source target)
- (let ((target (string-append "/root/" target)))
- (mkdir-p target)
- (mount-qemu-smb-share source target)))
- (('9p source target)
- (let ((target (string-append "/root/" target)))
- (mkdir-p target)
- (mount-qemu-9p source target))))
- 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