system: reconfigure: Use the disk-installer if provided.

[jackhill/guix/guix.git] / gnu / build / bootloader.scm

diff --git a/gnu/build/bootloader.scm b/gnu/build/bootloader.scm
index 9570d6d..3916930 100644 (file)
--- a/gnu/build/bootloader.scm
+++ b/gnu/build/bootloader.scm
@@ -18,8 +18,14 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (gnu build bootloader)
+  #:use-module (guix build utils)
+  #:use-module (guix utils)
   #:use-module (ice-9 binary-ports)
-  #:export (write-file-on-device))
+  #:use-module (ice-9 format)
+  #:use-module (rnrs io ports)
+  #:use-module (rnrs io simple)
+  #:export (write-file-on-device
+            install-efi-loader))
 
 \f
 ;;;
@@ -31,8 +37,64 @@
   (call-with-input-file file
     (lambda (input)
       (let ((bv (get-bytevector-n input size)))
-        (call-with-output-file device
-          (lambda (output)
-            (seek output offset SEEK_SET)
-            (put-bytevector output bv))
-          #:binary #t)))))
+        (call-with-port
+         ;; Do not use "call-with-output-file" that would truncate the file.
+         (open-file-output-port device
+                                (file-options no-truncate no-fail)
+                                (buffer-mode block)
+                                ;; Use the binary-friendly ISO-8859-1
+                                ;; encoding.
+                                (make-transcoder (latin-1-codec)))
+         (lambda (output)
+           (seek output offset SEEK_SET)
+           (put-bytevector output bv)))))))
+
+\f
+;;;
+;;; EFI bootloader.
+;;;
+
+(define (install-efi grub grub-config esp)
+  "Write a self-contained GRUB EFI loader to the mounted ESP using GRUB-CONFIG."
+  (let* ((system %host-type)
+         ;; Hard code the output location to a well-known path recognized by
+         ;; compliant firmware. See "3.5.1.1 Removable Media Boot Behaviour":
+         ;; http://www.uefi.org/sites/default/files/resources/UEFI%20Spec%202_6.pdf
+         (grub-mkstandalone (string-append grub "/bin/grub-mkstandalone"))
+         (efi-directory (string-append esp "/EFI/BOOT"))
+         ;; Map grub target names to boot file names.
+         (efi-targets (cond ((string-prefix? "x86_64" system)
+                             '("x86_64-efi" . "BOOTX64.EFI"))
+                            ((string-prefix? "i686" system)
+                             '("i386-efi" . "BOOTIA32.EFI"))
+                            ((string-prefix? "armhf" system)
+                             '("arm-efi" . "BOOTARM.EFI"))
+                            ((string-prefix? "aarch64" system)
+                             '("arm64-efi" . "BOOTAA64.EFI")))))
+    ;; grub-mkstandalone requires a TMPDIR to prepare the firmware image.
+    (setenv "TMPDIR" esp)
+
+    (mkdir-p efi-directory)
+    (invoke grub-mkstandalone "-O" (car efi-targets)
+            "-o" (string-append efi-directory "/"
+                                (cdr efi-targets))
+            ;; Graft the configuration file onto the image.
+            (string-append "boot/grub/grub.cfg=" grub-config))))
+
+(define (install-efi-loader grub-efi esp)
+  "Install in ESP directory the given GRUB-EFI bootloader.  Configure it to
+load the Grub bootloader located in the 'Guix_image' root partition."
+  (let ((grub-config "grub.cfg"))
+    (call-with-output-file grub-config
+      (lambda (port)
+        ;; Create a tiny configuration file telling the embedded grub where to
+        ;; load the real thing.  XXX This is quite fragile, and can prevent
+        ;; the image from booting when there's more than one volume with this
+        ;; label present.  Reproducible almost-UUIDs could reduce the risk
+        ;; (not eliminate it).
+        (format port
+                "insmod part_msdos~@
+               search --set=root --label Guix_image~@
+               configfile /boot/grub/grub.cfg~%")))
+    (install-efi grub-efi grub-config esp)
+    (delete-file grub-config)))