bootloader: Use 'invoke/quiet' when running 'grub-install' and co.

This hides potentially confusing GRUB messages from the user, such as
"Installing for i386-pc platform."

* gnu/bootloader/extlinux.scm (install-extlinux): Use 'invoke/quiet'
instead of 'system*' and 'error'.
* gnu/bootloader/grub.scm (install-grub, install-grub-efi): Likewise.
* guix/scripts/system.scm (bootloader-installer-script): Guard against
'message-condition?' and handle them properly.

2 files changed, 11 insertions, 13 deletions

diff --git a/gnu/bootloader/extlinux.scm b/gnu/bootloader/extlinux.scm
index 2bb711eed13..40108584a8f 100644
--- a/gnu/bootloader/extlinux.scm
+++ b/gnu/bootloader/extlinux.scm
@@ -91,11 +91,9 @@ TIMEOUT ~a~%"
         (for-each (lambda (file)
                     (install-file file install-dir))
                   (find-files syslinux-dir "\\.c32$"))
-        (unless
-            (and (zero? (system* extlinux "--install" install-dir))
-                 (write-file-on-device
-                  (string-append syslinux-dir "/" #$mbr) 440 device 0))
-          (error "failed to install SYSLINUX")))))
+        (invoke/quiet extlinux "--install" install-dir)
+        (write-file-on-device (string-append syslinux-dir "/" #$mbr)
+                              440 device 0))))
 
 (define install-extlinux-mbr
   (install-extlinux "mbr.bin"))
diff --git a/gnu/bootloader/grub.scm b/gnu/bootloader/grub.scm
index 51d57873643..14aede72c5e 100644
--- a/gnu/bootloader/grub.scm
+++ b/gnu/bootloader/grub.scm
@@ -369,10 +369,11 @@ submenu \"GNU system, old configurations...\" {~%")
         ;; root partition.
         (setenv "GRUB_ENABLE_CRYPTODISK" "y")
 
-        (unless (zero? (system* grub "--no-floppy" "--target=i386-pc"
-                                "--boot-directory" install-dir
-                                device))
-          (error "failed to install GRUB (BIOS)")))))
+        ;; Hide potentially confusing messages from the user, such as
+        ;; "Installing for i386-pc platform."
+        (invoke/quiet grub "--no-floppy" "--target=i386-pc"
+                      "--boot-directory" install-dir
+                      device))))
 
 (define install-grub-efi
   #~(lambda (bootloader efi-dir mount-point)
@@ -388,10 +389,9 @@ submenu \"GNU system, old configurations...\" {~%")
         ;; Tell 'grub-install' that there might be a LUKS-encrypted /boot or
         ;; root partition.
         (setenv "GRUB_ENABLE_CRYPTODISK" "y")
-        (unless (zero? (system* grub-install "--boot-directory" install-dir
-                                "--bootloader-id=Guix"
-                                "--efi-directory" target-esp))
-          (error "failed to install GRUB (EFI)")))))
+        (invoke/quiet grub-install "--boot-directory" install-dir
+                      "--bootloader-id=Guix"
+                      "--efi-directory" target-esp))))