install: Register agetty on primary console on AArch64.

This adds the possibility to parse /proc/consoles to find a primary console.
Then, on AArch64 this is used in the installation image. On AArch64, the boot
usually happens with chosen device tree that contains the serial console.
On x86_64, this does not happen so often, so we keep the installation iso
minimal there.

The primary console is chosen, but there is a fallback to any non-virtual one.
Virtual console (/dev/tty0) is skipped, because that one can point to any
console, like /dev/tty1 and so on. So it's not safe to register agetty on it.

* gnu/build/linux-boot.scm (read-linux-consoles): New variable.
* gnu/services/base.scm (default-serial-console): Use primary console as
fallback.
* gnu/system/install.scm (%installation-services): Add agetty tty for
consoles.

Change-Id: Iae01f7bc85b5ffdef2e52b1d0710889915b0f54a
Signed-off-by: Rutherther <rutherther@ditigal.xyz>

1 files changed, 11 insertions, 0 deletions

diff --git a/gnu/system/install.scm b/gnu/system/install.scm
index e5dfdbb427b..80332b7b534 100644
--- a/gnu/system/install.scm
+++ b/gnu/system/install.scm
@@ -483,6 +483,17 @@ Access documentation at any time by pressing Alt-F2.\x1b[0m
 
      ;; Specific system services
 
+     ;; AArch64 has a better detection of consoles, mainly because device
+     ;; trees are utilized.  On x86_64, the detection is usually done
+     ;; through BIOS and consoles do not get registered to /proc/console.
+     ;; The only way they would is if the user used console linux argument.
+     `(,@(if (target-aarch64? system)
+             (list (service agetty-service-type
+                            (agetty-configuration (tty #f)
+                                                  (auto-login "root")
+                                                  (login-pause? #t))))
+             '()))
+
      ;; Machines without Kernel Mode Setting (those with many old and
      ;; current AMD GPUs, SiS GPUs, ...) need uvesafb to show the GUI
      ;; installer.  Some may also need a kernel parameter like nomodeset