From 5ee79c57228cda29883dd61fd75dc4e5c05ea7b6 Mon Sep 17 00:00:00 2001
From: Lluis Batlle <viriketo@gmail.com>
Date: Mon, 24 Sep 2012 00:14:43 +0200
Subject: [PATCH] Adding a parameter 'ttyEmergency'

It specifies what mingetty will be stopped, if a bad filesystem
triggers an emergency shell.

That should be ttyS0 on headless systems, and in that case,
nixos should stop the ttyS0 mingetty from getting in.
---
 modules/tasks/filesystems.nix | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/modules/tasks/filesystems.nix b/modules/tasks/filesystems.nix
index 9495cac67855..5d6e4a4a3697 100644
--- a/modules/tasks/filesystems.nix
+++ b/modules/tasks/filesystems.nix
@@ -156,6 +156,16 @@ in
       description = "Names of supported filesystem types in the initial ramdisk.";
     };
 
+    boot.ttyEmergency = mkOption {
+      default =
+        if pkgs.stdenv.isArm
+          then "ttyS0" # presumably an embedded platform such as a plug
+        else "tty1";
+      description = ''
+        The tty that will be stopped in case an emergency shell is spawned
+        at boot.
+        '';
+    };
   };
 
 
@@ -247,7 +257,7 @@ in
             status="$(status xserver || true)"
             [[ "$status" =~ start/ ]] && exit 0
 
-            stop tty1 || true
+            stop ${config.boot.ttyEmergency} || true
             
             start --no-wait emergency-shell \
               DEVICE="$DEVICE" MOUNTPOINT="$MOUNTPOINT"