From bb030ece3b4dc6ca892907927345e8d109e42678 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 7 Feb 2018 17:23:05 +0100
Subject: [PATCH] nixos-enter: Check whether --root denotes a NixOS
 installation

---
 nixos/modules/installer/tools/nixos-enter.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/nixos/modules/installer/tools/nixos-enter.sh b/nixos/modules/installer/tools/nixos-enter.sh
index 96b6a017b810..fcd0c54f5db9 100644
--- a/nixos/modules/installer/tools/nixos-enter.sh
+++ b/nixos/modules/installer/tools/nixos-enter.sh
@@ -45,6 +45,11 @@ while [ "$#" -gt 0 ]; do
     esac
 done
 
+if [[ ! -e $mountPoint/etc/NIXOS ]]; then
+    echo "$0: '$mountPoint' is not a NixOS installation" >&2
+    exit 126
+fi
+
 mkdir -m 0755 -p "$mountPoint/dev"
 mount --rbind /dev "$mountPoint/dev"