From a3383f5fdb09b4d2d79f24f793d7784d0886c909 Mon Sep 17 00:00:00 2001
From: e2r2fx <61915524+e2r2fx@users.noreply.github.com>
Date: Tue, 18 Mar 2025 10:41:51 -0400
Subject: [PATCH] expressvpn: fix daemon not able to modify resolv.conf
 (#379943)

* fix(expressvpn): daemon not able to modify resolv.conf

* update expressvpndFHS wrapper pname

* remove unnecessary copying of hosts's resolv.conf
---
 pkgs/by-name/ex/expressvpn/package.nix | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/pkgs/by-name/ex/expressvpn/package.nix b/pkgs/by-name/ex/expressvpn/package.nix
index f97ec3967ee2..641edd36cb72 100644
--- a/pkgs/by-name/ex/expressvpn/package.nix
+++ b/pkgs/by-name/ex/expressvpn/package.nix
@@ -49,13 +49,21 @@ let
   };
 
   expressvpndFHS = buildFHSEnv {
-    inherit pname version;
+    inherit version;
+    pname = "expressvpnd";
 
     # When connected, it directly creates/deletes resolv.conf to change the DNS entries.
     # Since it's running in an FHS environment, it has no effect on actual resolv.conf.
     # Hence, place a watcher that updates host resolv.conf when FHS resolv.conf changes.
+
+    # Mount the host's resolv.conf to the container's /etc/resolv.conf
     runScript = writeScript "${pname}-wrapper" ''
-      cp /host/etc/resolv.conf /etc/resolv.conf;
+      mkdir -p /host/etc
+      [ -e /host/etc/resolv.conf ] || touch /host/etc/resolv.conf
+      mount --bind /etc/resolv.conf /host/etc/resolv.conf
+      mount -o remount,rw /host/etc/resolv.conf
+      trap "umount /host/etc/resolv.conf" EXIT
+
       while inotifywait /etc 2>/dev/null;
       do
         cp /etc/resolv.conf /host/etc/resolv.conf;