3 files changed, 22 insertions, 3 deletions
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index f5f4f15f011f..bfb40a07a237 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -113,6 +113,7 @@ void Settings::loadConfFile()
 void Settings::set(const string & name, const string & value)
 {
     settings[name] = value;
+    overrides[name] = value;
 }
 
 
@@ -193,4 +194,10 @@ string Settings::pack()
 }
 
 
+Settings::SettingsMap Settings::getOverrides()
+{
+    return overrides;
+}
+
+
 }
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 5783d9bf37ba..1fb196db2924 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -10,6 +10,8 @@ namespace nix {
 
 struct Settings {
 
+    typedef std::map<string, string> SettingsMap;
+
     Settings();
 
     void processEnvironment();
@@ -22,6 +24,8 @@ struct Settings {
 
     string pack();
 
+    SettingsMap getOverrides();
+
     /* The directory where we store sources and derived files. */
     Path nixStore;
 
@@ -172,9 +176,7 @@ struct Settings {
     bool envKeepDerivations;
 
 private:
-    typedef std::map<string, string> SettingsMap;
-
-    SettingsMap settings;
+    SettingsMap settings, overrides;
 
     void get(string & res, const string & name);
     void get(bool & res, const string & name);
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index c67e53bfb87e..56396541adec 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -184,6 +184,7 @@ RemoteStore::~RemoteStore()
 void RemoteStore::setOptions()
 {
     writeInt(wopSetOptions, to);
+
     writeInt(settings.keepFailed, to);
     writeInt(settings.keepGoing, to);
     writeInt(settings.tryFallback, to);
@@ -202,6 +203,15 @@ void RemoteStore::setOptions()
     if (GET_PROTOCOL_MINOR(daemonVersion) >= 10)
         writeInt(settings.useSubstitutes, to);
 
+    if (GET_PROTOCOL_MINOR(daemonVersion) >= 12) {
+        Settings::SettingsMap overrides = settings.getOverrides();
+        writeInt(overrides.size(), to);
+        foreach (Settings::SettingsMap::iterator, i, overrides) {
+            writeString(i->first, to);
+            writeString(i->second, to);
+        }
+    }
+
     processStderr();
 }