diff --git a/pkgs/servers/samba/default.nix b/pkgs/servers/samba/default.nix
index 0464943f8369..64b7c5fc7de4 100644
--- a/pkgs/servers/samba/default.nix
+++ b/pkgs/servers/samba/default.nix
@@ -1,5 +1,15 @@
 { stdenv, fetchurl, readline, pam, openldap, kerberos, popt
 , iniparser, libunwind, fam, acl
+
+# Eg. smbclient and smbspool require a smb.conf file.
+# If you set configDir to "" an empty configuration file
+# $out/lib/smb.conf is is created for you.
+#
+# configDir defaults to "/etc/samba" so that smbpassword picks up
+# the location of its passwd db files from the system configuration file
+# /etc/samba/smb.conf. That's why nixos touches /etc/samba/smb.conf even if you
+# don't enable the samba upstart service.
+, configDir ? "/etc/samba"
 }:
 
 stdenv.mkDerivation rec {
@@ -14,11 +24,14 @@ stdenv.mkDerivation rec {
 
   preConfigure = "cd source";
 
-  # Provide a dummy smb.conf to shut up programs like smbclient and smbspool.
-  postInstall = ''
-    touch $out/lib/smb.conf
-  '';
-  
+  postInstall = if configDir == ""
+    then "touch $out/lib/smb.conf"
+    else "";
+
+
+  # Don't pass --with-private-dir=/var/samba/private
+  #            --with-lockdir=/var/samba/lock
+  # the build system will try to create it.
   configureFlags = ''
     --with-pam
     --with-cifsmount
@@ -26,6 +39,7 @@ stdenv.mkDerivation rec {
     --with-pam_smbpass
     --disable-swat
     --enable-shared-libs
+    --with-configdir=${configDir}
     ${if stdenv.gcc.libc != null then "--with-libiconv=${stdenv.gcc.libc}" else ""}
   '';
 }
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 8fc08770b091..9e1104a90c61 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4482,7 +4482,7 @@ let
     inherit xmpppy python makeWrapper fetchcvs;
   };
 
-  samba = import ../servers/samba {
+  samba = makeOverridable (import ../servers/samba) {
     inherit stdenv fetchurl readline openldap pam kerberos popt iniparser
   libunwind acl fam;
   };