2 files changed, 6 insertions, 1 deletions

diff --git a/src/luarocks/cfg.lua b/src/luarocks/cfg.lua
index ea80e5b5..b4781840 100644
--- a/src/luarocks/cfg.lua
+++ b/src/luarocks/cfg.lua
@@ -139,7 +139,7 @@ else
    cfg.home = os.getenv("HOME") or ""
    sys_config_dir = sys_config_dir or "/etc/luarocks"
    home_config_dir = cfg.home.."/.luarocks"
-   cfg.home_tree = cfg.home.."/.luarocks/"
+   cfg.home_tree = (os.getenv("USER") ~= "root") and cfg.home.."/.luarocks/"
 end
 
 cfg.variables = {}
diff --git a/src/luarocks/command_line.lua b/src/luarocks/command_line.lua
index c885575e..a92a3f9d 100644
--- a/src/luarocks/command_line.lua
+++ b/src/luarocks/command_line.lua
@@ -153,6 +153,11 @@ function command_line.run_command(...)
          replace_tree(flags, args, root_dir)
       end
    elseif flags["local"] then
+      if not cfg.home_tree then
+         die("The --local flag is meant for operating in a user's home directory.\n"..
+             "You are running as a superuser, which is intended for system-wide operation.\n"..
+             "To force using the superuser's home, use --tree explicitly.")
+      end
       replace_tree(flags, args, cfg.home_tree)
    else
       local trees = cfg.rocks_trees