Make prim_file skip invalid filenames in unicode mode

The fix affects list_dir and read_link. Raw filenames are now
never produced, just consumed even if +fnu or +fna is used on
Linux etc.

This also adds the options to get error return or error handler
warning messages with +fn{u|a}{i|w|e} as an option to erl.

This is still not documented and there needs to be other versions
of read_dir and read_link to facilitate reading of all types
of filenames and links.

A check that we will not change to an invalid directory is also needed.

1 files changed, 11 insertions, 1 deletions

diff --git a/erts/preloaded/src/erl_prim_loader.erl b/erts/preloaded/src/erl_prim_loader.erl
index c2fac8c0fc..7490954f2d 100644
--- a/erts/preloaded/src/erl_prim_loader.erl
+++ b/erts/preloaded/src/erl_prim_loader.erl
@@ -150,7 +150,17 @@ start_it("inet", Id, Pid, Hosts) ->
 start_it("efile", Id, Pid, _Hosts) ->
     process_flag(trap_exit, true),
     {ok, Port} = prim_file:start(),
-    init_ack(Pid),
+    %% Check that we started in a valid directory.
+    case prim_file:get_cwd(Port) of
+	{error, _} ->
+	    %% At this point in the startup, we have no error_logger at all.
+	    Report = "Invalid current directory or invalid filename "
+		"mode: loader cannot read current directory\n",
+	    erlang:display(Report),
+	    exit({error, invalid_current_directory});
+	_ ->
+	    init_ack(Pid)
+    end,
     MultiGet = case erlang:system_info(thread_pool_size) of
                    0 -> false;
                    _ -> true