Don't attempt to access(2) a certificate file

Fixes #1375

src/ejabberd_config.erl

@@ -28,7 +28,7 @@
 
 -export([start/0, load_file/1, reload_file/0, read_file/1,
 	 get_option/1, get_option/2, add_option/2, has_option/1,
-	 get_vh_by_auth_method/1, is_file_readable/1,
+	 get_vh_by_auth_method/1,
 	 get_version/0, get_myhosts/0, get_mylang/0, get_lang/1,
 	 get_ejabberd_config_path/0, is_using_elixir_config/0,
 	 prepare_opt_val/4, transform_options/1, collect_options/1,
@@ -46,11 +46,12 @@
 	 get_global_option/2, get_local_option/2,
 	 get_global_option/3, get_local_option/3,
 	 get_option/3]).
+-export([is_file_readable/1]).
 
 -deprecated([{add_global_option, 2}, {add_local_option, 2},
 	     {get_global_option, 2}, {get_local_option, 2},
 	     {get_global_option, 3}, {get_local_option, 3},
-	     {get_option, 3}]).
+	     {get_option, 3}, {is_file_readable, 1}]).
 
 -include("ejabberd.hrl").
 -include("logger.hrl").

src/misc.erl

@@ -204,22 +204,12 @@ join_atoms(Atoms, Sep) ->
 %%      in configuration validators only.
 -spec try_read_file(file:filename_all()) -> binary().
 try_read_file(Path) ->
-    Res = case file:read_file_info(Path) of
-	      {ok, #file_info{type = Type, access = Access}} ->
-		  case {Type, Access} of
-		      {regular, read} -> ok;
-		      {regular, read_write} -> ok;
-		      {regular, _} -> {error, file:format_error(eaccess)};
-		      _ -> {error, "not a regular file"}
-		  end;
-	      {error, Why} ->
-		  {error, file:format_error(Why)}
-	  end,
-    case Res of
-	ok ->
+    case file:open(Path, [read]) of
+	{ok, Fd} ->
+	    file:close(Fd),
 	    iolist_to_binary(Path);
-	{error, Reason} ->
-	    ?ERROR_MSG("Failed to read ~s: ~s", [Path, Reason]),
+	{error, Why} ->
+	    ?ERROR_MSG("Failed to read ~s: ~s", [Path, file:format_error(Why)]),
 	    erlang:error(badarg)
     end.