Tolerate bad directories in the code path

A bad directory in the path would prevent the run-time system
from starting:

$ echo >foobar
$ erl -pa foobar
{"init terminating in do_boot",{load_failed,[supervisor,kernel,gen_server,file_io_server,filename,file,erl_parse,error_logger,code_server,erl_lint,proc_lib,code,application_controller,application_master,gen_event,application,error_handler,lists,heart,gen,file_server,ets,erl_eval]}}

Crash dump is being written to: erl_crash.dump...done
init terminating in do_boot ()

The reason is that when attempting to read each of the BEAM files,
there would be an 'enotdir' error which
erl_prim_load:get_modules/2,3 assumed was a fatal error.

Update erl_prim_load:get_modules/2,3 to ignore any error and try
the next directory in the path.

Reported-by: http://bugs.erlang.org/browse/ERL-142
Reported-by: Michael Truog

3 files changed, 21 insertions, 9 deletions

diff --git a/erts/preloaded/ebin/erl_prim_loader.beam b/erts/preloaded/ebin/erl_prim_loader.beam
index de2693472a..66e443f396 100644
--- a/erts/preloaded/ebin/erl_prim_loader.beam
+++ b/erts/preloaded/ebin/erl_prim_loader.beam
diff --git a/erts/preloaded/src/erl_prim_loader.erl b/erts/preloaded/src/erl_prim_loader.erl
index e18e187cb7..b3ec73a60e 100644
--- a/erts/preloaded/src/erl_prim_loader.erl
+++ b/erts/preloaded/src/erl_prim_loader.erl
@@ -558,11 +558,9 @@ efile_gm_get_1([P|Ps], File0, Mod, {Parent,Ref}=PR, Process) ->
     Res = try prim_file:read_file(File) of
 	      {ok,Bin} ->
 		  gm_process(Mod, File, Bin, Process);
-	      {error,enoent} ->
-		  efile_gm_get_1(Ps, File0, Mod, PR, Process);
 	      Error ->
-		  check_file_result(get_modules, File, Error),
-		  Error
+		  _ = check_file_result(get_modules, File, Error),
+		  efile_gm_get_1(Ps, File0, Mod, PR, Process)
 	  catch
 	      _:Reason ->
 		  {error,{crash,Reason}}
diff --git a/lib/kernel/test/erl_prim_loader_SUITE.erl b/lib/kernel/test/erl_prim_loader_SUITE.erl
index 4f3881d27e..b6417210b9 100644
--- a/lib/kernel/test/erl_prim_loader_SUITE.erl
+++ b/lib/kernel/test/erl_prim_loader_SUITE.erl
@@ -108,13 +108,18 @@ get_file(Config) when is_list(Config) ->
     error = erl_prim_loader:get_file({dummy}),
     ok.
 
-get_modules(_Config) ->
+get_modules(Config) ->
     case test_server:is_cover() of
-	false -> do_get_modules();
+	false -> do_get_modules(Config);
 	true -> {skip,"Cover"}
     end.
 
-do_get_modules() ->
+do_get_modules(Config) ->
+    PrivDir = proplists:get_value(priv_dir, Config),
+    NotADir = atom_to_list(?FUNCTION_NAME) ++ "_not_a_dir",
+    ok = file:write_file(filename:join(PrivDir, NotADir), <<>>),
+    ok = file:set_cwd(PrivDir),
+
     MsGood = lists:sort([lists,gen_server,gb_trees,code_server]),
     Ms = [certainly_not_existing|MsGood],
     SuccExp = [begin
@@ -129,8 +134,10 @@ do_get_modules() ->
 
     Path = code:get_path(),
     Process = fun(_, F, Code) -> {ok,{F,erlang:md5(Code)}} end,
-    {ok,{Succ,FailExp}} = erl_prim_loader:get_modules(Ms, Process, Path),
-    SuccExp = lists:sort(Succ),
+    {ok,{SuccExp,FailExp}} = get_modules_sorted(Ms, Process, Path),
+
+    %% Test that an 'enotdir' error can be handled.
+    {ok,{SuccExp,FailExp}} = get_modules_sorted(Ms, Process, [NotADir|Path]),
 
     Name = inet_get_modules,
     {ok, Node, BootPid} = complete_start_node(Name),
@@ -147,6 +154,13 @@ do_get_modules() ->
 
     ok.
 
+get_modules_sorted(Ms, Process, Path) ->
+    case erl_prim_loader:get_modules(Ms, Process, Path) of
+	{ok,{Succ,FailExp}} ->
+	    {ok,{lists:sort(Succ),lists:sort(FailExp)}};
+	Other ->
+	    Other
+    end.
 
 normalize_and_backslash(Config) ->
     %% Test OTP-11170