From ed06dd12ea74018b902a2c4c7924313d23cedb75 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Fri, 9 May 2014 12:35:22 +0200 Subject: Make pre-loaded modules permanently sticky Modules in the kernel, stdlib, and compiler applications are by default "sticky", meaning that the code server will refuse to re-load them. The pre-loaded modules (those that are part of the run-time system itself, such as 'erlang') are, however, not sticky. They used to be sticky a long time ago when the pre-loaded modules were part of the kernel application. Now they are part of the erts application. Since re-loading a pre-loaded module can be catastrophic (especially re-loading the 'erlang' module), the pre-loaded modules must be sticky. Furthermore, it should not be allowed to unstick them. The sticky_dir/1 test case in code_SUITE is never actually run and is broken. Rewrite it. --- lib/kernel/src/code_server.erl | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'lib/kernel/src/code_server.erl') diff --git a/lib/kernel/src/code_server.erl b/lib/kernel/src/code_server.erl index f891cb61c4..dd06affd70 100644 --- a/lib/kernel/src/code_server.erl +++ b/lib/kernel/src/code_server.erl @@ -63,7 +63,10 @@ init(Ref, Parent, [Root,Mode0]) -> process_flag(trap_exit, true), Db = ets:new(code, [private]), - foreach(fun (M) -> ets:insert(Db, {M,preloaded}) end, erlang:pre_loaded()), + foreach(fun (M) -> + %% Pre-loaded modules are always sticky. + ets:insert(Db, [{M,preloaded},{{sticky,M},true}]) + end, erlang:pre_loaded()), ets:insert(Db, init:fetch_loaded()), Mode = @@ -1165,7 +1168,7 @@ stick_dir(Dir, Stick, St) -> true -> foreach(fun (M) -> ets:insert(Db, {{sticky,M},true}) end, Mods); false -> - foreach(fun (M) -> ets:delete(Db, {sticky,M}) end, Mods) + foreach(fun (M) -> do_unstick_mod(Db, M) end, Mods) end; Error -> Error @@ -1177,6 +1180,15 @@ stick_mod(M, Stick, St) -> true -> ets:insert(Db, {{sticky,M},true}); false -> + do_unstick_mod(Db, M) + end. + +do_unstick_mod(Db, M) -> + case ets:lookup(Db, M) of + [{M,preloaded}] -> + %% Never unstick pre-loaded modules. + true; + _ -> ets:delete(Db, {sticky,M}) end. -- cgit v1.2.3