erts: Introduce erts_code_purger

as a system process with preloaded code.

6 files changed, 65 insertions, 2 deletions

diff --git a/erts/emulator/Makefile.in b/erts/emulator/Makefile.in
index 8cf435905b..f4b806fae9 100644
--- a/erts/emulator/Makefile.in
+++ b/erts/emulator/Makefile.in
@@ -591,6 +591,7 @@ ifeq ($(TARGET),win32)
 PRELOAD_OBJ = $(OBJDIR)/beams.$(RES_EXT)
 PRELOAD_SRC = $(TARGET)/beams.rc
 $(PRELOAD_SRC): $(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
+			$(ERL_TOP)/erts/preloaded/ebin/erts_code_purger.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/init.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/prim_eval.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/prim_inet.beam \
@@ -600,11 +601,13 @@ $(PRELOAD_SRC): $(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erl_prim_loader.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erlang.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erts_internal.beam
+
 	$(gen_verbose)LANG=C $(PERL) utils/make_preload $(MAKE_PRELOAD_EXTRA) -rc $^ > $@
 else
 PRELOAD_OBJ = $(OBJDIR)/preload.o
 PRELOAD_SRC = $(TARGET)/preload.c
 $(PRELOAD_SRC): $(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
+			$(ERL_TOP)/erts/preloaded/ebin/erts_code_purger.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/init.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/prim_eval.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/prim_inet.beam \
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 58ef09662c..42aca726bf 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -439,6 +439,29 @@ erl_first_process_otp(char* modname, void* code, unsigned size, int argc, char**
     return res;
 }
 
+static Eterm
+erl_system_process_otp(Eterm parent_pid, char* modname)
+{
+    Eterm start_mod;
+    Process* parent;
+    ErlSpawnOpts so;
+    Eterm res;
+
+    start_mod = erts_atom_put((byte *) modname, sys_strlen(modname), ERTS_ATOM_ENC_LATIN1, 1);
+    if (erts_find_function(start_mod, am_start, 0,
+			   erts_active_code_ix()) == NULL) {
+	erl_exit(5, "No function %s:start/0\n", modname);
+    }
+
+    parent = erts_pid2proc(NULL, 0, parent_pid, ERTS_PROC_LOCK_MAIN);
+
+    so.flags = erts_default_spo_flags|SPO_SYSTEM_PROC;
+    res = erl_create_process(parent, start_mod, am_start, NIL, &so);
+    erts_smp_proc_unlock(parent, ERTS_PROC_LOCK_MAIN);
+    return res;
+}
+
+
 Eterm
 erts_preloaded(Process* p)
 {
@@ -1234,6 +1257,7 @@ erl_start(int argc, char **argv)
     ErtsTimeWarpMode time_warp_mode;
     int node_tab_delete_delay = ERTS_NODE_TAB_DELAY_GC_DEFAULT;
     ErtsDbSpinCount db_spin_count = ERTS_DB_SPNCNT_NORMAL;
+    Eterm otp_ring0_pid;
 
     set_default_time_adj(&time_correction,
 			 &time_warp_mode);
@@ -2183,8 +2207,10 @@ erl_start(int argc, char **argv)
 
     erts_initialized = 1;
 
-    (void) erl_first_process_otp("otp_ring0", NULL, 0,
-				 boot_argc, boot_argv);
+    otp_ring0_pid = erl_first_process_otp("otp_ring0", NULL, 0,
+					  boot_argc, boot_argv);
+
+    (void) erl_system_process_otp(otp_ring0_pid, "erts_code_purger");
 
 #ifdef ERTS_SMP
     erts_start_schedulers();
diff --git a/erts/preloaded/ebin/erts_code_purger.beam b/erts/preloaded/ebin/erts_code_purger.beam
new file mode 100644
index 0000000000..176497b052
--- /dev/null
+++ b/erts/preloaded/ebin/erts_code_purger.beam
diff --git a/erts/preloaded/src/Makefile b/erts/preloaded/src/Makefile
index 52034a0881..31383dda83 100644
--- a/erts/preloaded/src/Makefile
+++ b/erts/preloaded/src/Makefile
@@ -41,6 +41,7 @@ PRE_LOADED_ERL_MODULES = \
 	zlib \
 	prim_zip \
 	otp_ring0 \
+	erts_code_purger \
 	erlang \
 	erts_internal
 
diff --git a/erts/preloaded/src/erts.app.src b/erts/preloaded/src/erts.app.src
index 8442aaf7e8..e53b6e5bab 100644
--- a/erts/preloaded/src/erts.app.src
+++ b/erts/preloaded/src/erts.app.src
@@ -27,6 +27,7 @@
 		erts_internal,
 		init,
 		otp_ring0,
+		erts_code_purger,
 		prim_eval,
 		prim_file,
 		prim_inet,
diff --git a/erts/preloaded/src/erts_code_purger.erl b/erts/preloaded/src/erts_code_purger.erl
new file mode 100644
index 0000000000..1ef4d096b7
--- /dev/null
+++ b/erts/preloaded/src/erts_code_purger.erl
@@ -0,0 +1,32 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(erts_code_purger).
+
+%% Purpose : Implement system process erts_code_purger
+%%           to handle code module purging.
+
+-export([start/0]).
+
+-spec start() -> term().
+start() ->
+    receive M ->
+	    erlang:display({"erts_code_purger got msg", M})
+    end,
+    start().