erts: Add erlang:system_flag(system_logger,_)

This flag allows logger and other components to set the
process which log messages from ERTS are to be sent.

4 files changed, 42 insertions, 64 deletions

diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index f1fac7f8d0..b13c6c90c6 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -4701,6 +4701,9 @@ BIF_RETTYPE system_flag_2(BIF_ALIST_2)
 	return erts_bind_schedulers(BIF_P, BIF_ARG_2);
     } else if (ERTS_IS_ATOM_STR("erts_alloc", BIF_ARG_1)) {
         return erts_alloc_set_dyn_param(BIF_P, BIF_ARG_2);
+    } else if (ERTS_IS_ATOM_STR("system_logger", BIF_ARG_1)) {
+        Eterm res = erts_set_system_logger(BIF_ARG_2);
+        if (is_value(res)) BIF_RET(res);
     }
     error:
     BIF_ERROR(BIF_P, BADARG);
@@ -5203,61 +5206,6 @@ erts_call_dirty_bif(ErtsSchedulerData *esdp, Process *c_p, BeamInstr *I, Eterm *
     return exiting;
 }
 
-
-
-#ifdef HARDDEBUG
-/*
-You'll need this line in bif.tab to be able to use this debug bif
-
-bif erlang:send_to_logger/2
-
-*/
-BIF_RETTYPE send_to_logger_2(BIF_ALIST_2)
-{
-    byte *buf;
-    ErlDrvSizeT len;
-    if (!is_atom(BIF_ARG_1) || !(is_list(BIF_ARG_2) ||
-				 is_nil(BIF_ARG_1))) {
-	BIF_ERROR(BIF_P,BADARG);
-    }
-    if (erts_iolist_size(BIF_ARG_2, &len) != 0)
-	BIF_ERROR(BIF_P,BADARG);
-    else if (len == 0)
-	buf = "";
-    else {
-#ifdef DEBUG
-	ErlDrvSizeT len2;
-#endif
-	buf = (byte *) erts_alloc(ERTS_ALC_T_TMP, len+1);
-#ifdef DEBUG
-	len2 =
-#else
-	(void)
-#endif
-	    erts_iolist_to_buf(BIF_ARG_2, buf, len);
-	ASSERT(len2 == len);
-	buf[len] = '\0';
-	switch (BIF_ARG_1) {
-	case am_info:
-	    erts_send_info_to_logger(BIF_P->group_leader, buf, len);
-	    break;
-	case am_warning:
-	    erts_send_warning_to_logger(BIF_P->group_leader, buf, len);
-	    break;
-	case am_error:
-	    erts_send_error_to_logger(BIF_P->group_leader, buf, len);
-	    break;
-	default:
-	{
-	    BIF_ERROR(BIF_P,BADARG);
-	}
-	}
-	erts_free(ERTS_ALC_T_TMP, (void *) buf);
-    }
-    BIF_RET(am_true);
-}
-#endif /* HARDDEBUG */
-
 BIF_RETTYPE get_module_info_1(BIF_ALIST_1)
 {
     Eterm ret = erts_module_info_0(BIF_P, BIF_ARG_1);
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 7fada0d548..9cc95a5c09 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -3139,6 +3139,8 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 	DECL_AM(tag);
 	BIF_RET(AM_tag);
 #endif
+    } else if (ERTS_IS_ATOM_STR("system_logger", BIF_ARG_1)) {
+        BIF_RET(erts_get_system_logger());
     }
 
     BIF_ERROR(BIF_P, BADARG);
diff --git a/erts/emulator/beam/erl_trace.c b/erts/emulator/beam/erl_trace.c
index 2350d4c02f..701fb38147 100644
--- a/erts/emulator/beam/erl_trace.c
+++ b/erts/emulator/beam/erl_trace.c
@@ -72,6 +72,7 @@ static ErtsTracer default_port_tracer;
 
 static Eterm system_monitor;
 static Eterm system_profile;
+static erts_aint_t system_logger;
 
 #ifdef HAVE_ERTS_NOW_CPU
 int erts_cpu_timestamp;
@@ -340,6 +341,7 @@ void erts_init_trace(void) {
     default_port_trace_flags = F_INITIAL_TRACE_FLAGS;
     default_port_tracer = erts_tracer_nil;
     system_seq_tracer = erts_tracer_nil;
+    erts_atomic_init_nob(&system_logger, am_logger);
     init_sys_msg_dispatcher();
     init_tracer_nif();
 }
@@ -2027,10 +2029,24 @@ enqueue_sys_msg(enum ErtsSysMsgType type,
     erts_mtx_unlock(&smq_mtx);
 }
 
+Eterm
+erts_get_system_logger(void)
+{
+    return (Eterm)erts_atomic_read_nob(&system_logger);
+}
+
+Eterm
+erts_set_system_logger(Eterm logger)
+{
+    if (logger != am_logger && logger != am_undefined && !is_internal_pid(logger))
+        return THE_NON_VALUE;
+    return (Eterm)erts_atomic_xchg_nob(&system_logger, logger);
+}
+
 void
 erts_queue_error_logger_message(Eterm from, Eterm msg, ErlHeapFragment *bp)
 {
-    enqueue_sys_msg(SYS_MSG_TYPE_ERRLGR, from, am_logger, msg, bp);
+    enqueue_sys_msg(SYS_MSG_TYPE_ERRLGR, from, erts_get_system_logger(), msg, bp);
 }
 
 void
@@ -2271,7 +2287,7 @@ sys_msg_dispatcher_func(void *unused)
 		}
 		break;
 	    case SYS_MSG_TYPE_ERRLGR:
-		receiver = am_logger;
+		receiver = smqp->to;
 		break;
 	    default:
 		receiver = NIL;
@@ -2285,8 +2301,15 @@ sys_msg_dispatcher_func(void *unused)
 	    if (is_internal_pid(receiver)) {
 		proc = erts_pid2proc(NULL, 0, receiver, proc_locks);
 		if (!proc) {
-		    /* Bad tracer */
-		    goto failure;
+                    if (smqp->type == SYS_MSG_TYPE_ERRLGR) {
+                        /* Bad logger process, send to kernel 'logger' process */
+                        erts_set_system_logger(am_logger);
+                        receiver = erts_get_system_logger();
+                        goto logger;
+                    } else {
+                        /* Bad tracer */
+                        goto failure;
+                    }
 		}
 		else {
 		    ErtsMessage *mp;
@@ -2299,9 +2322,9 @@ sys_msg_dispatcher_func(void *unused)
 #endif
 		    erts_proc_unlock(proc, proc_locks);
 		}
-	    }
-	    else if (receiver == am_logger) {
-		proc = erts_whereis_process(NULL,0,receiver,proc_locks,0);
+	    } else if (receiver == am_logger) {
+            logger:
+		proc = erts_whereis_process(NULL,0,am_logger,proc_locks,0);
 		if (!proc)
 		    goto failure;
 		else if (smqp->from == proc->common.id)
@@ -2309,7 +2332,10 @@ sys_msg_dispatcher_func(void *unused)
 		else
 		    goto queue_proc_msg;
 	    }
-	    else if (is_internal_port(receiver)) {
+            else if (receiver == am_undefined) {
+                goto drop_sys_msg;
+	    }
+            else if (is_internal_port(receiver)) {
 		port = erts_thr_id2port_sflgs(receiver,
 					      ERTS_PORT_SFLGS_INVALID_TRACER_LOOKUP);
 		if (!port)
@@ -2366,7 +2392,7 @@ erts_foreach_sys_msg_in_q(void (*func)(Eterm,
 	    to = erts_get_system_profile();
 	    break;
 	case SYS_MSG_TYPE_ERRLGR:
-	    to = am_logger;
+	    to = erts_get_system_logger();
 	    break;
 	default:
 	    to = NIL;
diff --git a/erts/emulator/beam/erl_trace.h b/erts/emulator/beam/erl_trace.h
index bccf31606e..b7844d1cb0 100644
--- a/erts/emulator/beam/erl_trace.h
+++ b/erts/emulator/beam/erl_trace.h
@@ -94,6 +94,8 @@ void erts_foreach_sys_msg_in_q(void (*func)(Eterm,
 					    Eterm,
 					    Eterm,
 					    ErlHeapFragment *));
+Eterm erts_set_system_logger(Eterm);
+Eterm erts_get_system_logger(void);
 void erts_queue_error_logger_message(Eterm, Eterm, ErlHeapFragment *);
 void erts_send_sys_msg_proc(Eterm, Eterm, Eterm, ErlHeapFragment *);