From fe720f6b2051c9bf8ff303f857c3db0a84b1c050 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Mon, 18 Sep 2017 17:15:19 +0200
Subject: erts: Refactor connection_id in ErtsDistExternal

Break out from 'flags' into new dedicated 'connection_id'
just for simplicity.

Also changed flags to low bits
and that affected enif_binary_to_term.
---
 erts/emulator/beam/erl_nif.c  | 11 ++++++-----
 erts/emulator/beam/external.c |  4 ++--
 erts/emulator/beam/external.h | 22 +++++++++-------------
 3 files changed, 17 insertions(+), 20 deletions(-)

(limited to 'erts')

diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index c21b139cfa..d1018bab26 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1201,11 +1201,12 @@ size_t enif_binary_to_term(ErlNifEnv *dst_env,
     Sint size;
     ErtsHeapFactory factory;
     byte *bp = (byte*) data;
+    Uint32 flags = 0;
 
-    ERTS_CT_ASSERT(ERL_NIF_BIN2TERM_SAFE == ERTS_DIST_EXT_BTT_SAFE);
-
-    if (opts & ~ERL_NIF_BIN2TERM_SAFE) {
-        return 0;
+    switch ((Uint32)opts) {
+    case 0: break;
+    case ERL_NIF_BIN2TERM_SAFE: flags = ERTS_DIST_EXT_BTT_SAFE; break;
+    default: return 0;
     }
     if ((size = erts_decode_ext_size(bp, data_sz)) < 0)
         return 0;
@@ -1217,7 +1218,7 @@ size_t enif_binary_to_term(ErlNifEnv *dst_env,
         erts_factory_dummy_init(&factory);
     }
 
-    *term = erts_decode_ext(&factory, &bp, (Uint32)opts);
+    *term = erts_decode_ext(&factory, &bp, flags);
 
     if (is_non_value(*term)) {
         return 0;
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 9230e1d8ab..3b851087d1 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -654,7 +654,7 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
         edep->flags |= ERTS_DIST_EXT_DFLAG_HDR;
 
     *connection_id = dep->connection_id;
-    edep->flags |= (dep->connection_id & ERTS_DIST_EXT_CON_ID_MASK);
+    edep->connection_id = dep->connection_id;
 
     if (ep[1] != DIST_HEADER) {
 	if (edep->flags & ERTS_DIST_EXT_DFLAG_HDR)
@@ -868,7 +868,7 @@ bad_dist_ext(ErtsDistExternal *edep)
 		erts_dsprintf(dsbufp, ", %d=%T", i, edep->attab.atom[i]);
 	}
 	erts_send_warning_to_logger_nogl(dsbufp);
-	erts_kill_dist_connection(dep, ERTS_DIST_EXT_CON_ID(edep));
+	erts_kill_dist_connection(dep, edep->connection_id);
     }
 }
 
diff --git a/erts/emulator/beam/external.h b/erts/emulator/beam/external.h
index fb7eec1a31..d6416edbc3 100644
--- a/erts/emulator/beam/external.h
+++ b/erts/emulator/beam/external.h
@@ -109,26 +109,22 @@ typedef struct {
 } ErtsAtomTranslationTable;
 
 /*
- * These flags are tagged onto the high bits of a connection ID and stored in
- * the ErtsDistExternal structure's flags field.  They are used to indicate
- * various bits of state necessary to decode binaries in a variety of
- * scenarios. The mask ERTS_DIST_EXT_CON_ID_MASK is used later to separate the
- * connection ID from the flags. Be careful to ensure that the mask does not
- * overlap any of the bits used for flags, or ERTS will leak flags bits into
- * connection IDs and leak connection ID bits into the flags.
+ * These flags are stored in the ErtsDistExternal structure's flags field.
+ * They are used to indicate various bits of state necessary to decode binaries
+ * in a variety of scenarios.
  */
-#define ERTS_DIST_EXT_DFLAG_HDR      ((Uint32) 0x80000000)
-#define ERTS_DIST_EXT_ATOM_TRANS_TAB ((Uint32) 0x40000000)
-#define ERTS_DIST_EXT_BTT_SAFE       ((Uint32) 0x20000000)
-#define ERTS_DIST_EXT_CON_ID_MASK    ((Uint32) 0x1fffffff)
+#define ERTS_DIST_EXT_DFLAG_HDR      ((Uint32) 0x1)
+#define ERTS_DIST_EXT_ATOM_TRANS_TAB ((Uint32) 0x2)
+#define ERTS_DIST_EXT_BTT_SAFE       ((Uint32) 0x4)
+
+#define ERTS_DIST_CON_ID_MASK    ((Uint32) 0x00ffffff)
 
-#define ERTS_DIST_EXT_CON_ID(DIST_EXTP) \
-  ((DIST_EXTP)->flags & ERTS_DIST_EXT_CON_ID_MASK)
 typedef struct {
     DistEntry *dep;
     byte *extp;
     byte *ext_endp;
     Sint heap_size;
+    Uint32 connection_id;
     Uint32 flags;
     ErtsAtomTranslationTable attab;
 } ErtsDistExternal;
-- 
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