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authorSverker Eriksson <[email protected]>2017-11-23 15:05:34 +0100
committerSverker Eriksson <[email protected]>2017-11-23 15:05:34 +0100
commit8ed0d75c186d9da24bd6cfb85732487b17a3b054 (patch)
treef458c4ef6fc080fe9859834cabe3e49d40da9908 /erts/emulator
parenta5aaba7c9a316327940d0b861dd300d59aa99209 (diff)
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erts: Fix erlang:monitor toward c-nodes
by suppressing DOP_MONITOR_P, DOP_MONITOR_P_EXIT and DOP_DEMONITOR_P if not supported by the remote node. In 17e198d6ee60f7dec9abfed272cf4226aea44535 I changed the behavior of erlang:monitor to not raise badarg for c-nodes but instead create a monitor to only supervise the connection. But I forgot to prevent DOP_MONITOR_P and friends from being sent to the node that does not expect them. Note: We test both DFLAG_DIST_MONITOR and DFLAG_DIST_MONITOR_NAME for the node to support process monitoring. This is because erl_interface is buggy as it sets DFLAG_DIST_MONITOR without really supporting it. ToDo: Should erl_interface stop setting DFLAG_DIST_MONITOR or should we change the meaning of these flags?
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/beam/dist.c26
-rw-r--r--erts/emulator/beam/dist.h4
-rw-r--r--erts/emulator/beam/external.c15
3 files changed, 43 insertions, 2 deletions
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index ee288dc0bd..8548dbb577 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -877,6 +877,13 @@ erts_dsig_send_m_exit(ErtsDSigData *dsdp, Eterm watcher, Eterm watched,
DeclareTmpHeapNoproc(ctl_heap,6);
int res;
+ if (~dsdp->dep->flags & (DFLAG_DIST_MONITOR | DFLAG_DIST_MONITOR_NAME)) {
+ /*
+ * Receiver does not support DOP_MONITOR_P_EXIT (see dsig_send_monitor)
+ */
+ return ERTS_DSIG_SEND_OK;
+ }
+
UseTmpHeapNoproc(6);
ctl = TUPLE5(&ctl_heap[0], make_small(DOP_MONITOR_P_EXIT),
@@ -904,6 +911,16 @@ erts_dsig_send_monitor(ErtsDSigData *dsdp, Eterm watcher, Eterm watched,
DeclareTmpHeapNoproc(ctl_heap,5);
int res;
+ if (~dsdp->dep->flags & (DFLAG_DIST_MONITOR | DFLAG_DIST_MONITOR_NAME)) {
+ /*
+ * Receiver does not support DOP_MONITOR_P.
+ * Just avoid sending it and by doing that reduce this monitor
+ * to only supervise the connection. This will work for simple c-nodes
+ * with a 1-to-1 relation between "Erlang process" and OS-process.
+ */
+ return ERTS_DSIG_SEND_OK;
+ }
+
UseTmpHeapNoproc(5);
ctl = TUPLE4(&ctl_heap[0],
make_small(DOP_MONITOR_P),
@@ -926,6 +943,13 @@ erts_dsig_send_demonitor(ErtsDSigData *dsdp, Eterm watcher,
DeclareTmpHeapNoproc(ctl_heap,5);
int res;
+ if (~dsdp->dep->flags & (DFLAG_DIST_MONITOR | DFLAG_DIST_MONITOR_NAME)) {
+ /*
+ * Receiver does not support DOP_DEMONITOR_P (see dsig_send_monitor)
+ */
+ return ERTS_DSIG_SEND_OK;
+ }
+
UseTmpHeapNoproc(5);
ctl = TUPLE4(&ctl_heap[0],
make_small(DOP_DEMONITOR_P),
@@ -2379,7 +2403,7 @@ erts_dist_command(Port *prt, int initial_reds)
break;
}
ASSERT(&oq.first->data[0] <= oq.first->extp
- && oq.first->extp < oq.first->ext_endp);
+ && oq.first->extp <= oq.first->ext_endp);
size = (*send)(prt, oq.first);
erts_atomic64_inc_nob(&dep->out);
esdp->io.out += (Uint64) size;
diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index a96e39be89..ea4697815f 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -56,7 +56,9 @@
/* Additional optimistic flags when encoding toward pending connection */
#define DFLAG_DIST_HOPEFULLY (DFLAG_NO_MAGIC \
| DFLAG_EXPORT_PTR_TAG \
- | DFLAG_BIT_BINARIES)
+ | DFLAG_BIT_BINARIES \
+ | DFLAG_DIST_MONITOR \
+ | DFLAG_DIST_MONITOR_NAME)
/* All flags that should be enabled when term_to_binary/1 is used. */
#define TERM_TO_BINARY_DFLAGS (DFLAG_EXTENDED_REFERENCES \
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index f2e6399ad7..9cc5e71afa 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -383,6 +383,21 @@ Sint erts_encode_ext_dist_header_finalize(ErtsDistOutputBuf* ob,
*/
ASSERT(ep[0] == SMALL_TUPLE_EXT || ep[0] == LARGE_TUPLE_EXT);
+ if (~dflags & (DFLAG_DIST_MONITOR | DFLAG_DIST_MONITOR_NAME)
+ && ep[0] == SMALL_TUPLE_EXT
+ && ep[1] == 4
+ && ep[2] == SMALL_INTEGER_EXT
+ && (ep[3] == DOP_MONITOR_P ||
+ ep[3] == DOP_MONITOR_P_EXIT ||
+ ep[3] == DOP_DEMONITOR_P)) {
+ /*
+ * Receiver does not support process monitoring.
+ * Suppress monitor control msg (see erts_dsig_send_monitor)
+ * by converting it to an empty (tick) packet.
+ */
+ ob->ext_endp = ob->extp;
+ return reds;
+ }
if (~dflags & (DFLAG_BIT_BINARIES | DFLAG_EXPORT_PTR_TAG
| DFLAG_DIST_HDR_ATOM_CACHE)) {
reds = transcode_dist_obuf(ob, dep, dflags, reds);