File 1000-erts-Fix-active-N-close-race-condition-on-windows.patch of Package erlang
From 73f294fba283f8b4c9d068cb70017e26d7850be2 Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Tue, 4 Jun 2019 15:26:02 +0200
Subject: [PATCH] erts: Fix {active,N} close race condition on windows
When a close is detected on windows, we need to keep track of
it as it will not trigger again.
---
erts/emulator/drivers/common/inet_drv.c | 44 ++++++++++++++++++++---------
lib/kernel/test/gen_tcp_misc_SUITE.erl | 49 +++++++++++++++++++++++++++++++--
2 files changed, 78 insertions(+), 15 deletions(-)
diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index c93966d24f..42f08cdc89 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -1077,6 +1077,7 @@ typedef struct {
long forced_events; /* Mask of events that are forcefully signalled
on windows see winsock_event_select
for details */
+ int err; /* Keeps error code for closed socket */
int send_would_block; /* Last send attempt failed with "WOULDBLOCK" */
#endif
ErlDrvPort port; /* the port identifier */
@@ -9063,6 +9064,7 @@ static ErlDrvData inet_start(ErlDrvPort port, int size, int protocol)
desc->event_mask = 0;
#ifdef __WIN32__
desc->forced_events = 0;
+ desc->err = 0;
desc->send_would_block = 0;
#endif
desc->port = port;
@@ -10914,7 +10916,7 @@ static int winsock_event_select(inet_descriptor *desc, int flags, int on)
{
int save_event_mask = desc->event_mask;
- desc->forced_events = 0;
+ desc->forced_events &= FD_CLOSE;
if (on)
desc->event_mask |= flags;
else
@@ -10966,7 +10968,7 @@ static int winsock_event_select(inet_descriptor *desc, int flags, int on)
TIMEVAL tmo = {0,0};
FD_SET fds;
int ret;
-
+
FD_ZERO(&fds);
FD_SET(desc->s,&fds);
do_force = (select(desc->s+1,0,&fds,0,&tmo) > 0);
@@ -10983,7 +10985,7 @@ static int winsock_event_select(inet_descriptor *desc, int flags, int on)
FD_SET fds;
int ret;
unsigned long arg;
-
+
FD_ZERO(&fds);
FD_SET(desc->s,&fds);
ret = select(desc->s+1,&fds,0,0,&tmo);
@@ -11022,13 +11024,16 @@ static void tcp_inet_event(ErlDrvData e, ErlDrvEvent event)
goto error;
}
- DEBUGF((" => event=%02X, mask=%02X\r\n",
- netEv.lNetworkEvents, desc->inet.event_mask));
+ DEBUGF((" => event=%02X, mask=%02X, forced=%02X\r\n",
+ netEv.lNetworkEvents, desc->inet.event_mask,
+ desc->inet.forced_events));
/* Add the forced events. */
-
netEv.lNetworkEvents |= desc->inet.forced_events;
+ if (desc->inet.forced_events & FD_CLOSE)
+ netEv.iErrorCode[FD_CLOSE_BIT] = desc->inet.err;
+
/*
* Calling WSAEventSelect() with a mask of 0 doesn't always turn off
* all events. To avoid acting on events we don't want, we mask
@@ -11048,16 +11053,29 @@ static void tcp_inet_event(ErlDrvData e, ErlDrvEvent event)
goto error;
}
if (netEv.lNetworkEvents & FD_CLOSE) {
- /*
+
+ /* We may not get any more FD_CLOSE events so we
+ keep this event and always signal it from
+ this moment on. */
+ if ((desc->inet.forced_events & FD_CLOSE) == 0) {
+ desc->inet.forced_events |= FD_CLOSE;
+ desc->inet.err = netEv.iErrorCode[FD_CLOSE_BIT];
+ }
+
+ /*
* We must loop to read out the remaining packets (if any).
*/
for (;;) {
- DEBUGF(("Retrying read due to closed port\r\n"));
- /* XXX The buffer will be thrown away on error (empty que).
- Possible SMP FIXME. */
- if (!desc->inet.active && (desc->inet.opt) == NULL) {
- goto error;
- }
+
+ /* if passive and no subscribers, break loop */
+ if (!desc->inet.active && desc->inet.opt == NULL) {
+ /* do not trigger close event when socket is
+ transitioned to passive */
+ netEv.lNetworkEvents &= ~FD_CLOSE;
+ break;
+ }
+
+ DEBUGF(("Retrying read due to FD_CLOSE\r\n"));
if (tcp_inet_input(desc, event) < 0) {
goto error;
}
--
2.16.4
