From 4e222f3f2772add6aa77a7c5535ab0c053c9318c Mon Sep 17 00:00:00 2001
From: Leonid Evdokimov <leon@darkk.net.ru>
Date: Thu, 17 Mar 2016 18:44:22 +0300
Subject: [PATCH] Avoid EBADF warnings from epoll using bufferevent_free more
 accurately

---
 http-connect.c |  3 +--
 http-relay.c   |  3 +--
 redsocks.c     | 20 ++++++++++++--------
 redsocks.h     |  3 +++
 redudp.c       | 11 +++--------
 utils.c        |  4 +++-
 6 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/http-connect.c b/http-connect.c
index 685ab54..c0e5cf2 100644
--- a/http-connect.c
+++ b/http-connect.c
@@ -132,8 +132,7 @@ static void httpc_read_cb(struct bufferevent *buffev, void *_arg)
 							}
 
 							/* close relay tunnel */
-							redsocks_close(EVENT_FD(&client->relay->ev_write));
-							bufferevent_free(client->relay);
+							redsocks_bufferevent_free(client->relay);
 
 							/* set to initial state*/
 							client->state = httpc_new;
diff --git a/http-relay.c b/http-relay.c
index 51c6f4c..24952d5 100644
--- a/http-relay.c
+++ b/http-relay.c
@@ -205,8 +205,7 @@ static void httpr_relay_read_cb(struct bufferevent *buffev, void *_arg)
 							}
 
 							/* close relay tunnel */
-							redsocks_close(EVENT_FD(&client->relay->ev_write));
-							bufferevent_free(client->relay);
+							redsocks_bufferevent_free(client->relay);
 
 							/* set to initial state*/
 							client->state = httpr_recv_request_headers;
diff --git a/redsocks.c b/redsocks.c
index b65fb1a..50e102e 100644
--- a/redsocks.c
+++ b/redsocks.c
@@ -352,15 +352,11 @@ void redsocks_drop_client(redsocks_client *client)
 	if (client->instance->relay_ss->fini)
 		client->instance->relay_ss->fini(client);
 
-	if (client->client) {
-		redsocks_close(EVENT_FD(&client->client->ev_write));
-		bufferevent_free(client->client);
-	}
+	if (client->client)
+		redsocks_bufferevent_free(client->client);
 
-	if (client->relay) {
-		redsocks_close(EVENT_FD(&client->relay->ev_write));
-		bufferevent_free(client->relay);
-	}
+	if (client->relay)
+		redsocks_bufferevent_free(client->relay);
 
 	list_del(&client->list);
 	free(client);
@@ -634,6 +630,14 @@ void redsocks_close_internal(int fd, const char* file, int line, const char *fun
 	}
 }
 
+void redsocks_bufferevent_free(struct bufferevent *buffev)
+{
+	int fd = bufferevent_getfd(buffev);
+	bufferevent_setfd(buffev, -1); // to avoid EBADFD warnings from epoll
+	bufferevent_free(buffev);
+	redsocks_close(fd);
+}
+
 static void redsocks_accept_client(int fd, short what, void *_arg)
 {
 	redsocks_instance *self = _arg;
diff --git a/redsocks.h b/redsocks.h
index 4f072d5..2704e0c 100644
--- a/redsocks.h
+++ b/redsocks.h
@@ -94,6 +94,9 @@ int redsocks_write_helper(
 #define redsocks_close(fd) redsocks_close_internal((fd), __FILE__, __LINE__, __func__)
 void redsocks_close_internal(int fd, const char* file, int line, const char *func);
 
+// I have to account descriptiors for accept-backoff, that's why BEV_OPT_CLOSE_ON_FREE is not used.
+void redsocks_bufferevent_free(struct bufferevent *buffev);
+
 #define redsocks_log_error(client, prio, msg...) \
 	redsocks_log_write_plain(__FILE__, __LINE__, __func__, 0, &(client)->clientaddr, &(client)->destaddr, prio, ## msg)
 #define redsocks_log_errno(client, prio, msg...) \
diff --git a/redudp.c b/redudp.c
index 05460dc..4c8d716 100644
--- a/redudp.c
+++ b/redudp.c
@@ -214,21 +214,16 @@ static struct evbuffer* socks5_mkassociate(void *p)
  */
 static void redudp_drop_client(redudp_client *client)
 {
-	int fd;
 	redudp_log_error(client, LOG_INFO, "Dropping...");
 	enqueued_packet *q, *tmp;
 	if (event_initialized(&client->timeout)) {
 		if (event_del(&client->timeout) == -1)
 			redudp_log_errno(client, LOG_ERR, "event_del");
 	}
-	if (client->relay) {
-		fd = EVENT_FD(&client->relay->ev_read);
-		bufferevent_free(client->relay);
-		shutdown(fd, SHUT_RDWR);
-		redsocks_close(fd);
-	}
+	if (client->relay)
+		redsocks_bufferevent_free(client->relay);
 	if (event_initialized(&client->udprelay)) {
-		fd = EVENT_FD(&client->udprelay);
+		int fd = EVENT_FD(&client->udprelay);
 		if (event_del(&client->udprelay) == -1)
 			redudp_log_errno(client, LOG_ERR, "event_del");
 		redsocks_close(fd);
diff --git a/utils.c b/utils.c
index 9c878e6..b101596 100644
--- a/utils.c
+++ b/utils.c
@@ -149,6 +149,8 @@ struct bufferevent* red_connect_relay(struct sockaddr_in *addr, evbuffercb write
 		goto fail;
 	}
 
+	relay_fd = -1;
+
 	error = bufferevent_enable(retval, EV_WRITE); // we wait for connection...
 	if (error) {
 		log_errno(LOG_ERR, "bufferevent_enable");
@@ -161,7 +163,7 @@ fail:
 	if (relay_fd != -1)
 		redsocks_close(relay_fd);
 	if (retval)
-		bufferevent_free(retval);
+		redsocks_bufferevent_free(retval);
 	return NULL;
 }