Commit 841cff6e authored by George Kadianakis's avatar George Kadianakis Committed by Nick Mathewson
Browse files

Stop libevent from reading data from closed connections.

Code adapted from Rob's proposed patch in #30344.

Also add a comment in connection_mark_for_close_internal_() on why we should
not be adding extra code there without a very good reason.
parent 7b9cb4c4
o Minor bugfixes (connection):
- Avoid reading data from closed connections, which can cause needless
loops in libevent and infinite loops in Shadow. Fixes bug 30344; bugfix
on 0.1.1.1-alpha.
......@@ -897,13 +897,19 @@ connection_mark_for_close_(connection_t *conn, int line, const char *file)
}
/** Mark <b>conn</b> to be closed next time we loop through
* conn_close_if_marked() in main.c; the _internal version bypasses the
* CONN_TYPE_OR checks; this should be called when you either are sure that
* if this is an or_connection_t the controlling channel has been notified
* (e.g. with connection_or_notify_error()), or you actually are the
* conn_close_if_marked() in main.c.
*
* This _internal version bypasses the CONN_TYPE_OR checks; this should be
* called when you either are sure that if this is an or_connection_t the
* controlling channel has been notified (e.g. with
* connection_or_notify_error()), or you actually are the
* connection_or_close_for_error() or connection_or_close_normally() function.
* For all other cases, use connection_mark_and_flush() instead, which
* checks for or_connection_t properly, instead. See below.
* For all other cases, use connection_mark_and_flush() which checks for
* or_connection_t properly, instead. See below.
*
* We want to keep this function simple and quick, since it can be called from
* quite deep in the call chain, and hence it should avoid having side-effects
* that interfere with its callers view of the connection.
*/
MOCK_IMPL(void,
connection_mark_for_close_internal_, (connection_t *conn,
......
......@@ -879,6 +879,16 @@ conn_read_callback(evutil_socket_t fd, short event, void *_conn)
/* assert_connection_ok(conn, time(NULL)); */
/* Handle marked for close connections early */
if (conn->marked_for_close && connection_is_reading(conn)) {
/* Libevent says we can read, but we are marked for close so we will never
* try to read again. We will try to close the connection below inside of
* close_closeable_connections(), but let's make sure not to cause Libevent
* to spin on conn_read_callback() while we wait for the socket to let us
* flush to it.*/
connection_stop_reading(conn);
}
if (connection_handle_read(conn) < 0) {
if (!conn->marked_for_close) {
#ifndef _WIN32
......
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