aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorEric Wong <e@80x24.org>2019-08-10 21:20:23 +0000
committerDaniel Stenberg <daniel@haxx.se>2019-08-11 22:58:01 +0200
commit17d1e27d309f16da960fd3b9933e6e2b1db22b17 (patch)
tree05063dda62c56bcd72525d7a5437c0281973770a
parent4a962ff2189e8bdbcd79813d67e3af0f1c465f7c (diff)
asyn-thread: issue CURL_POLL_REMOVE before closing socket
This avoids EBADF errors from EPOLL_CTL_DEL operations in the ephiperfifo.c example. EBADF is dangerous in multi-threaded applications where I rely on epoll_ctl to operate on the same epoll description from different threads. Follow-up to eb9a604f8d7db8 Bug: https://curl.haxx.se/mail/lib-2019-08/0026.html Closes #4211
-rwxr-xr-xlib/asyn-thread.c25
1 files changed, 20 insertions, 5 deletions
diff --git a/lib/asyn-thread.c b/lib/asyn-thread.c
index 222e78d98..24da74885 100755
--- a/lib/asyn-thread.c
+++ b/lib/asyn-thread.c
@@ -164,6 +164,7 @@ struct thread_sync_data {
duplicate */
int port;
#ifdef HAVE_SOCKETPAIR
+ struct connectdata *conn;
curl_socket_t sock_pair[2]; /* socket pair */
#endif
int sock_error;
@@ -201,11 +202,10 @@ void destroy_thread_sync_data(struct thread_sync_data * tsd)
Curl_freeaddrinfo(tsd->res);
#ifdef HAVE_SOCKETPAIR
- /* close socket pair */
- if(tsd->sock_pair[0] != CURL_SOCKET_BAD) {
- sclose(tsd->sock_pair[0]);
- }
-
+ /*
+ * close one end of the socket pair (may be done in resolver thread);
+ * the other end (for reading) is always closed in the parent thread.
+ */
if(tsd->sock_pair[1] != CURL_SOCKET_BAD) {
sclose(tsd->sock_pair[1]);
}
@@ -382,6 +382,10 @@ static void destroy_async_data(struct Curl_async *async)
if(async->os_specific) {
struct thread_data *td = (struct thread_data*) async->os_specific;
int done;
+#ifdef HAVE_SOCKETPAIR
+ curl_socket_t sock_rd = td->tsd.sock_pair[0];
+ struct connectdata *conn = td->tsd.conn;
+#endif
/*
* if the thread is still blocking in the resolve syscall, detach it and
@@ -403,6 +407,15 @@ static void destroy_async_data(struct Curl_async *async)
free(async->os_specific);
}
+#ifdef HAVE_SOCKETPAIR
+ /*
+ * ensure CURLMOPT_SOCKETFUNCTION fires CURL_POLL_REMOVE
+ * before the FD is invalidated to avoid EBADF on EPOLL_CTL_DEL
+ */
+ if(conn)
+ Curl_multi_closed(conn->data, sock_rd);
+ sclose(sock_rd);
+#endif
}
async->os_specific = NULL;
@@ -644,6 +657,8 @@ int Curl_resolver_getsock(struct connectdata *conn,
if(td) {
/* return read fd to client for polling the DNS resolution status */
socks[0] = td->tsd.sock_pair[0];
+ DEBUGASSERT(td->tsd.conn == conn || !td->tsd.conn);
+ td->tsd.conn = conn;
ret_val = GETSOCK_READSOCK(0);
}
else {