diff options
| -rw-r--r-- | chardev/char-socket.c | 90 |
1 files changed, 86 insertions, 4 deletions
diff --git a/chardev/char-socket.c b/chardev/char-socket.c index 86c1f502d6..4fcdd8aedd 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -80,6 +80,8 @@ typedef struct { GSource *reconnect_timer; int64_t reconnect_time; bool connect_err_reported; + + QIOTask *connect_task; } SocketChardev; #define SOCKET_CHARDEV(obj) \ @@ -118,6 +120,7 @@ static void qemu_chr_socket_restart_timer(Chardev *chr) char *name; assert(s->state == TCP_CHARDEV_STATE_DISCONNECTED); + assert(!s->reconnect_timer); name = g_strdup_printf("chardev-socket-reconnect-%s", chr->label); s->reconnect_timer = qemu_chr_timeout_add_ms(chr, s->reconnect_time * 1000, @@ -965,7 +968,56 @@ static int tcp_chr_wait_connected(Chardev *chr, Error **errp) } } - while (!s->ioc) { + tcp_chr_reconn_timer_cancel(s); + + /* + * We expect states to be as follows: + * + * - server + * - wait -> CONNECTED + * - nowait -> DISCONNECTED + * - client + * - reconnect == 0 -> CONNECTED + * - reconnect != 0 -> CONNECTING + * + */ + if (s->state == TCP_CHARDEV_STATE_CONNECTING) { + if (!s->connect_task) { + error_setg(errp, + "Unexpected 'connecting' state without connect task " + "while waiting for connection completion"); + return -1; + } + /* + * tcp_chr_wait_connected should only ever be run from the + * main loop thread associated with chr->gcontext, otherwise + * qio_task_wait_thread has a dangerous race condition with + * free'ing of the s->connect_task object. + * + * Acquiring the main context doesn't 100% prove we're in + * the main loop thread, but it does at least guarantee + * that the main loop won't be executed by another thread + * avoiding the race condition with the task idle callback. + */ + g_main_context_acquire(chr->gcontext); + qio_task_wait_thread(s->connect_task); + g_main_context_release(chr->gcontext); + + /* + * The completion callback (qemu_chr_socket_connected) for + * s->connect_task should have set this to NULL by the time + * qio_task_wait_thread has returned. + */ + assert(!s->connect_task); + + /* + * NB we are *not* guaranteed to have "s->state == ..CONNECTED" + * at this point as this first connect may be failed, so + * allow the next loop to run regardless. + */ + } + + while (s->state != TCP_CHARDEV_STATE_CONNECTED) { if (s->is_listen) { tcp_chr_accept_server_sync(chr); } else { @@ -1014,6 +1066,8 @@ static void qemu_chr_socket_connected(QIOTask *task, void *opaque) SocketChardev *s = SOCKET_CHARDEV(chr); Error *err = NULL; + s->connect_task = NULL; + if (qio_task_propagate_error(task, &err)) { tcp_chr_change_state(s, TCP_CHARDEV_STATE_DISCONNECTED); check_report_connect_error(chr, err); @@ -1028,6 +1082,20 @@ cleanup: object_unref(OBJECT(sioc)); } + +static void tcp_chr_connect_client_task(QIOTask *task, + gpointer opaque) +{ + QIOChannelSocket *ioc = QIO_CHANNEL_SOCKET(qio_task_get_source(task)); + SocketAddress *addr = opaque; + Error *err = NULL; + + qio_channel_socket_connect_sync(ioc, addr, &err); + + qio_task_set_error(task, err); +} + + static void tcp_chr_connect_client_async(Chardev *chr) { SocketChardev *s = SOCKET_CHARDEV(chr); @@ -1036,9 +1104,23 @@ static void tcp_chr_connect_client_async(Chardev *chr) tcp_chr_change_state(s, TCP_CHARDEV_STATE_CONNECTING); sioc = qio_channel_socket_new(); tcp_chr_set_client_ioc_name(chr, sioc); - qio_channel_socket_connect_async(sioc, s->addr, - qemu_chr_socket_connected, - chr, NULL, chr->gcontext); + /* + * Normally code would use the qio_channel_socket_connect_async + * method which uses a QIOTask + qio_task_set_error internally + * to avoid blocking. The tcp_chr_wait_connected method, however, + * needs a way to synchronize with completion of the background + * connect task which can't be done with the QIOChannelSocket + * async APIs. Thus we must use QIOTask directly to implement + * the non-blocking concept locally. + */ + s->connect_task = qio_task_new(OBJECT(sioc), + qemu_chr_socket_connected, + chr, NULL); + qio_task_run_in_thread(s->connect_task, + tcp_chr_connect_client_task, + s->addr, + NULL, + chr->gcontext); } static gboolean socket_reconnect_timeout(gpointer opaque) |