chardev: use a state machine for socket connection state
The socket connection state is indicated via the 'bool connected' field
in the SocketChardev struct. This variable is somewhat misleading
though, as it is only set to true once the connection has completed all
required handshakes (eg for TLS, telnet or websockets). IOW there is a
period of time in which the socket is connected, but the "connected"
flag is still false.
The socket chardev really has three states that it can be in,
disconnected, connecting and connected and those should be tracked
explicitly.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190211182442.8542-12-berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 90dafef..d6de5d2 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -46,6 +46,12 @@
size_t buflen;
} TCPChardevTelnetInit;
+typedef enum {
+ TCP_CHARDEV_STATE_DISCONNECTED,
+ TCP_CHARDEV_STATE_CONNECTING,
+ TCP_CHARDEV_STATE_CONNECTED,
+} TCPChardevState;
+
typedef struct {
Chardev parent;
QIOChannel *ioc; /* Client I/O channel */
@@ -53,7 +59,7 @@
QIONetListener *listener;
GSource *hup_source;
QCryptoTLSCreds *tls_creds;
- int connected;
+ TCPChardevState state;
int max_size;
int do_telnetopt;
int do_nodelay;
@@ -82,6 +88,21 @@
static gboolean socket_reconnect_timeout(gpointer opaque);
static void tcp_chr_telnet_init(Chardev *chr);
+static void tcp_chr_change_state(SocketChardev *s, TCPChardevState state)
+{
+ switch (state) {
+ case TCP_CHARDEV_STATE_DISCONNECTED:
+ break;
+ case TCP_CHARDEV_STATE_CONNECTING:
+ assert(s->state == TCP_CHARDEV_STATE_DISCONNECTED);
+ break;
+ case TCP_CHARDEV_STATE_CONNECTED:
+ assert(s->state == TCP_CHARDEV_STATE_CONNECTING);
+ break;
+ }
+ s->state = state;
+}
+
static void tcp_chr_reconn_timer_cancel(SocketChardev *s)
{
if (s->reconnect_timer) {
@@ -96,7 +117,7 @@
SocketChardev *s = SOCKET_CHARDEV(chr);
char *name;
- assert(s->connected == 0);
+ assert(s->state == TCP_CHARDEV_STATE_DISCONNECTED);
name = g_strdup_printf("chardev-socket-reconnect-%s", chr->label);
s->reconnect_timer = qemu_chr_timeout_add_ms(chr,
s->reconnect_time * 1000,
@@ -131,7 +152,7 @@
{
SocketChardev *s = SOCKET_CHARDEV(chr);
- if (s->connected) {
+ if (s->state == TCP_CHARDEV_STATE_CONNECTED) {
int ret = io_channel_send_full(s->ioc, buf, len,
s->write_msgfds,
s->write_msgfds_num);
@@ -164,7 +185,7 @@
{
Chardev *chr = CHARDEV(opaque);
SocketChardev *s = SOCKET_CHARDEV(opaque);
- if (!s->connected) {
+ if (s->state != TCP_CHARDEV_STATE_CONNECTED) {
return 0;
}
s->max_size = qemu_chr_be_can_write(chr);
@@ -277,7 +298,7 @@
s->write_msgfds = NULL;
s->write_msgfds_num = 0;
- if (!s->connected ||
+ if ((s->state != TCP_CHARDEV_STATE_CONNECTED) ||
!qio_channel_has_feature(s->ioc,
QIO_CHANNEL_FEATURE_FD_PASS)) {
return -1;
@@ -389,7 +410,7 @@
s->ioc = NULL;
g_free(chr->filename);
chr->filename = NULL;
- s->connected = 0;
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_DISCONNECTED);
}
static const char *qemu_chr_socket_protocol(SocketChardev *s)
@@ -442,12 +463,12 @@
/* NB may be called even if tcp_chr_connect has not been
* reached, due to TLS or telnet initialization failure,
- * so can *not* assume s->connected == true
+ * so can *not* assume s->state == TCP_CHARDEV_STATE_CONNECTED
*/
static void tcp_chr_disconnect(Chardev *chr)
{
SocketChardev *s = SOCKET_CHARDEV(chr);
- bool emit_close = s->connected;
+ bool emit_close = s->state == TCP_CHARDEV_STATE_CONNECTED;
tcp_chr_free_connection(chr);
@@ -471,7 +492,8 @@
uint8_t buf[CHR_READ_BUF_LEN];
int len, size;
- if (!s->connected || s->max_size <= 0) {
+ if ((s->state != TCP_CHARDEV_STATE_CONNECTED) ||
+ s->max_size <= 0) {
return TRUE;
}
len = sizeof(buf);
@@ -508,7 +530,7 @@
SocketChardev *s = SOCKET_CHARDEV(chr);
int size;
- if (!s->connected) {
+ if (s->state != TCP_CHARDEV_STATE_CONNECTED) {
return 0;
}
@@ -564,7 +586,7 @@
{
Chardev *chr = CHARDEV(s);
- if (!s->connected) {
+ if (s->state != TCP_CHARDEV_STATE_CONNECTED) {
return;
}
@@ -589,7 +611,7 @@
g_free(chr->filename);
chr->filename = qemu_chr_compute_filename(s);
- s->connected = 1;
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_CONNECTED);
update_ioc_handlers(s);
qemu_chr_be_event(chr, CHR_EVENT_OPENED);
}
@@ -828,7 +850,7 @@
{
SocketChardev *s = SOCKET_CHARDEV(chr);
- if (s->ioc != NULL) {
+ if (s->state != TCP_CHARDEV_STATE_CONNECTING) {
return -1;
}
@@ -865,11 +887,17 @@
{
int ret;
QIOChannelSocket *sioc;
+ SocketChardev *s = SOCKET_CHARDEV(chr);
+
+ if (s->state != TCP_CHARDEV_STATE_DISCONNECTED) {
+ return -1;
+ }
sioc = qio_channel_socket_new_fd(fd, NULL);
if (!sioc) {
return -1;
}
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_CONNECTING);
tcp_chr_set_client_ioc_name(chr, sioc);
ret = tcp_chr_new_client(chr, sioc);
object_unref(OBJECT(sioc));
@@ -881,7 +909,9 @@
void *opaque)
{
Chardev *chr = CHARDEV(opaque);
+ SocketChardev *s = SOCKET_CHARDEV(chr);
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_CONNECTING);
tcp_chr_set_client_ioc_name(chr, cioc);
tcp_chr_new_client(chr, cioc);
}
@@ -891,8 +921,10 @@
{
SocketChardev *s = SOCKET_CHARDEV(chr);
QIOChannelSocket *sioc = qio_channel_socket_new();
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_CONNECTING);
tcp_chr_set_client_ioc_name(chr, sioc);
if (qio_channel_socket_connect_sync(sioc, s->addr, errp) < 0) {
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_DISCONNECTED);
object_unref(OBJECT(sioc));
return -1;
}
@@ -908,6 +940,7 @@
QIOChannelSocket *sioc;
info_report("QEMU waiting for connection on: %s",
chr->filename);
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_CONNECTING);
sioc = qio_net_listener_wait_client(s->listener);
tcp_chr_set_client_ioc_name(chr, sioc);
tcp_chr_new_client(chr, sioc);
@@ -963,6 +996,7 @@
Error *err = NULL;
if (qio_task_propagate_error(task, &err)) {
+ tcp_chr_change_state(s, TCP_CHARDEV_STATE_DISCONNECTED);
check_report_connect_error(chr, err);
error_free(err);
goto cleanup;
@@ -980,6 +1014,7 @@
SocketChardev *s = SOCKET_CHARDEV(chr);
QIOChannelSocket *sioc;
+ 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,
@@ -1307,7 +1342,7 @@
{
SocketChardev *s = SOCKET_CHARDEV(obj);
- return s->connected;
+ return s->state == TCP_CHARDEV_STATE_CONNECTED;
}
static void char_socket_class_init(ObjectClass *oc, void *data)
