char: restore read callback on a reattached (hotplug) chardev

Fix a bug that was introduced in commit 386a5a1e. A removal of a device
set the chr handlers to NULL. However when the device is plugged back,
its read callback is not restored so data can't be transferred from the
host to the guest (e.g. via the virtio-serial port).

https://bugzilla.redhat.com/show_bug.cgi?id=1027181

Signed-off-by: Gal Hammer <ghammer@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/qemu-char.c b/qemu-char.c
index 4d50838b3b88f61460c1753a3300c99ddc8c4b37..54ed24454223819e4eb157388c8c0014f836865a 100644 (file)
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -213,7 +213,7 @@ void qemu_chr_add_handlers(CharDriverState *s,
     s->chr_read = fd_read;
     s->chr_event = fd_event;
     s->handler_opaque = opaque;
-    if (s->chr_update_read_handler)
+    if (fe_open && s->chr_update_read_handler)
         s->chr_update_read_handler(s);
 
     if (!s->explicit_fe_open) {
@@ -1136,13 +1136,14 @@ static void pty_chr_state(CharDriverState *chr, int connected)
         if (!s->connected) {
             s->connected = 1;
             qemu_chr_be_generic_open(chr);
+        }
+        if (!chr->fd_in_tag) {
             chr->fd_in_tag = io_add_watch_poll(s->fd, pty_chr_read_poll,
                                                pty_chr_read, chr);
         }
     }
 }
 
-
 static void pty_chr_close(struct CharDriverState *chr)
 {
     PtyCharDriver *s = chr->opaque;
@@ -2509,6 +2510,17 @@ static void tcp_chr_connect(void *opaque)
     qemu_chr_be_generic_open(chr);
 }
 
+static void tcp_chr_update_read_handler(CharDriverState *chr)
+{
+    TCPCharDriver *s = chr->opaque;
+
+    remove_fd_in_watch(chr);
+    if (s->chan) {
+        chr->fd_in_tag = io_add_watch_poll(s->chan, tcp_chr_read_poll,
+                                           tcp_chr_read, chr);
+    }
+}
+
 #define IACSET(x,a,b,c) x[0] = a; x[1] = b; x[2] = c;
 static void tcp_chr_telnet_init(int fd)
 {
@@ -2664,6 +2676,7 @@ static CharDriverState *qemu_chr_open_socket_fd(int fd, bool do_nodelay,
     chr->get_msgfd = tcp_get_msgfd;
     chr->chr_add_client = tcp_chr_add_client;
     chr->chr_add_watch = tcp_chr_add_watch;
+    chr->chr_update_read_handler = tcp_chr_update_read_handler;
     /* be isn't opened until we get a connection */
     chr->explicit_be_open = true;