Add G_IO_HUP handler for socket chardev

This is used to detect that the remote end has disconnected. Just call
tcp_char_disconnect on receiving this event.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/qemu-char.c b/qemu-char.c
index b9bef44..b3bd3b5 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2680,6 +2680,25 @@
 }
 #endif
 
+static gboolean tcp_chr_chan_close(GIOChannel *channel, GIOCondition cond,
+                                   void *opaque)
+{
+    CharDriverState *chr = opaque;
+
+    if (cond != G_IO_HUP) {
+        return FALSE;
+    }
+
+    /* connection closed */
+    tcp_chr_disconnect(chr);
+    if (chr->fd_hup_tag) {
+        g_source_remove(chr->fd_hup_tag);
+        chr->fd_hup_tag = 0;
+    }
+
+    return TRUE;
+}
+
 static void tcp_chr_connect(void *opaque)
 {
     CharDriverState *chr = opaque;
@@ -2689,6 +2708,8 @@
     if (s->chan) {
         chr->fd_in_tag = io_add_watch_poll(s->chan, tcp_chr_read_poll,
                                            tcp_chr_read, chr);
+        chr->fd_hup_tag = g_io_add_watch(s->chan, G_IO_HUP, tcp_chr_chan_close,
+                                         chr);
     }
     qemu_chr_be_generic_open(chr);
 }