qemu-char: Automatically do fe_open / fe_close on qemu_chr_add_handlers

Most frontends can't really determine if the guest actually has the frontend
side open. So lets automatically generate fe_open / fe_close as soon as a
frontend becomes ready (as signalled by calling qemu_chr_add_handlers) /
becomes non ready (as signalled by setting all handlers to NULL).

And allow frontends which can actually determine if the guest is listening to
opt-out of this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364292483-16564-5-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/qemu-char.c b/qemu-char.c
index c9890ad20f..947541a559 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -221,9 +221,14 @@ void qemu_chr_add_handlers(CharDriverState *s,
                            IOEventHandler *fd_event,
                            void *opaque)
 {
+    int fe_open;
+
     if (!opaque && !fd_can_read && !fd_read && !fd_event) {
         /* chr driver being released. */
         ++s->avail_connections;
+        fe_open = 0;
+    } else {
+        fe_open = 1;
     }
     s->chr_can_read = fd_can_read;
     s->chr_read = fd_read;
@@ -232,6 +237,14 @@ void qemu_chr_add_handlers(CharDriverState *s,
     if (s->chr_update_read_handler)
         s->chr_update_read_handler(s);
 
+    if (!s->explicit_fe_open) {
+        if (fe_open) {
+            qemu_chr_fe_open(s);
+        } else {
+            qemu_chr_fe_close(s);
+        }
+    }
+
     /* We're connecting to an already opened device, so let's make sure we
        also get the open event */
     if (s->be_open) {