qemu-char: Call fe_claim / fe_release when not using qdev chr properties

chardev-frontends need to explictly check, increase and decrement the
avail_connections "property" of the chardev when they are not using a
qdev-chardev-property for the chardev.

This fixes things like:
qemu-kvm -chardev stdio,id=foo -device isa-serial,chardev=foo \
  -mon chardev=foo

Working, where they should fail. Most of the changes here are due to
old hardware emulation code which is using serial_hds directly rather then
a qdev-chardev-property.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Message-id: 1364412581-3672-3-git-send-email-hdegoede@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/backends/rng-egd.c b/backends/rng-egd.c
index 5e012e9e3..cc6f5ee28 100644
--- a/backends/rng-egd.c
+++ b/backends/rng-egd.c
@@ -149,6 +149,11 @@ static void rng_egd_opened(RngBackend *b, Error **errp)
         return;
     }
 
+    if (qemu_chr_fe_claim(s->chr) != 0) {
+        error_set(errp, QERR_DEVICE_IN_USE, s->chr_name);
+        return;
+    }
+
     /* FIXME we should resubmit pending requests when the CDS reconnects. */
     qemu_chr_add_handlers(s->chr, rng_egd_chr_can_read, rng_egd_chr_read,
                           NULL, s);
@@ -191,6 +196,7 @@ static void rng_egd_finalize(Object *obj)
 
     if (s->chr) {
         qemu_chr_add_handlers(s->chr, NULL, NULL, NULL, NULL);
+        qemu_chr_fe_release(s->chr);
     }
 
     g_free(s->chr_name);