[Qemu-devel] [PATCH] spice-qemu-char: Generate chardev open/close events (v2)

[Hans de Goede <hdegoede@redhat.com>]

Define a state callback and make that generate chardev open/close events when
called by the spice-server. Note the code ignores these events for a spicevmc
with a subtypem of vdagent, this subtype specific knowledge is undesirable,
but unavoidable, see:
http://lists.freedesktop.org/archives/spice-devel/2011-July/004837.html

Changes in v2:
-Only ignore the state callback for spicevmc chardevs with a subtype of
 vdagent, instead of only allowing them for a subtype of usbredir

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 spice-qemu-char.c |   42 +++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 41 insertions(+), 1 deletions(-)

diff --git a/spice-qemu-char.c b/spice-qemu-char.c
index ce75e91..4f82231 100644
--- a/spice-qemu-char.c
+++ b/spice-qemu-char.c
@@ -89,11 +89,48 @@ static int vmc_read(SpiceCharDeviceInstance *sin, uint8_t *buf, int len)
     return bytes;
 }
 
+static void vmc_state(SpiceCharDeviceInstance *sin, int connected)
+{
+    SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
+    int event;
+
+    /*
+     * spice-server calls the state callback for the agent channel when the
+     * spice client connects / disconnects. Given that not the client but
+     * the server is doing the parsing of the messages this is wrong as the
+     * server is still listening. Worse, this causes the parser in the server
+     * to go out of sync, so we ignore state calls for subtype vdagent
+     * spicevmc chardevs. For the full story see:
+     * http://lists.freedesktop.org/archives/spice-devel/2011-July/004837.html
+     */
+    if (strcmp(subtype, "vdagent") == 0) {
+        return;
+    }
+
+    if ((scd->chr->opened && connected) ||
+        (!scd->chr->opened && !connected)) {
+        return;
+    }
+
+    if (connected) {
+        scd->chr->opened = 1;
+        event = CHR_EVENT_OPENED;
+    } else {
+        scd->chr->opened = 0;
+        event = CHR_EVENT_CLOSED;
+    }
+
+    if (scd->chr->chr_event) {
+        scd->chr->chr_event(scd->chr->handler_opaque, event);
+    }
+}
+
 static SpiceCharDeviceInterface vmc_interface = {
     .base.type          = SPICE_INTERFACE_CHAR_DEVICE,
     .base.description   = "spice virtual channel char device",
     .base.major_version = SPICE_INTERFACE_CHAR_DEVICE_MAJOR,
     .base.minor_version = SPICE_INTERFACE_CHAR_DEVICE_MINOR,
+    .state              = vmc_state,
     .write              = vmc_write,
     .read               = vmc_read,
 };
@@ -222,7 +259,10 @@ CharDriverState *qemu_chr_open_spice(QemuOpts *opts)
     chr->chr_guest_close = spice_chr_guest_close;
     s->unblock_timer = qemu_new_timer_ms(vm_clock, spice_chr_unblock, s);
 
-    qemu_chr_generic_open(chr);
+    /* See comment in vmc_state() */
+    if (strcmp(subtype, "vdagent") == 0) {
+        qemu_chr_generic_open(chr);
+    }
 
     return chr;
 }
-- 
1.7.5.1