Rename usbredir channel code to spicevmc

While discussing various things with Alon in Vancouver, it came up that
having a channel which simply passes through data coming out of a qemu
chardev frontend unmodified, like the usbredir channel does, can be used
for a lot of other cases too. To facilitate this the usbredir channel code
will be turned into a generic spicevmc channel, which is just a passthrough
to the client, from the spicevmc chardev.

This patch renames usbredir.c to spicevmc.c and changes the prefix of all
functions / structs to match. This should make clear that the code is not
usbredir specific.

Some examples of why having a generic spicevmc pass through is good:
1) We could add a monitor channel, allowing access to the qemu monitor from
the spice client, since the monitor is a chardev frontend we could re-use
the generic spicevmc channel server code, so all that is needed to add this
(server side) would be reserving a new channel id for this.

2) We could allow users to come up with new channels of their own, without
requiring qemu or server modification. The idea is to allow doing something
like this on the qemu startup cmdline:
-chardev spicevmc,name=generic,channelid=128

To ensure these new "generic" channels cannot conflict with newly added
official types, they must start at the SPICE_CHANNEL_USER_DEFINED_START value
(128).

These new user defined channels could then either be used with a special
modified client, with client plugins (if we add support for those), or
by exporting them on the client side for use by an external ap, see below.

3) We could also add support to the client to make user-defined channels
end in a unix socket / pipe, allowing handling of the data by an external app,
we could for example have a new spice client cmdline argument like this:
--custom-channel unixsocket=/tmp/mysocket,channelid=128

This would allow for something like:
$random app on guest -> virtio-serial -> spicevmc chardev ->
 -> spicevmc channel -> unix socket -> $random app on client

4) On hind sight this could also have been used for the smartcard stuff,
with a 1 channel / reader model, rather then the current multiplexing code
where we've our own multiplexing protocol wrapper over the libcacard
smartcard protocol.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/server/char_device.h b/server/char_device.h
index 4b558698..bdb32ae9 100644
--- a/server/char_device.h
+++ b/server/char_device.h
@@ -7,8 +7,8 @@ struct SpiceCharDeviceState {
     void (*wakeup)(SpiceCharDeviceInstance *sin);
 };
 
-int usbredir_device_connect(SpiceCharDeviceInstance *char_device);
-void usbredir_device_disconnect(SpiceCharDeviceInstance *char_device);
+void spicevmc_device_connect(SpiceCharDeviceInstance *sin,
+                             uint8_t channel_type);
+void spicevmc_device_disconnect(SpiceCharDeviceInstance *char_device);
 
 #endif // __CHAR_DEVICE_H__
-