qemu/chardev/meson.build
Roman Penyaev b66ed23238 chardev/char-hub: implement backend chardev aggregator
This patch implements a new chardev backend `hub` device, which
aggregates input from multiple backend devices and forwards it to a
single frontend device. Additionally, `hub` device takes the output
from the frontend device and sends it back to all the connected
backend devices. This allows for seamless interaction between
different backend devices and a single frontend interface.

The idea of the change is trivial: keep list of backend devices
(up to 4), init them on demand and forward data buffer back and
forth.

The following is QEMU command line example:

   -chardev pty,path=/tmp/pty,id=pty0 \
   -chardev vc,id=vc0 \
   -chardev hub,id=hub0,chardevs.0=pty0,chardevs.1=vc0 \
   -device virtconsole,chardev=hub0 \
   -vnc 0.0.0.0:0

Which creates 2 backend devices: text virtual console (`vc0`) and a
pseudo TTY (`pty0`) connected to the single virtio hvc console with
the backend aggregator (`hub0`) help. `vc0` renders text to an image,
which can be shared over the VNC protocol.  `pty0` is a pseudo TTY
backend which provides biderectional communication to the virtio hvc
console.

'chardevs.N' list syntax is used for the sake of compatibility with
the representation of JSON lists in 'key=val' pairs format of the
util/keyval.c, despite the fact that modern QAPI way of parsing,
namely qobject_input_visitor_new_str(), is not used. Choice of keeping
QAPI list syntax may help to smoothly switch to modern parsing in the
future.

Signed-off-by: Roman Penyaev <r.peniaev@gmail.com>
Reviewed-by: "Marc-André Lureau" <marcandre.lureau@redhat.com>
Cc: qemu-devel@nongnu.org
Message-ID: <20250123085327.965501-3-r.peniaev@gmail.com>
2025-02-03 13:57:08 +04:00

52 lines
991 B
Meson

chardev_ss.add(files(
'char-fe.c',
'char-file.c',
'char-io.c',
'char-mux.c',
'char-hub.c',
'char-null.c',
'char-pipe.c',
'char-ringbuf.c',
'char-serial.c',
'char-socket.c',
'char-stdio.c',
'char-udp.c',
'char.c',
))
if host_os == 'windows'
chardev_ss.add(files(
'char-console.c',
'char-win-stdio.c',
'char-win.c',
))
else
chardev_ss.add(files(
'char-fd.c',
'char-parallel.c',
'char-pty.c',
), util)
endif
chardev_ss = chardev_ss.apply({})
system_ss.add(files(
'char-hmp-cmds.c',
'msmouse.c',
'wctablet.c',
'testdev.c'))
chardev_modules = {}
if brlapi.found()
module_ss = ss.source_set()
module_ss.add(when: [brlapi], if_true: [files('baum.c'), pixman])
chardev_modules += { 'baum': module_ss }
endif
if spice.found()
module_ss = ss.source_set()
module_ss.add(when: [spice], if_true: files('spice.c'))
chardev_modules += { 'spice': module_ss }
endif
modules += { 'chardev': chardev_modules }