Currently, filter-redirector does not implement the status_changed
callback, which means the 'status' property cannot be used to
dynamically enable/disable the filter at runtime. When status is
set to 'off' via QMP/HMP, the filter still receives data from the
indev chardev because the chardev handlers remain registered.
This patch adds proper support for the 'status' property:
1. Implement filter_redirector_status_changed() callback:
- When status changes to 'off': remove chardev read handlers
- When status changes to 'on': re-register chardev handlers
(only if chardev is already open)
2. Update filter_redirector_setup() to respect initial status:
- If filter is created with status=off, do not register handlers
- This allows creating disabled filters via command line or QMP
3. Handle chardev OPENED/CLOSED events to re-arm handlers on reconnect:
- Keep the chr_event callback installed on CLOSE so a later OPENED
can re-register the read handlers when nf->on
- Use qemu_chr_fe_set_handlers_full(..., set_open=false, sync_state=false)
instead of qemu_chr_fe_set_handlers() because the latter forces
sync_state=true and may emit CHR_EVENT_OPENED for an already-open
backend. Doing that from inside the chr_event callback would cause
recursive/re-entrant OPENED handling.
Signed-off-by: Jason Wang <jasowang@redhat.com>
5193528b9f