Refactor the serial buffer handling in order to write the serial
buffer's output to a PTY connected after the serial device stops being
written to by the guest.
This change moves the serial buffer initialization inside the serial
manager. That is done to allow the serial buffer to be made aware of
the PTY and epoll fds needed in order to modify the
EpollDispatch::File trigger. These are then used by the serial buffer
to trigger an epoll event when the PTY fd is writable and the buffer
has content in it. They are also used to remove the trigger when the
buffer is emptied in order to avoid unnecessary wake-ups.
Signed-off-by: William Douglas <william.douglas@intel.com>
Introduce a dynamic buffer for storing output from the serial port. The
SerialBuffer implements std::io::Write and can be used in place of the
direct output for the serial device.
The internals of the buffer is a vector that grows dynamically based on
demand up to a fixed size at which point old data will be overwritten.
Currently the buffer is only flushed upon writes.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
