On September 18, 2025 9:53:27 AM GMT+02:00, Maximilian Immanuel Brandtner <[email protected]> wrote: > On Wed, 2025-09-17 at 14:31 +0100, Daniel P. Berrangé wrote: > > On Wed, Sep 17, 2025 at 03:09:50PM +0200, Filip Hejsek wrote: > > > > > > > > > On September 17, 2025 11:39:55 AM GMT+02:00, Maximilian Immanuel > > > Brandtner <[email protected]> wrote: > > > > On Tue, 2025-09-16 at 00:02 +0200, Filip Hejsek wrote: > > > > > On Mon, 2025-09-15 at 18:34 +0200, Maximilian Immanuel > > > > > Brandtner > > > > > wrote: > > > > > > Update the terminal size upon SIGWINCH delivery. > > > > > > > > > > > > Signed-off-by: Maximilian Immanuel Brandtner > > > > > > <[email protected]> > > > > > > > > > > I don't think this will work, because SIGWINCH is only > > > > > delivered for > > > > > the process' controling terminal. Unfortunately I don't think > > > > > there > > > > > is > > > > > any way to get size notifications for arbitrary terminal. > > > > > > > > In that case there are two solutions: > > > > 1. make qemu the controlling process of the pty (this has the > > > > disadvantage of QEMU being quit when the pty is closed) > > > > > > A bigger disadvantage is that a process can only have one > > > controlling terminal, and a terminal can only be the controlling > > > terminal for a single session (and only sends signals to the > > > foreground process group of that session). It would require forking > > > a process for each pty, and I don't even know if the master end can > > > have its own session. > > > > > > > 2. create a timer polling every eg 100ms to check if the winsize > > > > has > > > > changed > > > > > > > > I would go with the second approach then > > > > > > Me too, the timer is a bit unfortunate, but it's probably the less > > > bad option. > > > > I don't think we want a timer polling for an situation that will very > > rarely arise. We already add the 'chardev_resize' QMP command, which > > is > > a good enough way to kick QEMU to re-read the size. > > > > With regards, > > Daniel > > This approach would only work with libvirt and not generic pty > applications though. Perhaps a bool poll_resize could be added to the > struct Chardev which is disabled, as soon as the chardev_resize QMP > command is used to avoid race conditions.
Well, terminal emulators that set the pty size typically create their own pty and control it from the master side. I don't know what pty applications you have in mind—changing the window size from the slave side is somewhat atypical. Applications designed for a real serial port probably don't set the size at all. Regards, Filip
