Re: [PATCH v2] char-pty: add support for the terminal size

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Sep 15, 2025 at 06:34:15PM +0200, Maximilian Immanuel Brandtner wrote:
> Update the terminal size upon SIGWINCH delivery.
> 
> Signed-off-by: Maximilian Immanuel Brandtner <maxbr@linux.ibm.com>


Maximilian, on  a related note, could you comment on the revert
of your patch that I posted to lkml? Thanks!

> ---
> 
> To be committed with the patch-set: [PATCH v4 00/10] virtio-console: notify about the terminal size
> 
> v1 -> v2: Move comment regarding patch dependencies to note section
> ---
>  chardev/char-pty.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/chardev/char-pty.c b/chardev/char-pty.c
> index 674e9b3f14..802bae9037 100644
> --- a/chardev/char-pty.c
> +++ b/chardev/char-pty.c
> @@ -28,6 +28,7 @@
>  #include "io/channel-file.h"
>  #include "qemu/sockets.h"
>  #include "qemu/error-report.h"
> +#include "qemu/main-loop.h"
>  #include "qemu/module.h"
>  #include "qemu/option.h"
>  #include "qemu/qemu-print.h"
> @@ -35,6 +36,8 @@
>  #include "chardev/char-io.h"
>  #include "qom/object.h"
>  
> +#include <sys/ioctl.h>
> +
>  struct PtyChardev {
>      Chardev parent;
>      QIOChannel *ioc;
> @@ -43,6 +46,8 @@ struct PtyChardev {
>      int connected;
>      GSource *timer_src;
>      char *path;
> +
> +    Notifier resize_notifier;
>  };
>  typedef struct PtyChardev PtyChardev;
>  
> @@ -85,6 +90,15 @@ static void pty_chr_rearm_timer(Chardev *chr, int ms)
>      g_free(name);
>  }
>  
> +static void pty_chr_resize(PtyChardev *s)
> +{
> +    struct winsize ws;
> +
> +    if (ioctl(QIO_CHANNEL_FILE(s->ioc)->fd, TIOCGWINSZ, &ws) != -1) {
> +        qemu_chr_resize(CHARDEV(s), ws.ws_col, ws.ws_row);
> +    }
> +}
> +
>  static void pty_chr_update_read_handler(Chardev *chr)
>  {
>      PtyChardev *s = PTY_CHARDEV(chr);
> @@ -331,6 +345,12 @@ static int qemu_openpty_raw(int *aslave, char *pty_name)
>      return amaster;
>  }
>  
> +static void term_resize_notify(Notifier *n, void *data)
> +{
> +    PtyChardev *s = container_of(n, PtyChardev, resize_notifier);
> +    pty_chr_resize(s);
> +}
> +
>  static void char_pty_open(Chardev *chr,
>                            ChardevBackend *backend,
>                            bool *be_opened,
> @@ -376,6 +396,10 @@ static void char_pty_open(Chardev *chr,
>              s->path = g_strdup(path);
>          }
>      }
> +
> +    pty_chr_resize(s);
> +    s->resize_notifier.notify = term_resize_notify;
> +    sigwinch_add_notifier(&s->resize_notifier);
>  }
>  
>  static void char_pty_parse(QemuOpts *opts, ChardevBackend *backend,
> -- 
> 2.50.1