Re: [Qemu-devel] [PATCH] chardev: don't splatter terminal settings on exit if not previously set

[Marc-André Lureau]

On Mon, Jun 4, 2018 at 2:30 PM, Daniel P. Berrangé <address@hidden> wrote:
> The stdio chardev finalize method calls term_exit() to restore the
> original terminal settings that were saved in the "oldtty" global. If
> the qemu_chr_open_stdio() method exited with an error, we might not have
> any original terminal settings saved in "oldtty" yet.
>
> eg
>
>   $ qemu-system-x86_64 -monitor stdio -daemonize
>   qemu-system-x86_64: -monitor stdio: cannot use stdio with -daemonize
>
> will cause QEMU to splatter the terminal settings with an all-zeros
> "struct termios", with predictably unpleasant results. Fortunately the
> existing "stdio_in_use" flag is suitable witness for whether "oldtty"
> contains settings that need restoring.
>
> Signed-off-by: Daniel P. Berrangé <address@hidden>

Reviewed-by: Marc-André Lureau <address@hidden>

> ---
>  chardev/char-stdio.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c
> index d83e60e787..8039e85f64 100644
> --- a/chardev/char-stdio.c
> +++ b/chardev/char-stdio.c
> @@ -46,8 +46,10 @@ static bool stdio_echo_state;
>
>  static void term_exit(void)
>  {
> -    tcsetattr(0, TCSANOW, &oldtty);
> -    fcntl(0, F_SETFL, old_fd0_flags);
> +    if (stdio_in_use) {
> +        tcsetattr(0, TCSANOW, &oldtty);
> +        fcntl(0, F_SETFL, old_fd0_flags);
> +    }
>  }
>
>  static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
> --
> 2.17.0
>