Re: [Qemu-devel] [PATCH] char: disable stdio echo on resume from suspend.

[Peter Maydell <peter.maydell@linaro.org>]

On 5 January 2015 at 09:21, Gal Hammer <ghammer@redhat.com> wrote:
> The monitor's auto-completion feature stopped working when stdio is used
> as an input and qemu was resumed after it was suspended (using ctrl-z).
>
> Signed-off-by: Gal Hammer <ghammer@redhat.com>
> ---
>  qemu-char.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index ef84b53..786df33 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -1113,12 +1113,22 @@ static int old_fd0_flags;
>  static bool stdio_in_use;
>  static bool stdio_allow_signal;
>
> +static void qemu_chr_set_echo_stdio(CharDriverState *chr, bool echo);
> +
>  static void term_exit(void)
>  {
>      tcsetattr (0, TCSANOW, &oldtty);
>      fcntl(0, F_SETFL, old_fd0_flags);
>  }
>
> +static void term_stdio_handler(int sig)
> +{
> +    if (sig == SIGCONT) {

...why do we need this check? We don't register the function
for any other signals...

> +        /* echo should be off after resume from suspend. */
> +        qemu_chr_set_echo_stdio(NULL, false);

Should echo really be always off, even if the thing using the
char device had set it to on?

> +    }
> +}
> +
>  static void qemu_chr_set_echo_stdio(CharDriverState *chr, bool echo)
>  {
>      struct termios tty;
> @@ -1165,6 +1175,7 @@ static CharDriverState *qemu_chr_open_stdio(ChardevStdio *opts)
>      tcgetattr(0, &oldtty);
>      qemu_set_nonblock(0);
>      atexit(term_exit);
> +    signal(SIGCONT, term_stdio_handler);

This should probably be using sigaction() which is what we use
elsewhere for signal handler registration.

-- PMM