Re: [win-pv-devel] [PATCH 05/14] Add a short Sleep between CreateFile calls

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: win-pv-devel [mailto:win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx] On
> Behalf Of owen.smith@xxxxxxxxxx
> Sent: 24 January 2018 14:05
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Owen Smith <owen.smith@xxxxxxxxxx>
> Subject: [win-pv-devel] [PATCH 05/14] Add a short Sleep between CreateFile
> calls
> 
> From: Owen Smith <owen.smith@xxxxxxxxxx>
> 
> If there is no delay, its possible for the second call to CreateFile
> to fail with all pipe instances busy. Give the server end time to
> get back to ConnectNamedPipe
> 
> Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>
> ---
>  src/tty/tty.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/tty/tty.c b/src/tty/tty.c
> index 0ed599e..76f4651 100644
> --- a/src/tty/tty.c
> +++ b/src/tty/tty.c
> @@ -413,6 +413,11 @@ _tmain(
>      if (Context->Device.Read == INVALID_HANDLE_VALUE)
>          ExitProcess(1);
> 
> +    // add a small delay here, to prevent the second CreateFile returning 
> with
> +    // all pipe instances busy - this gives the server end some time to spawn
> +    // the read pipe and return to ConnectNamedPipe
> +    Sleep(50);
> +
>      Context->Device.Write = CreateFile(PIPE_NAME,
>                                         GENERIC_WRITE,
>                                         FILE_SHARE_READ | FILE_SHARE_WRITE,

I'm not fan of arbitrary delays. Could you handle this by catching the error 
and retrying instead?

  Paul

> --
> 2.8.3
> 
> 
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