[libvirt] [PATCH 1/3] rpc: socket: Add possibility to suppress errors on read hangup

[Daniel P. Berrange]

On Fri, Mar 17, 2017 at 04:48:49PM +0100, Peter Krempa wrote:
> In some cases a read error due to connection hangup is expected. This
> patch adds a flag that removes the logging of a virError in such case.
> ---
>  src/rpc/virnetsocket.c | 33 +++++++++++++++++++++++++++------
>  src/rpc/virnetsocket.h |  2 ++
>  2 files changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
> index 325a7c7cf..4d1dc6446 100644
> --- a/src/rpc/virnetsocket.c
> +++ b/src/rpc/virnetsocket.c
> @@ -82,6 +82,7 @@ struct _virNetSocket {
>      int errfd;
>      bool client;
>      bool ownsFd;
> +    bool quietEOF;
> 
>      /* Event callback fields */
>      virNetSocketIOFunc func;
> @@ -1792,12 +1793,18 @@ static ssize_t virNetSocketReadWire(virNetSocketPtr sock, char *buf, size_t len)
>                                   _("Cannot recv data"));
>          ret = -1;
>      } else if (ret == 0) {
> -        if (errout)
> -            virReportSystemError(EIO,
> -                                 _("End of file while reading data: %s"), errout);
> -        else
> -            virReportSystemError(EIO, "%s",
> -                                 _("End of file while reading data"));
> +        if (sock->quietEOF) {
> +            VIR_DEBUG("socket='%p' EOF while reading: errout='%s'",
> +                      socket, NULLSTR(errout));
> +        } else {
> +            if (errout)
> +                virReportSystemError(EIO,
> +                                     _("End of file while reading data: %s"),
> +                                     errout);
> +            else
> +                virReportSystemError(EIO, "%s",
> +                                     _("End of file while reading data"));
> +        }
>          ret = -1;

I'm a little uncomfortable with the idea of returning '-1' without reporting
an error message. I would suggest returning 0, but we used that to indicate
EAGAIN condition. Can we at least make it return '-2' as a distinct code
when we don't report errors.


Regards,
Daniel
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