[libvirt] [PATCH 1/2] socket: preserve real errno when socket/bind calls fail

[Jiri Denemark]

On Tue, Jul 24, 2018 at 15:18:09 +0100, Daniel P. Berrangé wrote:
> When reporting socket/bind failures we want to ensure any fatal error
> reported is as accurate as possible. We'll prefer reporting a bind()
> errno over a socket() errno, because if socket() works but bind() fails
> that is a more significant event.
> 
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>  src/rpc/virnetsocket.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
> index fee61ace60..8e04d61e98 100644
> --- a/src/rpc/virnetsocket.c
> +++ b/src/rpc/virnetsocket.c
> @@ -310,8 +310,8 @@ int virNetSocketNewListenTCP(const char *nodename,
>      struct addrinfo hints;
>      int fd = -1;
>      size_t i;
> -    bool addrInUse = false;
> -    bool familyNotSupported = false;
> +    int socketErrno = 0;
> +    int bindErrno = 0;
>      virSocketAddr tmp_addr;
>  
>      *retsocks = NULL;
> @@ -351,7 +351,7 @@ int virNetSocketNewListenTCP(const char *nodename,
>          if ((fd = socket(runp->ai_family, runp->ai_socktype,
>                           runp->ai_protocol)) < 0) {
>              if (errno == EAFNOSUPPORT) {
> -                familyNotSupported = true;
> +                socketErrno = errno;
>                  runp = runp->ai_next;
>                  continue;
>              }
> @@ -386,7 +386,7 @@ int virNetSocketNewListenTCP(const char *nodename,
>                  virReportSystemError(errno, "%s", _("Unable to bind to port"));
>                  goto error;
>              }
> -            addrInUse = true;
> +            bindErrno = errno;
>              VIR_FORCE_CLOSE(fd);
>              runp = runp->ai_next;
>              continue;
> @@ -409,14 +409,14 @@ int virNetSocketNewListenTCP(const char *nodename,
>          fd = -1;
>      }
>  
> -    if (nsocks == 0 && familyNotSupported) {
> -        virReportSystemError(EAFNOSUPPORT, "%s", _("Unable to bind to port"));
> -        goto error;
> -    }
> -
> -    if (nsocks == 0 &&
> -        addrInUse) {
> -        virReportSystemError(EADDRINUSE, "%s", _("Unable to bind to port"));
> +    if (nsocks == 0) {
> +        if (bindErrno) {
> +            virReportSystemError(bindErrno, "%s", _("Unable to bind to port"));
> +        } else if (socketErrno) {
> +            virReportSystemError(socketErrno, "%s", _("Unable to create socket"));
> +        } else {
> +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("No addresses to bind to"));
> +        }

We usually don't use {} around single line bodies, you can remove all of
them here.

>          goto error;
>      }

Reviewed-by: Jiri Denemark <jdenemar at redhat.com>