Re: [Qemu-devel] [PATCH v6 4/4] net/socket: Improve -net socket error reporting

[Daniel P. Berrange]

On Wed, Jun 28, 2017 at 09:08:50PM +0800, Mao Zhongyi wrote:
> When -net socket fails, it first reports a specific error, then
> a generic one, like this:
> 
>     $ qemu-system-x86_64 -net socket,
>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, 
> mcast= or udp= is required
>     qemu-system-x86_64: -net socket: Device 'socket' could not be initialized

This second line of error message comes from net/net.c in the
net_client_init1 method:

        /* FIXME drop when all init functions store an Error */
        if (errp && !*errp) {
            error_setg(errp, QERR_DEVICE_INIT_FAILED,
                       NetClientDriver_lookup[netdev->type]);
        }


hopefully your patch could drop this code too ?

In fact this is the only use of QERR_DEVICE_INIT_FAILED in the
whole tree, so the QERR constant could possibly be killed too.


> 
> Convert net_socket_*_init() to Error to get rid of the superfluous second
> error message. After the patch, the effect like this:
> 
>     $ qemu-system-x86_64 -net socket,
>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, 
> mcast= or udp= is required
> 
> At the same time, add many explicit error handling message when it fails.
> 
> Cc: address@hidden
> Cc: address@hidden
> Signed-off-by: Mao Zhongyi <address@hidden>
> ---
>  net/socket.c | 92 
> +++++++++++++++++++++++++++++-------------------------------
>  1 file changed, 44 insertions(+), 48 deletions(-)
> 
> diff --git a/net/socket.c b/net/socket.c
> index 90dd4c0..47e6706 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -494,22 +494,21 @@ static void net_socket_accept(void *opaque)
>  static int net_socket_listen_init(NetClientState *peer,
>                                    const char *model,
>                                    const char *name,
> -                                  const char *host_str)
> +                                  const char *host_str,
> +                                  Error **errp)
>  {
>      NetClientState *nc;
>      NetSocketState *s;
>      struct sockaddr_in saddr;
>      int fd, ret;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>          return -1;
>      }
>  
>      fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>      if (fd < 0) {
> -        perror("socket");
> +        error_setg_errno(errp, errno, "failed to create stream socket");
>          return -1;
>      }
>      qemu_set_nonblock(fd);
> @@ -518,13 +517,14 @@ static int net_socket_listen_init(NetClientState *peer,
>  
>      ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
>      if (ret < 0) {
> -        perror("bind");
> +        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
> +                         inet_ntoa(saddr.sin_addr));
>          closesocket(fd);
>          return -1;
>      }
>      ret = listen(fd, 0);
>      if (ret < 0) {
> -        perror("listen");
> +        error_setg_errno(errp, errno, "listen socket failed");
>          closesocket(fd);
>          return -1;
>      }
> @@ -543,21 +543,20 @@ static int net_socket_listen_init(NetClientState *peer,
>  static int net_socket_connect_init(NetClientState *peer,
>                                     const char *model,
>                                     const char *name,
> -                                   const char *host_str)
> +                                   const char *host_str,
> +                                   Error **errp)
>  {
>      NetSocketState *s;
>      int fd, connected, ret;
>      struct sockaddr_in saddr;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>          return -1;
>      }
>  
>      fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>      if (fd < 0) {
> -        perror("socket");
> +        error_setg_errno(errp, errno, "failed to create stream socket");
>          return -1;
>      }
>      qemu_set_nonblock(fd);
> @@ -573,7 +572,7 @@ static int net_socket_connect_init(NetClientState *peer,
>                         errno == EINVAL) {
>                  break;
>              } else {
> -                perror("connect");
> +                error_setg_errno(errp, errno, "connection failed");
>                  closesocket(fd);
>                  return -1;
>              }
> @@ -582,9 +581,8 @@ static int net_socket_connect_init(NetClientState *peer,
>              break;
>          }
>      }
> -    s = net_socket_fd_init(peer, model, name, fd, connected, &err);
> +    s = net_socket_fd_init(peer, model, name, fd, connected, errp);
>      if (!s) {
> -        error_report_err(err);
>          return -1;
>      }
>      snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> @@ -597,36 +595,36 @@ static int net_socket_mcast_init(NetClientState *peer,
>                                   const char *model,
>                                   const char *name,
>                                   const char *host_str,
> -                                 const char *localaddr_str)
> +                                 const char *localaddr_str,
> +                                 Error **errp)
>  {
>      NetSocketState *s;
>      int fd;
>      struct sockaddr_in saddr;
>      struct in_addr localaddr, *param_localaddr;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>          return -1;
>      }
>  
>      if (localaddr_str != NULL) {
> -        if (inet_aton(localaddr_str, &localaddr) == 0)
> +        if (inet_aton(localaddr_str, &localaddr) == 0) {
> +            error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
> +                       localaddr_str);
>              return -1;
> +        }
>          param_localaddr = &localaddr;
>      } else {
>          param_localaddr = NULL;
>      }
>  
> -    fd = net_socket_mcast_create(&saddr, param_localaddr, &err);
> +    fd = net_socket_mcast_create(&saddr, param_localaddr, errp);
>      if (fd < 0) {
> -        error_report_err(err);
>          return -1;
>      }
>  
> -    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
> +    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
>      if (!s) {
> -        error_report_err(err);
>          return -1;
>      }
>  
> @@ -643,45 +641,45 @@ static int net_socket_udp_init(NetClientState *peer,
>                                   const char *model,
>                                   const char *name,
>                                   const char *rhost,
> -                                 const char *lhost)
> +                                 const char *lhost,
> +                                 Error **errp)
>  {
>      NetSocketState *s;
>      int fd, ret;
>      struct sockaddr_in laddr, raddr;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&laddr, lhost, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&laddr, lhost, errp) < 0) {
>          return -1;
>      }
>  
> -    if (parse_host_port(&raddr, rhost, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&raddr, rhost, errp) < 0) {
>          return -1;
>      }
>  
>      fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
>      if (fd < 0) {
> -        perror("socket(PF_INET, SOCK_DGRAM)");
> +        error_setg_errno(errp, errno, "failed to create datagram socket");
>          return -1;
>      }
>  
>      ret = socket_set_fast_reuse(fd);
>      if (ret < 0) {
> +        error_setg_errno(errp, errno, "set the socket 'SO_REUSEADDR'"
> +                         " attribute failed");
>          closesocket(fd);
>          return -1;
>      }
>      ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
>      if (ret < 0) {
> -        perror("bind");
> +        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
> +                         inet_ntoa(laddr.sin_addr));
>          closesocket(fd);
>          return -1;
>      }
>      qemu_set_nonblock(fd);
>  
> -    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
> +    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
>      if (!s) {
> -        error_report_err(err);
>          return -1;
>      }
>  
> @@ -696,8 +694,6 @@ static int net_socket_udp_init(NetClientState *peer,
>  int net_init_socket(const Netdev *netdev, const char *name,
>                      NetClientState *peer, Error **errp)
>  {
> -    /* FIXME error_setg(errp, ...) on failure */
> -    Error *err = NULL;
>      const NetdevSocketOptions *sock;
>  
>      assert(netdev->type == NET_CLIENT_DRIVER_SOCKET);
> @@ -705,22 +701,21 @@ int net_init_socket(const Netdev *netdev, const char 
> *name,
>  
>      if (sock->has_fd + sock->has_listen + sock->has_connect + 
> sock->has_mcast +
>          sock->has_udp != 1) {
> -        error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
> +        error_setg(errp, "exactly one of fd=, listen=, connect=, mcast= or 
> udp="
>                       " is required");
>          return -1;
>      }
>  
>      if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
> -        error_report("localaddr= is only valid with mcast= or udp=");
> +        error_setg(errp, "localaddr= is only valid with mcast= or udp=");
>          return -1;
>      }
>  
>      if (sock->has_fd) {
>          int fd;
>  
> -        fd = monitor_fd_param(cur_mon, sock->fd, &err);
> +        fd = monitor_fd_param(cur_mon, sock->fd, errp);
>          if (fd == -1) {
> -            error_report_err(err);
>              return -1;
>          }
>          qemu_set_nonblock(fd);
> @@ -731,15 +726,16 @@ int net_init_socket(const Netdev *netdev, const char 
> *name,
>      }
>  
>      if (sock->has_listen) {
> -        if (net_socket_listen_init(peer, "socket", name, sock->listen) == 
> -1) {
> +        if (net_socket_listen_init(peer, "socket", name,
> +            sock->listen, errp) == -1) {
>              return -1;
>          }
>          return 0;
>      }
>  
>      if (sock->has_connect) {
> -        if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
> -            -1) {
> +        if (net_socket_connect_init(peer, "socket", name,
> +            sock->connect, errp) == -1) {
>              return -1;
>          }
>          return 0;
> @@ -748,8 +744,8 @@ int net_init_socket(const Netdev *netdev, const char 
> *name,
>      if (sock->has_mcast) {
>          /* if sock->localaddr is missing, it has been initialized to "all 
> bits
>           * zero" */
> -        if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
> -            sock->localaddr) == -1) {
> +        if (net_socket_mcast_init(peer, "socket", name,
> +            sock->mcast, sock->localaddr, errp) == -1) {
>              return -1;
>          }
>          return 0;
> @@ -757,11 +753,11 @@ int net_init_socket(const Netdev *netdev, const char 
> *name,
>  
>      assert(sock->has_udp);
>      if (!sock->has_localaddr) {
> -        error_report("localaddr= is mandatory with udp=");
> +        error_setg(errp, "localaddr= is mandatory with udp=");
>          return -1;
>      }
> -    if (net_socket_udp_init(peer, "socket", name, sock->udp, 
> sock->localaddr) ==
> -        -1) {
> +    if (net_socket_udp_init(peer, "socket", name,
> +        sock->udp, sock->localaddr, errp) == -1) {
>          return -1;
>      }
>      return 0;
> -- 
> 2.9.4
> 
> 
> 
> 

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|