[Qemu-devel] Re: [PATCH] net: Remove dead code from net/socket.c

[Jan Kiszka <jan.kiszka@siemens.com>]

Miguel Di Ciurcio Filho wrote:
> When a connection is accepted, the handler net_socket_accept() calls
> net_socket_fd_init(). If the socket is UDP/multicast,
> net_socket_fd_init() calls net_socket_fd_init_dgram, if
> the socket is TCP it calls net_socket_fd_init_dgram_stream.
> 
> In both cases the info_str string is written inside
> net_socket_fd_init_(stream|dgram), and after that, it is
> overwritten on a subsequent snprintf() in net_socket_accept().
> 

There is non-zero time window between registration and acceptance. And
you have the path taken for fd sockets.

Jan

> net_socket_fd_init_(stream|dgram) always puts into the info_str the fd
> number, and this information is overwritten latter. No one has noticed this for
> so long that I believe this code is dead.
> 
> Signed-off-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com>
> ---
>  net/socket.c |    7 -------
>  1 files changed, 0 insertions(+), 7 deletions(-)
> 
> diff --git a/net/socket.c b/net/socket.c
> index 1c4e153..b72a2de 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -267,11 +267,6 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>  
>      nc = qemu_new_net_client(&net_dgram_socket_info, vlan, NULL, model, name);
>  
> -    snprintf(nc->info_str, sizeof(nc->info_str),
> -	    "socket: fd=%d (%s mcast=%s:%d)",
> -	    fd, is_connected ? "cloned" : "",
> -	    inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
> -
>      s = DO_UPCAST(NetSocketState, nc, nc);
>  
>      s->fd = fd;
> @@ -307,8 +302,6 @@ static NetSocketState *net_socket_fd_init_stream(VLANState *vlan,
>  
>      nc = qemu_new_net_client(&net_socket_info, vlan, NULL, model, name);
>  
> -    snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d", fd);
> -
>      s = DO_UPCAST(NetSocketState, nc, nc);
>  
>      s->fd = fd;

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