Re: [Qemu-devel] [PATCH v4 1/2] qemu-socket: change inet_connect() to to support nonblock socket

[Orit Wasserman <owasserm@redhat.com>]

On 03/19/2012 04:11 PM, Amos Kong wrote:
> Change inet_connect(const char *str, int socktype) to
> inet_connect(const char *str, bool block, int *sock_err),
> socktype is unused, block is used to assign if set socket
> to block/nonblock, sock_err is used to restore socket error.

It is more common to call the parameter blocking/nonblocking.

You removed socktype (I noticed it was not implemented) , can you keep the same API but fix the implementation ?
I don't like the use of sock_err.
How about adding a function set_socket_error that will set the errno and for win32 you can use SetLastError,
you will be able to read the error using socket_error function.

Cheers,
Orit
> 
> Connect's successful for nonblock socket when following errors are returned:
>   -EINPROGRESS or -EWOULDBLOCK
>   -WSAEALREADY or -WSAEINVAL (win32)
> 
> Also change the wrap function inet_connect_opts(QemuOpts *opts)
> to inet_connect_opts(QemuOpts *opts, int *sock_err).
> 
> Add a bool entry(block) for dummy_opts to tag block type.
> Change nbd, vnc to use new interface.
> 
> Signed-off-by: Amos Kong <akong@redhat.com>
> ---
>  nbd.c          |    2 +-
>  qemu-char.c    |    2 +-
>  qemu-sockets.c |   73 ++++++++++++++++++++++++++++++++++++++++++++------------
>  qemu_socket.h  |    4 ++-
>  ui/vnc.c       |    2 +-
>  5 files changed, 62 insertions(+), 21 deletions(-)
> 
> diff --git a/nbd.c b/nbd.c
> index 567e94e..ad4de06 100644
> --- a/nbd.c
> +++ b/nbd.c
> @@ -146,7 +146,7 @@ int tcp_socket_outgoing(const char *address, uint16_t port)
>  
>  int tcp_socket_outgoing_spec(const char *address_and_port)
>  {
> -    return inet_connect(address_and_port, SOCK_STREAM);
> +    return inet_connect(address_and_port, true, NULL);
>  }
>  
>  int tcp_socket_incoming(const char *address, uint16_t port)
> diff --git a/qemu-char.c b/qemu-char.c
> index bb9e3f5..d3543ea 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2443,7 +2443,7 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
>          if (is_listen) {
>              fd = inet_listen_opts(opts, 0);
>          } else {
> -            fd = inet_connect_opts(opts);
> +            fd = inet_connect_opts(opts, NULL);
>          }
>      }
>      if (fd < 0) {
> diff --git a/qemu-sockets.c b/qemu-sockets.c
> index 6bcb8e3..8ed45f8 100644
> --- a/qemu-sockets.c
> +++ b/qemu-sockets.c
> @@ -51,6 +51,9 @@ static QemuOptsList dummy_opts = {
>          },{
>              .name = "ipv6",
>              .type = QEMU_OPT_BOOL,
> +        },{
> +            .name = "block",
> +            .type = QEMU_OPT_BOOL,
>          },
>          { /* end if list */ }
>      },
> @@ -194,14 +197,15 @@ listen:
>      return slisten;
>  }
>  
> -int inet_connect_opts(QemuOpts *opts)
> +int inet_connect_opts(QemuOpts *opts, int *sock_err)
>  {
>      struct addrinfo ai,*res,*e;
>      const char *addr;
>      const char *port;
>      char uaddr[INET6_ADDRSTRLEN+1];
>      char uport[33];
> -    int sock,rc;
> +    int sock, rc, err;
> +    bool block;
>  
>      memset(&ai,0, sizeof(ai));
>      ai.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
> @@ -210,9 +214,11 @@ int inet_connect_opts(QemuOpts *opts)
>  
>      addr = qemu_opt_get(opts, "host");
>      port = qemu_opt_get(opts, "port");
> +    block = qemu_opt_get_bool(opts, "block", 0);
>      if (addr == NULL || port == NULL) {
>          fprintf(stderr, "inet_connect: host and/or port not specified\n");
> -        return -1;
> +        err = -EINVAL;
> +        goto err;
>      }
>  
>      if (qemu_opt_get_bool(opts, "ipv4", 0))
> @@ -224,7 +230,8 @@ int inet_connect_opts(QemuOpts *opts)
>      if (0 != (rc = getaddrinfo(addr, port, &ai, &res))) {
>          fprintf(stderr,"getaddrinfo(%s,%s): %s\n", addr, port,
>                  gai_strerror(rc));
> -	return -1;
> +        err = -EINVAL;
> +        goto err;
>      }
>  
>      for (e = res; e != NULL; e = e->ai_next) {
> @@ -241,21 +248,52 @@ int inet_connect_opts(QemuOpts *opts)
>              continue;
>          }
>          setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(void*)&on,sizeof(on));
> -
> +        if (!block) {
> +            socket_set_nonblock(sock);
> +        }
>          /* connect to peer */
> -        if (connect(sock,e->ai_addr,e->ai_addrlen) < 0) {
> -            if (NULL == e->ai_next)
> -                fprintf(stderr, "%s: connect(%s,%s,%s,%s): %s\n", __FUNCTION__,
> -                        inet_strfamily(e->ai_family),
> -                        e->ai_canonname, uaddr, uport, strerror(errno));
> -            closesocket(sock);
> -            continue;
> +        do {
> +            err = 0;
> +            if (connect(sock, e->ai_addr, e->ai_addrlen) < 0) {
> +                err = -socket_error();
> +                if (block) {
> +                    break;
> +                }
> +            }
> +        } while (err == -EINTR);
> +
> +        if (err >= 0) {
> +            goto success;
> +        } else if (!block && (err == -EINPROGRESS || err == -EWOULDBLOCK)) {
> +            goto success;
> +#ifdef _WIN32
> +        } else if (!block && (sock_err == -WSAEALREADY ||
> +                              sock_err == -WSAEINVAL)) {
> +            goto success;
> +#endif
>          }
> -        freeaddrinfo(res);
> -        return sock;
> +
> +        if (NULL == e->ai_next) {
> +            fprintf(stderr, "%s: connect(%s,%s,%s,%s): %s\n", __func__,
> +                    inet_strfamily(e->ai_family),
> +                    e->ai_canonname, uaddr, uport, strerror(errno));
> +        }
> +        closesocket(sock);
>      }
>      freeaddrinfo(res);
> +
> +err:
> +    if (sock_err) {
> +        *sock_err = err;
> +    }
>      return -1;
> +
> +success:
> +    freeaddrinfo(res);
> +    if (sock_err) {
> +        *sock_err = err;
> +    }
> +    return sock;
>  }
>  
>  int inet_dgram_opts(QemuOpts *opts)
> @@ -449,14 +487,17 @@ int inet_listen(const char *str, char *ostr, int olen,
>      return sock;
>  }
>  
> -int inet_connect(const char *str, int socktype)
> +int inet_connect(const char *str, bool block, int *sock_err)
>  {
>      QemuOpts *opts;
>      int sock = -1;
>  
>      opts = qemu_opts_create(&dummy_opts, NULL, 0);
>      if (inet_parse(opts, str) == 0)
> -        sock = inet_connect_opts(opts);
> +        if (block) {
> +            qemu_opt_set(opts, "block", "on");
> +        }
> +        sock = inet_connect_opts(opts, sock_err);
>      qemu_opts_del(opts);
>      return sock;
>  }
> diff --git a/qemu_socket.h b/qemu_socket.h
> index fe4cf6c..4810506 100644
> --- a/qemu_socket.h
> +++ b/qemu_socket.h
> @@ -44,8 +44,8 @@ int send_all(int fd, const void *buf, int len1);
>  int inet_listen_opts(QemuOpts *opts, int port_offset);
>  int inet_listen(const char *str, char *ostr, int olen,
>                  int socktype, int port_offset);
> -int inet_connect_opts(QemuOpts *opts);
> -int inet_connect(const char *str, int socktype);
> +int inet_connect_opts(QemuOpts *opts, int *sock_err);
> +int inet_connect(const char *str, bool block, int *sock_err);
>  int inet_dgram_opts(QemuOpts *opts);
>  const char *inet_strfamily(int family);
>  
> diff --git a/ui/vnc.c b/ui/vnc.c
> index deb9ecd..3ae7704 100644
> --- a/ui/vnc.c
> +++ b/ui/vnc.c
> @@ -3068,7 +3068,7 @@ int vnc_display_open(DisplayState *ds, const char *display)
>          if (strncmp(display, "unix:", 5) == 0)
>              vs->lsock = unix_connect(display+5);
>          else
> -            vs->lsock = inet_connect(display, SOCK_STREAM);
> +            vs->lsock = inet_connect(display, true, NULL);
>          if (-1 == vs->lsock) {
>              g_free(vs->display);
>              vs->display = NULL;
> 
>