On 8 Apr 2016, at 23:05, Eric Blake <ebl...@redhat.com> wrote:
> Rather than open-coding NBD_REP_SERVER, reuse the code we
> already have by adding a length parameter. The code gets
> longer because of added comments, but the refactoring will
> make adding NBD_OPT_GO in a later patch easier.
>
> Signed-off-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: Alex Bligh <a...@alex.org.uk>
> ---
> nbd/server.c | 59 +++++++++++++++++++++++++++++------------------------------
> 1 file changed, 29 insertions(+), 30 deletions(-)
>
> diff --git a/nbd/server.c b/nbd/server.c
> index c8666ab..69724c9 100644
> --- a/nbd/server.c
> +++ b/nbd/server.c
> @@ -192,12 +192,15 @@ static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc,
> size_t size)
>
> */
>
> -static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t
> opt)
> +/* Send a reply header, including length, but no payload.
> + * Return -errno to kill connection, 0 to continue negotiation */
> +static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
> + uint32_t opt, uint32_t len)
> {
> uint64_t magic;
> - uint32_t len;
>
> - TRACE("Reply opt=%" PRIx32 " type=%" PRIx32, type, opt);
> + TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32,
> + type, opt, len);
>
> magic = cpu_to_be64(NBD_REP_MAGIC);
> if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
> @@ -214,7 +217,7 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc,
> uint32_t type, uint32_t opt)
> LOG("write failed (rep type)");
> return -EINVAL;
> }
> - len = cpu_to_be32(0);
> + len = cpu_to_be32(len);
> if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
> LOG("write failed (rep data length)");
> return -EINVAL;
> @@ -222,39 +225,35 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc,
> uint32_t type, uint32_t opt)
> return 0;
> }
>
> +/* Send a reply header with default 0 length.
> + * Return -errno to kill connection, 0 to continue negotiation */
> +static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t
> opt)
> +{
> + return nbd_negotiate_send_rep_len(ioc, type, opt, 0);
> +}
> +
> +/* Send an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
> + * Return -errno to kill connection, 0 to continue negotiation */
> static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
> {
> - uint64_t magic, name_len;
> - uint32_t opt, type, len;
> + uint32_t len;
> + int rc;
>
> TRACE("Advertising export name '%s'", exp->name ? exp->name : "");
> - name_len = strlen(exp->name);
> - magic = cpu_to_be64(NBD_REP_MAGIC);
> - if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
> - LOG("write failed (magic)");
> - return -EINVAL;
> - }
> - opt = cpu_to_be32(NBD_OPT_LIST);
> - if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
> - LOG("write failed (opt)");
> - return -EINVAL;
> - }
> - type = cpu_to_be32(NBD_REP_SERVER);
> - if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
> - LOG("write failed (reply type)");
> - return -EINVAL;
> - }
> - len = cpu_to_be32(name_len + sizeof(len));
> - if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
> - LOG("write failed (length)");
> - return -EINVAL;
> - }
> - len = cpu_to_be32(name_len);
> + len = strlen(exp->name);
> + rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST,
> + len + sizeof(len));
> + if (rc < 0) {
> + return rc;
> + }
> +
> + len = cpu_to_be32(len);
> if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
> - LOG("write failed (length)");
> + LOG("write failed (name length)");
> return -EINVAL;
> }
> - if (nbd_negotiate_write(ioc, exp->name, name_len) != name_len) {
> + len = be32_to_cpu(len);
> + if (nbd_negotiate_write(ioc, exp->name, len) != len) {
> LOG("write failed (buffer)");
> return -EINVAL;
> }
> --
> 2.5.5
>
>
--
Alex Bligh
