Commit 12296459 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

nbd/server: add nbd_read_opt_name helper 



Add helper to read name in format:

  uint32 len       (<= NBD_MAX_NAME_SIZE)
  len bytes string (not 0-terminated)

The helper will be reused in following patch.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180312152126.286890-3-vsementsov@virtuozzo.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
[eblake: grammar fixes, actually check error]
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 2e425fd5

nbd/server.c

+43 −10
Original line number Diff line number Diff line
@@ -273,6 +273,48 @@ static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 
    return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;

}



/* nbd_opt_read_name

 *

 * Read a string with the format:

 *   uint32_t len     (<= NBD_MAX_NAME_SIZE)

 *   len bytes string (not 0-terminated)

 *

 * @name should be enough to store NBD_MAX_NAME_SIZE+1.

 * If @length is non-null, it will be set to the actual string length.

 *

 * Return -errno on I/O error, 0 if option was completely handled by

 * sending a reply about inconsistent lengths, or 1 on success.

 */

static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length,

                             Error **errp)

{

    int ret;

    uint32_t len;



    ret = nbd_opt_read(client, &len, sizeof(len), errp);

    if (ret <= 0) {

        return ret;

    }

    cpu_to_be32s(&len);



    if (len > NBD_MAX_NAME_SIZE) {

        return nbd_opt_invalid(client, errp,

                               "Invalid name length: %" PRIu32, len);

    }



    ret = nbd_opt_read(client, name, len, errp);

    if (ret <= 0) {

        return ret;

    }

    name[len] = '\0';



    if (length) {

        *length = len;

    }



    return 1;

}



/* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.

 * Return -errno on error, 0 on success. */

static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
@@ -455,19 +497,10 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 
        2 bytes: N, number of requests (can be 0)

        N * 2 bytes: N requests

    */

    rc = nbd_opt_read(client, &namelen, sizeof(namelen), errp);

    if (rc <= 0) {

        return rc;

    }

    be32_to_cpus(&namelen);

    if (namelen >= sizeof(name)) {

        return nbd_opt_invalid(client, errp, "name too long for qemu");

    }

    rc = nbd_opt_read(client, name, namelen, errp);

    rc = nbd_opt_read_name(client, name, &namelen, errp);

    if (rc <= 0) {

        return rc;

    }

    name[namelen] = '\0';

    trace_nbd_negotiate_handle_export_name_request(name);



    rc = nbd_opt_read(client, &requests, sizeof(requests), errp);