nbd/common.c

   1 /*
   2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   3  *
   4  *  Network Block Device Common Code
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "qemu/osdep.h"
  20 #include "qapi/error.h"
  21 #include "nbd-internal.h"
  22
  23 /* nbd_wr_syncv
  24  * The function may be called from coroutine or from non-coroutine context.
  25  * When called from non-coroutine context @ioc must be in blocking mode.
  26  */
  27 ssize_t nbd_rwv(QIOChannel *ioc, struct iovec *iov, size_t niov, size_t length,
  28                 bool do_read, Error **errp)
  29 {
  30     ssize_t done = 0;
  31     struct iovec *local_iov = g_new(struct iovec, niov);
  32     struct iovec *local_iov_head = local_iov;
  33     unsigned int nlocal_iov = niov;
  34
  35     nlocal_iov = iov_copy(local_iov, nlocal_iov, iov, niov, 0, length);
  36
  37     while (nlocal_iov > 0) {
  38         ssize_t len;
  39         if (do_read) {
  40             len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
  41         } else {
  42             len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
  43         }
  44         if (len == QIO_CHANNEL_ERR_BLOCK) {
  45             /* errp should not be set */
  46             assert(qemu_in_coroutine());
  47             qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
  48             continue;
  49         }
  50         if (len < 0) {
  51             done = -EIO;
  52             goto cleanup;
  53         }
  54
  55         if (do_read && len == 0) {
  56             break;
  57         }
  58
  59         iov_discard_front(&local_iov, &nlocal_iov, len);
  60         done += len;
  61     }
  62
  63  cleanup:
  64     g_free(local_iov_head);
  65     return done;
  66 }
  67
  68 /* Discard length bytes from channel.  Return -errno on failure and 0 on
  69  * success */
  70 int nbd_drop(QIOChannel *ioc, size_t size, Error **errp)
  71 {
  72     ssize_t ret = 0;
  73     char small[1024];
  74     char *buffer;
  75
  76     buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
  77     while (size > 0) {
  78         ssize_t count = MIN(65536, size);
  79         ret = nbd_read(ioc, buffer, MIN(65536, size), errp);
  80
  81         if (ret < 0) {
  82             goto cleanup;
  83         }
  84         size -= count;
  85     }
  86
  87  cleanup:
  88     if (buffer != small) {
  89         g_free(buffer);
  90     }
  91     return ret;
  92 }
  93
  94
  95 void nbd_tls_handshake(QIOTask *task,
  96                        void *opaque)
  97 {
  98     struct NBDTLSHandshakeData *data = opaque;
  99
 100     qio_task_propagate_error(task, &data->error);
 101     data->complete = true;
 102     g_main_loop_quit(data->loop);
 103 }