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 "nbd-internal.h"
  21
  22 ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
  23 {
  24     size_t offset = 0;
  25     int err;
  26
  27     if (qemu_in_coroutine()) {
  28         if (do_read) {
  29             return qemu_co_recv(fd, buffer, size);
  30         } else {
  31             return qemu_co_send(fd, buffer, size);
  32         }
  33     }
  34
  35     while (offset < size) {
  36         ssize_t len;
  37
  38         if (do_read) {
  39             len = qemu_recv(fd, buffer + offset, size - offset, 0);
  40         } else {
  41             len = send(fd, buffer + offset, size - offset, 0);
  42         }
  43
  44         if (len < 0) {
  45             err = socket_error();
  46
  47             /* recoverable error */
  48             if (err == EINTR || (offset > 0 && (err == EAGAIN || err == EWOULDBLOCK))) {
  49                 continue;
  50             }
  51
  52             /* unrecoverable error */
  53             return -err;
  54         }
  55
  56         /* eof */
  57         if (len == 0) {
  58             break;
  59         }
  60
  61         offset += len;
  62     }
  63
  64     return offset;
  65 }