xref: /qemu/nbd/common.c (revision 2c533c54) 
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 ssize_t nbd_wr_syncv(QIOChannel *ioc,
24                      struct iovec *iov,
25                      size_t niov,
26                      size_t length,
27                      bool do_read)
28 {
29     ssize_t done = 0;
30     Error *local_err = NULL;
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, &local_err);
41         } else {
42             len = qio_channel_writev(ioc, local_iov, nlocal_iov, &local_err);
43         }
44         if (len == QIO_CHANNEL_ERR_BLOCK) {
45             if (qemu_in_coroutine()) {
46                 /* XXX figure out if we can create a variant on
47                  * qio_channel_yield() that works with AIO contexts
48                  * and consider using that in this branch */
49                 qemu_coroutine_yield();
50             } else if (done) {
51                 /* XXX this is needed by nbd_reply_ready.  */
52                 qio_channel_wait(ioc,
53                                  do_read ? G_IO_IN : G_IO_OUT);
54             } else {
55                 return -EAGAIN;
56             }
57             continue;
58         }
59         if (len < 0) {
60             TRACE("I/O error: %s", error_get_pretty(local_err));
61             error_free(local_err);
62             /* XXX handle Error objects */
63             done = -EIO;
64             goto cleanup;
65         }
66 
67         if (do_read && len == 0) {
68             break;
69         }
70 
71         iov_discard_front(&local_iov, &nlocal_iov, len);
72         done += len;
73     }
74 
75  cleanup:
76     g_free(local_iov_head);
77     return done;
78 }
79 
80 
81 void nbd_tls_handshake(Object *src,
82                        Error *err,
83                        void *opaque)
84 {
85     struct NBDTLSHandshakeData *data = opaque;
86 
87     if (err) {
88         TRACE("TLS failed %s", error_get_pretty(err));
89         data->error = error_copy(err);
90     }
91     data->complete = true;
92     g_main_loop_quit(data->loop);
93 }
94