2 * Serving QEMU block devices via NBD
4 * Copyright (c) 2012 Red Hat, Inc.
6 * Author: Paolo Bonzini <pbonzini@redhat.com>
8 * This work is licensed under the terms of the GNU GPL, version 2 or
9 * later. See the COPYING file in the top-level directory.
12 #include "sysemu/blockdev.h"
13 #include "sysemu/block-backend.h"
14 #include "hw/block/block.h"
15 #include "monitor/monitor.h"
16 #include "qapi/qmp/qerror.h"
17 #include "sysemu/sysemu.h"
18 #include "qmp-commands.h"
20 #include "block/nbd.h"
21 #include "qemu/sockets.h"
23 static int server_fd
= -1;
25 static void nbd_accept(void *opaque
)
27 struct sockaddr_in addr
;
28 socklen_t addr_len
= sizeof(addr
);
30 int fd
= accept(server_fd
, (struct sockaddr
*)&addr
, &addr_len
);
31 if (fd
>= 0 && !nbd_client_new(NULL
, fd
, nbd_client_put
)) {
37 void qmp_nbd_server_start(SocketAddress
*addr
, Error
**errp
)
39 if (server_fd
!= -1) {
40 error_setg(errp
, "NBD server already running");
44 server_fd
= socket_listen(addr
, errp
);
45 if (server_fd
!= -1) {
46 qemu_set_fd_handler(server_fd
, nbd_accept
, NULL
, NULL
);
51 * Hook into the BlockBackend notifiers to close the export when the
54 typedef struct NBDCloseNotifier
{
57 QTAILQ_ENTRY(NBDCloseNotifier
) next
;
60 static QTAILQ_HEAD(, NBDCloseNotifier
) close_notifiers
=
61 QTAILQ_HEAD_INITIALIZER(close_notifiers
);
63 static void nbd_close_notifier(Notifier
*n
, void *data
)
65 NBDCloseNotifier
*cn
= DO_UPCAST(NBDCloseNotifier
, n
, n
);
67 notifier_remove(&cn
->n
);
68 QTAILQ_REMOVE(&close_notifiers
, cn
, next
);
70 nbd_export_close(cn
->exp
);
71 nbd_export_put(cn
->exp
);
75 void qmp_nbd_server_add(const char *device
, bool has_writable
, bool writable
,
82 if (server_fd
== -1) {
83 error_setg(errp
, "NBD server not running");
87 if (nbd_export_find(device
)) {
88 error_setg(errp
, "NBD server already exporting device '%s'", device
);
92 blk
= blk_by_name(device
);
94 error_set(errp
, QERR_DEVICE_NOT_FOUND
, device
);
97 if (!blk_is_inserted(blk
)) {
98 error_set(errp
, QERR_DEVICE_HAS_NO_MEDIUM
, device
);
105 if (blk_is_read_only(blk
)) {
109 exp
= nbd_export_new(blk
, 0, -1, writable
? 0 : NBD_FLAG_READ_ONLY
, NULL
,
115 nbd_export_set_name(exp
, device
);
117 n
= g_new0(NBDCloseNotifier
, 1);
118 n
->n
.notify
= nbd_close_notifier
;
120 blk_add_close_notifier(blk
, &n
->n
);
121 QTAILQ_INSERT_TAIL(&close_notifiers
, n
, next
);
124 void qmp_nbd_server_stop(Error
**errp
)
126 while (!QTAILQ_EMPTY(&close_notifiers
)) {
127 NBDCloseNotifier
*cn
= QTAILQ_FIRST(&close_notifiers
);
128 nbd_close_notifier(&cn
->n
, nbd_export_get_blockdev(cn
->exp
));
131 if (server_fd
!= -1) {
132 qemu_set_fd_handler(server_fd
, NULL
, NULL
, NULL
);