hw/net: fix mcf_fec driver receiver
[qemu.git] / blockdev-nbd.c
1 /*
2 * Serving QEMU block devices via NBD
3 *
4 * Copyright (c) 2012 Red Hat, Inc.
5 *
6 * Author: Paolo Bonzini <pbonzini@redhat.com>
7 *
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.
10 */
11
12 #include "sysemu/blockdev.h"
13 #include "sysemu/block-backend.h"
14 #include "hw/block/block.h"
15 #include "qapi/qmp/qerror.h"
16 #include "sysemu/sysemu.h"
17 #include "qmp-commands.h"
18 #include "trace.h"
19 #include "block/nbd.h"
20 #include "qemu/sockets.h"
21
22 static int server_fd = -1;
23
24 static void nbd_accept(void *opaque)
25 {
26 struct sockaddr_in addr;
27 socklen_t addr_len = sizeof(addr);
28
29 int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
30 if (fd >= 0 && !nbd_client_new(NULL, fd, nbd_client_put)) {
31 shutdown(fd, 2);
32 close(fd);
33 }
34 }
35
36 void qmp_nbd_server_start(SocketAddress *addr, Error **errp)
37 {
38 if (server_fd != -1) {
39 error_setg(errp, "NBD server already running");
40 return;
41 }
42
43 server_fd = socket_listen(addr, errp);
44 if (server_fd != -1) {
45 qemu_set_fd_handler(server_fd, nbd_accept, NULL, NULL);
46 }
47 }
48
49 /*
50 * Hook into the BlockBackend notifiers to close the export when the
51 * backend is closed.
52 */
53 typedef struct NBDCloseNotifier {
54 Notifier n;
55 NBDExport *exp;
56 QTAILQ_ENTRY(NBDCloseNotifier) next;
57 } NBDCloseNotifier;
58
59 static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers =
60 QTAILQ_HEAD_INITIALIZER(close_notifiers);
61
62 static void nbd_close_notifier(Notifier *n, void *data)
63 {
64 NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n);
65
66 notifier_remove(&cn->n);
67 QTAILQ_REMOVE(&close_notifiers, cn, next);
68
69 nbd_export_close(cn->exp);
70 nbd_export_put(cn->exp);
71 g_free(cn);
72 }
73
74 void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
75 Error **errp)
76 {
77 BlockBackend *blk;
78 NBDExport *exp;
79 NBDCloseNotifier *n;
80
81 if (server_fd == -1) {
82 error_setg(errp, "NBD server not running");
83 return;
84 }
85
86 if (nbd_export_find(device)) {
87 error_setg(errp, "NBD server already exporting device '%s'", device);
88 return;
89 }
90
91 blk = blk_by_name(device);
92 if (!blk) {
93 error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
94 "Device '%s' not found", device);
95 return;
96 }
97 if (!blk_is_inserted(blk)) {
98 error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
99 return;
100 }
101
102 if (!has_writable) {
103 writable = false;
104 }
105 if (blk_is_read_only(blk)) {
106 writable = false;
107 }
108
109 exp = nbd_export_new(blk, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, NULL,
110 errp);
111 if (!exp) {
112 return;
113 }
114
115 nbd_export_set_name(exp, device);
116
117 n = g_new0(NBDCloseNotifier, 1);
118 n->n.notify = nbd_close_notifier;
119 n->exp = exp;
120 blk_add_close_notifier(blk, &n->n);
121 QTAILQ_INSERT_TAIL(&close_notifiers, n, next);
122 }
123
124 void qmp_nbd_server_stop(Error **errp)
125 {
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));
129 }
130
131 if (server_fd != -1) {
132 qemu_set_fd_handler(server_fd, NULL, NULL, NULL);
133 close(server_fd);
134 server_fd = -1;
135 }
136 }