virtio-scsi: suppress virtqueue kick during processing
[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 "qemu/osdep.h"
13 #include "sysemu/blockdev.h"
14 #include "sysemu/block-backend.h"
15 #include "hw/block/block.h"
16 #include "qapi/qmp/qerror.h"
17 #include "sysemu/sysemu.h"
18 #include "qmp-commands.h"
19 #include "trace.h"
20 #include "block/nbd.h"
21 #include "io/channel-socket.h"
22
23 typedef struct NBDServerData {
24 QIOChannelSocket *listen_ioc;
25 int watch;
26 QCryptoTLSCreds *tlscreds;
27 } NBDServerData;
28
29 static NBDServerData *nbd_server;
30
31
32 static gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition,
33 gpointer opaque)
34 {
35 QIOChannelSocket *cioc;
36
37 if (!nbd_server) {
38 return FALSE;
39 }
40
41 cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
42 NULL);
43 if (!cioc) {
44 return TRUE;
45 }
46
47 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
48 nbd_client_new(NULL, cioc,
49 nbd_server->tlscreds, NULL,
50 nbd_client_put);
51 object_unref(OBJECT(cioc));
52 return TRUE;
53 }
54
55
56 static void nbd_server_free(NBDServerData *server)
57 {
58 if (!server) {
59 return;
60 }
61
62 if (server->watch != -1) {
63 g_source_remove(server->watch);
64 }
65 object_unref(OBJECT(server->listen_ioc));
66 if (server->tlscreds) {
67 object_unref(OBJECT(server->tlscreds));
68 }
69
70 g_free(server);
71 }
72
73 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
74 {
75 Object *obj;
76 QCryptoTLSCreds *creds;
77
78 obj = object_resolve_path_component(
79 object_get_objects_root(), id);
80 if (!obj) {
81 error_setg(errp, "No TLS credentials with id '%s'",
82 id);
83 return NULL;
84 }
85 creds = (QCryptoTLSCreds *)
86 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
87 if (!creds) {
88 error_setg(errp, "Object with id '%s' is not TLS credentials",
89 id);
90 return NULL;
91 }
92
93 if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
94 error_setg(errp,
95 "Expecting TLS credentials with a server endpoint");
96 return NULL;
97 }
98 object_ref(obj);
99 return creds;
100 }
101
102
103 void qmp_nbd_server_start(SocketAddress *addr,
104 bool has_tls_creds, const char *tls_creds,
105 Error **errp)
106 {
107 if (nbd_server) {
108 error_setg(errp, "NBD server already running");
109 return;
110 }
111
112 nbd_server = g_new0(NBDServerData, 1);
113 nbd_server->watch = -1;
114 nbd_server->listen_ioc = qio_channel_socket_new();
115 qio_channel_set_name(QIO_CHANNEL(nbd_server->listen_ioc),
116 "nbd-listener");
117 if (qio_channel_socket_listen_sync(
118 nbd_server->listen_ioc, addr, errp) < 0) {
119 goto error;
120 }
121
122 if (has_tls_creds) {
123 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
124 if (!nbd_server->tlscreds) {
125 goto error;
126 }
127
128 if (addr->type != SOCKET_ADDRESS_KIND_INET) {
129 error_setg(errp, "TLS is only supported with IPv4/IPv6");
130 goto error;
131 }
132 }
133
134 nbd_server->watch = qio_channel_add_watch(
135 QIO_CHANNEL(nbd_server->listen_ioc),
136 G_IO_IN,
137 nbd_accept,
138 NULL,
139 NULL);
140
141 return;
142
143 error:
144 nbd_server_free(nbd_server);
145 nbd_server = NULL;
146 }
147
148 void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
149 Error **errp)
150 {
151 BlockDriverState *bs = NULL;
152 BlockBackend *on_eject_blk;
153 NBDExport *exp;
154
155 if (!nbd_server) {
156 error_setg(errp, "NBD server not running");
157 return;
158 }
159
160 if (nbd_export_find(device)) {
161 error_setg(errp, "NBD server already exporting device '%s'", device);
162 return;
163 }
164
165 on_eject_blk = blk_by_name(device);
166
167 bs = bdrv_lookup_bs(device, device, errp);
168 if (!bs) {
169 return;
170 }
171
172 if (!has_writable) {
173 writable = false;
174 }
175 if (bdrv_is_read_only(bs)) {
176 writable = false;
177 }
178
179 exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
180 NULL, false, on_eject_blk, errp);
181 if (!exp) {
182 return;
183 }
184
185 nbd_export_set_name(exp, device);
186
187 /* The list of named exports has a strong reference to this export now and
188 * our only way of accessing it is through nbd_export_find(), so we can drop
189 * the strong reference that is @exp. */
190 nbd_export_put(exp);
191 }
192
193 void qmp_nbd_server_stop(Error **errp)
194 {
195 nbd_export_close_all();
196
197 nbd_server_free(nbd_server);
198 nbd_server = NULL;
199 }