Merge tag 'pull-target-arm-20220812' of https://git.linaro.org/people/pmaydell/qemu...
[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/error.h"
17 #include "qapi/clone-visitor.h"
18 #include "qapi/qapi-visit-block-export.h"
19 #include "qapi/qapi-commands-block-export.h"
20 #include "block/nbd.h"
21 #include "io/channel-socket.h"
22 #include "io/net-listener.h"
23
24 typedef struct NBDServerData {
25 QIONetListener *listener;
26 QCryptoTLSCreds *tlscreds;
27 char *tlsauthz;
28 uint32_t max_connections;
29 uint32_t connections;
30 } NBDServerData;
31
32 static NBDServerData *nbd_server;
33 static int qemu_nbd_connections = -1; /* Non-negative if this is qemu-nbd */
34
35 static void nbd_update_server_watch(NBDServerData *s);
36
37 void nbd_server_is_qemu_nbd(int max_connections)
38 {
39 qemu_nbd_connections = max_connections;
40 }
41
42 bool nbd_server_is_running(void)
43 {
44 return nbd_server || qemu_nbd_connections >= 0;
45 }
46
47 int nbd_server_max_connections(void)
48 {
49 return nbd_server ? nbd_server->max_connections : qemu_nbd_connections;
50 }
51
52 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
53 {
54 nbd_client_put(client);
55 assert(nbd_server->connections > 0);
56 nbd_server->connections--;
57 nbd_update_server_watch(nbd_server);
58 }
59
60 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
61 gpointer opaque)
62 {
63 nbd_server->connections++;
64 nbd_update_server_watch(nbd_server);
65
66 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
67 nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
68 nbd_blockdev_client_closed);
69 }
70
71 static void nbd_update_server_watch(NBDServerData *s)
72 {
73 if (!s->max_connections || s->connections < s->max_connections) {
74 qio_net_listener_set_client_func(s->listener, nbd_accept, NULL, NULL);
75 } else {
76 qio_net_listener_set_client_func(s->listener, NULL, NULL, NULL);
77 }
78 }
79
80 static void nbd_server_free(NBDServerData *server)
81 {
82 if (!server) {
83 return;
84 }
85
86 qio_net_listener_disconnect(server->listener);
87 object_unref(OBJECT(server->listener));
88 if (server->tlscreds) {
89 object_unref(OBJECT(server->tlscreds));
90 }
91 g_free(server->tlsauthz);
92
93 g_free(server);
94 }
95
96 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
97 {
98 Object *obj;
99 QCryptoTLSCreds *creds;
100
101 obj = object_resolve_path_component(
102 object_get_objects_root(), id);
103 if (!obj) {
104 error_setg(errp, "No TLS credentials with id '%s'",
105 id);
106 return NULL;
107 }
108 creds = (QCryptoTLSCreds *)
109 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
110 if (!creds) {
111 error_setg(errp, "Object with id '%s' is not TLS credentials",
112 id);
113 return NULL;
114 }
115
116 if (!qcrypto_tls_creds_check_endpoint(creds,
117 QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
118 errp)) {
119 return NULL;
120 }
121 object_ref(obj);
122 return creds;
123 }
124
125
126 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
127 const char *tls_authz, uint32_t max_connections,
128 Error **errp)
129 {
130 if (nbd_server) {
131 error_setg(errp, "NBD server already running");
132 return;
133 }
134
135 nbd_server = g_new0(NBDServerData, 1);
136 nbd_server->max_connections = max_connections;
137 nbd_server->listener = qio_net_listener_new();
138
139 qio_net_listener_set_name(nbd_server->listener,
140 "nbd-listener");
141
142 /*
143 * Because this server is persistent, a backlog of SOMAXCONN is
144 * better than trying to size it to max_connections.
145 */
146 if (qio_net_listener_open_sync(nbd_server->listener, addr, SOMAXCONN,
147 errp) < 0) {
148 goto error;
149 }
150
151 if (tls_creds) {
152 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
153 if (!nbd_server->tlscreds) {
154 goto error;
155 }
156 }
157
158 nbd_server->tlsauthz = g_strdup(tls_authz);
159
160 nbd_update_server_watch(nbd_server);
161
162 return;
163
164 error:
165 nbd_server_free(nbd_server);
166 nbd_server = NULL;
167 }
168
169 void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
170 {
171 nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz,
172 arg->max_connections, errp);
173 }
174
175 void qmp_nbd_server_start(SocketAddressLegacy *addr,
176 bool has_tls_creds, const char *tls_creds,
177 bool has_tls_authz, const char *tls_authz,
178 bool has_max_connections, uint32_t max_connections,
179 Error **errp)
180 {
181 SocketAddress *addr_flat = socket_address_flatten(addr);
182
183 nbd_server_start(addr_flat, tls_creds, tls_authz, max_connections, errp);
184 qapi_free_SocketAddress(addr_flat);
185 }
186
187 void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
188 {
189 BlockExport *export;
190 BlockDriverState *bs;
191 BlockBackend *on_eject_blk;
192 BlockExportOptions *export_opts;
193
194 bs = bdrv_lookup_bs(arg->device, arg->device, errp);
195 if (!bs) {
196 return;
197 }
198
199 /*
200 * block-export-add would default to the node-name, but we may have to use
201 * the device name as a default here for compatibility.
202 */
203 if (!arg->has_name) {
204 arg->has_name = true;
205 arg->name = g_strdup(arg->device);
206 }
207
208 export_opts = g_new(BlockExportOptions, 1);
209 *export_opts = (BlockExportOptions) {
210 .type = BLOCK_EXPORT_TYPE_NBD,
211 .id = g_strdup(arg->name),
212 .node_name = g_strdup(bdrv_get_node_name(bs)),
213 .has_writable = arg->has_writable,
214 .writable = arg->writable,
215 };
216 QAPI_CLONE_MEMBERS(BlockExportOptionsNbdBase, &export_opts->u.nbd,
217 qapi_NbdServerAddOptions_base(arg));
218 if (arg->has_bitmap) {
219 BlockDirtyBitmapOrStr *el = g_new(BlockDirtyBitmapOrStr, 1);
220
221 *el = (BlockDirtyBitmapOrStr) {
222 .type = QTYPE_QSTRING,
223 .u.local = g_strdup(arg->bitmap),
224 };
225 export_opts->u.nbd.has_bitmaps = true;
226 QAPI_LIST_PREPEND(export_opts->u.nbd.bitmaps, el);
227 }
228
229 /*
230 * nbd-server-add doesn't complain when a read-only device should be
231 * exported as writable, but simply downgrades it. This is an error with
232 * block-export-add.
233 */
234 if (bdrv_is_read_only(bs)) {
235 export_opts->has_writable = true;
236 export_opts->writable = false;
237 }
238
239 export = blk_exp_add(export_opts, errp);
240 if (!export) {
241 goto fail;
242 }
243
244 /*
245 * nbd-server-add removes the export when the named BlockBackend used for
246 * @device goes away.
247 */
248 on_eject_blk = blk_by_name(arg->device);
249 if (on_eject_blk) {
250 nbd_export_set_on_eject_blk(export, on_eject_blk);
251 }
252
253 fail:
254 qapi_free_BlockExportOptions(export_opts);
255 }
256
257 void qmp_nbd_server_remove(const char *name,
258 bool has_mode, BlockExportRemoveMode mode,
259 Error **errp)
260 {
261 BlockExport *exp;
262
263 exp = blk_exp_find(name);
264 if (exp && exp->drv->type != BLOCK_EXPORT_TYPE_NBD) {
265 error_setg(errp, "Block export '%s' is not an NBD export", name);
266 return;
267 }
268
269 qmp_block_export_del(name, has_mode, mode, errp);
270 }
271
272 void qmp_nbd_server_stop(Error **errp)
273 {
274 if (!nbd_server) {
275 error_setg(errp, "NBD server not running");
276 return;
277 }
278
279 blk_exp_close_all_type(BLOCK_EXPORT_TYPE_NBD);
280
281 nbd_server_free(nbd_server);
282 nbd_server = NULL;
283 }