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/qapi-commands-block-export.h" 18 #include "block/nbd.h" 19 #include "io/channel-socket.h" 20 #include "io/net-listener.h" 21 22 typedef struct NBDServerData { 23 QIONetListener *listener; 24 QCryptoTLSCreds *tlscreds; 25 char *tlsauthz; 26 } NBDServerData; 27 28 static NBDServerData *nbd_server; 29 30 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored) 31 { 32 nbd_client_put(client); 33 } 34 35 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc, 36 gpointer opaque) 37 { 38 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server"); 39 nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz, 40 nbd_blockdev_client_closed); 41 } 42 43 44 static void nbd_server_free(NBDServerData *server) 45 { 46 if (!server) { 47 return; 48 } 49 50 qio_net_listener_disconnect(server->listener); 51 object_unref(OBJECT(server->listener)); 52 if (server->tlscreds) { 53 object_unref(OBJECT(server->tlscreds)); 54 } 55 g_free(server->tlsauthz); 56 57 g_free(server); 58 } 59 60 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) 61 { 62 Object *obj; 63 QCryptoTLSCreds *creds; 64 65 obj = object_resolve_path_component( 66 object_get_objects_root(), id); 67 if (!obj) { 68 error_setg(errp, "No TLS credentials with id '%s'", 69 id); 70 return NULL; 71 } 72 creds = (QCryptoTLSCreds *) 73 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS); 74 if (!creds) { 75 error_setg(errp, "Object with id '%s' is not TLS credentials", 76 id); 77 return NULL; 78 } 79 80 if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { 81 error_setg(errp, 82 "Expecting TLS credentials with a server endpoint"); 83 return NULL; 84 } 85 object_ref(obj); 86 return creds; 87 } 88 89 90 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 91 const char *tls_authz, Error **errp) 92 { 93 if (nbd_server) { 94 error_setg(errp, "NBD server already running"); 95 return; 96 } 97 98 nbd_server = g_new0(NBDServerData, 1); 99 nbd_server->listener = qio_net_listener_new(); 100 101 qio_net_listener_set_name(nbd_server->listener, 102 "nbd-listener"); 103 104 if (qio_net_listener_open_sync(nbd_server->listener, addr, 1, errp) < 0) { 105 goto error; 106 } 107 108 if (tls_creds) { 109 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp); 110 if (!nbd_server->tlscreds) { 111 goto error; 112 } 113 114 /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */ 115 if (addr->type != SOCKET_ADDRESS_TYPE_INET) { 116 error_setg(errp, "TLS is only supported with IPv4/IPv6"); 117 goto error; 118 } 119 } 120 121 nbd_server->tlsauthz = g_strdup(tls_authz); 122 123 qio_net_listener_set_client_func(nbd_server->listener, 124 nbd_accept, 125 NULL, 126 NULL); 127 128 return; 129 130 error: 131 nbd_server_free(nbd_server); 132 nbd_server = NULL; 133 } 134 135 void nbd_server_start_options(NbdServerOptions *arg, Error **errp) 136 { 137 nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz, errp); 138 } 139 140 void qmp_nbd_server_start(SocketAddressLegacy *addr, 141 bool has_tls_creds, const char *tls_creds, 142 bool has_tls_authz, const char *tls_authz, 143 Error **errp) 144 { 145 SocketAddress *addr_flat = socket_address_flatten(addr); 146 147 nbd_server_start(addr_flat, tls_creds, tls_authz, errp); 148 qapi_free_SocketAddress(addr_flat); 149 } 150 151 BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp) 152 { 153 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 154 BlockDriverState *bs = NULL; 155 NBDExport *exp = NULL; 156 AioContext *aio_context; 157 158 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 159 160 if (!nbd_server) { 161 error_setg(errp, "NBD server not running"); 162 return NULL; 163 } 164 165 if (!arg->has_name) { 166 arg->name = arg->device; 167 } 168 169 if (strlen(arg->name) > NBD_MAX_STRING_SIZE) { 170 error_setg(errp, "export name '%s' too long", arg->name); 171 return NULL; 172 } 173 174 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 175 error_setg(errp, "description '%s' too long", arg->description); 176 return NULL; 177 } 178 179 if (nbd_export_find(arg->name)) { 180 error_setg(errp, "NBD server already has export named '%s'", arg->name); 181 return NULL; 182 } 183 184 bs = bdrv_lookup_bs(arg->device, arg->device, errp); 185 if (!bs) { 186 return NULL; 187 } 188 189 aio_context = bdrv_get_aio_context(bs); 190 aio_context_acquire(aio_context); 191 192 if (!arg->has_writable) { 193 arg->writable = false; 194 } 195 if (bdrv_is_read_only(bs) && arg->writable) { 196 error_setg(errp, "Cannot export read-only node as writable"); 197 goto out; 198 } 199 200 exp = nbd_export_new(bs, arg->name, arg->description, arg->bitmap, 201 !arg->writable, !arg->writable, 202 NULL, false, errp); 203 if (!exp) { 204 goto out; 205 } 206 207 /* The list of named exports has a strong reference to this export now and 208 * our only way of accessing it is through nbd_export_find(), so we can drop 209 * the strong reference that is @exp. */ 210 nbd_export_put(exp); 211 212 out: 213 aio_context_release(aio_context); 214 /* TODO Remove the cast: nbd_export_new() will return a BlockExport. */ 215 return (BlockExport*) exp; 216 } 217 218 void qmp_nbd_server_add(BlockExportOptionsNbd *arg, Error **errp) 219 { 220 BlockExport *export; 221 BlockDriverState *bs; 222 BlockBackend *on_eject_blk; 223 BlockExportOptions export_opts; 224 225 bs = bdrv_lookup_bs(arg->device, arg->device, errp); 226 if (!bs) { 227 return; 228 } 229 230 export_opts = (BlockExportOptions) { 231 .type = BLOCK_EXPORT_TYPE_NBD, 232 .u.nbd = *arg, 233 }; 234 235 /* 236 * nbd-server-add doesn't complain when a read-only device should be 237 * exported as writable, but simply downgrades it. This is an error with 238 * block-export-add. 239 */ 240 if (bdrv_is_read_only(bs)) { 241 export_opts.u.nbd.has_writable = true; 242 export_opts.u.nbd.writable = false; 243 } 244 245 export = blk_exp_add(&export_opts, errp); 246 if (!export) { 247 return; 248 } 249 250 /* 251 * nbd-server-add removes the export when the named BlockBackend used for 252 * @device goes away. 253 */ 254 on_eject_blk = blk_by_name(arg->device); 255 if (on_eject_blk) { 256 nbd_export_set_on_eject_blk(export, on_eject_blk); 257 } 258 } 259 260 void qmp_nbd_server_remove(const char *name, 261 bool has_mode, NbdServerRemoveMode mode, 262 Error **errp) 263 { 264 NBDExport *exp; 265 AioContext *aio_context; 266 267 if (!nbd_server) { 268 error_setg(errp, "NBD server not running"); 269 return; 270 } 271 272 exp = nbd_export_find(name); 273 if (exp == NULL) { 274 error_setg(errp, "Export '%s' is not found", name); 275 return; 276 } 277 278 if (!has_mode) { 279 mode = NBD_SERVER_REMOVE_MODE_SAFE; 280 } 281 282 aio_context = nbd_export_aio_context(exp); 283 aio_context_acquire(aio_context); 284 nbd_export_remove(exp, mode, errp); 285 aio_context_release(aio_context); 286 } 287 288 void qmp_nbd_server_stop(Error **errp) 289 { 290 if (!nbd_server) { 291 error_setg(errp, "NBD server not running"); 292 return; 293 } 294 295 nbd_export_close_all(); 296 297 nbd_server_free(nbd_server); 298 nbd_server = NULL; 299 } 300