/* * Serving QEMU block devices via NBD * * Copyright (c) 2012 Red Hat, Inc. * * Author: Paolo Bonzini <pbonzini@redhat.com> * * This work is licensed under the terms of the GNU GPL, version 2 or * later. See the COPYING file in the top-level directory. */ #include "qemu/osdep.h" #include "sysemu/blockdev.h" #include "sysemu/block-backend.h" #include "hw/block/block.h" #include "qapi/error.h" #include "qapi/qapi-commands-block.h" #include "block/nbd.h" #include "io/channel-socket.h" #include "io/net-listener.h" typedef struct NBDServerData { QIONetListener *listener; QCryptoTLSCreds *tlscreds; char *tlsauthz; } NBDServerData; static NBDServerData *nbd_server; static void nbd_blockdev_client_closed(NBDClient *client, bool ignored) { nbd_client_put(client); } static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc, gpointer opaque) { qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server"); nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz, nbd_blockdev_client_closed); } static void nbd_server_free(NBDServerData *server) { if (!server) { return; } qio_net_listener_disconnect(server->listener); object_unref(OBJECT(server->listener)); if (server->tlscreds) { object_unref(OBJECT(server->tlscreds)); } g_free(server->tlsauthz); g_free(server); } static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) { Object *obj; QCryptoTLSCreds *creds; obj = object_resolve_path_component( object_get_objects_root(), id); if (!obj) { error_setg(errp, "No TLS credentials with id '%s'", id); return NULL; } creds = (QCryptoTLSCreds *) object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS); if (!creds) { error_setg(errp, "Object with id '%s' is not TLS credentials", id); return NULL; } if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { error_setg(errp, "Expecting TLS credentials with a server endpoint"); return NULL; } object_ref(obj); return creds; } void nbd_server_start(SocketAddress *addr, const char *tls_creds, const char *tls_authz, Error **errp) { if (nbd_server) { error_setg(errp, "NBD server already running"); return; } nbd_server = g_new0(NBDServerData, 1); nbd_server->listener = qio_net_listener_new(); qio_net_listener_set_name(nbd_server->listener, "nbd-listener"); if (qio_net_listener_open_sync(nbd_server->listener, addr, 1, errp) < 0) { goto error; } if (tls_creds) { nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp); if (!nbd_server->tlscreds) { goto error; } /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */ if (addr->type != SOCKET_ADDRESS_TYPE_INET) { error_setg(errp, "TLS is only supported with IPv4/IPv6"); goto error; } } nbd_server->tlsauthz = g_strdup(tls_authz); qio_net_listener_set_client_func(nbd_server->listener, nbd_accept, NULL, NULL); return; error: nbd_server_free(nbd_server); nbd_server = NULL; } void qmp_nbd_server_start(SocketAddressLegacy *addr, bool has_tls_creds, const char *tls_creds, bool has_tls_authz, const char *tls_authz, Error **errp) { SocketAddress *addr_flat = socket_address_flatten(addr); nbd_server_start(addr_flat, tls_creds, tls_authz, errp); qapi_free_SocketAddress(addr_flat); } void qmp_nbd_server_add(const char *device, bool has_name, const char *name, bool has_writable, bool writable, bool has_bitmap, const char *bitmap, Error **errp) { BlockDriverState *bs = NULL; BlockBackend *on_eject_blk; NBDExport *exp; int64_t len; AioContext *aio_context; if (!nbd_server) { error_setg(errp, "NBD server not running"); return; } if (!has_name) { name = device; } if (strlen(name) > NBD_MAX_STRING_SIZE) { error_setg(errp, "export name '%s' too long", name); return; } if (nbd_export_find(name)) { error_setg(errp, "NBD server already has export named '%s'", name); return; } on_eject_blk = blk_by_name(device); bs = bdrv_lookup_bs(device, device, errp); if (!bs) { return; } aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); len = bdrv_getlength(bs); if (len < 0) { error_setg_errno(errp, -len, "Failed to determine the NBD export's length"); goto out; } if (!has_writable) { writable = false; } if (bdrv_is_read_only(bs)) { writable = false; } exp = nbd_export_new(bs, 0, len, name, NULL, bitmap, !writable, !writable, NULL, false, on_eject_blk, errp); if (!exp) { goto out; } /* The list of named exports has a strong reference to this export now and * our only way of accessing it is through nbd_export_find(), so we can drop * the strong reference that is @exp. */ nbd_export_put(exp); out: aio_context_release(aio_context); } void qmp_nbd_server_remove(const char *name, bool has_mode, NbdServerRemoveMode mode, Error **errp) { NBDExport *exp; AioContext *aio_context; if (!nbd_server) { error_setg(errp, "NBD server not running"); return; } exp = nbd_export_find(name); if (exp == NULL) { error_setg(errp, "Export '%s' is not found", name); return; } if (!has_mode) { mode = NBD_SERVER_REMOVE_MODE_SAFE; } aio_context = nbd_export_aio_context(exp); aio_context_acquire(aio_context); nbd_export_remove(exp, mode, errp); aio_context_release(aio_context); } void qmp_nbd_server_stop(Error **errp) { if (!nbd_server) { error_setg(errp, "NBD server not running"); return; } nbd_export_close_all(); nbd_server_free(nbd_server); nbd_server = NULL; }