/* * Serving QEMU block devices via NBD * * Copyright (c) 2012 Red Hat, Inc. * * Author: Paolo Bonzini * * 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/qmp/qerror.h" #include "sysemu/sysemu.h" #include "qmp-commands.h" #include "block/nbd.h" #include "io/channel-socket.h" typedef struct NBDServerData { QIOChannelSocket *listen_ioc; int watch; QCryptoTLSCreds *tlscreds; } NBDServerData; static NBDServerData *nbd_server; static void nbd_blockdev_client_closed(NBDClient *client, bool ignored) { nbd_client_put(client); } static gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition, gpointer opaque) { QIOChannelSocket *cioc; if (!nbd_server) { return FALSE; } cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc), NULL); if (!cioc) { return TRUE; } qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server"); nbd_client_new(NULL, cioc, nbd_server->tlscreds, NULL, nbd_blockdev_client_closed); object_unref(OBJECT(cioc)); return TRUE; } static void nbd_server_free(NBDServerData *server) { if (!server) { return; } if (server->watch != -1) { g_source_remove(server->watch); } object_unref(OBJECT(server->listen_ioc)); if (server->tlscreds) { object_unref(OBJECT(server->tlscreds)); } 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 qmp_nbd_server_start(SocketAddress *addr, bool has_tls_creds, const char *tls_creds, Error **errp) { if (nbd_server) { error_setg(errp, "NBD server already running"); return; } nbd_server = g_new0(NBDServerData, 1); nbd_server->watch = -1; nbd_server->listen_ioc = qio_channel_socket_new(); qio_channel_set_name(QIO_CHANNEL(nbd_server->listen_ioc), "nbd-listener"); if (qio_channel_socket_listen_sync( nbd_server->listen_ioc, addr, errp) < 0) { goto error; } if (has_tls_creds) { nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp); if (!nbd_server->tlscreds) { goto error; } /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */ if (addr->type != SOCKET_ADDRESS_KIND_INET) { error_setg(errp, "TLS is only supported with IPv4/IPv6"); goto error; } } nbd_server->watch = qio_channel_add_watch( QIO_CHANNEL(nbd_server->listen_ioc), G_IO_IN, nbd_accept, NULL, NULL); return; error: nbd_server_free(nbd_server); nbd_server = NULL; } void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, Error **errp) { BlockDriverState *bs = NULL; BlockBackend *on_eject_blk; NBDExport *exp; if (!nbd_server) { error_setg(errp, "NBD server not running"); return; } if (nbd_export_find(device)) { error_setg(errp, "NBD server already exporting device '%s'", device); return; } on_eject_blk = blk_by_name(device); bs = bdrv_lookup_bs(device, device, errp); if (!bs) { return; } if (!has_writable) { writable = false; } if (bdrv_is_read_only(bs)) { writable = false; } exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, NULL, false, on_eject_blk, errp); if (!exp) { return; } nbd_export_set_name(exp, device); /* 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); } void qmp_nbd_server_stop(Error **errp) { nbd_export_close_all(); nbd_server_free(nbd_server); nbd_server = NULL; }