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/*
* 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/qmp/qerror.h"
#include "sysemu/sysemu.h"
#include "qmp-commands.h"
#include "trace.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 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;
}
nbd_client_new(NULL, cioc,
nbd_server->tlscreds, NULL,
nbd_client_put);
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();
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;
}
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)
{
BlockBackend *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;
}
blk = blk_by_name(device);
if (!blk) {
error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
"Device '%s' not found", device);
return;
}
if (!blk_is_inserted(blk)) {
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
return;
}
if (!has_writable) {
writable = false;
}
if (blk_is_read_only(blk)) {
writable = false;
}
exp = nbd_export_new(blk, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, NULL,
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;
}