Import QEMU upstream snapshot d2e570c

Upstream: https://gitlab.com/qemu-project/qemu.git

Upstream-Commit: d2e570cc0f97b936902a5b1b86b73c0f5998b475

blockdev-nbd.c

@@ -0,0 +1,339 @@
+/*
+ * Serving QEMU block devices via NBD
+ *
+ * Copyright (c) 2012 Red Hat, Inc.
+ *
+ * Author: Paolo Bonzini <[email protected]>
+ *
+ * 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 "system/blockdev.h"
+#include "system/block-backend.h"
+#include "hw/block/block.h"
+#include "qapi/error.h"
+#include "qapi/clone-visitor.h"
+#include "qapi/qapi-visit-block-export.h"
+#include "qapi/qapi-commands-block-export.h"
+#include "block/nbd.h"
+#include "io/channel-socket.h"
+#include "io/net-listener.h"
+
+typedef struct NBDConn {
+    QIOChannelSocket *cioc;
+    QLIST_ENTRY(NBDConn) next;
+} NBDConn;
+
+typedef struct NBDServerData {
+    QIONetListener *listener;
+    uint32_t handshake_max_secs;
+    QCryptoTLSCreds *tlscreds;
+    char *tlsauthz;
+    uint32_t max_connections;
+    uint32_t connections;
+    QLIST_HEAD(, NBDConn) conns;
+} NBDServerData;
+
+static NBDServerData *nbd_server;
+static int qemu_nbd_connections = -1; /* Non-negative if this is qemu-nbd */
+
+static void nbd_update_server_watch(NBDServerData *s);
+
+void nbd_server_is_qemu_nbd(int max_connections)
+{
+    qemu_nbd_connections = max_connections;
+}
+
+bool nbd_server_is_running(void)
+{
+    return nbd_server || qemu_nbd_connections >= 0;
+}
+
+int nbd_server_max_connections(void)
+{
+    return nbd_server ? nbd_server->max_connections : qemu_nbd_connections;
+}
+
+static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
+{
+    NBDConn *conn = nbd_client_owner(client);
+
+    assert(qemu_in_main_thread() && nbd_server);
+
+    object_unref(OBJECT(conn->cioc));
+    QLIST_REMOVE(conn, next);
+    g_free(conn);
+
+    nbd_client_put(client);
+    assert(nbd_server->connections > 0);
+    nbd_server->connections--;
+    nbd_update_server_watch(nbd_server);
+}
+
+static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
+                       gpointer opaque)
+{
+    NBDConn *conn = g_new0(NBDConn, 1);
+
+    assert(qemu_in_main_thread() && nbd_server);
+    nbd_server->connections++;
+    object_ref(OBJECT(cioc));
+    conn->cioc = cioc;
+    QLIST_INSERT_HEAD(&nbd_server->conns, conn, next);
+    nbd_update_server_watch(nbd_server);
+
+    qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
+    nbd_client_new(cioc, nbd_server->handshake_max_secs,
+                   nbd_server->tlscreds, nbd_server->tlsauthz,
+                   nbd_blockdev_client_closed, conn);
+}
+
+static void nbd_update_server_watch(NBDServerData *s)
+{
+    if (s->listener) {
+        if (!s->max_connections || s->connections < s->max_connections) {
+            qio_net_listener_set_client_aio_func(s->listener, nbd_accept, NULL,
+                                             NULL);
+        } else {
+            qio_net_listener_set_client_aio_func(s->listener, NULL, NULL, NULL);
+        }
+    }
+}
+
+static void nbd_server_free(NBDServerData *server)
+{
+    NBDConn *conn, *tmp;
+
+    if (!server) {
+        return;
+    }
+
+    /*
+     * Forcefully close the listener socket, and any clients that have
+     * not yet disconnected on their own.
+     */
+    qio_net_listener_disconnect(server->listener);
+    object_unref(OBJECT(server->listener));
+    server->listener = NULL;
+    QLIST_FOREACH_SAFE(conn, &server->conns, next, tmp) {
+        qio_channel_shutdown(QIO_CHANNEL(conn->cioc), QIO_CHANNEL_SHUTDOWN_BOTH,
+                             NULL);
+    }
+
+    AIO_WAIT_WHILE_UNLOCKED(NULL, server->connections > 0);
+
+    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 (!qcrypto_tls_creds_check_endpoint(creds,
+                                          QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
+                                          errp)) {
+        return NULL;
+    }
+    object_ref(obj);
+    return creds;
+}
+
+
+void nbd_server_start(SocketAddress *addr, uint32_t handshake_max_secs,
+                      const char *tls_creds, const char *tls_authz,
+                      uint32_t max_connections, Error **errp)
+{
+    if (nbd_server) {
+        error_setg(errp, "NBD server already running");
+        return;
+    }
+
+    nbd_server = g_new0(NBDServerData, 1);
+    nbd_server->max_connections = max_connections;
+    nbd_server->handshake_max_secs = handshake_max_secs;
+    nbd_server->listener = qio_net_listener_new();
+
+    qio_net_listener_set_name(nbd_server->listener,
+                              "nbd-listener");
+
+    /*
+     * Because this server is persistent, a backlog of SOMAXCONN is
+     * better than trying to size it to max_connections.
+     */
+    if (qio_net_listener_open_sync(nbd_server->listener, addr, SOMAXCONN,
+                                   errp) < 0) {
+        goto error;
+    }
+
+    if (tls_creds) {
+        nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
+        if (!nbd_server->tlscreds) {
+            goto error;
+        }
+    }
+
+    nbd_server->tlsauthz = g_strdup(tls_authz);
+
+    nbd_update_server_watch(nbd_server);
+
+    return;
+
+ error:
+    nbd_server_free(nbd_server);
+    nbd_server = NULL;
+}
+
+void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
+{
+    if (!arg->has_max_connections) {
+        arg->max_connections = NBD_DEFAULT_MAX_CONNECTIONS;
+    }
+    if (!arg->has_handshake_max_seconds) {
+        arg->handshake_max_seconds = NBD_DEFAULT_HANDSHAKE_MAX_SECS;
+    }
+
+    nbd_server_start(arg->addr, arg->handshake_max_seconds, arg->tls_creds,
+                     arg->tls_authz, arg->max_connections, errp);
+}
+
+void qmp_nbd_server_start(bool has_handshake_max_secs,
+                          uint32_t handshake_max_secs,
+                          const char *tls_creds,
+                          const char *tls_authz,
+                          bool has_max_connections, uint32_t max_connections,
+                          SocketAddressLegacy *addr,
+                          Error **errp)
+{
+    SocketAddress *addr_flat = socket_address_flatten(addr);
+
+    if (!has_max_connections) {
+        max_connections = NBD_DEFAULT_MAX_CONNECTIONS;
+    }
+    if (!has_handshake_max_secs) {
+        handshake_max_secs = NBD_DEFAULT_HANDSHAKE_MAX_SECS;
+    }
+
+    nbd_server_start(addr_flat, handshake_max_secs, tls_creds, tls_authz,
+                     max_connections, errp);
+    qapi_free_SocketAddress(addr_flat);
+}
+
+void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
+{
+    BlockExport *export;
+    BlockDriverState *bs;
+    BlockBackend *on_eject_blk;
+    BlockExportOptions *export_opts;
+
+    bs = bdrv_lookup_bs(arg->device, arg->device, errp);
+    if (!bs) {
+        return;
+    }
+
+    /*
+     * block-export-add would default to the node-name, but we may have to use
+     * the device name as a default here for compatibility.
+     */
+    if (!arg->name) {
+        arg->name = g_strdup(arg->device);
+    }
+
+    export_opts = g_new(BlockExportOptions, 1);
+    *export_opts = (BlockExportOptions) {
+        .type                   = BLOCK_EXPORT_TYPE_NBD,
+        .id                     = g_strdup(arg->name),
+        .node_name              = g_strdup(bdrv_get_node_name(bs)),
+        .has_writable           = arg->has_writable,
+        .writable               = arg->writable,
+    };
+    QAPI_CLONE_MEMBERS(BlockExportOptionsNbdBase, &export_opts->u.nbd,
+                       qapi_NbdServerAddOptions_base(arg));
+    if (arg->bitmap) {
+        BlockDirtyBitmapOrStr *el = g_new(BlockDirtyBitmapOrStr, 1);
+
+        *el = (BlockDirtyBitmapOrStr) {
+            .type = QTYPE_QSTRING,
+            .u.local = g_strdup(arg->bitmap),
+        };
+        export_opts->u.nbd.has_bitmaps = true;
+        QAPI_LIST_PREPEND(export_opts->u.nbd.bitmaps, el);
+    }
+
+    /*
+     * nbd-server-add doesn't complain when a read-only device should be
+     * exported as writable, but simply downgrades it. This is an error with
+     * block-export-add.
+     */
+    if (bdrv_is_read_only(bs)) {
+        export_opts->has_writable = true;
+        export_opts->writable = false;
+    }
+
+    export = blk_exp_add(export_opts, errp);
+    if (!export) {
+        goto fail;
+    }
+
+    /*
+     * nbd-server-add removes the export when the named BlockBackend used for
+     * @device goes away.
+     */
+    on_eject_blk = blk_by_name(arg->device);
+    if (on_eject_blk) {
+        nbd_export_set_on_eject_blk(export, on_eject_blk);
+    }
+
+fail:
+    qapi_free_BlockExportOptions(export_opts);
+}
+
+void qmp_nbd_server_remove(const char *name,
+                           bool has_mode, BlockExportRemoveMode mode,
+                           Error **errp)
+{
+    BlockExport *exp;
+
+    exp = blk_exp_find(name);
+    if (exp && exp->drv->type != BLOCK_EXPORT_TYPE_NBD) {
+        error_setg(errp, "Block export '%s' is not an NBD export", name);
+        return;
+    }
+
+    qmp_block_export_del(name, has_mode, mode, errp);
+}
+
+void qmp_nbd_server_stop(Error **errp)
+{
+    if (!nbd_server) {
+        error_setg(errp, "NBD server not running");
+        return;
+    }
+
+    blk_exp_close_all_type(BLOCK_EXPORT_TYPE_NBD);
+
+    nbd_server_free(nbd_server);
+    nbd_server = NULL;
+}