| /* |
| * 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 "sysemu/blockdev.h" |
| #include "hw/block-common.h" |
| #include "monitor/monitor.h" |
| #include "qapi/qmp/qerror.h" |
| #include "sysemu/sysemu.h" |
| #include "qmp-commands.h" |
| #include "trace.h" |
| #include "block/nbd.h" |
| #include "qemu/sockets.h" |
| |
| static int server_fd = -1; |
| |
| static void nbd_accept(void *opaque) |
| { |
| struct sockaddr_in addr; |
| socklen_t addr_len = sizeof(addr); |
| |
| int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); |
| if (fd >= 0) { |
| nbd_client_new(NULL, fd, nbd_client_put); |
| } |
| } |
| |
| void qmp_nbd_server_start(SocketAddress *addr, Error **errp) |
| { |
| if (server_fd != -1) { |
| error_setg(errp, "NBD server already running"); |
| return; |
| } |
| |
| server_fd = socket_listen(addr, errp); |
| if (server_fd != -1) { |
| qemu_set_fd_handler2(server_fd, NULL, nbd_accept, NULL, NULL); |
| } |
| } |
| |
| /* Hook into the BlockDriverState notifiers to close the export when |
| * the file is closed. |
| */ |
| typedef struct NBDCloseNotifier { |
| Notifier n; |
| NBDExport *exp; |
| QTAILQ_ENTRY(NBDCloseNotifier) next; |
| } NBDCloseNotifier; |
| |
| static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers = |
| QTAILQ_HEAD_INITIALIZER(close_notifiers); |
| |
| static void nbd_close_notifier(Notifier *n, void *data) |
| { |
| NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n); |
| |
| notifier_remove(&cn->n); |
| QTAILQ_REMOVE(&close_notifiers, cn, next); |
| |
| nbd_export_close(cn->exp); |
| nbd_export_put(cn->exp); |
| g_free(cn); |
| } |
| |
| static void nbd_server_put_ref(NBDExport *exp) |
| { |
| BlockDriverState *bs = nbd_export_get_blockdev(exp); |
| drive_put_ref(drive_get_by_blockdev(bs)); |
| } |
| |
| void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, |
| Error **errp) |
| { |
| BlockDriverState *bs; |
| NBDExport *exp; |
| NBDCloseNotifier *n; |
| |
| if (server_fd == -1) { |
| error_setg(errp, "NBD server not running"); |
| return; |
| } |
| |
| if (nbd_export_find(device)) { |
| error_setg(errp, "NBD server already exporting device '%s'", device); |
| return; |
| } |
| |
| bs = bdrv_find(device); |
| if (!bs) { |
| error_set(errp, QERR_DEVICE_NOT_FOUND, device); |
| 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, |
| nbd_server_put_ref); |
| |
| nbd_export_set_name(exp, device); |
| drive_get_ref(drive_get_by_blockdev(bs)); |
| |
| n = g_malloc0(sizeof(NBDCloseNotifier)); |
| n->n.notify = nbd_close_notifier; |
| n->exp = exp; |
| bdrv_add_close_notifier(bs, &n->n); |
| QTAILQ_INSERT_TAIL(&close_notifiers, n, next); |
| } |
| |
| void qmp_nbd_server_stop(Error **errp) |
| { |
| while (!QTAILQ_EMPTY(&close_notifiers)) { |
| NBDCloseNotifier *cn = QTAILQ_FIRST(&close_notifiers); |
| nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp)); |
| } |
| |
| if (server_fd != -1) { |
| qemu_set_fd_handler2(server_fd, NULL, NULL, NULL, NULL); |
| close(server_fd); |
| server_fd = -1; |
| } |
| } |