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1 | /* | |
2 | * Serving QEMU block devices via NBD | |
3 | * | |
4 | * Copyright (c) 2012 Red Hat, Inc. | |
5 | * | |
6 | * Author: Paolo Bonzini <pbonzini@redhat.com> | |
7 | * | |
8 | * This work is licensed under the terms of the GNU GPL, version 2 or | |
9 | * later. See the COPYING file in the top-level directory. | |
10 | */ | |
11 | ||
12 | #include "sysemu/blockdev.h" | |
13 | #include "hw/block/block.h" | |
14 | #include "monitor/monitor.h" | |
15 | #include "qapi/qmp/qerror.h" | |
16 | #include "sysemu/sysemu.h" | |
17 | #include "qmp-commands.h" | |
18 | #include "trace.h" | |
19 | #include "block/nbd.h" | |
20 | #include "qemu/sockets.h" | |
21 | ||
22 | static int server_fd = -1; | |
23 | ||
24 | static void nbd_accept(void *opaque) | |
25 | { | |
26 | struct sockaddr_in addr; | |
27 | socklen_t addr_len = sizeof(addr); | |
28 | ||
29 | int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); | |
30 | if (fd >= 0 && !nbd_client_new(NULL, fd, nbd_client_put)) { | |
31 | shutdown(fd, 2); | |
32 | close(fd); | |
33 | } | |
34 | } | |
35 | ||
36 | void qmp_nbd_server_start(SocketAddress *addr, Error **errp) | |
37 | { | |
38 | if (server_fd != -1) { | |
39 | error_setg(errp, "NBD server already running"); | |
40 | return; | |
41 | } | |
42 | ||
43 | server_fd = socket_listen(addr, errp); | |
44 | if (server_fd != -1) { | |
45 | qemu_set_fd_handler2(server_fd, NULL, nbd_accept, NULL, NULL); | |
46 | } | |
47 | } | |
48 | ||
49 | /* Hook into the BlockDriverState notifiers to close the export when | |
50 | * the file is closed. | |
51 | */ | |
52 | typedef struct NBDCloseNotifier { | |
53 | Notifier n; | |
54 | NBDExport *exp; | |
55 | QTAILQ_ENTRY(NBDCloseNotifier) next; | |
56 | } NBDCloseNotifier; | |
57 | ||
58 | static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers = | |
59 | QTAILQ_HEAD_INITIALIZER(close_notifiers); | |
60 | ||
61 | static void nbd_close_notifier(Notifier *n, void *data) | |
62 | { | |
63 | NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n); | |
64 | ||
65 | notifier_remove(&cn->n); | |
66 | QTAILQ_REMOVE(&close_notifiers, cn, next); | |
67 | ||
68 | nbd_export_close(cn->exp); | |
69 | nbd_export_put(cn->exp); | |
70 | g_free(cn); | |
71 | } | |
72 | ||
73 | void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, | |
74 | Error **errp) | |
75 | { | |
76 | BlockDriverState *bs; | |
77 | NBDExport *exp; | |
78 | NBDCloseNotifier *n; | |
79 | ||
80 | if (server_fd == -1) { | |
81 | error_setg(errp, "NBD server not running"); | |
82 | return; | |
83 | } | |
84 | ||
85 | if (nbd_export_find(device)) { | |
86 | error_setg(errp, "NBD server already exporting device '%s'", device); | |
87 | return; | |
88 | } | |
89 | ||
90 | bs = bdrv_find(device); | |
91 | if (!bs) { | |
92 | error_set(errp, QERR_DEVICE_NOT_FOUND, device); | |
93 | return; | |
94 | } | |
95 | if (!bdrv_is_inserted(bs)) { | |
96 | error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device); | |
97 | return; | |
98 | } | |
99 | ||
100 | if (!has_writable) { | |
101 | writable = false; | |
102 | } | |
103 | if (bdrv_is_read_only(bs)) { | |
104 | writable = false; | |
105 | } | |
106 | ||
107 | exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, NULL); | |
108 | ||
109 | nbd_export_set_name(exp, device); | |
110 | ||
111 | n = g_new0(NBDCloseNotifier, 1); | |
112 | n->n.notify = nbd_close_notifier; | |
113 | n->exp = exp; | |
114 | bdrv_add_close_notifier(bs, &n->n); | |
115 | QTAILQ_INSERT_TAIL(&close_notifiers, n, next); | |
116 | } | |
117 | ||
118 | void qmp_nbd_server_stop(Error **errp) | |
119 | { | |
120 | while (!QTAILQ_EMPTY(&close_notifiers)) { | |
121 | NBDCloseNotifier *cn = QTAILQ_FIRST(&close_notifiers); | |
122 | nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp)); | |
123 | } | |
124 | ||
125 | if (server_fd != -1) { | |
126 | qemu_set_fd_handler2(server_fd, NULL, NULL, NULL, NULL); | |
127 | close(server_fd); | |
128 | server_fd = -1; | |
129 | } | |
130 | } |