trap signals for "-serial mon:stdio"
[qemu.git] / blockdev-nbd.c
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) {
31 nbd_client_new(NULL, fd, nbd_client_put);
32 }
33 }
34
35 void qmp_nbd_server_start(SocketAddress *addr, Error **errp)
36 {
37 if (server_fd != -1) {
38 error_setg(errp, "NBD server already running");
39 return;
40 }
41
42 server_fd = socket_listen(addr, errp);
43 if (server_fd != -1) {
44 qemu_set_fd_handler2(server_fd, NULL, nbd_accept, NULL, NULL);
45 }
46 }
47
48 /* Hook into the BlockDriverState notifiers to close the export when
49 * the file is closed.
50 */
51 typedef struct NBDCloseNotifier {
52 Notifier n;
53 NBDExport *exp;
54 QTAILQ_ENTRY(NBDCloseNotifier) next;
55 } NBDCloseNotifier;
56
57 static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers =
58 QTAILQ_HEAD_INITIALIZER(close_notifiers);
59
60 static void nbd_close_notifier(Notifier *n, void *data)
61 {
62 NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n);
63
64 notifier_remove(&cn->n);
65 QTAILQ_REMOVE(&close_notifiers, cn, next);
66
67 nbd_export_close(cn->exp);
68 nbd_export_put(cn->exp);
69 g_free(cn);
70 }
71
72 static void nbd_server_put_ref(NBDExport *exp)
73 {
74 BlockDriverState *bs = nbd_export_get_blockdev(exp);
75 drive_put_ref(drive_get_by_blockdev(bs));
76 }
77
78 void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
79 Error **errp)
80 {
81 BlockDriverState *bs;
82 NBDExport *exp;
83 NBDCloseNotifier *n;
84
85 if (server_fd == -1) {
86 error_setg(errp, "NBD server not running");
87 return;
88 }
89
90 if (nbd_export_find(device)) {
91 error_setg(errp, "NBD server already exporting device '%s'", device);
92 return;
93 }
94
95 bs = bdrv_find(device);
96 if (!bs) {
97 error_set(errp, QERR_DEVICE_NOT_FOUND, device);
98 return;
99 }
100
101 if (!has_writable) {
102 writable = false;
103 }
104 if (bdrv_is_read_only(bs)) {
105 writable = false;
106 }
107
108 exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
109 nbd_server_put_ref);
110
111 nbd_export_set_name(exp, device);
112 drive_get_ref(drive_get_by_blockdev(bs));
113
114 n = g_malloc0(sizeof(NBDCloseNotifier));
115 n->n.notify = nbd_close_notifier;
116 n->exp = exp;
117 bdrv_add_close_notifier(bs, &n->n);
118 QTAILQ_INSERT_TAIL(&close_notifiers, n, next);
119 }
120
121 void qmp_nbd_server_stop(Error **errp)
122 {
123 while (!QTAILQ_EMPTY(&close_notifiers)) {
124 NBDCloseNotifier *cn = QTAILQ_FIRST(&close_notifiers);
125 nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp));
126 }
127
128 if (server_fd != -1) {
129 qemu_set_fd_handler2(server_fd, NULL, NULL, NULL, NULL);
130 close(server_fd);
131 server_fd = -1;
132 }
133 }