Don't leak file descriptors
[qemu.git] / migration-unix.c
1 /*
2 * QEMU live migration via Unix Domain Sockets
3 *
4 * Copyright Red Hat, Inc. 2009
5 *
6 * Authors:
7 * Chris Lalancette <clalance@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
11 *
12 */
13
14 #include "qemu-common.h"
15 #include "qemu_socket.h"
16 #include "migration.h"
17 #include "qemu-char.h"
18 #include "sysemu.h"
19 #include "buffered_file.h"
20 #include "block.h"
21
22 //#define DEBUG_MIGRATION_UNIX
23
24 #ifdef DEBUG_MIGRATION_UNIX
25 #define dprintf(fmt, ...) \
26 do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
27 #else
28 #define dprintf(fmt, ...) \
29 do { } while (0)
30 #endif
31
32 static int unix_errno(FdMigrationState *s)
33 {
34 return errno;
35 }
36
37 static int unix_write(FdMigrationState *s, const void * buf, size_t size)
38 {
39 return write(s->fd, buf, size);
40 }
41
42 static int unix_close(FdMigrationState *s)
43 {
44 dprintf("unix_close\n");
45 if (s->fd != -1) {
46 close(s->fd);
47 s->fd = -1;
48 }
49 return 0;
50 }
51
52 static void unix_wait_for_connect(void *opaque)
53 {
54 FdMigrationState *s = opaque;
55 int val, ret;
56 socklen_t valsize = sizeof(val);
57
58 dprintf("connect completed\n");
59 do {
60 ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, (void *) &val, &valsize);
61 } while (ret == -1 && (s->get_error(s)) == EINTR);
62
63 if (ret < 0) {
64 migrate_fd_error(s);
65 return;
66 }
67
68 qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
69
70 if (val == 0)
71 migrate_fd_connect(s);
72 else {
73 dprintf("error connecting %d\n", val);
74 migrate_fd_error(s);
75 }
76 }
77
78 MigrationState *unix_start_outgoing_migration(Monitor *mon,
79 const char *path,
80 int64_t bandwidth_limit,
81 int detach,
82 int blk,
83 int inc)
84 {
85 FdMigrationState *s;
86 struct sockaddr_un addr;
87 int ret;
88
89 addr.sun_family = AF_UNIX;
90 snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
91
92 s = qemu_mallocz(sizeof(*s));
93
94 s->get_error = unix_errno;
95 s->write = unix_write;
96 s->close = unix_close;
97 s->mig_state.cancel = migrate_fd_cancel;
98 s->mig_state.get_status = migrate_fd_get_status;
99 s->mig_state.release = migrate_fd_release;
100
101 s->mig_state.blk = blk;
102 s->mig_state.shared = inc;
103
104 s->state = MIG_STATE_ACTIVE;
105 s->mon = NULL;
106 s->bandwidth_limit = bandwidth_limit;
107 s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
108 if (s->fd < 0) {
109 dprintf("Unable to open socket");
110 goto err_after_alloc;
111 }
112
113 socket_set_nonblock(s->fd);
114
115 if (!detach) {
116 migrate_fd_monitor_suspend(s, mon);
117 }
118
119 do {
120 ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
121 if (ret == -1)
122 ret = -(s->get_error(s));
123
124 if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
125 qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
126 } while (ret == -EINTR);
127
128 if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
129 dprintf("connect failed\n");
130 goto err_after_open;
131 } else if (ret >= 0)
132 migrate_fd_connect(s);
133
134 return &s->mig_state;
135
136 err_after_open:
137 close(s->fd);
138
139 err_after_alloc:
140 qemu_free(s);
141 return NULL;
142 }
143
144 static void unix_accept_incoming_migration(void *opaque)
145 {
146 struct sockaddr_un addr;
147 socklen_t addrlen = sizeof(addr);
148 int s = (unsigned long)opaque;
149 QEMUFile *f;
150 int c, ret;
151
152 do {
153 c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
154 } while (c == -1 && socket_error() == EINTR);
155
156 dprintf("accepted migration\n");
157
158 if (c == -1) {
159 fprintf(stderr, "could not accept migration connection\n");
160 return;
161 }
162
163 f = qemu_fopen_socket(c);
164 if (f == NULL) {
165 fprintf(stderr, "could not qemu_fopen socket\n");
166 goto out;
167 }
168
169 ret = qemu_loadvm_state(f);
170 if (ret < 0) {
171 fprintf(stderr, "load of migration failed\n");
172 goto out_fopen;
173 }
174 qemu_announce_self();
175 dprintf("successfully loaded vm state\n");
176
177 /* we've successfully migrated, close the server socket */
178 qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
179 close(s);
180
181 out_fopen:
182 qemu_fclose(f);
183 out:
184 close(c);
185 }
186
187 int unix_start_incoming_migration(const char *path)
188 {
189 struct sockaddr_un un;
190 int sock;
191
192 dprintf("Attempting to start an incoming migration\n");
193
194 sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
195 if (sock < 0) {
196 fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
197 return -EINVAL;
198 }
199
200 memset(&un, 0, sizeof(un));
201 un.sun_family = AF_UNIX;
202 snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
203
204 unlink(un.sun_path);
205 if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
206 fprintf(stderr, "bind(unix:%s): %s\n", un.sun_path, strerror(errno));
207 goto err;
208 }
209 if (listen(sock, 1) < 0) {
210 fprintf(stderr, "listen(unix:%s): %s\n", un.sun_path, strerror(errno));
211 goto err;
212 }
213
214 qemu_set_fd_handler2(sock, NULL, unix_accept_incoming_migration, NULL,
215 (void *)(unsigned long)sock);
216
217 return 0;
218
219 err:
220 close(sock);
221
222 return -EINVAL;
223 }