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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 "buffered_file.h" | |
19 | #include "block.h" | |
20 | ||
21 | //#define DEBUG_MIGRATION_UNIX | |
22 | ||
23 | #ifdef DEBUG_MIGRATION_UNIX | |
24 | #define DPRINTF(fmt, ...) \ | |
25 | do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0) | |
26 | #else | |
27 | #define DPRINTF(fmt, ...) \ | |
28 | do { } while (0) | |
29 | #endif | |
30 | ||
31 | static int unix_errno(MigrationState *s) | |
32 | { | |
33 | return errno; | |
34 | } | |
35 | ||
36 | static int unix_write(MigrationState *s, const void * buf, size_t size) | |
37 | { | |
38 | return write(s->fd, buf, size); | |
39 | } | |
40 | ||
41 | static int unix_close(MigrationState *s) | |
42 | { | |
43 | int r = 0; | |
44 | DPRINTF("unix_close\n"); | |
45 | if (s->fd != -1) { | |
46 | if (close(s->fd) < 0) { | |
47 | r = -errno; | |
48 | } | |
49 | s->fd = -1; | |
50 | } | |
51 | return r; | |
52 | } | |
53 | ||
54 | static void unix_wait_for_connect(void *opaque) | |
55 | { | |
56 | MigrationState *s = opaque; | |
57 | int val, ret; | |
58 | socklen_t valsize = sizeof(val); | |
59 | ||
60 | DPRINTF("connect completed\n"); | |
61 | do { | |
62 | ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, (void *) &val, &valsize); | |
63 | } while (ret == -1 && errno == EINTR); | |
64 | ||
65 | if (ret < 0) { | |
66 | migrate_fd_error(s); | |
67 | return; | |
68 | } | |
69 | ||
70 | qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); | |
71 | ||
72 | if (val == 0) | |
73 | migrate_fd_connect(s); | |
74 | else { | |
75 | DPRINTF("error connecting %d\n", val); | |
76 | migrate_fd_error(s); | |
77 | } | |
78 | } | |
79 | ||
80 | int unix_start_outgoing_migration(MigrationState *s, const char *path) | |
81 | { | |
82 | struct sockaddr_un addr; | |
83 | int ret; | |
84 | ||
85 | addr.sun_family = AF_UNIX; | |
86 | snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path); | |
87 | s->get_error = unix_errno; | |
88 | s->write = unix_write; | |
89 | s->close = unix_close; | |
90 | ||
91 | s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0); | |
92 | if (s->fd == -1) { | |
93 | DPRINTF("Unable to open socket"); | |
94 | return -errno; | |
95 | } | |
96 | ||
97 | socket_set_nonblock(s->fd); | |
98 | ||
99 | do { | |
100 | ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr)); | |
101 | if (ret == -1) { | |
102 | ret = -errno; | |
103 | } | |
104 | if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) { | |
105 | qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s); | |
106 | return 0; | |
107 | } | |
108 | } while (ret == -EINTR); | |
109 | ||
110 | if (ret < 0) { | |
111 | DPRINTF("connect failed\n"); | |
112 | migrate_fd_error(s); | |
113 | return ret; | |
114 | } | |
115 | migrate_fd_connect(s); | |
116 | return 0; | |
117 | } | |
118 | ||
119 | static void unix_accept_incoming_migration(void *opaque) | |
120 | { | |
121 | struct sockaddr_un addr; | |
122 | socklen_t addrlen = sizeof(addr); | |
123 | int s = (intptr_t)opaque; | |
124 | QEMUFile *f; | |
125 | int c; | |
126 | ||
127 | do { | |
128 | c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen); | |
129 | } while (c == -1 && errno == EINTR); | |
130 | ||
131 | DPRINTF("accepted migration\n"); | |
132 | ||
133 | if (c == -1) { | |
134 | fprintf(stderr, "could not accept migration connection\n"); | |
135 | goto out2; | |
136 | } | |
137 | ||
138 | f = qemu_fopen_socket(c); | |
139 | if (f == NULL) { | |
140 | fprintf(stderr, "could not qemu_fopen socket\n"); | |
141 | goto out; | |
142 | } | |
143 | ||
144 | process_incoming_migration(f); | |
145 | qemu_fclose(f); | |
146 | out: | |
147 | close(c); | |
148 | out2: | |
149 | qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL); | |
150 | close(s); | |
151 | } | |
152 | ||
153 | int unix_start_incoming_migration(const char *path) | |
154 | { | |
155 | struct sockaddr_un addr; | |
156 | int s; | |
157 | int ret; | |
158 | ||
159 | DPRINTF("Attempting to start an incoming migration\n"); | |
160 | ||
161 | s = qemu_socket(PF_UNIX, SOCK_STREAM, 0); | |
162 | if (s == -1) { | |
163 | fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno)); | |
164 | return -errno; | |
165 | } | |
166 | ||
167 | memset(&addr, 0, sizeof(addr)); | |
168 | addr.sun_family = AF_UNIX; | |
169 | snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path); | |
170 | ||
171 | unlink(addr.sun_path); | |
172 | if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) { | |
173 | ret = -errno; | |
174 | fprintf(stderr, "bind(unix:%s): %s\n", addr.sun_path, strerror(errno)); | |
175 | goto err; | |
176 | } | |
177 | if (listen(s, 1) == -1) { | |
178 | fprintf(stderr, "listen(unix:%s): %s\n", addr.sun_path, | |
179 | strerror(errno)); | |
180 | ret = -errno; | |
181 | goto err; | |
182 | } | |
183 | ||
184 | qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL, | |
185 | (void *)(intptr_t)s); | |
186 | ||
187 | return 0; | |
188 | ||
189 | err: | |
190 | close(s); | |
191 | return ret; | |
192 | } |