xref: /illumos-kvm-cmd/migration-unix.c (revision 68396ea9)
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 
unix_errno(FdMigrationState * s)32 static int unix_errno(FdMigrationState *s)
33 {
34     return errno;
35 }
36 
unix_write(FdMigrationState * s,const void * buf,size_t size)37 static int unix_write(FdMigrationState *s, const void * buf, size_t size)
38 {
39     return write(s->fd, buf, size);
40 }
41 
unix_close(FdMigrationState * s)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 
unix_wait_for_connect(void * opaque)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 
unix_start_outgoing_migration(Monitor * mon,const char * path,int64_t bandwidth_limit,int detach,int blk,int inc)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     do {
116         ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
117         if (ret == -1)
118 	    ret = -(s->get_error(s));
119 
120         if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
121 	    qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
122     } while (ret == -EINTR);
123 
124     if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
125         DPRINTF("connect failed\n");
126         goto err_after_open;
127     }
128 
129     if (!detach) {
130         migrate_fd_monitor_suspend(s, mon);
131     }
132 
133     if (ret >= 0)
134         migrate_fd_connect(s);
135 
136     return &s->mig_state;
137 
138 err_after_open:
139     close(s->fd);
140 
141 err_after_alloc:
142     qemu_free(s);
143     return NULL;
144 }
145 
unix_accept_incoming_migration(void * opaque)146 static void unix_accept_incoming_migration(void *opaque)
147 {
148     struct sockaddr_un addr;
149     socklen_t addrlen = sizeof(addr);
150     int s = (unsigned long)opaque;
151     QEMUFile *f;
152     int c;
153 
154     do {
155         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
156     } while (c == -1 && socket_error() == EINTR);
157 
158     DPRINTF("accepted migration\n");
159 
160     if (c == -1) {
161         fprintf(stderr, "could not accept migration connection\n");
162         return;
163     }
164 
165     f = qemu_fopen_socket(c);
166     if (f == NULL) {
167         fprintf(stderr, "could not qemu_fopen socket\n");
168         goto out;
169     }
170 
171     process_incoming_migration(f);
172     qemu_fclose(f);
173 out:
174     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
175     close(s);
176     close(c);
177 }
178 
unix_start_incoming_migration(const char * path)179 int unix_start_incoming_migration(const char *path)
180 {
181     struct sockaddr_un un;
182     int sock;
183 
184     DPRINTF("Attempting to start an incoming migration\n");
185 
186     sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
187     if (sock < 0) {
188         fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
189         return -EINVAL;
190     }
191 
192     memset(&un, 0, sizeof(un));
193     un.sun_family = AF_UNIX;
194     snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
195 
196     unlink(un.sun_path);
197     if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
198         fprintf(stderr, "bind(unix:%s): %s\n", un.sun_path, strerror(errno));
199         goto err;
200     }
201     if (listen(sock, 1) < 0) {
202         fprintf(stderr, "listen(unix:%s): %s\n", un.sun_path, strerror(errno));
203         goto err;
204     }
205 
206     qemu_set_fd_handler2(sock, NULL, unix_accept_incoming_migration, NULL,
207 			 (void *)(unsigned long)sock);
208 
209     return 0;
210 
211 err:
212     close(sock);
213 
214     return -EINVAL;
215 }
216