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Tag: 20130207
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/*
* QEMU live migration via Unix Domain Sockets
*
* Copyright Red Hat, Inc. 2009
*
* Authors:
* Chris Lalancette <clalance@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu-common.h"
#include "qemu_socket.h"
#include "migration.h"
#include "qemu-char.h"
#include "sysemu.h"
#include "buffered_file.h"
#include "block.h"
//#define DEBUG_MIGRATION_UNIX
#ifdef DEBUG_MIGRATION_UNIX
#define DPRINTF(fmt, ...) \
do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
do { } while (0)
#endif
static int unix_errno(FdMigrationState *s)
{
return errno;
}
static int unix_write(FdMigrationState *s, const void * buf, size_t size)
{
return write(s->fd, buf, size);
}
static int unix_close(FdMigrationState *s)
{
DPRINTF("unix_close\n");
if (s->fd != -1) {
close(s->fd);
s->fd = -1;
}
return 0;
}
static void unix_wait_for_connect(void *opaque)
{
FdMigrationState *s = opaque;
int val, ret;
socklen_t valsize = sizeof(val);
DPRINTF("connect completed\n");
do {
ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, (void *) &val, &valsize);
} while (ret == -1 && (s->get_error(s)) == EINTR);
if (ret < 0) {
migrate_fd_error(s);
return;
}
qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
if (val == 0)
migrate_fd_connect(s);
else {
DPRINTF("error connecting %d\n", val);
migrate_fd_error(s);
}
}
MigrationState *unix_start_outgoing_migration(Monitor *mon,
const char *path,
int64_t bandwidth_limit,
int detach,
int blk,
int inc)
{
FdMigrationState *s;
struct sockaddr_un addr;
int ret;
addr.sun_family = AF_UNIX;
snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);
s = qemu_mallocz(sizeof(*s));
s->get_error = unix_errno;
s->write = unix_write;
s->close = unix_close;
s->mig_state.cancel = migrate_fd_cancel;
s->mig_state.get_status = migrate_fd_get_status;
s->mig_state.release = migrate_fd_release;
s->mig_state.blk = blk;
s->mig_state.shared = inc;
s->state = MIG_STATE_ACTIVE;
s->mon = NULL;
s->bandwidth_limit = bandwidth_limit;
s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
if (s->fd < 0) {
DPRINTF("Unable to open socket");
goto err_after_alloc;
}
socket_set_nonblock(s->fd);
do {
ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
if (ret == -1)
ret = -(s->get_error(s));
if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
} while (ret == -EINTR);
if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
DPRINTF("connect failed\n");
goto err_after_open;
}
if (!detach) {
migrate_fd_monitor_suspend(s, mon);
}
if (ret >= 0)
migrate_fd_connect(s);
return &s->mig_state;
err_after_open:
close(s->fd);
err_after_alloc:
qemu_free(s);
return NULL;
}
static void unix_accept_incoming_migration(void *opaque)
{
struct sockaddr_un addr;
socklen_t addrlen = sizeof(addr);
int s = (unsigned long)opaque;
QEMUFile *f;
int c;
do {
c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
} while (c == -1 && socket_error() == EINTR);
DPRINTF("accepted migration\n");
if (c == -1) {
fprintf(stderr, "could not accept migration connection\n");
return;
}
f = qemu_fopen_socket(c);
if (f == NULL) {
fprintf(stderr, "could not qemu_fopen socket\n");
goto out;
}
process_incoming_migration(f);
qemu_fclose(f);
out:
qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
close(s);
close(c);
}
int unix_start_incoming_migration(const char *path)
{
struct sockaddr_un un;
int sock;
DPRINTF("Attempting to start an incoming migration\n");
sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
fprintf(stderr, "Could not open unix socket: %s\n", strerror(errno));
return -EINVAL;
}
memset(&un, 0, sizeof(un));
un.sun_family = AF_UNIX;
snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
unlink(un.sun_path);
if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
fprintf(stderr, "bind(unix:%s): %s\n", un.sun_path, strerror(errno));
goto err;
}
if (listen(sock, 1) < 0) {
fprintf(stderr, "listen(unix:%s): %s\n", un.sun_path, strerror(errno));
goto err;
}
qemu_set_fd_handler2(sock, NULL, unix_accept_incoming_migration, NULL,
(void *)(unsigned long)sock);
return 0;
err:
close(sock);
return -EINVAL;
}
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