migration-tcp.c - qemu - Git at Google

 /*
  * QEMU live migration
  *
  * Copyright IBM, Corp. 2008
  *
  * Authors:
  *  Anthony Liguori   <aliguori@us.ibm.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 "console.h"
 #include "buffered_file.h"
 #include "block.h"

 //#define DEBUG_MIGRATION_TCP

 typedef struct FdMigrationState
 {
     MigrationState mig_state;
     QEMUFile *file;
     int64_t bandwidth_limit;
     int fd;
     int detach;
     int state;
 } FdMigrationState;

 #ifdef DEBUG_MIGRATION_TCP
 #define dprintf(fmt, ...) \
     do { printf("migration-tcp: " fmt, ## __VA_ARGS__); } while (0)
 #else
 #define dprintf(fmt, ...) \
     do { } while (0)
 #endif

 int debug_me = 0;

 static void tcp_cleanup(FdMigrationState *s)
 {
     if (s->detach == 2) {
         monitor_resume();
         s->detach = 0;
     }

     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

     if (s->file) {
         debug_me = 1;
         dprintf("closing file\n");
         qemu_fclose(s->file);
     }

     if (s->fd != -1)
         close(s->fd);

     s->fd = -1;
 }

 static void tcp_error(FdMigrationState *s)
 {
     dprintf("setting error state\n");
     s->state = MIG_STATE_ERROR;
     tcp_cleanup(s);
 }

 static void fd_put_notify(void *opaque)
 {
     FdMigrationState *s = opaque;

     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
     qemu_file_put_notify(s->file);
 }

 static ssize_t fd_put_buffer(void *opaque, const void *data, size_t size)
 {
     FdMigrationState *s = opaque;
     ssize_t ret;

     do {
         ret = send(s->fd, data, size, 0);
     } while (ret == -1 && (socket_error() == EINTR || socket_error() == EWOULDBLOCK));

     if (ret == -1)
         ret = -socket_error();

     if (ret == -EAGAIN)
         qemu_set_fd_handler2(s->fd, NULL, NULL, fd_put_notify, s);

     return ret;
 }

 static int fd_close(void *opaque)
 {
     FdMigrationState *s = opaque;
     dprintf("fd_close\n");
     if (s->fd != -1) {
         close(s->fd);
         s->fd = -1;
     }
     return 0;
 }

 static void fd_wait_for_unfreeze(void *opaque)
 {
     FdMigrationState *s = opaque;
     int ret;

     dprintf("wait for unfreeze\n");
     if (s->state != MIG_STATE_ACTIVE)
         return;

     do {
         fd_set wfds;

         FD_ZERO(&wfds);
         FD_SET(s->fd, &wfds);

         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
     } while (ret == -1 && socket_error() == EINTR);
 }

 static void fd_put_ready(void *opaque)
 {
     FdMigrationState *s = opaque;

     if (s->state != MIG_STATE_ACTIVE) {
         dprintf("put_ready returning because of non-active state\n");
         return;
     }

     dprintf("iterate\n");
     if (qemu_savevm_state_iterate(s->file) == 1) {
         dprintf("done iterating\n");
         vm_stop(0);

         bdrv_flush_all();
         qemu_savevm_state_complete(s->file);
         s->state = MIG_STATE_COMPLETED;
         tcp_cleanup(s);
     }
 }

 static void tcp_connect_migrate(FdMigrationState *s)
 {
     int ret;

     s->file = qemu_fopen_ops_buffered(s,
                                       s->bandwidth_limit,
                                       fd_put_buffer,
                                       fd_put_ready,
                                       fd_wait_for_unfreeze,
                                       fd_close);

     dprintf("beginning savevm\n");
     ret = qemu_savevm_state_begin(s->file);
     if (ret < 0) {
         dprintf("failed, %d\n", ret);
         tcp_error(s);
         return;
     }

     fd_put_ready(s);
 }

 static void tcp_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, &val, &valsize);
     } while (ret == -1 && socket_error() == EINTR);

     if (ret < 0) {
         tcp_error(s);
         return;
     }

     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

     if (val == 0)
         tcp_connect_migrate(s);
     else {
         dprintf("error connecting %d\n", val);
         tcp_error(s);
     }
 }

 static FdMigrationState *to_fms(MigrationState *mig_state)
 {
     return container_of(mig_state, FdMigrationState, mig_state);
 }

 static int tcp_get_status(MigrationState *mig_state)
 {
     FdMigrationState *s = to_fms(mig_state);

     return s->state;
 }

 static void tcp_cancel(MigrationState *mig_state)
 {
     FdMigrationState *s = to_fms(mig_state);

     if (s->state != MIG_STATE_ACTIVE)
         return;

     dprintf("cancelling migration\n");

     s->state = MIG_STATE_CANCELLED;

     tcp_cleanup(s);
 }

 static void tcp_release(MigrationState *mig_state)
 {
     FdMigrationState *s = to_fms(mig_state);

     dprintf("releasing state\n");

     if (s->state == MIG_STATE_ACTIVE) {
         s->state = MIG_STATE_CANCELLED;
         tcp_cleanup(s);
     }
     free(s);
 }

 MigrationState *tcp_start_outgoing_migration(const char *host_port,
                                              int64_t bandwidth_limit,
                                              int async)
 {
     struct sockaddr_in addr;
     FdMigrationState *s;
     int ret;

     if (parse_host_port(&addr, host_port) < 0)
         return NULL;

     s = qemu_mallocz(sizeof(*s));
     if (s == NULL)
         return NULL;

     s->mig_state.cancel = tcp_cancel;
     s->mig_state.get_status = tcp_get_status;
     s->mig_state.release = tcp_release;

     s->state = MIG_STATE_ACTIVE;
     s->detach = !async;
     s->bandwidth_limit = bandwidth_limit;
     s->fd = socket(PF_INET, SOCK_STREAM, 0);
     if (s->fd == -1) {
         qemu_free(s);
         return NULL;
     }

     socket_set_nonblock(s->fd);

     if (s->detach == 1) {
         dprintf("detaching from monitor\n");
         monitor_suspend();
         s->detach = 2;
     }

     do {
         ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
         if (ret == -1)
             ret = -socket_error();

         if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
             qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
     } while (ret == -EINTR);

     if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
         dprintf("connect failed\n");
         close(s->fd);
         qemu_free(s);
         return NULL;
     } else if (ret >= 0)
         tcp_connect_migrate(s);

     return &s->mig_state;
 }

 static void tcp_accept_incoming_migration(void *opaque)
 {
     struct sockaddr_in addr;
     socklen_t addrlen = sizeof(addr);
     int s = (unsigned long)opaque;
     QEMUFile *f;
     int c, ret;

     do {
         c = 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;
     }

     vm_stop(0); /* just in case */
     ret = qemu_loadvm_state(f);
     if (ret < 0) {
         fprintf(stderr, "load of migration failed\n");
         goto out_fopen;
     }
     qemu_announce_self();
     dprintf("successfully loaded vm state\n");

     /* we've successfully migrated, close the server socket */
     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
     close(s);

     vm_start();

 out_fopen:
     qemu_fclose(f);
 out:
     close(c);
 }

 int tcp_start_incoming_migration(const char *host_port)
 {
     struct sockaddr_in addr;
     int val;
     int s;

     if (parse_host_port(&addr, host_port) < 0) {
         fprintf(stderr, "invalid host/port combination: %s\n", host_port);
         return -EINVAL;
     }

     s = socket(PF_INET, SOCK_STREAM, 0);
     if (s == -1)
         return -socket_error();

     val = 1;
     setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));

     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
         goto err;

     if (listen(s, 1) == -1)
         goto err;

     qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
                          (void *)(unsigned long)s);

     return 0;

 err:
     close(s);
     return -socket_error();
 }
	/*
	* QEMU live migration
	*
	* Copyright IBM, Corp. 2008
	*
	* Authors:
	* Anthony Liguori <aliguori@us.ibm.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 "console.h"
	#include "buffered_file.h"
	#include "block.h"

	//#define DEBUG_MIGRATION_TCP

	typedef struct FdMigrationState
	{
	MigrationState mig_state;
	QEMUFile *file;
	int64_t bandwidth_limit;
	int fd;
	int detach;
	int state;
	} FdMigrationState;

	#ifdef DEBUG_MIGRATION_TCP
	#define dprintf(fmt, ...) \
	do { printf("migration-tcp: " fmt, ## __VA_ARGS__); } while (0)
	#else
	#define dprintf(fmt, ...) \
	do { } while (0)
	#endif

	int debug_me = 0;

	static void tcp_cleanup(FdMigrationState *s)
	{
	if (s->detach == 2) {
	monitor_resume();
	s->detach = 0;
	}

	qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

	if (s->file) {
	debug_me = 1;
	dprintf("closing file\n");
	qemu_fclose(s->file);
	}

	if (s->fd != -1)
	close(s->fd);

	s->fd = -1;
	}

	static void tcp_error(FdMigrationState *s)
	{
	dprintf("setting error state\n");
	s->state = MIG_STATE_ERROR;
	tcp_cleanup(s);
	}

	static void fd_put_notify(void *opaque)
	{
	FdMigrationState *s = opaque;

	qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
	qemu_file_put_notify(s->file);
	}

	static ssize_t fd_put_buffer(void opaque, const void data, size_t size)
	{
	FdMigrationState *s = opaque;
	ssize_t ret;

	do {
	ret = send(s->fd, data, size, 0);
	} while (ret == -1 && (socket_error() == EINTR \|\| socket_error() == EWOULDBLOCK));

	if (ret == -1)
	ret = -socket_error();

	if (ret == -EAGAIN)
	qemu_set_fd_handler2(s->fd, NULL, NULL, fd_put_notify, s);

	return ret;
	}

	static int fd_close(void *opaque)
	{
	FdMigrationState *s = opaque;
	dprintf("fd_close\n");
	if (s->fd != -1) {
	close(s->fd);
	s->fd = -1;
	}
	return 0;
	}

	static void fd_wait_for_unfreeze(void *opaque)
	{
	FdMigrationState *s = opaque;
	int ret;

	dprintf("wait for unfreeze\n");
	if (s->state != MIG_STATE_ACTIVE)
	return;

	do {
	fd_set wfds;

	FD_ZERO(&wfds);
	FD_SET(s->fd, &wfds);

	ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
	} while (ret == -1 && socket_error() == EINTR);
	}

	static void fd_put_ready(void *opaque)
	{
	FdMigrationState *s = opaque;

	if (s->state != MIG_STATE_ACTIVE) {
	dprintf("put_ready returning because of non-active state\n");
	return;
	}

	dprintf("iterate\n");
	if (qemu_savevm_state_iterate(s->file) == 1) {
	dprintf("done iterating\n");
	vm_stop(0);

	bdrv_flush_all();
	qemu_savevm_state_complete(s->file);
	s->state = MIG_STATE_COMPLETED;
	tcp_cleanup(s);
	}
	}

	static void tcp_connect_migrate(FdMigrationState *s)
	{
	int ret;

	s->file = qemu_fopen_ops_buffered(s,
	s->bandwidth_limit,
	fd_put_buffer,
	fd_put_ready,
	fd_wait_for_unfreeze,
	fd_close);

	dprintf("beginning savevm\n");
	ret = qemu_savevm_state_begin(s->file);
	if (ret < 0) {
	dprintf("failed, %d\n", ret);
	tcp_error(s);
	return;
	}

	fd_put_ready(s);
	}

	static void tcp_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, &val, &valsize);
	} while (ret == -1 && socket_error() == EINTR);

	if (ret < 0) {
	tcp_error(s);
	return;
	}

	qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

	if (val == 0)
	tcp_connect_migrate(s);
	else {
	dprintf("error connecting %d\n", val);
	tcp_error(s);
	}
	}

	static FdMigrationState to_fms(MigrationState mig_state)
	{
	return container_of(mig_state, FdMigrationState, mig_state);
	}

	static int tcp_get_status(MigrationState *mig_state)
	{
	FdMigrationState *s = to_fms(mig_state);

	return s->state;
	}

	static void tcp_cancel(MigrationState *mig_state)
	{
	FdMigrationState *s = to_fms(mig_state);

	if (s->state != MIG_STATE_ACTIVE)
	return;

	dprintf("cancelling migration\n");

	s->state = MIG_STATE_CANCELLED;

	tcp_cleanup(s);
	}

	static void tcp_release(MigrationState *mig_state)
	{
	FdMigrationState *s = to_fms(mig_state);

	dprintf("releasing state\n");

	if (s->state == MIG_STATE_ACTIVE) {
	s->state = MIG_STATE_CANCELLED;
	tcp_cleanup(s);
	}
	free(s);
	}

	MigrationState tcp_start_outgoing_migration(const char host_port,
	int64_t bandwidth_limit,
	int async)
	{
	struct sockaddr_in addr;
	FdMigrationState *s;
	int ret;

	if (parse_host_port(&addr, host_port) < 0)
	return NULL;

	s = qemu_mallocz(sizeof(*s));
	if (s == NULL)
	return NULL;

	s->mig_state.cancel = tcp_cancel;
	s->mig_state.get_status = tcp_get_status;
	s->mig_state.release = tcp_release;

	s->state = MIG_STATE_ACTIVE;
	s->detach = !async;
	s->bandwidth_limit = bandwidth_limit;
	s->fd = socket(PF_INET, SOCK_STREAM, 0);
	if (s->fd == -1) {
	qemu_free(s);
	return NULL;
	}

	socket_set_nonblock(s->fd);

	if (s->detach == 1) {
	dprintf("detaching from monitor\n");
	monitor_suspend();
	s->detach = 2;
	}

	do {
	ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
	if (ret == -1)
	ret = -socket_error();

	if (ret == -EINPROGRESS \|\| ret == -EWOULDBLOCK)
	qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
	} while (ret == -EINTR);

	if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
	dprintf("connect failed\n");
	close(s->fd);
	qemu_free(s);
	return NULL;
	} else if (ret >= 0)
	tcp_connect_migrate(s);

	return &s->mig_state;
	}

	static void tcp_accept_incoming_migration(void *opaque)
	{
	struct sockaddr_in addr;
	socklen_t addrlen = sizeof(addr);
	int s = (unsigned long)opaque;
	QEMUFile *f;
	int c, ret;

	do {
	c = 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;
	}

	vm_stop(0); /* just in case */
	ret = qemu_loadvm_state(f);
	if (ret < 0) {
	fprintf(stderr, "load of migration failed\n");
	goto out_fopen;
	}
	qemu_announce_self();
	dprintf("successfully loaded vm state\n");

	/* we've successfully migrated, close the server socket */
	qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
	close(s);

	vm_start();

	out_fopen:
	qemu_fclose(f);
	out:
	close(c);
	}

	int tcp_start_incoming_migration(const char *host_port)
	{
	struct sockaddr_in addr;
	int val;
	int s;

	if (parse_host_port(&addr, host_port) < 0) {
	fprintf(stderr, "invalid host/port combination: %s\n", host_port);
	return -EINVAL;
	}

	s = socket(PF_INET, SOCK_STREAM, 0);
	if (s == -1)
	return -socket_error();

	val = 1;
	setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));

	if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
	goto err;

	if (listen(s, 1) == -1)
	goto err;

	qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
	(void *)(unsigned long)s);

	return 0;

	err:
	close(s);
	return -socket_error();
	}