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Reintroduce migrate-to-exec: support (Charles Duffy)

Browse source 
KVM's live migration support included support for exec: URLs, allowing system
state to be written or received via an arbitrary popen()ed subprocess. This
provides a convenient way to pipe state through a compression algorithm or an
arbitrary network transport on its way to its destination, and a convenient way
to write state to disk; libvirt's qemu driver currently uses migration to exec:
targets for this latter purpose.

This version of the patch refactors now-common code from migrate-tcp.c into
migrate.c. 

Signed-off-by: Charles Duffy <Charles_Duffy@messageone.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5694 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2008-11-11 16:46:33 +00:00
parent a74b4d2c23
commit 065e281356
7 changed files with 453 additions and 171 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
Makefile.target
View file

@ -596,7 +596,7 @@ endif
ifdef CONFIG_WIN32
OBJS+=block-raw-win32.o
else
OBJS+=block-raw-posix.o
OBJS+=block-raw-posix.o migration-exec.o
endif
LIBS+=-lz

2
hw/hw.h
View file

@ -35,6 +35,8 @@ QEMUFile *qemu_fopen_ops(void *opaque, QEMUFilePutBufferFunc *put_buffer,
QEMUFileRateLimit *rate_limit);
QEMUFile *qemu_fopen(const char *filename, const char *mode);
QEMUFile *qemu_fopen_socket(int fd);
QEMUFile *qemu_popen(FILE *popen_file, const char *mode);
QEMUFile *qemu_popen_cmd(const char *command, const char *mode);
void qemu_fflush(QEMUFile *f);
int qemu_fclose(QEMUFile *f);
void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size);

141
migration-exec.c Normal file
View file

@ -0,0 +1,141 @@
/*
* QEMU live migration
*
* Copyright IBM, Corp. 2008
* Copyright Dell MessageOne 2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Charles Duffy <charles_duffy@messageone.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_EXEC
#ifdef DEBUG_MIGRATION_EXEC
#define dprintf(fmt, ...) \
do { printf("migration-exec: " fmt, ## __VA_ARGS__); } while (0)
#else
#define dprintf(fmt, ...) \
do { } while (0)
#endif
static int file_errno(FdMigrationState *s)
{
return errno;
}
static int file_write(FdMigrationState *s, const void * buf, size_t size)
{
return write(s->fd, buf, size);
}
static int exec_close(FdMigrationState *s)
{
dprintf("exec_close\n");
if (s->opaque) {
qemu_fclose(s->opaque);
s->opaque = NULL;
s->fd = -1;
}
return 0;
}
MigrationState *exec_start_outgoing_migration(const char *command,
int64_t bandwidth_limit,
int async)
{
FdMigrationState *s;
FILE *f;
s = qemu_mallocz(sizeof(*s));
if (s == NULL) {
dprintf("Unable to allocate FdMigrationState\n");
goto err;
}
f = popen(command, "w");
if (f == NULL) {
dprintf("Unable to popen exec target\n");
goto err_after_alloc;
}
s->fd = fileno(f);
if (s->fd == -1) {
dprintf("Unable to retrieve file descriptor for popen'd handle\n");
goto err_after_open;
}
if (fcntl(s->fd, F_SETFD, O_NONBLOCK) == -1) {
dprintf("Unable to set nonblocking mode on file descriptor\n");
goto err_after_open;
}
s->opaque = qemu_popen(f, "w");
s->get_error = file_errno;
s->write = file_write;
s->mig_state.cancel = migrate_fd_cancel;
s->mig_state.get_status = migrate_fd_get_status;
s->mig_state.release = migrate_fd_release;
s->state = MIG_STATE_ACTIVE;
s->detach = !async;
s->bandwidth_limit = bandwidth_limit;
if (s->detach == 1) {
dprintf("detaching from monitor\n");
monitor_suspend();
s->detach = 2;
}
migrate_fd_connect(s);
return &s->mig_state;
err_after_open:
pclose(f);
err_after_alloc:
qemu_free(s);
err:
return NULL;
}
int exec_start_incoming_migration(const char *command)
{
int ret;
QEMUFile *f;
dprintf("Attempting to start an incoming migration\n");
f = qemu_popen_cmd(command, "r");
if(f == NULL) {
dprintf("Unable to apply qemu wrapper to popen file\n");
return -errno;
}
vm_stop(0); /* just in case */
ret = qemu_loadvm_state(f);
if (ret < 0) {
fprintf(stderr, "load of migration failed\n");
goto err;
}
qemu_announce_self();
dprintf("successfully loaded vm state\n");
vm_start();
qemu_fclose(f);
return 0;
err:
qemu_fclose(f);
return -errno;
}

188
migration-tcp.c
View file

@ -22,16 +22,6 @@
//#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)
@ -40,64 +30,19 @@ typedef struct FdMigrationState
do { } while (0)
#endif
static void tcp_cleanup(FdMigrationState *s)
static int socket_errno(FdMigrationState *s)
{
qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
if (s->file) {
dprintf("closing file\n");
qemu_fclose(s->file);
}
if (s->fd != -1)
close(s->fd);
/* Don't resume monitor until we've flushed all of the buffers */
if (s->detach == 2) {
monitor_resume();
s->detach = 0;
}
s->fd = -1;
return (s->get_error(s));
}
static void tcp_error(FdMigrationState *s)
static int socket_write(FdMigrationState *s, const void * buf, size_t size)
{
dprintf("setting error state\n");
s->state = MIG_STATE_ERROR;
tcp_cleanup(s);
return send(s->fd, buf, size, 0);
}
static void fd_put_notify(void *opaque)
static int tcp_close(FdMigrationState *s)
{
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");
dprintf("tcp_close\n");
if (s->fd != -1) {
close(s->fd);
s->fd = -1;
@ -105,67 +50,6 @@ static int fd_close(void *opaque)
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)
{
@ -176,62 +60,23 @@ static void tcp_wait_for_connect(void *opaque)
dprintf("connect completed\n");
do {
ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, &val, &valsize);
} while (ret == -1 && socket_error() == EINTR);
} while (ret == -1 && (s->get_error(s)) == EINTR);
if (ret < 0) {
tcp_error(s);
migrate_fd_error(s);
return;
}
qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
if (val == 0)
tcp_connect_migrate(s);
migrate_fd_connect(s);
else {
dprintf("error connecting %d\n", val);
tcp_error(s);
migrate_fd_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)
@ -247,9 +92,12 @@ MigrationState *tcp_start_outgoing_migration(const char *host_port,
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->get_error = socket_errno;
s->write = socket_write;
s->close = tcp_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->state = MIG_STATE_ACTIVE;
s->detach = !async;
@ -271,7 +119,7 @@ MigrationState *tcp_start_outgoing_migration(const char *host_port,
do {
ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
if (ret == -1)
ret = -socket_error();
ret = -(s->get_error(s));
if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
@ -283,7 +131,7 @@ MigrationState *tcp_start_outgoing_migration(const char *host_port,
qemu_free(s);
return NULL;
} else if (ret >= 0)
tcp_connect_migrate(s);
migrate_fd_connect(s);
return &s->mig_state;
}

178
migration.c
View file

@ -14,6 +14,20 @@
#include "qemu-common.h"
#include "migration.h"
#include "console.h"
#include "buffered_file.h"
#include "sysemu.h"
#include "block.h"
#include "qemu_socket.h"
//#define DEBUG_MIGRATION
#ifdef DEBUG_MIGRATION
#define dprintf(fmt, ...) \
do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
#else
#define dprintf(fmt, ...) \
do { } while (0)
#endif
/* Migration speed throttling */
static uint32_t max_throttle = (32 << 20);
@ -26,6 +40,10 @@ void qemu_start_incoming_migration(const char *uri)
if (strstart(uri, "tcp:", &p))
tcp_start_incoming_migration(p);
#if !defined(WIN32)
else if (strstart(uri, "exec:", &p))
exec_start_incoming_migration(p);
#endif
else
fprintf(stderr, "unknown migration protocol: %s\n", uri);
}
@ -37,6 +55,10 @@ void do_migrate(int detach, const char *uri)
if (strstart(uri, "tcp:", &p))
s = tcp_start_outgoing_migration(p, max_throttle, detach);
#if !defined(WIN32)
else if (strstart(uri, "exec:", &p))
s = exec_start_outgoing_migration(p, max_throttle, detach);
#endif
else
term_printf("unknown migration protocol: %s\n", uri);
@ -101,3 +123,159 @@ void do_info_migrate(void)
}
}
/* shared migration helpers */
void migrate_fd_error(FdMigrationState *s)
{
dprintf("setting error state\n");
s->state = MIG_STATE_ERROR;
migrate_fd_cleanup(s);
}
void migrate_fd_cleanup(FdMigrationState *s)
{
qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
if (s->file) {
dprintf("closing file\n");
qemu_fclose(s->file);
}
if (s->fd != -1)
close(s->fd);
/* Don't resume monitor until we've flushed all of the buffers */
if (s->detach == 2) {
monitor_resume();
s->detach = 0;
}
s->fd = -1;
}
void migrate_fd_put_notify(void *opaque)
{
FdMigrationState *s = opaque;
qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
qemu_file_put_notify(s->file);
}
ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
{
FdMigrationState *s = opaque;
ssize_t ret;
do {
ret = s->write(s, data, size);
} while (ret == -1 && ((s->get_error(s)) == EINTR || (s->get_error(s)) == EWOULDBLOCK));
if (ret == -1)
ret = -(s->get_error(s));
if (ret == -EAGAIN)
qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
return ret;
}
void migrate_fd_connect(FdMigrationState *s)
{
int ret;
s->file = qemu_fopen_ops_buffered(s,
s->bandwidth_limit,
migrate_fd_put_buffer,
migrate_fd_put_ready,
migrate_fd_wait_for_unfreeze,
migrate_fd_close);
dprintf("beginning savevm\n");
ret = qemu_savevm_state_begin(s->file);
if (ret < 0) {
dprintf("failed, %d\n", ret);
migrate_fd_error(s);
return;
}
migrate_fd_put_ready(s);
}
void migrate_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;
migrate_fd_cleanup(s);
}
}
int migrate_fd_get_status(MigrationState *mig_state)
{
FdMigrationState *s = migrate_to_fms(mig_state);
return s->state;
}
void migrate_fd_cancel(MigrationState *mig_state)
{
FdMigrationState *s = migrate_to_fms(mig_state);
if (s->state != MIG_STATE_ACTIVE)
return;
dprintf("cancelling migration\n");
s->state = MIG_STATE_CANCELLED;
migrate_fd_cleanup(s);
}
void migrate_fd_release(MigrationState *mig_state)
{
FdMigrationState *s = migrate_to_fms(mig_state);
dprintf("releasing state\n");
if (s->state == MIG_STATE_ACTIVE) {
s->state = MIG_STATE_CANCELLED;
migrate_fd_cleanup(s);
}
free(s);
}
void migrate_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 && (s->get_error(s)) == EINTR);
}
int migrate_fd_close(void *opaque)
{
FdMigrationState *s = opaque;
return s->close(s);
}

49
migration.h
View file

@ -29,6 +29,22 @@ struct MigrationState
void (*release)(MigrationState *s);
};
typedef struct FdMigrationState FdMigrationState;
struct FdMigrationState
{
MigrationState mig_state;
int64_t bandwidth_limit;
QEMUFile *file;
int fd;
int detach;
int state;
int (*get_error)(struct FdMigrationState*);
int (*close)(struct FdMigrationState*);
int (*write)(struct FdMigrationState*, const void *, size_t);
void *opaque;
};
void qemu_start_incoming_migration(const char *uri);
void do_migrate(int detach, const char *uri);
@ -39,11 +55,44 @@ void do_migrate_set_speed(const char *value);
void do_info_migrate(void);
int exec_start_incoming_migration(const char *host_port);
MigrationState *exec_start_outgoing_migration(const char *host_port,
int64_t bandwidth_limit,
int detach);
int tcp_start_incoming_migration(const char *host_port);
MigrationState *tcp_start_outgoing_migration(const char *host_port,
int64_t bandwidth_limit,
int detach);
void migrate_fd_error(FdMigrationState *s);
void migrate_fd_cleanup(FdMigrationState *s);
void migrate_fd_put_notify(void *opaque);
ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size);
void migrate_fd_connect(FdMigrationState *s);
void migrate_fd_put_ready(void *opaque);
int migrate_fd_get_status(MigrationState *mig_state);
void migrate_fd_cancel(MigrationState *mig_state);
void migrate_fd_release(MigrationState *mig_state);
void migrate_fd_wait_for_unfreeze(void *opaque);
int migrate_fd_close(void *opaque);
static inline FdMigrationState *migrate_to_fms(MigrationState *mig_state)
{
return container_of(mig_state, FdMigrationState, mig_state);
}
#endif

64
vl.c
View file

@ -2964,6 +2964,12 @@ struct QEMUFile {
int has_error;
};
typedef struct QEMUFilePopen
{
FILE *popen_file;
QEMUFile *file;
} QEMUFilePopen;
typedef struct QEMUFileSocket
{
int fd;
@ -2992,6 +2998,64 @@ static int socket_close(void *opaque)
return 0;
}
static int popen_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size)
{
QEMUFilePopen *s = opaque;
return fwrite(buf, 1, size, s->popen_file);
}
static int popen_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
{
QEMUFilePopen *s = opaque;
return fread(buf, 1, size, s->popen_file);
}
static int popen_close(void *opaque)
{
QEMUFilePopen *s = opaque;
pclose(s->popen_file);
qemu_free(s);
return 0;
}
QEMUFile *qemu_popen(FILE *popen_file, const char *mode)
{
QEMUFilePopen *s;
if (popen_file == NULL || mode == NULL || (mode[0] != 'r' && mode[0] != 'w') || mode[1] != 0) {
fprintf(stderr, "qemu_popen: Argument validity check failed\n");
return NULL;
}
s = qemu_mallocz(sizeof(QEMUFilePopen));
if (!s) {
fprintf(stderr, "qemu_popen: malloc failed\n");
return NULL;
}
s->popen_file = popen_file;
if(mode[0] == 'r') {
s->file = qemu_fopen_ops(s, NULL, popen_get_buffer, popen_close, NULL);
} else {
s->file = qemu_fopen_ops(s, popen_put_buffer, NULL, popen_close, NULL);
}
fprintf(stderr, "qemu_popen: returning result of qemu_fopen_ops\n");
return s->file;
}
QEMUFile *qemu_popen_cmd(const char *command, const char *mode)
{
FILE *popen_file;
popen_file = popen(command, mode);
if(popen_file == NULL) {
return NULL;
}
return qemu_popen(popen_file, mode);
}
QEMUFile *qemu_fopen_socket(int fd)
{
QEMUFileSocket *s = qemu_mallocz(sizeof(QEMUFileSocket));