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/*

 * QEMU live migration via generic fd

 *

 * 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.

 *

 * Contributions after 2012-01-13 are licensed under the terms of the

 * GNU GPL, version 2 or (at your option) any later version.

 */

#include "qemu-common.h"

#include "qemu/sockets.h"

#include "migration/migration.h"

#include "monitor/monitor.h"

#include "migration/qemu-file.h"

#include "block/block.h"

//#define DEBUG_MIGRATION_FD

#ifdef DEBUG_MIGRATION_FD

#define DPRINTF(fmt, ...) \

    do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)

#else

#define DPRINTF(fmt, ...) \

    do { } while (0)

#endif

static int fd_errno(MigrationState *s)

{

    return errno;

}

static int fd_write(MigrationState *s, const void * buf, size_t size)

{

    return write(s->fd, buf, size);

}

static int fd_close(MigrationState *s)

{

    struct stat st;

    int ret;

    DPRINTF("fd_close\n");

    ret = fstat(s->fd, &st);

    if (ret == 0 && S_ISREG(st.st_mode)) {

        /*

         * If the file handle is a regular file make sure the

         * data is flushed to disk before signaling success.

         */

        ret = fsync(s->fd);

        if (ret != 0) {

            ret = -errno;

            perror("migration-fd: fsync");

            return ret;

        }

    }

    ret = close(s->fd);

    s->fd = -1;

    if (ret != 0) {

        ret = -errno;

        perror("migration-fd: close");

    }

    return ret;

}

void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)

{

    s->fd = monitor_get_fd(cur_mon, fdname, errp);

    if (s->fd == -1) {

        return;

    }

    s->get_error = fd_errno;

    s->write = fd_write;

    s->close = fd_close;

    migrate_fd_connect(s);

}

static void fd_accept_incoming_migration(void *opaque)

{

    QEMUFile *f = opaque;

    qemu_set_fd_handler2(qemu_get_fd(f), NULL, NULL, NULL, NULL);

    process_incoming_migration(f);

}

void fd_start_incoming_migration(const char *infd, Error **errp)

{

    int fd;

    QEMUFile *f;

    DPRINTF("Attempting to start an incoming migration via fd\n");

    fd = strtol(infd, NULL, 0);

    f = qemu_fdopen(fd, "rb");

    if(f == NULL) {

        error_setg_errno(errp, errno, "failed to open the source descriptor");

        return;

    }

    qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL, f);

}