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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 "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(MigrationState *s)

{

    return errno;

}

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

{

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

}

static int unix_close(MigrationState *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)

{

    MigrationState *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 && errno == 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);

    }

}

int unix_start_outgoing_migration(MigrationState *s, const char *path)

{

    struct sockaddr_un addr;

    int ret;

    addr.sun_family = AF_UNIX;

    snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", path);

    s->get_error = unix_errno;

    s->write = unix_write;

    s->close = unix_close;

    s->fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);

    if (s->fd < 0) {

        DPRINTF("Unable to open socket");

        goto err_after_socket;

    }

    socket_set_nonblock(s->fd);

    do {

        ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));

        if (ret == -1)

            ret = -errno;

        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 (ret >= 0)

        migrate_fd_connect(s);

    return 0;

err_after_open:

    close(s->fd);

err_after_socket:

    return -1;

}

static void unix_accept_incoming_migration(void *opaque)

{

    struct sockaddr_un addr;

    socklen_t addrlen = sizeof(addr);

    int s = (intptr_t)opaque;

    QEMUFile *f;

    int c;

    do {

        c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);

    } while (c == -1 && errno == 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 *)(intptr_t)sock);

    return 0;

err:

    close(sock);

    return -EINVAL;

}