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