LXR qemu/migration-unix.c

   1/*
   2 * QEMU live migration via Unix Domain Sockets
   3 *
   4 * Copyright Red Hat, Inc. 2009
   5 *
   6 * Authors:
   7 *  Chris Lalancette <clalance@redhat.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2.  See
  10 * the COPYING file in the top-level directory.
  11 *
  12 * Contributions after 2012-01-13 are licensed under the terms of the
  13 * GNU GPL, version 2 or (at your option) any later version.
  14 */
  15
  16#include "qemu-common.h"
  17#include "qemu/sockets.h"
  18#include "migration/migration.h"
  19#include "migration/qemu-file.h"
  20#include "block/block.h"
  21
  22//#define DEBUG_MIGRATION_UNIX
  23
  24#ifdef DEBUG_MIGRATION_UNIX
  25#define DPRINTF(fmt, ...) \
  26    do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
  27#else
  28#define DPRINTF(fmt, ...) \
  29    do { } while (0)
  30#endif
  31
  32static int unix_errno(MigrationState *s)
  33{
  34    return errno;
  35}
  36
  37static int unix_write(MigrationState *s, const void * buf, size_t size)
  38{
  39    return write(s->fd, buf, size);
  40}
  41
  42static int unix_close(MigrationState *s)
  43{
  44    int r = 0;
  45    DPRINTF("unix_close\n");
  46    if (close(s->fd) < 0) {
  47        r = -errno;
  48    }
  49    return r;
  50}
  51
  52static void unix_wait_for_connect(int fd, void *opaque)
  53{
  54    MigrationState *s = opaque;
  55
  56    if (fd < 0) {
  57        DPRINTF("migrate connect error\n");
  58        s->fd = -1;
  59        migrate_fd_error(s);
  60    } else {
  61        DPRINTF("migrate connect success\n");
  62        s->fd = fd;
  63        qemu_set_block(s->fd);
  64        migrate_fd_connect(s);
  65    }
  66}
  67
  68void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
  69{
  70    s->get_error = unix_errno;
  71    s->write = unix_write;
  72    s->close = unix_close;
  73
  74    s->fd = unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
  75}
  76
  77static void unix_accept_incoming_migration(void *opaque)
  78{
  79    struct sockaddr_un addr;
  80    socklen_t addrlen = sizeof(addr);
  81    int s = (intptr_t)opaque;
  82    QEMUFile *f;
  83    int c;
  84
  85    do {
  86        c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  87    } while (c == -1 && errno == EINTR);
  88    qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
  89    close(s);
  90
  91    DPRINTF("accepted migration\n");
  92
  93    if (c == -1) {
  94        fprintf(stderr, "could not accept migration connection\n");
  95        goto out;
  96    }
  97
  98    f = qemu_fopen_socket(c);
  99    if (f == NULL) {
 100        fprintf(stderr, "could not qemu_fopen socket\n");
 101        goto out;
 102    }
 103
 104    process_incoming_migration(f);
 105    return;
 106
 107out:
 108    close(c);
 109}
 110
 111void unix_start_incoming_migration(const char *path, Error **errp)
 112{
 113    int s;
 114
 115    s = unix_listen(path, NULL, 0, errp);
 116    if (s < 0) {
 117        return;
 118    }
 119
 120    qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
 121                         (void *)(intptr_t)s);
 122}
 123