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 "qemu/main-loop.h"
  19 #include "migration/migration.h"
  20 #include "migration/qemu-file.h"
  21 #include "block/block.h"
  22
  23 //#define DEBUG_MIGRATION_UNIX
  24
  25 #ifdef DEBUG_MIGRATION_UNIX
  26 #define DPRINTF(fmt, ...) \
  27     do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
  28 #else
  29 #define DPRINTF(fmt, ...) \
  30     do { } while (0)
  31 #endif
  32
  33 static void unix_wait_for_connect(int fd, void *opaque)
  34 {
  35     MigrationState *s = opaque;
  36
  37     if (fd < 0) {
  38         DPRINTF("migrate connect error\n");
  39         s->file = NULL;
  40         migrate_fd_error(s);
  41     } else {
  42         DPRINTF("migrate connect success\n");
  43         s->file = qemu_fopen_socket(fd, "wb");
  44         migrate_fd_connect(s);
  45     }
  46 }
  47
  48 void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
  49 {
  50     unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
  51 }
  52
  53 static void unix_accept_incoming_migration(void *opaque)
  54 {
  55     struct sockaddr_un addr;
  56     socklen_t addrlen = sizeof(addr);
  57     int s = (intptr_t)opaque;
  58     QEMUFile *f;
  59     int c;
  60
  61     do {
  62         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  63     } while (c == -1 && errno == EINTR);
  64     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
  65     close(s);
  66
  67     DPRINTF("accepted migration\n");
  68
  69     if (c == -1) {
  70         fprintf(stderr, "could not accept migration connection\n");
  71         goto out;
  72     }
  73
  74     f = qemu_fopen_socket(c, "rb");
  75     if (f == NULL) {
  76         fprintf(stderr, "could not qemu_fopen socket\n");
  77         goto out;
  78     }
  79
  80     process_incoming_migration(f);
  81     return;
  82
  83 out:
  84     close(c);
  85 }
  86
  87 void unix_start_incoming_migration(const char *path, Error **errp)
  88 {
  89     int s;
  90
  91     s = unix_listen(path, NULL, 0, errp);
  92     if (s < 0) {
  93         return;
  94     }
  95
  96     qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
  97                          (void *)(intptr_t)s);
  98 }