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