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 int unix_errno(MigrationState *s)
  33 {
  34     return errno;
  35 }
  36
  37 static int unix_write(MigrationState *s, const void * buf, size_t size)
  38 {
  39     return write(s->fd, buf, size);
  40 }
  41
  42 static void unix_wait_for_connect(int fd, void *opaque)
  43 {
  44     MigrationState *s = opaque;
  45
  46     if (fd < 0) {
  47         DPRINTF("migrate connect error\n");
  48         s->migration_file = NULL;
  49         migrate_fd_error(s);
  50     } else {
  51         DPRINTF("migrate connect success\n");
  52         s->migration_file = qemu_fopen_socket(fd, "wb");
  53         migrate_fd_connect(s);
  54     }
  55 }
  56
  57 void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
  58 {
  59     s->get_error = unix_errno;
  60     s->write = unix_write;
  61     unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
  62 }
  63
  64 static void unix_accept_incoming_migration(void *opaque)
  65 {
  66     struct sockaddr_un addr;
  67     socklen_t addrlen = sizeof(addr);
  68     int s = (intptr_t)opaque;
  69     QEMUFile *f;
  70     int c;
  71
  72     do {
  73         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  74     } while (c == -1 && errno == EINTR);
  75     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
  76     close(s);
  77
  78     DPRINTF("accepted migration\n");
  79
  80     if (c == -1) {
  81         fprintf(stderr, "could not accept migration connection\n");
  82         goto out;
  83     }
  84
  85     f = qemu_fopen_socket(c, "rb");
  86     if (f == NULL) {
  87         fprintf(stderr, "could not qemu_fopen socket\n");
  88         goto out;
  89     }
  90
  91     process_incoming_migration(f);
  92     return;
  93
  94 out:
  95     close(c);
  96 }
  97
  98 void unix_start_incoming_migration(const char *path, Error **errp)
  99 {
 100     int s;
 101
 102     s = unix_listen(path, NULL, 0, errp);
 103     if (s < 0) {
 104         return;
 105     }
 106
 107     qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
 108                          (void *)(intptr_t)s);
 109 }