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/osdep.h"
  17
  18 #include "qemu-common.h"
  19 #include "qemu/error-report.h"
  20 #include "qemu/sockets.h"
  21 #include "qemu/main-loop.h"
  22 #include "migration/migration.h"
  23 #include "migration/qemu-file.h"
  24 #include "block/block.h"
  25
  26 //#define DEBUG_MIGRATION_UNIX
  27
  28 #ifdef DEBUG_MIGRATION_UNIX
  29 #define DPRINTF(fmt, ...) \
  30     do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
  31 #else
  32 #define DPRINTF(fmt, ...) \
  33     do { } while (0)
  34 #endif
  35
  36 static void unix_wait_for_connect(int fd, Error *err, void *opaque)
  37 {
  38     MigrationState *s = opaque;
  39
  40     if (fd < 0) {
  41         DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
  42         s->to_dst_file = NULL;
  43         migrate_fd_error(s);
  44     } else {
  45         DPRINTF("migrate connect success\n");
  46         s->to_dst_file = qemu_fopen_socket(fd, "wb");
  47         migrate_fd_connect(s);
  48     }
  49 }
  50
  51 void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
  52 {
  53     unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
  54 }
  55
  56 static void unix_accept_incoming_migration(void *opaque)
  57 {
  58     struct sockaddr_un addr;
  59     socklen_t addrlen = sizeof(addr);
  60     int s = (intptr_t)opaque;
  61     QEMUFile *f;
  62     int c, err;
  63
  64     do {
  65         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  66         err = errno;
  67     } while (c < 0 && err == EINTR);
  68     qemu_set_fd_handler(s, NULL, NULL, NULL);
  69     close(s);
  70
  71     DPRINTF("accepted migration\n");
  72
  73     if (c < 0) {
  74         error_report("could not accept migration connection (%s)",
  75                      strerror(err));
  76         return;
  77     }
  78
  79     f = qemu_fopen_socket(c, "rb");
  80     if (f == NULL) {
  81         error_report("could not qemu_fopen socket");
  82         goto out;
  83     }
  84
  85     process_incoming_migration(f);
  86     return;
  87
  88 out:
  89     close(c);
  90 }
  91
  92 void unix_start_incoming_migration(const char *path, Error **errp)
  93 {
  94     int s;
  95
  96     s = unix_listen(path, NULL, 0, errp);
  97     if (s < 0) {
  98         return;
  99     }
 100
 101     qemu_set_fd_handler(s, unix_accept_incoming_migration, NULL,
 102                         (void *)(intptr_t)s);
 103 }