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_socket.h"
  18 #include "migration.h"
  19 #include "qemu-char.h"
  20 #include "buffered_file.h"
  21 #include "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 int unix_errno(MigrationState *s)
  34 {
  35     return errno;
  36 }
  37
  38 static int unix_write(MigrationState *s, const void * buf, size_t size)
  39 {
  40     return write(s->fd, buf, size);
  41 }
  42
  43 static int unix_close(MigrationState *s)
  44 {
  45     int r = 0;
  46     DPRINTF("unix_close\n");
  47     if (s->fd != -1) {
  48         if (close(s->fd) < 0) {
  49             r = -errno;
  50         }
  51         s->fd = -1;
  52     }
  53     return r;
  54 }
  55
  56 static void unix_wait_for_connect(int fd, void *opaque)
  57 {
  58     MigrationState *s = opaque;
  59
  60     if (fd < 0) {
  61         DPRINTF("migrate connect error\n");
  62         s->fd = -1;
  63         migrate_fd_error(s);
  64     } else {
  65         DPRINTF("migrate connect success\n");
  66         s->fd = fd;
  67         migrate_fd_connect(s);
  68     }
  69 }
  70
  71 int unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
  72 {
  73     Error *local_err = NULL;
  74
  75     s->get_error = unix_errno;
  76     s->write = unix_write;
  77     s->close = unix_close;
  78
  79     s->fd = unix_nonblocking_connect(path, unix_wait_for_connect, s, &local_err);
  80     if (local_err != NULL) {
  81         error_propagate(errp, local_err);
  82         return -1;
  83     }
  84     return 0;
  85 }
  86
  87 static void unix_accept_incoming_migration(void *opaque)
  88 {
  89     struct sockaddr_un addr;
  90     socklen_t addrlen = sizeof(addr);
  91     int s = (intptr_t)opaque;
  92     QEMUFile *f;
  93     int c;
  94
  95     do {
  96         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
  97     } while (c == -1 && errno == EINTR);
  98
  99     DPRINTF("accepted migration\n");
 100
 101     if (c == -1) {
 102         fprintf(stderr, "could not accept migration connection\n");
 103         goto out2;
 104     }
 105
 106     f = qemu_fopen_socket(c);
 107     if (f == NULL) {
 108         fprintf(stderr, "could not qemu_fopen socket\n");
 109         goto out;
 110     }
 111
 112     process_incoming_migration(f);
 113     qemu_fclose(f);
 114 out:
 115     close(c);
 116 out2:
 117     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
 118     close(s);
 119 }
 120
 121 int unix_start_incoming_migration(const char *path, Error **errp)
 122 {
 123     int s;
 124
 125     s = unix_listen(path, NULL, 0, errp);
 126     if (s < 0) {
 127         return -1;
 128     }
 129
 130     qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
 131                          (void *)(intptr_t)s);
 132     return 0;
 133 }