migration-fd.c

   1 /*
   2  * QEMU live migration via generic fd
   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  */
  13
  14 #include "qemu-common.h"
  15 #include "qemu_socket.h"
  16 #include "migration.h"
  17 #include "monitor.h"
  18 #include "qemu-char.h"
  19 #include "buffered_file.h"
  20 #include "block.h"
  21 #include "qemu_socket.h"
  22
  23 //#define DEBUG_MIGRATION_FD
  24
  25 #ifdef DEBUG_MIGRATION_FD
  26 #define DPRINTF(fmt, ...) \
  27     do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
  28 #else
  29 #define DPRINTF(fmt, ...) \
  30     do { } while (0)
  31 #endif
  32
  33 static int fd_errno(MigrationState *s)
  34 {
  35     return errno;
  36 }
  37
  38 static int fd_write(MigrationState *s, const void * buf, size_t size)
  39 {
  40     return write(s->fd, buf, size);
  41 }
  42
  43 static int fd_close(MigrationState *s)
  44 {
  45     DPRINTF("fd_close\n");
  46     if (s->fd != -1) {
  47         close(s->fd);
  48         s->fd = -1;
  49     }
  50     return 0;
  51 }
  52
  53 int fd_start_outgoing_migration(MigrationState *s, const char *fdname)
  54 {
  55     s->fd = monitor_get_fd(s->mon, fdname);
  56     if (s->fd == -1) {
  57         DPRINTF("fd_migration: invalid file descriptor identifier\n");
  58         goto err_after_get_fd;
  59     }
  60
  61     if (fcntl(s->fd, F_SETFL, O_NONBLOCK) == -1) {
  62         DPRINTF("Unable to set nonblocking mode on file descriptor\n");
  63         goto err_after_open;
  64     }
  65
  66     s->get_error = fd_errno;
  67     s->write = fd_write;
  68     s->close = fd_close;
  69
  70     migrate_fd_connect(s);
  71     return 0;
  72
  73 err_after_open:
  74     close(s->fd);
  75 err_after_get_fd:
  76     return -1;
  77 }
  78
  79 static void fd_accept_incoming_migration(void *opaque)
  80 {
  81     QEMUFile *f = opaque;
  82
  83     process_incoming_migration(f);
  84     qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
  85     qemu_fclose(f);
  86 }
  87
  88 int fd_start_incoming_migration(const char *infd)
  89 {
  90     int fd;
  91     QEMUFile *f;
  92
  93     DPRINTF("Attempting to start an incoming migration via fd\n");
  94
  95     fd = strtol(infd, NULL, 0);
  96     f = qemu_fdopen(fd, "rb");
  97     if(f == NULL) {
  98         DPRINTF("Unable to apply qemu wrapper to file descriptor\n");
  99         return -errno;
 100     }
 101
 102     qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL, f);
 103
 104     return 0;
 105 }