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 "sysemu.h"
  20 #include "buffered_file.h"
  21 #include "block.h"
  22 #include "qemu_socket.h"
  23
  24 //#define DEBUG_MIGRATION_FD
  25
  26 #ifdef DEBUG_MIGRATION_FD
  27 #define dprintf(fmt, ...) \
  28     do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
  29 #else
  30 #define dprintf(fmt, ...) \
  31     do { } while (0)
  32 #endif
  33
  34 static int fd_errno(FdMigrationState *s)
  35 {
  36     return errno;
  37 }
  38
  39 static int fd_write(FdMigrationState *s, const void * buf, size_t size)
  40 {
  41     return write(s->fd, buf, size);
  42 }
  43
  44 static int fd_close(FdMigrationState *s)
  45 {
  46     dprintf("fd_close\n");
  47     if (s->fd != -1) {
  48         close(s->fd);
  49         s->fd = -1;
  50     }
  51     return 0;
  52 }
  53
  54 MigrationState *fd_start_outgoing_migration(Monitor *mon,
  55                                             const char *fdname,
  56                                             int64_t bandwidth_limit,
  57                                             int detach,
  58                                             int blk,
  59                                             int inc)
  60 {
  61     FdMigrationState *s;
  62
  63     s = qemu_mallocz(sizeof(*s));
  64
  65     s->fd = monitor_get_fd(mon, fdname);
  66     if (s->fd == -1) {
  67         dprintf("fd_migration: invalid file descriptor identifier\n");
  68         goto err_after_alloc;
  69     }
  70
  71     if (fcntl(s->fd, F_SETFL, O_NONBLOCK) == -1) {
  72         dprintf("Unable to set nonblocking mode on file descriptor\n");
  73         goto err_after_open;
  74     }
  75
  76     s->get_error = fd_errno;
  77     s->write = fd_write;
  78     s->close = fd_close;
  79     s->mig_state.cancel = migrate_fd_cancel;
  80     s->mig_state.get_status = migrate_fd_get_status;
  81     s->mig_state.release = migrate_fd_release;
  82
  83     s->mig_state.blk = blk;
  84     s->mig_state.shared = inc;
  85
  86     s->state = MIG_STATE_ACTIVE;
  87     s->mon = NULL;
  88     s->bandwidth_limit = bandwidth_limit;
  89
  90     if (!detach) {
  91         migrate_fd_monitor_suspend(s, mon);
  92     }
  93
  94     migrate_fd_connect(s);
  95     return &s->mig_state;
  96
  97 err_after_open:
  98     close(s->fd);
  99 err_after_alloc:
 100     qemu_free(s);
 101     return NULL;
 102 }
 103
 104 static void fd_accept_incoming_migration(void *opaque)
 105 {
 106     QEMUFile *f = opaque;
 107     int ret;
 108
 109     ret = qemu_loadvm_state(f);
 110     if (ret < 0) {
 111         fprintf(stderr, "load of migration failed\n");
 112         goto err;
 113     }
 114     qemu_announce_self();
 115     dprintf("successfully loaded vm state\n");
 116     /* we've successfully migrated, close the fd */
 117     qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
 118     if (autostart)
 119         vm_start();
 120
 121 err:
 122     qemu_fclose(f);
 123 }
 124
 125 int fd_start_incoming_migration(const char *infd)
 126 {
 127     int fd;
 128     QEMUFile *f;
 129
 130     dprintf("Attempting to start an incoming migration via fd\n");
 131
 132     fd = strtol(infd, NULL, 0);
 133     f = qemu_fdopen(fd, "rb");
 134     if(f == NULL) {
 135         dprintf("Unable to apply qemu wrapper to file descriptor\n");
 136         return -errno;
 137     }
 138
 139     qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL,
 140                          (void *)(unsigned long)f);
 141
 142     return 0;
 143 }