migration/global_state.c

   1 /*
   2  * Global State configuration
   3  *
   4  * Copyright (c) 2014-2017 Red Hat Inc
   5  *
   6  * Authors:
   7  *  Juan Quintela <quintela@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qemu/cutils.h"
  15 #include "qemu/error-report.h"
  16 #include "qapi/error.h"
  17 #include "qapi/util.h"
  18 #include "migration.h"
  19 #include "migration/global_state.h"
  20 #include "migration/vmstate.h"
  21 #include "trace.h"
  22
  23 typedef struct {
  24     uint32_t size;
  25     uint8_t runstate[100];
  26     RunState state;
  27     bool received;
  28 } GlobalState;
  29
  30 static GlobalState global_state;
  31
  32 int global_state_store(void)
  33 {
  34     if (!runstate_store((char *)global_state.runstate,
  35                         sizeof(global_state.runstate))) {
  36         error_report("runstate name too big: %s", global_state.runstate);
  37         trace_migrate_state_too_big();
  38         return -EINVAL;
  39     }
  40     return 0;
  41 }
  42
  43 void global_state_store_running(void)
  44 {
  45     const char *state = RunState_lookup[RUN_STATE_RUNNING];
  46     strncpy((char *)global_state.runstate,
  47            state, sizeof(global_state.runstate));
  48 }
  49
  50 bool global_state_received(void)
  51 {
  52     return global_state.received;
  53 }
  54
  55 RunState global_state_get_runstate(void)
  56 {
  57     return global_state.state;
  58 }
  59
  60 static bool global_state_needed(void *opaque)
  61 {
  62     GlobalState *s = opaque;
  63     char *runstate = (char *)s->runstate;
  64
  65     /* If it is not optional, it is mandatory */
  66
  67     if (migrate_get_current()->store_global_state) {
  68         return true;
  69     }
  70
  71     /* If state is running or paused, it is not needed */
  72
  73     if (strcmp(runstate, "running") == 0 ||
  74         strcmp(runstate, "paused") == 0) {
  75         return false;
  76     }
  77
  78     /* for any other state it is needed */
  79     return true;
  80 }
  81
  82 static int global_state_post_load(void *opaque, int version_id)
  83 {
  84     GlobalState *s = opaque;
  85     Error *local_err = NULL;
  86     int r;
  87     char *runstate = (char *)s->runstate;
  88
  89     s->received = true;
  90     trace_migrate_global_state_post_load(runstate);
  91
  92     r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE__MAX,
  93                                 -1, &local_err);
  94
  95     if (r == -1) {
  96         if (local_err) {
  97             error_report_err(local_err);
  98         }
  99         return -EINVAL;
 100     }
 101     s->state = r;
 102
 103     return 0;
 104 }
 105
 106 static void global_state_pre_save(void *opaque)
 107 {
 108     GlobalState *s = opaque;
 109
 110     trace_migrate_global_state_pre_save((char *)s->runstate);
 111     s->size = strlen((char *)s->runstate) + 1;
 112 }
 113
 114 static const VMStateDescription vmstate_globalstate = {
 115     .name = "globalstate",
 116     .version_id = 1,
 117     .minimum_version_id = 1,
 118     .post_load = global_state_post_load,
 119     .pre_save = global_state_pre_save,
 120     .needed = global_state_needed,
 121     .fields = (VMStateField[]) {
 122         VMSTATE_UINT32(size, GlobalState),
 123         VMSTATE_BUFFER(runstate, GlobalState),
 124         VMSTATE_END_OF_LIST()
 125     },
 126 };
 127
 128 void register_global_state(void)
 129 {
 130     /* We would use it independently that we receive it */
 131     strcpy((char *)&global_state.runstate, "");
 132     global_state.received = false;
 133     vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
 134 }