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 "migration.h"
  18 #include "migration/global_state.h"
  19 #include "migration/vmstate.h"
  20 #include "trace.h"
  21
  22 typedef struct {
  23     uint32_t size;
  24     uint8_t runstate[100];
  25     RunState state;
  26     bool received;
  27 } GlobalState;
  28
  29 static GlobalState global_state;
  30
  31 int global_state_store(void)
  32 {
  33     if (!runstate_store((char *)global_state.runstate,
  34                         sizeof(global_state.runstate))) {
  35         error_report("runstate name too big: %s", global_state.runstate);
  36         trace_migrate_state_too_big();
  37         return -EINVAL;
  38     }
  39     return 0;
  40 }
  41
  42 void global_state_store_running(void)
  43 {
  44     const char *state = RunState_str(RUN_STATE_RUNNING);
  45     strncpy((char *)global_state.runstate,
  46            state, sizeof(global_state.runstate));
  47 }
  48
  49 bool global_state_received(void)
  50 {
  51     return global_state.received;
  52 }
  53
  54 RunState global_state_get_runstate(void)
  55 {
  56     return global_state.state;
  57 }
  58
  59 static bool global_state_needed(void *opaque)
  60 {
  61     GlobalState *s = opaque;
  62     char *runstate = (char *)s->runstate;
  63
  64     /* If it is not optional, it is mandatory */
  65
  66     if (migrate_get_current()->store_global_state) {
  67         return true;
  68     }
  69
  70     /* If state is running or paused, it is not needed */
  71
  72     if (strcmp(runstate, "running") == 0 ||
  73         strcmp(runstate, "paused") == 0) {
  74         return false;
  75     }
  76
  77     /* for any other state it is needed */
  78     return true;
  79 }
  80
  81 static int global_state_post_load(void *opaque, int version_id)
  82 {
  83     GlobalState *s = opaque;
  84     Error *local_err = NULL;
  85     int r;
  86     char *runstate = (char *)s->runstate;
  87
  88     s->received = true;
  89     trace_migrate_global_state_post_load(runstate);
  90
  91     r = qapi_enum_parse(&RunState_lookup, runstate, -1, &local_err);
  92
  93     if (r == -1) {
  94         if (local_err) {
  95             error_report_err(local_err);
  96         }
  97         return -EINVAL;
  98     }
  99     s->state = r;
 100
 101     return 0;
 102 }
 103
 104 static int global_state_pre_save(void *opaque)
 105 {
 106     GlobalState *s = opaque;
 107
 108     trace_migrate_global_state_pre_save((char *)s->runstate);
 109     s->size = strlen((char *)s->runstate) + 1;
 110
 111     return 0;
 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 }