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/global_state.h"
  19 #include "migration/vmstate.h"
  20 #include "trace.h"
  21
  22 typedef struct {
  23     bool optional;
  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 void global_state_set_optional(void)
  61 {
  62     global_state.optional = true;
  63 }
  64
  65 static bool global_state_needed(void *opaque)
  66 {
  67     GlobalState *s = opaque;
  68     char *runstate = (char *)s->runstate;
  69
  70     /* If it is not optional, it is mandatory */
  71
  72     if (s->optional == false) {
  73         return true;
  74     }
  75
  76     /* If state is running or paused, it is not needed */
  77
  78     if (strcmp(runstate, "running") == 0 ||
  79         strcmp(runstate, "paused") == 0) {
  80         return false;
  81     }
  82
  83     /* for any other state it is needed */
  84     return true;
  85 }
  86
  87 static int global_state_post_load(void *opaque, int version_id)
  88 {
  89     GlobalState *s = opaque;
  90     Error *local_err = NULL;
  91     int r;
  92     char *runstate = (char *)s->runstate;
  93
  94     s->received = true;
  95     trace_migrate_global_state_post_load(runstate);
  96
  97     r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE__MAX,
  98                                 -1, &local_err);
  99
 100     if (r == -1) {
 101         if (local_err) {
 102             error_report_err(local_err);
 103         }
 104         return -EINVAL;
 105     }
 106     s->state = r;
 107
 108     return 0;
 109 }
 110
 111 static void global_state_pre_save(void *opaque)
 112 {
 113     GlobalState *s = opaque;
 114
 115     trace_migrate_global_state_pre_save((char *)s->runstate);
 116     s->size = strlen((char *)s->runstate) + 1;
 117 }
 118
 119 static const VMStateDescription vmstate_globalstate = {
 120     .name = "globalstate",
 121     .version_id = 1,
 122     .minimum_version_id = 1,
 123     .post_load = global_state_post_load,
 124     .pre_save = global_state_pre_save,
 125     .needed = global_state_needed,
 126     .fields = (VMStateField[]) {
 127         VMSTATE_UINT32(size, GlobalState),
 128         VMSTATE_BUFFER(runstate, GlobalState),
 129         VMSTATE_END_OF_LIST()
 130     },
 131 };
 132
 133 void register_global_state(void)
 134 {
 135     /* We would use it independently that we receive it */
 136     strcpy((char *)&global_state.runstate, "");
 137     global_state.received = false;
 138     vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
 139 }