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 "sysemu/sysemu.h"
  21 #include "trace.h"
  22
  23 typedef struct {
  24     bool optional;
  25     uint32_t size;
  26     uint8_t runstate[100];
  27     RunState state;
  28     bool received;
  29 } GlobalState;
  30
  31 static GlobalState global_state;
  32
  33 int global_state_store(void)
  34 {
  35     if (!runstate_store((char *)global_state.runstate,
  36                         sizeof(global_state.runstate))) {
  37         error_report("runstate name too big: %s", global_state.runstate);
  38         trace_migrate_state_too_big();
  39         return -EINVAL;
  40     }
  41     return 0;
  42 }
  43
  44 void global_state_store_running(void)
  45 {
  46     const char *state = RunState_lookup[RUN_STATE_RUNNING];
  47     strncpy((char *)global_state.runstate,
  48            state, sizeof(global_state.runstate));
  49 }
  50
  51 bool global_state_received(void)
  52 {
  53     return global_state.received;
  54 }
  55
  56 RunState global_state_get_runstate(void)
  57 {
  58     return global_state.state;
  59 }
  60
  61 void global_state_set_optional(void)
  62 {
  63     global_state.optional = true;
  64 }
  65
  66 static bool global_state_needed(void *opaque)
  67 {
  68     GlobalState *s = opaque;
  69     char *runstate = (char *)s->runstate;
  70
  71     /* If it is not optional, it is mandatory */
  72
  73     if (s->optional == false) {
  74         return true;
  75     }
  76
  77     /* If state is running or paused, it is not needed */
  78
  79     if (strcmp(runstate, "running") == 0 ||
  80         strcmp(runstate, "paused") == 0) {
  81         return false;
  82     }
  83
  84     /* for any other state it is needed */
  85     return true;
  86 }
  87
  88 static int global_state_post_load(void *opaque, int version_id)
  89 {
  90     GlobalState *s = opaque;
  91     Error *local_err = NULL;
  92     int r;
  93     char *runstate = (char *)s->runstate;
  94
  95     s->received = true;
  96     trace_migrate_global_state_post_load(runstate);
  97
  98     r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE__MAX,
  99                                 -1, &local_err);
 100
 101     if (r == -1) {
 102         if (local_err) {
 103             error_report_err(local_err);
 104         }
 105         return -EINVAL;
 106     }
 107     s->state = r;
 108
 109     return 0;
 110 }
 111
 112 static void global_state_pre_save(void *opaque)
 113 {
 114     GlobalState *s = opaque;
 115
 116     trace_migrate_global_state_pre_save((char *)s->runstate);
 117     s->size = strlen((char *)s->runstate) + 1;
 118 }
 119
 120 static const VMStateDescription vmstate_globalstate = {
 121     .name = "globalstate",
 122     .version_id = 1,
 123     .minimum_version_id = 1,
 124     .post_load = global_state_post_load,
 125     .pre_save = global_state_pre_save,
 126     .needed = global_state_needed,
 127     .fields = (VMStateField[]) {
 128         VMSTATE_UINT32(size, GlobalState),
 129         VMSTATE_BUFFER(runstate, GlobalState),
 130         VMSTATE_END_OF_LIST()
 131     },
 132 };
 133
 134 void register_global_state(void)
 135 {
 136     /* We would use it independently that we receive it */
 137     strcpy((char *)&global_state.runstate, "");
 138     global_state.received = false;
 139     vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
 140 }