LXR qemu/migration/global

   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
  22typedef struct {
  23    uint32_t size;
  24    uint8_t runstate[100];
  25    RunState state;
  26    bool received;
  27} GlobalState;
  28
  29static GlobalState global_state;
  30
  31int 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
  42void global_state_store_running(void)
  43{
  44    const char *state = RunState_str(RUN_STATE_RUNNING);
  45    assert(strlen(state) < sizeof(global_state.runstate));
  46    strncpy((char *)global_state.runstate,
  47           state, sizeof(global_state.runstate));
  48}
  49
  50bool global_state_received(void)
  51{
  52    return global_state.received;
  53}
  54
  55RunState global_state_get_runstate(void)
  56{
  57    return global_state.state;
  58}
  59
  60static 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
  82static 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    if (strnlen((char *)s->runstate,
  93                sizeof(s->runstate)) == sizeof(s->runstate)) {
  94        /*
  95         * This condition should never happen during migration, because
  96         * all runstate names are shorter than 100 bytes (the size of
  97         * s->runstate). However, a malicious stream could overflow
  98         * the qapi_enum_parse() call, so we force the last character
  99         * to a NUL byte.
 100         */
 101        s->runstate[sizeof(s->runstate) - 1] = '\0';
 102    }
 103    r = qapi_enum_parse(&RunState_lookup, runstate, -1, &local_err);
 104
 105    if (r == -1) {
 106        if (local_err) {
 107            error_report_err(local_err);
 108        }
 109        return -EINVAL;
 110    }
 111    s->state = r;
 112
 113    return 0;
 114}
 115
 116static int global_state_pre_save(void *opaque)
 117{
 118    GlobalState *s = opaque;
 119
 120    trace_migrate_global_state_pre_save((char *)s->runstate);
 121    s->size = strnlen((char *)s->runstate, sizeof(s->runstate)) + 1;
 122    assert(s->size <= sizeof(s->runstate));
 123
 124    return 0;
 125}
 126
 127static const VMStateDescription vmstate_globalstate = {
 128    .name = "globalstate",
 129    .version_id = 1,
 130    .minimum_version_id = 1,
 131    .post_load = global_state_post_load,
 132    .pre_save = global_state_pre_save,
 133    .needed = global_state_needed,
 134    .fields = (VMStateField[]) {
 135        VMSTATE_UINT32(size, GlobalState),
 136        VMSTATE_BUFFER(runstate, GlobalState),
 137        VMSTATE_END_OF_LIST()
 138    },
 139};
 140
 141void register_global_state(void)
 142{
 143    /* We would use it independently that we receive it */
 144    strcpy((char *)&global_state.runstate, "");
 145    global_state.received = false;
 146    vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
 147}
 148