xref: /qemu/migration/global_state.c (revision 7271a819) 
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 }
135