Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
[qemu.git] / 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 "sysemu/runstate.h"
17 #include "qapi/error.h"
18 #include "migration.h"
19 #include "migration/global_state.h"
20 #include "migration/vmstate.h"
21 #include "trace.h"
22
23 typedef struct {
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_str(RUN_STATE_RUNNING);
46 assert(strlen(state) < sizeof(global_state.runstate));
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 static bool global_state_needed(void *opaque)
62 {
63 GlobalState *s = opaque;
64 char *runstate = (char *)s->runstate;
65
66 /* If it is not optional, it is mandatory */
67
68 if (migrate_get_current()->store_global_state) {
69 return true;
70 }
71
72 /* If state is running or paused, it is not needed */
73
74 if (strcmp(runstate, "running") == 0 ||
75 strcmp(runstate, "paused") == 0) {
76 return false;
77 }
78
79 /* for any other state it is needed */
80 return true;
81 }
82
83 static int global_state_post_load(void *opaque, int version_id)
84 {
85 GlobalState *s = opaque;
86 Error *local_err = NULL;
87 int r;
88 char *runstate = (char *)s->runstate;
89
90 s->received = true;
91 trace_migrate_global_state_post_load(runstate);
92
93 if (strnlen((char *)s->runstate,
94 sizeof(s->runstate)) == sizeof(s->runstate)) {
95 /*
96 * This condition should never happen during migration, because
97 * all runstate names are shorter than 100 bytes (the size of
98 * s->runstate). However, a malicious stream could overflow
99 * the qapi_enum_parse() call, so we force the last character
100 * to a NUL byte.
101 */
102 s->runstate[sizeof(s->runstate) - 1] = '\0';
103 }
104 r = qapi_enum_parse(&RunState_lookup, runstate, -1, &local_err);
105
106 if (r == -1) {
107 if (local_err) {
108 error_report_err(local_err);
109 }
110 return -EINVAL;
111 }
112 s->state = r;
113
114 return 0;
115 }
116
117 static int global_state_pre_save(void *opaque)
118 {
119 GlobalState *s = opaque;
120
121 trace_migrate_global_state_pre_save((char *)s->runstate);
122 s->size = strnlen((char *)s->runstate, sizeof(s->runstate)) + 1;
123 assert(s->size <= sizeof(s->runstate));
124
125 return 0;
126 }
127
128 static const VMStateDescription vmstate_globalstate = {
129 .name = "globalstate",
130 .version_id = 1,
131 .minimum_version_id = 1,
132 .post_load = global_state_post_load,
133 .pre_save = global_state_pre_save,
134 .needed = global_state_needed,
135 .fields = (VMStateField[]) {
136 VMSTATE_UINT32(size, GlobalState),
137 VMSTATE_BUFFER(runstate, GlobalState),
138 VMSTATE_END_OF_LIST()
139 },
140 };
141
142 void register_global_state(void)
143 {
144 /* We would use it independently that we receive it */
145 strcpy((char *)&global_state.runstate, "");
146 global_state.received = false;
147 vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
148 }