xref: /openbmc/qemu/migration/global_state.c (revision 0221d73c)
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 }
149