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