1 /* 2 * Core Definitions for QAPI/QMP Dispatch 3 * 4 * Copyright IBM, Corp. 2011 5 * 6 * Authors: 7 * Anthony Liguori <aliguori@us.ibm.com> 8 * 9 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. 10 * See the COPYING.LIB file in the top-level directory. 11 * 12 */ 13 14 #include "qemu/osdep.h" 15 16 #include "block/aio.h" 17 #include "qapi/compat-policy.h" 18 #include "qapi/error.h" 19 #include "qapi/qmp/dispatch.h" 20 #include "qapi/qmp/qdict.h" 21 #include "qapi/qmp/qjson.h" 22 #include "qapi/qobject-output-visitor.h" 23 #include "sysemu/runstate.h" 24 #include "qapi/qmp/qbool.h" 25 #include "qemu/coroutine.h" 26 #include "qemu/main-loop.h" 27 28 CompatPolicy compat_policy; 29 30 Visitor *qobject_output_visitor_new_qmp(QObject **result) 31 { 32 Visitor *v = qobject_output_visitor_new(result); 33 34 qobject_output_visitor_set_policy(v, compat_policy.deprecated_output); 35 return v; 36 } 37 38 static QDict *qmp_dispatch_check_obj(QDict *dict, bool allow_oob, 39 Error **errp) 40 { 41 const char *exec_key = NULL; 42 const QDictEntry *ent; 43 const char *arg_name; 44 const QObject *arg_obj; 45 46 for (ent = qdict_first(dict); ent; 47 ent = qdict_next(dict, ent)) { 48 arg_name = qdict_entry_key(ent); 49 arg_obj = qdict_entry_value(ent); 50 51 if (!strcmp(arg_name, "execute") 52 || (!strcmp(arg_name, "exec-oob") && allow_oob)) { 53 if (qobject_type(arg_obj) != QTYPE_QSTRING) { 54 error_setg(errp, "QMP input member '%s' must be a string", 55 arg_name); 56 return NULL; 57 } 58 if (exec_key) { 59 error_setg(errp, "QMP input member '%s' clashes with '%s'", 60 arg_name, exec_key); 61 return NULL; 62 } 63 exec_key = arg_name; 64 } else if (!strcmp(arg_name, "arguments")) { 65 if (qobject_type(arg_obj) != QTYPE_QDICT) { 66 error_setg(errp, 67 "QMP input member 'arguments' must be an object"); 68 return NULL; 69 } 70 } else if (!strcmp(arg_name, "id")) { 71 continue; 72 } else { 73 error_setg(errp, "QMP input member '%s' is unexpected", 74 arg_name); 75 return NULL; 76 } 77 } 78 79 if (!exec_key) { 80 error_setg(errp, "QMP input lacks member 'execute'"); 81 return NULL; 82 } 83 84 return dict; 85 } 86 87 QDict *qmp_error_response(Error *err) 88 { 89 QDict *rsp; 90 91 rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }", 92 QapiErrorClass_str(error_get_class(err)), 93 error_get_pretty(err)); 94 error_free(err); 95 return rsp; 96 } 97 98 /* 99 * Does @qdict look like a command to be run out-of-band? 100 */ 101 bool qmp_is_oob(const QDict *dict) 102 { 103 return qdict_haskey(dict, "exec-oob") 104 && !qdict_haskey(dict, "execute"); 105 } 106 107 typedef struct QmpDispatchBH { 108 const QmpCommand *cmd; 109 Monitor *cur_mon; 110 QDict *args; 111 QObject **ret; 112 Error **errp; 113 Coroutine *co; 114 } QmpDispatchBH; 115 116 static void do_qmp_dispatch_bh(void *opaque) 117 { 118 QmpDispatchBH *data = opaque; 119 120 assert(monitor_cur() == NULL); 121 monitor_set_cur(qemu_coroutine_self(), data->cur_mon); 122 data->cmd->fn(data->args, data->ret, data->errp); 123 monitor_set_cur(qemu_coroutine_self(), NULL); 124 aio_co_wake(data->co); 125 } 126 127 /* 128 * Runs outside of coroutine context for OOB commands, but in coroutine 129 * context for everything else. 130 */ 131 QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request, 132 bool allow_oob, Monitor *cur_mon) 133 { 134 Error *err = NULL; 135 bool oob; 136 const char *command; 137 QDict *args; 138 const QmpCommand *cmd; 139 QDict *dict; 140 QObject *id; 141 QObject *ret = NULL; 142 QDict *rsp = NULL; 143 144 dict = qobject_to(QDict, request); 145 if (!dict) { 146 id = NULL; 147 error_setg(&err, "QMP input must be a JSON object"); 148 goto out; 149 } 150 151 id = qdict_get(dict, "id"); 152 153 if (!qmp_dispatch_check_obj(dict, allow_oob, &err)) { 154 goto out; 155 } 156 157 command = qdict_get_try_str(dict, "execute"); 158 oob = false; 159 if (!command) { 160 assert(allow_oob); 161 command = qdict_get_str(dict, "exec-oob"); 162 oob = true; 163 } 164 cmd = qmp_find_command(cmds, command); 165 if (cmd == NULL) { 166 error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND, 167 "The command %s has not been found", command); 168 goto out; 169 } 170 if (!cmd->enabled) { 171 error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND, 172 "Command %s has been disabled%s%s", 173 command, 174 cmd->disable_reason ? ": " : "", 175 cmd->disable_reason ?: ""); 176 goto out; 177 } 178 if (oob && !(cmd->options & QCO_ALLOW_OOB)) { 179 error_setg(&err, "The command %s does not support OOB", 180 command); 181 goto out; 182 } 183 184 if (!qmp_command_available(cmd, &err)) { 185 goto out; 186 } 187 188 if (!qdict_haskey(dict, "arguments")) { 189 args = qdict_new(); 190 } else { 191 args = qdict_get_qdict(dict, "arguments"); 192 qobject_ref(args); 193 } 194 195 assert(!(oob && qemu_in_coroutine())); 196 assert(monitor_cur() == NULL); 197 if (!!(cmd->options & QCO_COROUTINE) == qemu_in_coroutine()) { 198 monitor_set_cur(qemu_coroutine_self(), cur_mon); 199 cmd->fn(args, &ret, &err); 200 monitor_set_cur(qemu_coroutine_self(), NULL); 201 } else { 202 /* 203 * Actual context doesn't match the one the command needs. 204 * 205 * Case 1: we are in coroutine context, but command does not 206 * have QCO_COROUTINE. We need to drop out of coroutine 207 * context for executing it. 208 * 209 * Case 2: we are outside coroutine context, but command has 210 * QCO_COROUTINE. Can't actually happen, because we get here 211 * outside coroutine context only when executing a command 212 * out of band, and OOB commands never have QCO_COROUTINE. 213 */ 214 assert(!oob && qemu_in_coroutine() && !(cmd->options & QCO_COROUTINE)); 215 216 QmpDispatchBH data = { 217 .cur_mon = cur_mon, 218 .cmd = cmd, 219 .args = args, 220 .ret = &ret, 221 .errp = &err, 222 .co = qemu_coroutine_self(), 223 }; 224 aio_bh_schedule_oneshot(qemu_get_aio_context(), do_qmp_dispatch_bh, 225 &data); 226 qemu_coroutine_yield(); 227 } 228 qobject_unref(args); 229 if (err) { 230 /* or assert(!ret) after reviewing all handlers: */ 231 qobject_unref(ret); 232 goto out; 233 } 234 235 if (cmd->options & QCO_NO_SUCCESS_RESP) { 236 g_assert(!ret); 237 return NULL; 238 } else if (!ret) { 239 /* 240 * When the command's schema has no 'returns', cmd->fn() 241 * leaves @ret null. The QMP spec calls for an empty object 242 * then; supply it. 243 */ 244 ret = QOBJECT(qdict_new()); 245 } 246 247 rsp = qdict_new(); 248 qdict_put_obj(rsp, "return", ret); 249 250 out: 251 if (err) { 252 assert(!rsp); 253 rsp = qmp_error_response(err); 254 } 255 256 assert(rsp); 257 258 if (id) { 259 qdict_put_obj(rsp, "id", qobject_ref(id)); 260 } 261 262 return rsp; 263 } 264