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 #include "qapi/error.h" 16 #include "qapi/qmp/dispatch.h" 17 #include "qapi/qmp/qdict.h" 18 #include "qapi/qmp/qjson.h" 19 #include "sysemu/runstate.h" 20 #include "qapi/qmp/qbool.h" 21 22 static QDict *qmp_dispatch_check_obj(QDict *dict, bool allow_oob, 23 Error **errp) 24 { 25 const char *exec_key = NULL; 26 const QDictEntry *ent; 27 const char *arg_name; 28 const QObject *arg_obj; 29 30 for (ent = qdict_first(dict); ent; 31 ent = qdict_next(dict, ent)) { 32 arg_name = qdict_entry_key(ent); 33 arg_obj = qdict_entry_value(ent); 34 35 if (!strcmp(arg_name, "execute") 36 || (!strcmp(arg_name, "exec-oob") && allow_oob)) { 37 if (qobject_type(arg_obj) != QTYPE_QSTRING) { 38 error_setg(errp, "QMP input member '%s' must be a string", 39 arg_name); 40 return NULL; 41 } 42 if (exec_key) { 43 error_setg(errp, "QMP input member '%s' clashes with '%s'", 44 arg_name, exec_key); 45 return NULL; 46 } 47 exec_key = arg_name; 48 } else if (!strcmp(arg_name, "arguments")) { 49 if (qobject_type(arg_obj) != QTYPE_QDICT) { 50 error_setg(errp, 51 "QMP input member 'arguments' must be an object"); 52 return NULL; 53 } 54 } else if (!strcmp(arg_name, "id")) { 55 continue; 56 } else { 57 error_setg(errp, "QMP input member '%s' is unexpected", 58 arg_name); 59 return NULL; 60 } 61 } 62 63 if (!exec_key) { 64 error_setg(errp, "QMP input lacks member 'execute'"); 65 return NULL; 66 } 67 68 return dict; 69 } 70 71 QDict *qmp_error_response(Error *err) 72 { 73 QDict *rsp; 74 75 rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }", 76 QapiErrorClass_str(error_get_class(err)), 77 error_get_pretty(err)); 78 error_free(err); 79 return rsp; 80 } 81 82 /* 83 * Does @qdict look like a command to be run out-of-band? 84 */ 85 bool qmp_is_oob(const QDict *dict) 86 { 87 return qdict_haskey(dict, "exec-oob") 88 && !qdict_haskey(dict, "execute"); 89 } 90 91 QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request, 92 bool allow_oob) 93 { 94 Error *err = NULL; 95 bool oob; 96 const char *command; 97 QDict *args; 98 const QmpCommand *cmd; 99 QDict *dict; 100 QObject *id; 101 QObject *ret = NULL; 102 QDict *rsp = NULL; 103 104 dict = qobject_to(QDict, request); 105 if (!dict) { 106 id = NULL; 107 error_setg(&err, "QMP input must be a JSON object"); 108 goto out; 109 } 110 111 id = qdict_get(dict, "id"); 112 113 if (!qmp_dispatch_check_obj(dict, allow_oob, &err)) { 114 goto out; 115 } 116 117 command = qdict_get_try_str(dict, "execute"); 118 oob = false; 119 if (!command) { 120 assert(allow_oob); 121 command = qdict_get_str(dict, "exec-oob"); 122 oob = true; 123 } 124 cmd = qmp_find_command(cmds, command); 125 if (cmd == NULL) { 126 error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND, 127 "The command %s has not been found", command); 128 goto out; 129 } 130 if (!cmd->enabled) { 131 error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND, 132 "The command %s has been disabled for this instance", 133 command); 134 goto out; 135 } 136 if (oob && !(cmd->options & QCO_ALLOW_OOB)) { 137 error_setg(&err, "The command %s does not support OOB", 138 command); 139 goto out; 140 } 141 142 if (runstate_check(RUN_STATE_PRECONFIG) && 143 !(cmd->options & QCO_ALLOW_PRECONFIG)) { 144 error_setg(&err, "The command '%s' isn't permitted in '%s' state", 145 cmd->name, RunState_str(RUN_STATE_PRECONFIG)); 146 goto out; 147 } 148 149 if (!qdict_haskey(dict, "arguments")) { 150 args = qdict_new(); 151 } else { 152 args = qdict_get_qdict(dict, "arguments"); 153 qobject_ref(args); 154 } 155 cmd->fn(args, &ret, &err); 156 qobject_unref(args); 157 if (err) { 158 /* or assert(!ret) after reviewing all handlers: */ 159 qobject_unref(ret); 160 goto out; 161 } 162 163 if (cmd->options & QCO_NO_SUCCESS_RESP) { 164 g_assert(!ret); 165 return NULL; 166 } else if (!ret) { 167 /* 168 * When the command's schema has no 'returns', cmd->fn() 169 * leaves @ret null. The QMP spec calls for an empty object 170 * then; supply it. 171 */ 172 ret = QOBJECT(qdict_new()); 173 } 174 175 rsp = qdict_new(); 176 qdict_put_obj(rsp, "return", ret); 177 178 out: 179 if (err) { 180 assert(!rsp); 181 rsp = qmp_error_response(err); 182 } 183 184 assert(rsp); 185 186 if (id) { 187 qdict_put_obj(rsp, "id", qobject_ref(id)); 188 } 189 190 return rsp; 191 } 192