qapi/qmp-dispatch.c

   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/json-parser.h"
  18 #include "qapi/qmp/qdict.h"
  19 #include "qapi/qmp/qjson.h"
  20 #include "qapi/qmp/qbool.h"
  21 #include "sysemu/sysemu.h"
  22
  23 QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp)
  24 {
  25     const QDictEntry *ent;
  26     const char *arg_name;
  27     const QObject *arg_obj;
  28     bool has_exec_key = false;
  29     QDict *dict = NULL;
  30
  31     dict = qobject_to(QDict, request);
  32     if (!dict) {
  33         error_setg(errp, "QMP input must be a JSON object");
  34         return NULL;
  35     }
  36
  37     for (ent = qdict_first(dict); ent;
  38          ent = qdict_next(dict, ent)) {
  39         arg_name = qdict_entry_key(ent);
  40         arg_obj = qdict_entry_value(ent);
  41
  42         if (!strcmp(arg_name, "execute")) {
  43             if (qobject_type(arg_obj) != QTYPE_QSTRING) {
  44                 error_setg(errp,
  45                            "QMP input member 'execute' must be a string");
  46                 return NULL;
  47             }
  48             has_exec_key = true;
  49         } else if (!strcmp(arg_name, "arguments")) {
  50             if (qobject_type(arg_obj) != QTYPE_QDICT) {
  51                 error_setg(errp,
  52                            "QMP input member 'arguments' must be an object");
  53                 return NULL;
  54             }
  55         } else if (!strcmp(arg_name, "id")) {
  56             continue;
  57         } else if (!strcmp(arg_name, "control")) {
  58             if (qobject_type(arg_obj) != QTYPE_QDICT) {
  59                 error_setg(errp,
  60                            "QMP input member 'control' must be a dict");
  61                 return NULL;
  62             }
  63         } else {
  64             error_setg(errp, "QMP input member '%s' is unexpected",
  65                        arg_name);
  66             return NULL;
  67         }
  68     }
  69
  70     if (!has_exec_key) {
  71         error_setg(errp, "QMP input lacks member 'execute'");
  72         return NULL;
  73     }
  74
  75     return dict;
  76 }
  77
  78 static QObject *do_qmp_dispatch(QmpCommandList *cmds, QObject *request,
  79                                 Error **errp)
  80 {
  81     Error *local_err = NULL;
  82     const char *command;
  83     QDict *args, *dict;
  84     QmpCommand *cmd;
  85     QObject *ret = NULL;
  86
  87     dict = qmp_dispatch_check_obj(request, errp);
  88     if (!dict) {
  89         return NULL;
  90     }
  91
  92     command = qdict_get_str(dict, "execute");
  93     cmd = qmp_find_command(cmds, command);
  94     if (cmd == NULL) {
  95         error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
  96                   "The command %s has not been found", command);
  97         return NULL;
  98     }
  99     if (!cmd->enabled) {
 100         error_setg(errp, "The command %s has been disabled for this instance",
 101                    command);
 102         return NULL;
 103     }
 104
 105     if (runstate_check(RUN_STATE_PRECONFIG) &&
 106         !(cmd->options & QCO_ALLOW_PRECONFIG)) {
 107         error_setg(errp, "The command '%s' isn't permitted in '%s' state",
 108                    cmd->name, RunState_str(RUN_STATE_PRECONFIG));
 109         return NULL;
 110     }
 111
 112     if (!qdict_haskey(dict, "arguments")) {
 113         args = qdict_new();
 114     } else {
 115         args = qdict_get_qdict(dict, "arguments");
 116         qobject_ref(args);
 117     }
 118
 119     cmd->fn(args, &ret, &local_err);
 120     if (local_err) {
 121         error_propagate(errp, local_err);
 122     } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 123         g_assert(!ret);
 124     } else if (!ret) {
 125         ret = QOBJECT(qdict_new());
 126     }
 127
 128     qobject_unref(args);
 129
 130     return ret;
 131 }
 132
 133 QObject *qmp_build_error_object(Error *err)
 134 {
 135     return qobject_from_jsonf("{ 'class': %s, 'desc': %s }",
 136                               QapiErrorClass_str(error_get_class(err)),
 137                               error_get_pretty(err));
 138 }
 139
 140 /*
 141  * Detect whether a request should be run out-of-band, by quickly
 142  * peeking at whether we have: { "control": { "run-oob": true } }. By
 143  * default commands are run in-band.
 144  */
 145 bool qmp_is_oob(QDict *dict)
 146 {
 147     QBool *bool_obj;
 148
 149     dict = qdict_get_qdict(dict, "control");
 150     if (!dict) {
 151         return false;
 152     }
 153
 154     bool_obj = qobject_to(QBool, qdict_get(dict, "run-oob"));
 155     if (!bool_obj) {
 156         return false;
 157     }
 158
 159     return qbool_get_bool(bool_obj);
 160 }
 161
 162 QObject *qmp_dispatch(QmpCommandList *cmds, QObject *request)
 163 {
 164     Error *err = NULL;
 165     QObject *ret;
 166     QDict *rsp;
 167
 168     ret = do_qmp_dispatch(cmds, request, &err);
 169
 170     rsp = qdict_new();
 171     if (err) {
 172         qdict_put_obj(rsp, "error", qmp_build_error_object(err));
 173         error_free(err);
 174     } else if (ret) {
 175         qdict_put_obj(rsp, "return", ret);
 176     } else {
 177         qobject_unref(rsp);
 178         return NULL;
 179     }
 180
 181     return QOBJECT(rsp);
 182 }