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