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
  21 static QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp)
  22 {
  23     const QDictEntry *ent;
  24     const char *arg_name;
  25     const QObject *arg_obj;
  26     bool has_exec_key = false;
  27     QDict *dict = NULL;
  28
  29     dict = qobject_to(QDict, request);
  30     if (!dict) {
  31         error_setg(errp, "QMP input must be a JSON object");
  32         return NULL;
  33     }
  34
  35     for (ent = qdict_first(dict); ent;
  36          ent = qdict_next(dict, ent)) {
  37         arg_name = qdict_entry_key(ent);
  38         arg_obj = qdict_entry_value(ent);
  39
  40         if (!strcmp(arg_name, "execute")) {
  41             if (qobject_type(arg_obj) != QTYPE_QSTRING) {
  42                 error_setg(errp,
  43                            "QMP input member 'execute' must be a string");
  44                 return NULL;
  45             }
  46             has_exec_key = true;
  47         } else if (!strcmp(arg_name, "arguments")) {
  48             if (qobject_type(arg_obj) != QTYPE_QDICT) {
  49                 error_setg(errp,
  50                            "QMP input member 'arguments' must be an object");
  51                 return NULL;
  52             }
  53         } else {
  54             error_setg(errp, "QMP input member '%s' is unexpected",
  55                        arg_name);
  56             return NULL;
  57         }
  58     }
  59
  60     if (!has_exec_key) {
  61         error_setg(errp, "QMP input lacks member 'execute'");
  62         return NULL;
  63     }
  64
  65     return dict;
  66 }
  67
  68 static QObject *do_qmp_dispatch(QmpCommandList *cmds, QObject *request,
  69                                 Error **errp)
  70 {
  71     Error *local_err = NULL;
  72     const char *command;
  73     QDict *args, *dict;
  74     QmpCommand *cmd;
  75     QObject *ret = NULL;
  76
  77     dict = qmp_dispatch_check_obj(request, errp);
  78     if (!dict) {
  79         return NULL;
  80     }
  81
  82     command = qdict_get_str(dict, "execute");
  83     cmd = qmp_find_command(cmds, command);
  84     if (cmd == NULL) {
  85         error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
  86                   "The command %s has not been found", command);
  87         return NULL;
  88     }
  89     if (!cmd->enabled) {
  90         error_setg(errp, "The command %s has been disabled for this instance",
  91                    command);
  92         return NULL;
  93     }
  94
  95     if (!qdict_haskey(dict, "arguments")) {
  96         args = qdict_new();
  97     } else {
  98         args = qdict_get_qdict(dict, "arguments");
  99         QINCREF(args);
 100     }
 101
 102     cmd->fn(args, &ret, &local_err);
 103     if (local_err) {
 104         error_propagate(errp, local_err);
 105     } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 106         g_assert(!ret);
 107     } else if (!ret) {
 108         ret = QOBJECT(qdict_new());
 109     }
 110
 111     QDECREF(args);
 112
 113     return ret;
 114 }
 115
 116 QObject *qmp_build_error_object(Error *err)
 117 {
 118     return qobject_from_jsonf("{ 'class': %s, 'desc': %s }",
 119                               QapiErrorClass_str(error_get_class(err)),
 120                               error_get_pretty(err));
 121 }
 122
 123 QObject *qmp_dispatch(QmpCommandList *cmds, QObject *request)
 124 {
 125     Error *err = NULL;
 126     QObject *ret;
 127     QDict *rsp;
 128
 129     ret = do_qmp_dispatch(cmds, request, &err);
 130
 131     rsp = qdict_new();
 132     if (err) {
 133         qdict_put_obj(rsp, "error", qmp_build_error_object(err));
 134         error_free(err);
 135     } else if (ret) {
 136         qdict_put_obj(rsp, "return", ret);
 137     } else {
 138         QDECREF(rsp);
 139         return NULL;
 140     }
 141
 142     return QOBJECT(rsp);
 143 }