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/types.h"
  17 #include "qapi/qmp/dispatch.h"
  18 #include "qapi/qmp/json-parser.h"
  19 #include "qapi/qmp/qjson.h"
  20 #include "qapi-types.h"
  21 #include "qapi/qmp/qerror.h"
  22
  23 static 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 {
  56             error_setg(errp, "QMP input member '%s' is unexpected",
  57                        arg_name);
  58             return NULL;
  59         }
  60     }
  61
  62     if (!has_exec_key) {
  63         error_setg(errp, "QMP input lacks member 'execute'");
  64         return NULL;
  65     }
  66
  67     return dict;
  68 }
  69
  70 static QObject *do_qmp_dispatch(QmpCommandList *cmds, QObject *request,
  71                                 Error **errp)
  72 {
  73     Error *local_err = NULL;
  74     const char *command;
  75     QDict *args, *dict;
  76     QmpCommand *cmd;
  77     QObject *ret = NULL;
  78
  79     dict = qmp_dispatch_check_obj(request, errp);
  80     if (!dict) {
  81         return NULL;
  82     }
  83
  84     command = qdict_get_str(dict, "execute");
  85     cmd = qmp_find_command(cmds, command);
  86     if (cmd == NULL) {
  87         error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
  88                   "The command %s has not been found", command);
  89         return NULL;
  90     }
  91     if (!cmd->enabled) {
  92         error_setg(errp, "The command %s has been disabled for this instance",
  93                    command);
  94         return NULL;
  95     }
  96
  97     if (!qdict_haskey(dict, "arguments")) {
  98         args = qdict_new();
  99     } else {
 100         args = qdict_get_qdict(dict, "arguments");
 101         QINCREF(args);
 102     }
 103
 104     cmd->fn(args, &ret, &local_err);
 105     if (local_err) {
 106         error_propagate(errp, local_err);
 107     } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 108         g_assert(!ret);
 109     } else if (!ret) {
 110         ret = QOBJECT(qdict_new());
 111     }
 112
 113     QDECREF(args);
 114
 115     return ret;
 116 }
 117
 118 QObject *qmp_build_error_object(Error *err)
 119 {
 120     return qobject_from_jsonf("{ 'class': %s, 'desc': %s }",
 121                               QapiErrorClass_lookup[error_get_class(err)],
 122                               error_get_pretty(err));
 123 }
 124
 125 QObject *qmp_dispatch(QmpCommandList *cmds, QObject *request)
 126 {
 127     Error *err = NULL;
 128     QObject *ret;
 129     QDict *rsp;
 130
 131     ret = do_qmp_dispatch(cmds, request, &err);
 132
 133     rsp = qdict_new();
 134     if (err) {
 135         qdict_put_obj(rsp, "error", qmp_build_error_object(err));
 136         error_free(err);
 137     } else if (ret) {
 138         qdict_put_obj(rsp, "return", ret);
 139     } else {
 140         QDECREF(rsp);
 141         return NULL;
 142     }
 143
 144     return QOBJECT(rsp);
 145 }