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