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/qdict.h"
  18 #include "qapi/qmp/qjson.h"
  19 #include "sysemu/runstate.h"
  20 #include "qapi/qmp/qbool.h"
  21
  22 static QDict *qmp_dispatch_check_obj(const QObject *request, bool allow_oob,
  23                                      Error **errp)
  24 {
  25     const char *exec_key = NULL;
  26     const QDictEntry *ent;
  27     const char *arg_name;
  28     const QObject *arg_obj;
  29     QDict *dict;
  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             || (!strcmp(arg_name, "exec-oob") && allow_oob)) {
  44             if (qobject_type(arg_obj) != QTYPE_QSTRING) {
  45                 error_setg(errp, "QMP input member '%s' must be a string",
  46                            arg_name);
  47                 return NULL;
  48             }
  49             if (exec_key) {
  50                 error_setg(errp, "QMP input member '%s' clashes with '%s'",
  51                            arg_name, exec_key);
  52                 return NULL;
  53             }
  54             exec_key = arg_name;
  55         } else if (!strcmp(arg_name, "arguments")) {
  56             if (qobject_type(arg_obj) != QTYPE_QDICT) {
  57                 error_setg(errp,
  58                            "QMP input member 'arguments' must be an object");
  59                 return NULL;
  60             }
  61         } else if (!strcmp(arg_name, "id")) {
  62             continue;
  63         } else {
  64             error_setg(errp, "QMP input member '%s' is unexpected",
  65                        arg_name);
  66             return NULL;
  67         }
  68     }
  69
  70     if (!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                                 bool allow_oob, Error **errp)
  80 {
  81     Error *local_err = NULL;
  82     bool oob;
  83     const char *command;
  84     QDict *args, *dict;
  85     QmpCommand *cmd;
  86     QObject *ret = NULL;
  87
  88     dict = qmp_dispatch_check_obj(request, allow_oob, errp);
  89     if (!dict) {
  90         return NULL;
  91     }
  92
  93     command = qdict_get_try_str(dict, "execute");
  94     oob = false;
  95     if (!command) {
  96         assert(allow_oob);
  97         command = qdict_get_str(dict, "exec-oob");
  98         oob = true;
  99     }
 100     cmd = qmp_find_command(cmds, command);
 101     if (cmd == NULL) {
 102         error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
 103                   "The command %s has not been found", command);
 104         return NULL;
 105     }
 106     if (!cmd->enabled) {
 107         error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
 108                   "The command %s has been disabled for this instance",
 109                   command);
 110         return NULL;
 111     }
 112     if (oob && !(cmd->options & QCO_ALLOW_OOB)) {
 113         error_setg(errp, "The command %s does not support OOB",
 114                    command);
 115         return NULL;
 116     }
 117
 118     if (runstate_check(RUN_STATE_PRECONFIG) &&
 119         !(cmd->options & QCO_ALLOW_PRECONFIG)) {
 120         error_setg(errp, "The command '%s' isn't permitted in '%s' state",
 121                    cmd->name, RunState_str(RUN_STATE_PRECONFIG));
 122         return NULL;
 123     }
 124
 125     if (!qdict_haskey(dict, "arguments")) {
 126         args = qdict_new();
 127     } else {
 128         args = qdict_get_qdict(dict, "arguments");
 129         qobject_ref(args);
 130     }
 131
 132     cmd->fn(args, &ret, &local_err);
 133     if (local_err) {
 134         error_propagate(errp, local_err);
 135     } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 136         g_assert(!ret);
 137     } else if (!ret) {
 138         /* TODO turn into assertion */
 139         ret = QOBJECT(qdict_new());
 140     }
 141
 142     qobject_unref(args);
 143
 144     return ret;
 145 }
 146
 147 QDict *qmp_error_response(Error *err)
 148 {
 149     QDict *rsp;
 150
 151     rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }",
 152                                   QapiErrorClass_str(error_get_class(err)),
 153                                   error_get_pretty(err));
 154     error_free(err);
 155     return rsp;
 156 }
 157
 158 /*
 159  * Does @qdict look like a command to be run out-of-band?
 160  */
 161 bool qmp_is_oob(const QDict *dict)
 162 {
 163     return qdict_haskey(dict, "exec-oob")
 164         && !qdict_haskey(dict, "execute");
 165 }
 166
 167 QDict *qmp_dispatch(QmpCommandList *cmds, QObject *request,
 168                     bool allow_oob)
 169 {
 170     Error *err = NULL;
 171     QDict *dict = qobject_to(QDict, request);
 172     QObject *ret, *id = dict ? qdict_get(dict, "id") : NULL;
 173     QDict *rsp;
 174
 175     ret = do_qmp_dispatch(cmds, request, allow_oob, &err);
 176     if (err) {
 177         rsp = qmp_error_response(err);
 178     } else if (ret) {
 179         rsp = qdict_new();
 180         qdict_put_obj(rsp, "return", ret);
 181     } else {
 182         /* Can only happen for commands with QCO_NO_SUCCESS_RESP */
 183         rsp = NULL;
 184     }
 185
 186     if (rsp && id) {
 187         qdict_put_obj(rsp, "id", qobject_ref(id));
 188     }
 189
 190     return rsp;
 191 }