LXR qemu/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 "qapi/qmp/qbool.h"
  20#include "sysemu/sysemu.h"
  21
  22static 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
  78static 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_setg(errp, "The command %s has been disabled for this instance",
 108                   command);
 109        return NULL;
 110    }
 111    if (oob && !(cmd->options & QCO_ALLOW_OOB)) {
 112        error_setg(errp, "The command %s does not support OOB",
 113                   command);
 114        return NULL;
 115    }
 116
 117    if (runstate_check(RUN_STATE_PRECONFIG) &&
 118        !(cmd->options & QCO_ALLOW_PRECONFIG)) {
 119        error_setg(errp, "The command '%s' isn't permitted in '%s' state",
 120                   cmd->name, RunState_str(RUN_STATE_PRECONFIG));
 121        return NULL;
 122    }
 123
 124    if (!qdict_haskey(dict, "arguments")) {
 125        args = qdict_new();
 126    } else {
 127        args = qdict_get_qdict(dict, "arguments");
 128        qobject_ref(args);
 129    }
 130
 131    cmd->fn(args, &ret, &local_err);
 132    if (local_err) {
 133        error_propagate(errp, local_err);
 134    } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 135        g_assert(!ret);
 136    } else if (!ret) {
 137        /* TODO turn into assertion */
 138        ret = QOBJECT(qdict_new());
 139    }
 140
 141    qobject_unref(args);
 142
 143    return ret;
 144}
 145
 146QDict *qmp_error_response(Error *err)
 147{
 148    QDict *rsp;
 149
 150    rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }",
 151                                  QapiErrorClass_str(error_get_class(err)),
 152                                  error_get_pretty(err));
 153    error_free(err);
 154    return rsp;
 155}
 156
 157/*
 158 * Does @qdict look like a command to be run out-of-band?
 159 */
 160bool qmp_is_oob(const QDict *dict)
 161{
 162    return qdict_haskey(dict, "exec-oob")
 163        && !qdict_haskey(dict, "execute");
 164}
 165
 166QDict *qmp_dispatch(QmpCommandList *cmds, QObject *request,
 167                    bool allow_oob)
 168{
 169    Error *err = NULL;
 170    QDict *dict = qobject_to(QDict, request);
 171    QObject *ret, *id = dict ? qdict_get(dict, "id") : NULL;
 172    QDict *rsp;
 173
 174    ret = do_qmp_dispatch(cmds, request, allow_oob, &err);
 175    if (err) {
 176        rsp = qmp_error_response(err);
 177    } else if (ret) {
 178        rsp = qdict_new();
 179        qdict_put_obj(rsp, "return", ret);
 180    } else {
 181        /* Can only happen for commands with QCO_NO_SUCCESS_RESP */
 182        rsp = NULL;
 183    }
 184
 185    if (rsp && id) {
 186        qdict_put_obj(rsp, "id", qobject_ref(id));
 187    }
 188
 189    return rsp;
 190}
 191