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 "sysemu/runstate.h"
  20#include "qapi/qmp/qbool.h"
  21
  22static QDict *qmp_dispatch_check_obj(QDict *dict, 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
  30    for (ent = qdict_first(dict); ent;
  31         ent = qdict_next(dict, ent)) {
  32        arg_name = qdict_entry_key(ent);
  33        arg_obj = qdict_entry_value(ent);
  34
  35        if (!strcmp(arg_name, "execute")
  36            || (!strcmp(arg_name, "exec-oob") && allow_oob)) {
  37            if (qobject_type(arg_obj) != QTYPE_QSTRING) {
  38                error_setg(errp, "QMP input member '%s' must be a string",
  39                           arg_name);
  40                return NULL;
  41            }
  42            if (exec_key) {
  43                error_setg(errp, "QMP input member '%s' clashes with '%s'",
  44                           arg_name, exec_key);
  45                return NULL;
  46            }
  47            exec_key = arg_name;
  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 if (!strcmp(arg_name, "id")) {
  55            continue;
  56        } else {
  57            error_setg(errp, "QMP input member '%s' is unexpected",
  58                       arg_name);
  59            return NULL;
  60        }
  61    }
  62
  63    if (!exec_key) {
  64        error_setg(errp, "QMP input lacks member 'execute'");
  65        return NULL;
  66    }
  67
  68    return dict;
  69}
  70
  71QDict *qmp_error_response(Error *err)
  72{
  73    QDict *rsp;
  74
  75    rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }",
  76                                  QapiErrorClass_str(error_get_class(err)),
  77                                  error_get_pretty(err));
  78    error_free(err);
  79    return rsp;
  80}
  81
  82/*
  83 * Does @qdict look like a command to be run out-of-band?
  84 */
  85bool qmp_is_oob(const QDict *dict)
  86{
  87    return qdict_haskey(dict, "exec-oob")
  88        && !qdict_haskey(dict, "execute");
  89}
  90
  91QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request,
  92                    bool allow_oob)
  93{
  94    Error *err = NULL;
  95    bool oob;
  96    const char *command;
  97    QDict *args;
  98    const QmpCommand *cmd;
  99    QDict *dict;
 100    QObject *id;
 101    QObject *ret = NULL;
 102    QDict *rsp = NULL;
 103
 104    dict = qobject_to(QDict, request);
 105    if (!dict) {
 106        id = NULL;
 107        error_setg(&err, "QMP input must be a JSON object");
 108        goto out;
 109    }
 110
 111    id = qdict_get(dict, "id");
 112
 113    if (!qmp_dispatch_check_obj(dict, allow_oob, &err)) {
 114        goto out;
 115    }
 116
 117    command = qdict_get_try_str(dict, "execute");
 118    oob = false;
 119    if (!command) {
 120        assert(allow_oob);
 121        command = qdict_get_str(dict, "exec-oob");
 122        oob = true;
 123    }
 124    cmd = qmp_find_command(cmds, command);
 125    if (cmd == NULL) {
 126        error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND,
 127                  "The command %s has not been found", command);
 128        goto out;
 129    }
 130    if (!cmd->enabled) {
 131        error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND,
 132                  "The command %s has been disabled for this instance",
 133                  command);
 134        goto out;
 135    }
 136    if (oob && !(cmd->options & QCO_ALLOW_OOB)) {
 137        error_setg(&err, "The command %s does not support OOB",
 138                   command);
 139        goto out;
 140    }
 141
 142    if (runstate_check(RUN_STATE_PRECONFIG) &&
 143        !(cmd->options & QCO_ALLOW_PRECONFIG)) {
 144        error_setg(&err, "The command '%s' isn't permitted in '%s' state",
 145                   cmd->name, RunState_str(RUN_STATE_PRECONFIG));
 146        goto out;
 147    }
 148
 149    if (!qdict_haskey(dict, "arguments")) {
 150        args = qdict_new();
 151    } else {
 152        args = qdict_get_qdict(dict, "arguments");
 153        qobject_ref(args);
 154    }
 155    cmd->fn(args, &ret, &err);
 156    qobject_unref(args);
 157    if (err) {
 158        /* or assert(!ret) after reviewing all handlers: */
 159        qobject_unref(ret);
 160        goto out;
 161    }
 162
 163    if (cmd->options & QCO_NO_SUCCESS_RESP) {
 164        g_assert(!ret);
 165        return NULL;
 166    } else if (!ret) {
 167        /*
 168         * When the command's schema has no 'returns', cmd->fn()
 169         * leaves @ret null.  The QMP spec calls for an empty object
 170         * then; supply it.
 171         */
 172        ret = QOBJECT(qdict_new());
 173    }
 174
 175    rsp = qdict_new();
 176    qdict_put_obj(rsp, "return", ret);
 177
 178out:
 179    if (err) {
 180        assert(!rsp);
 181        rsp = qmp_error_response(err);
 182    }
 183
 184    assert(rsp);
 185
 186    if (id) {
 187        qdict_put_obj(rsp, "id", qobject_ref(id));
 188    }
 189
 190    return rsp;
 191}
 192