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/json-parser.h"
  18#include "qapi/qmp/qdict.h"
  19#include "qapi/qmp/qjson.h"
  20#include "qapi/qmp/qbool.h"
  21#include "sysemu/sysemu.h"
  22
  23static QDict *qmp_dispatch_check_obj(const QObject *request, bool allow_oob,
  24                                     Error **errp)
  25{
  26    const char *exec_key = NULL;
  27    const QDictEntry *ent;
  28    const char *arg_name;
  29    const QObject *arg_obj;
  30    QDict *dict;
  31
  32    dict = qobject_to(QDict, request);
  33    if (!dict) {
  34        error_setg(errp, "QMP input must be a JSON object");
  35        return NULL;
  36    }
  37
  38    for (ent = qdict_first(dict); ent;
  39         ent = qdict_next(dict, ent)) {
  40        arg_name = qdict_entry_key(ent);
  41        arg_obj = qdict_entry_value(ent);
  42
  43        if (!strcmp(arg_name, "execute")
  44            || (!strcmp(arg_name, "exec-oob") && allow_oob)) {
  45            if (qobject_type(arg_obj) != QTYPE_QSTRING) {
  46                error_setg(errp, "QMP input member '%s' must be a string",
  47                           arg_name);
  48                return NULL;
  49            }
  50            if (exec_key) {
  51                error_setg(errp, "QMP input member '%s' clashes with '%s'",
  52                           arg_name, exec_key);
  53                return NULL;
  54            }
  55            exec_key = arg_name;
  56        } else if (!strcmp(arg_name, "arguments")) {
  57            if (qobject_type(arg_obj) != QTYPE_QDICT) {
  58                error_setg(errp,
  59                           "QMP input member 'arguments' must be an object");
  60                return NULL;
  61            }
  62        } else {
  63            error_setg(errp, "QMP input member '%s' is unexpected",
  64                       arg_name);
  65            return NULL;
  66        }
  67    }
  68
  69    if (!exec_key) {
  70        error_setg(errp, "QMP input lacks member 'execute'");
  71        return NULL;
  72    }
  73
  74    return dict;
  75}
  76
  77static QObject *do_qmp_dispatch(QmpCommandList *cmds, QObject *request,
  78                                bool allow_oob, Error **errp)
  79{
  80    Error *local_err = NULL;
  81    bool oob;
  82    const char *command;
  83    QDict *args, *dict;
  84    QmpCommand *cmd;
  85    QObject *ret = NULL;
  86
  87    dict = qmp_dispatch_check_obj(request, allow_oob, errp);
  88    if (!dict) {
  89        return NULL;
  90    }
  91
  92    command = qdict_get_try_str(dict, "execute");
  93    oob = false;
  94    if (!command) {
  95        assert(allow_oob);
  96        command = qdict_get_str(dict, "exec-oob");
  97        oob = true;
  98    }
  99    cmd = qmp_find_command(cmds, command);
 100    if (cmd == NULL) {
 101        error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
 102                  "The command %s has not been found", command);
 103        return NULL;
 104    }
 105    if (!cmd->enabled) {
 106        error_setg(errp, "The command %s has been disabled for this instance",
 107                   command);
 108        return NULL;
 109    }
 110    if (oob && !(cmd->options & QCO_ALLOW_OOB)) {
 111        error_setg(errp, "The command %s does not support OOB",
 112                   command);
 113        return false;
 114    }
 115
 116    if (runstate_check(RUN_STATE_PRECONFIG) &&
 117        !(cmd->options & QCO_ALLOW_PRECONFIG)) {
 118        error_setg(errp, "The command '%s' isn't permitted in '%s' state",
 119                   cmd->name, RunState_str(RUN_STATE_PRECONFIG));
 120        return NULL;
 121    }
 122
 123    if (!qdict_haskey(dict, "arguments")) {
 124        args = qdict_new();
 125    } else {
 126        args = qdict_get_qdict(dict, "arguments");
 127        qobject_ref(args);
 128    }
 129
 130    cmd->fn(args, &ret, &local_err);
 131    if (local_err) {
 132        error_propagate(errp, local_err);
 133    } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 134        g_assert(!ret);
 135    } else if (!ret) {
 136        /* TODO turn into assertion */
 137        ret = QOBJECT(qdict_new());
 138    }
 139
 140    qobject_unref(args);
 141
 142    return ret;
 143}
 144
 145QDict *qmp_error_response(Error *err)
 146{
 147    QDict *rsp;
 148
 149    rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }",
 150                                  QapiErrorClass_str(error_get_class(err)),
 151                                  error_get_pretty(err));
 152    error_free(err);
 153    return rsp;
 154}
 155
 156/*
 157 * Does @qdict look like a command to be run out-of-band?
 158 */
 159bool qmp_is_oob(QDict *dict)
 160{
 161    return qdict_haskey(dict, "exec-oob")
 162        && !qdict_haskey(dict, "execute");
 163}
 164
 165QDict *qmp_dispatch(QmpCommandList *cmds, QObject *request,
 166                    bool allow_oob)
 167{
 168    Error *err = NULL;
 169    QObject *ret;
 170    QDict *rsp;
 171
 172    ret = do_qmp_dispatch(cmds, request, allow_oob, &err);
 173
 174    if (err) {
 175        rsp = qmp_error_response(err);
 176    } else if (ret) {
 177        rsp = qdict_new();
 178        qdict_put_obj(rsp, "return", ret);
 179    } else {
 180        /* Can only happen for commands with QCO_NO_SUCCESS_RESP */
 181        rsp = NULL;
 182    }
 183
 184    return rsp;
 185}
 186