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 {
  62            error_setg(errp, "QMP input member '%s' is unexpected",
  63                       arg_name);
  64            return NULL;
  65        }
  66    }
  67
  68    if (!exec_key) {
  69        error_setg(errp, "QMP input lacks member 'execute'");
  70        return NULL;
  71    }
  72
  73    return dict;
  74}
  75
  76static QObject *do_qmp_dispatch(QmpCommandList *cmds, QObject *request,
  77                                bool allow_oob, Error **errp)
  78{
  79    Error *local_err = NULL;
  80    bool oob;
  81    const char *command;
  82    QDict *args, *dict;
  83    QmpCommand *cmd;
  84    QObject *ret = NULL;
  85
  86    dict = qmp_dispatch_check_obj(request, allow_oob, errp);
  87    if (!dict) {
  88        return NULL;
  89    }
  90
  91    command = qdict_get_try_str(dict, "execute");
  92    oob = false;
  93    if (!command) {
  94        assert(allow_oob);
  95        command = qdict_get_str(dict, "exec-oob");
  96        oob = true;
  97    }
  98    cmd = qmp_find_command(cmds, command);
  99    if (cmd == NULL) {
 100        error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
 101                  "The command %s has not been found", command);
 102        return NULL;
 103    }
 104    if (!cmd->enabled) {
 105        error_setg(errp, "The command %s has been disabled for this instance",
 106                   command);
 107        return NULL;
 108    }
 109    if (oob && !(cmd->options & QCO_ALLOW_OOB)) {
 110        error_setg(errp, "The command %s does not support OOB",
 111                   command);
 112        return false;
 113    }
 114
 115    if (runstate_check(RUN_STATE_PRECONFIG) &&
 116        !(cmd->options & QCO_ALLOW_PRECONFIG)) {
 117        error_setg(errp, "The command '%s' isn't permitted in '%s' state",
 118                   cmd->name, RunState_str(RUN_STATE_PRECONFIG));
 119        return NULL;
 120    }
 121
 122    if (!qdict_haskey(dict, "arguments")) {
 123        args = qdict_new();
 124    } else {
 125        args = qdict_get_qdict(dict, "arguments");
 126        qobject_ref(args);
 127    }
 128
 129    cmd->fn(args, &ret, &local_err);
 130    if (local_err) {
 131        error_propagate(errp, local_err);
 132    } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
 133        g_assert(!ret);
 134    } else if (!ret) {
 135        /* TODO turn into assertion */
 136        ret = QOBJECT(qdict_new());
 137    }
 138
 139    qobject_unref(args);
 140
 141    return ret;
 142}
 143
 144QDict *qmp_error_response(Error *err)
 145{
 146    QDict *rsp;
 147
 148    rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }",
 149                                  QapiErrorClass_str(error_get_class(err)),
 150                                  error_get_pretty(err));
 151    error_free(err);
 152    return rsp;
 153}
 154
 155/*
 156 * Does @qdict look like a command to be run out-of-band?
 157 */
 158bool qmp_is_oob(const QDict *dict)
 159{
 160    return qdict_haskey(dict, "exec-oob")
 161        && !qdict_haskey(dict, "execute");
 162}
 163
 164QDict *qmp_dispatch(QmpCommandList *cmds, QObject *request,
 165                    bool allow_oob)
 166{
 167    Error *err = NULL;
 168    QObject *ret;
 169    QDict *rsp;
 170
 171    ret = do_qmp_dispatch(cmds, request, allow_oob, &err);
 172
 173    if (err) {
 174        rsp = qmp_error_response(err);
 175    } else if (ret) {
 176        rsp = qdict_new();
 177        qdict_put_obj(rsp, "return", ret);
 178    } else {
 179        /* Can only happen for commands with QCO_NO_SUCCESS_RESP */
 180        rsp = NULL;
 181    }
 182
 183    return rsp;
 184}
 185