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
  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 {
  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
  76 static 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
 144 QDict *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  */
 158 bool qmp_is_oob(const QDict *dict)
 159 {
 160     return qdict_haskey(dict, "exec-oob")
 161         && !qdict_haskey(dict, "execute");
 162 }
 163
 164 QDict *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 }