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
  23 static 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
  77 static 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
 145 QDict *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  */
 159 bool qmp_is_oob(QDict *dict)
 160 {
 161     return qdict_haskey(dict, "exec-oob")
 162         && !qdict_haskey(dict, "execute");
 163 }
 164
 165 QDict *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 }