/* * Core Definitions for QAPI/QMP Dispatch * * Copyright IBM, Corp. 2011 * * Authors: * Anthony Liguori <aliguori@us.ibm.com> * * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. * See the COPYING.LIB file in the top-level directory. * */ #include "qemu/osdep.h" #include "block/aio.h" #include "qapi/compat-policy.h" #include "qapi/error.h" #include "qapi/qmp/dispatch.h" #include "qapi/qmp/qdict.h" #include "qapi/qmp/qjson.h" #include "qapi/qobject-input-visitor.h" #include "qapi/qobject-output-visitor.h" #include "qapi/qmp/qbool.h" #include "qemu/coroutine.h" #include "qemu/main-loop.h" Visitor *qobject_input_visitor_new_qmp(QObject *obj) { Visitor *v = qobject_input_visitor_new(obj); visit_set_policy(v, &compat_policy); return v; } Visitor *qobject_output_visitor_new_qmp(QObject **result) { Visitor *v = qobject_output_visitor_new(result); visit_set_policy(v, &compat_policy); return v; } static QDict *qmp_dispatch_check_obj(QDict *dict, bool allow_oob, Error **errp) { const char *exec_key = NULL; const QDictEntry *ent; const char *arg_name; const QObject *arg_obj; for (ent = qdict_first(dict); ent; ent = qdict_next(dict, ent)) { arg_name = qdict_entry_key(ent); arg_obj = qdict_entry_value(ent); if (!strcmp(arg_name, "execute") || (!strcmp(arg_name, "exec-oob") && allow_oob)) { if (qobject_type(arg_obj) != QTYPE_QSTRING) { error_setg(errp, "QMP input member '%s' must be a string", arg_name); return NULL; } if (exec_key) { error_setg(errp, "QMP input member '%s' clashes with '%s'", arg_name, exec_key); return NULL; } exec_key = arg_name; } else if (!strcmp(arg_name, "arguments")) { if (qobject_type(arg_obj) != QTYPE_QDICT) { error_setg(errp, "QMP input member 'arguments' must be an object"); return NULL; } } else if (!strcmp(arg_name, "id")) { continue; } else { error_setg(errp, "QMP input member '%s' is unexpected", arg_name); return NULL; } } if (!exec_key) { error_setg(errp, "QMP input lacks member 'execute'"); return NULL; } return dict; } QDict *qmp_error_response(Error *err) { QDict *rsp; rsp = qdict_from_jsonf_nofail("{ 'error': { 'class': %s, 'desc': %s } }", QapiErrorClass_str(error_get_class(err)), error_get_pretty(err)); error_free(err); return rsp; } /* * Does @qdict look like a command to be run out-of-band? */ bool qmp_is_oob(const QDict *dict) { return qdict_haskey(dict, "exec-oob") && !qdict_haskey(dict, "execute"); } typedef struct QmpDispatchBH { const QmpCommand *cmd; Monitor *cur_mon; QDict *args; QObject **ret; Error **errp; Coroutine *co; } QmpDispatchBH; static void do_qmp_dispatch_bh(void *opaque) { QmpDispatchBH *data = opaque; assert(monitor_cur() == NULL); monitor_set_cur(qemu_coroutine_self(), data->cur_mon); data->cmd->fn(data->args, data->ret, data->errp); monitor_set_cur(qemu_coroutine_self(), NULL); aio_co_wake(data->co); } /* * Runs outside of coroutine context for OOB commands, but in coroutine * context for everything else. */ QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request, bool allow_oob, Monitor *cur_mon) { Error *err = NULL; bool oob; const char *command; QDict *args; const QmpCommand *cmd; QDict *dict; QObject *id; QObject *ret = NULL; QDict *rsp = NULL; dict = qobject_to(QDict, request); if (!dict) { id = NULL; error_setg(&err, "QMP input must be a JSON object"); goto out; } id = qdict_get(dict, "id"); if (!qmp_dispatch_check_obj(dict, allow_oob, &err)) { goto out; } command = qdict_get_try_str(dict, "execute"); oob = false; if (!command) { assert(allow_oob); command = qdict_get_str(dict, "exec-oob"); oob = true; } cmd = qmp_find_command(cmds, command); if (cmd == NULL) { error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND, "The command %s has not been found", command); goto out; } if (!compat_policy_input_ok(cmd->special_features, &compat_policy, ERROR_CLASS_COMMAND_NOT_FOUND, "command", command, &err)) { goto out; } if (!cmd->enabled) { error_set(&err, ERROR_CLASS_COMMAND_NOT_FOUND, "Command %s has been disabled%s%s", command, cmd->disable_reason ? ": " : "", cmd->disable_reason ?: ""); goto out; } if (oob && !(cmd->options & QCO_ALLOW_OOB)) { error_setg(&err, "The command %s does not support OOB", command); goto out; } if (!qmp_command_available(cmd, &err)) { goto out; } if (!qdict_haskey(dict, "arguments")) { args = qdict_new(); } else { args = qdict_get_qdict(dict, "arguments"); qobject_ref(args); } assert(!(oob && qemu_in_coroutine())); assert(monitor_cur() == NULL); if (!!(cmd->options & QCO_COROUTINE) == qemu_in_coroutine()) { monitor_set_cur(qemu_coroutine_self(), cur_mon); cmd->fn(args, &ret, &err); monitor_set_cur(qemu_coroutine_self(), NULL); } else { /* * Actual context doesn't match the one the command needs. * * Case 1: we are in coroutine context, but command does not * have QCO_COROUTINE. We need to drop out of coroutine * context for executing it. * * Case 2: we are outside coroutine context, but command has * QCO_COROUTINE. Can't actually happen, because we get here * outside coroutine context only when executing a command * out of band, and OOB commands never have QCO_COROUTINE. */ assert(!oob && qemu_in_coroutine() && !(cmd->options & QCO_COROUTINE)); QmpDispatchBH data = { .cur_mon = cur_mon, .cmd = cmd, .args = args, .ret = &ret, .errp = &err, .co = qemu_coroutine_self(), }; aio_bh_schedule_oneshot(qemu_get_aio_context(), do_qmp_dispatch_bh, &data); qemu_coroutine_yield(); } qobject_unref(args); if (err) { /* or assert(!ret) after reviewing all handlers: */ qobject_unref(ret); goto out; } if (cmd->options & QCO_NO_SUCCESS_RESP) { g_assert(!ret); return NULL; } else if (!ret) { /* * When the command's schema has no 'returns', cmd->fn() * leaves @ret null. The QMP spec calls for an empty object * then; supply it. */ ret = QOBJECT(qdict_new()); } rsp = qdict_new(); qdict_put_obj(rsp, "return", ret); out: if (err) { assert(!rsp); rsp = qmp_error_response(err); } assert(rsp); if (id) { qdict_put_obj(rsp, "id", qobject_ref(id)); } return rsp; }