Re: [Qemu-devel] [PATCH v5 17/20] monitor: use qmp_dispatch()

[Marc-André Lureau]

Hi

----- Original Message -----
> Replace the old manual dispatch and validation code by the generic one
> provided by qapi common code.
> 
> Note that it is now possible to call the following commands that used to
> be disabled by compile-time conditionals:
> - dump-skeys
> - query-spice
> - rtc-reset-reinjection
> - query-gic-capabilities
> 
> Their fallback functions return an appropriate "feature disabled" error.

This is no longer valid, I dropped that comment.

> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  monitor.c    | 326
>  +++++++----------------------------------------------------
>  trace-events |   1 -
>  2 files changed, 34 insertions(+), 293 deletions(-)
> 
> diff --git a/monitor.c b/monitor.c
> index f07fc31..81926c7 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -166,7 +166,6 @@ struct MonFdset {
>  };
>  
>  typedef struct {
> -    QObject *id;
>      JSONMessageParser parser;
>      /*
>       * When a client connects, we're in capabilities negotiation mode.
> @@ -229,8 +228,6 @@ static int mon_refcount;
>  static mon_cmd_t mon_cmds[];
>  static mon_cmd_t info_cmds[];
>  
> -static const mon_cmd_t qmp_cmds[];
> -
>  Monitor *cur_mon;
>  
>  static QEMUClockType event_clock_type = QEMU_CLOCK_REALTIME;
> @@ -401,49 +398,6 @@ static void monitor_json_emitter(Monitor *mon, const
> QObject *data)
>      QDECREF(json);
>  }
>  
> -static QDict *build_qmp_error_dict(Error *err)
> -{
> -    QObject *obj;
> -
> -    obj = qobject_from_jsonf("{ 'error': { 'class': %s, 'desc': %s } }",
> -                             QapiErrorClass_lookup[error_get_class(err)],
> -                             error_get_pretty(err));
> -
> -    return qobject_to_qdict(obj);
> -}
> -
> -static void monitor_protocol_emitter(Monitor *mon, QObject *data,
> -                                     Error *err)
> -{
> -    QDict *qmp;
> -
> -    trace_monitor_protocol_emitter(mon);
> -
> -    if (!err) {
> -        /* success response */
> -        qmp = qdict_new();
> -        if (data) {
> -            qobject_incref(data);
> -            qdict_put_obj(qmp, "return", data);
> -        } else {
> -            /* return an empty QDict by default */
> -            qdict_put(qmp, "return", qdict_new());
> -        }
> -    } else {
> -        /* error response */
> -        qmp = build_qmp_error_dict(err);
> -    }
> -
> -    if (mon->qmp.id) {
> -        qdict_put_obj(qmp, "id", mon->qmp.id);
> -        mon->qmp.id = NULL;
> -    }
> -
> -    monitor_json_emitter(mon, QOBJECT(qmp));
> -    QDECREF(qmp);
> -}
> -
> -
>  static MonitorQAPIEventConf monitor_qapi_event_conf[QAPI_EVENT__MAX] = {
>      /* Limit guest-triggerable events to 1 per second */
>      [QAPI_EVENT_RTC_CHANGE]        = { 1000 * SCALE_MS },
> @@ -2180,11 +2134,6 @@ static mon_cmd_t mon_cmds[] = {
>      { NULL, NULL, },
>  };
>  
> -static const mon_cmd_t qmp_cmds[] = {
> -#include "qmp-commands-old.h"
> -    { /* NULL */ },
> -};
> -
>  /*******************************************************************/
>  
>  static const char *pch;
> @@ -2535,11 +2484,6 @@ static const mon_cmd_t *search_dispatch_table(const
> mon_cmd_t *disp_table,
>      return NULL;
>  }
>  
> -static const mon_cmd_t *qmp_find_cmd(const char *cmdname)
> -{
> -    return search_dispatch_table(qmp_cmds, cmdname);
> -}
> -
>  /*
>   * Parse command name from @cmdp according to command table @table.
>   * If blank, return NULL.
> @@ -3690,199 +3634,6 @@ static bool invalid_qmp_mode(const Monitor *mon,
> const char *cmd,
>      return false;
>  }
>  
> -/*
> - * Argument validation rules:
> - *
> - * 1. The argument must exist in cmd_args qdict
> - * 2. The argument type must be the expected one
> - *
> - * Special case: If the argument doesn't exist in cmd_args and
> - *               the QMP_ACCEPT_UNKNOWNS flag is set, then the
> - *               checking is skipped for it.
> - */
> -static void check_client_args_type(const QDict *client_args,
> -                                   const QDict *cmd_args, int flags,
> -                                   Error **errp)
> -{
> -    const QDictEntry *ent;
> -
> -    for (ent = qdict_first(client_args); ent;ent =
> qdict_next(client_args,ent)){
> -        QObject *obj;
> -        QString *arg_type;
> -        const QObject *client_arg = qdict_entry_value(ent);
> -        const char *client_arg_name = qdict_entry_key(ent);
> -
> -        obj = qdict_get(cmd_args, client_arg_name);
> -        if (!obj) {
> -            if (flags & QMP_ACCEPT_UNKNOWNS) {
> -                /* handler accepts unknowns */
> -                continue;
> -            }
> -            /* client arg doesn't exist */
> -            error_setg(errp, QERR_INVALID_PARAMETER, client_arg_name);
> -            return;
> -        }
> -
> -        arg_type = qobject_to_qstring(obj);
> -        assert(arg_type != NULL);
> -
> -        /* check if argument's type is correct */
> -        switch (qstring_get_str(arg_type)[0]) {
> -        case 'F':
> -        case 'B':
> -        case 's':
> -            if (qobject_type(client_arg) != QTYPE_QSTRING) {
> -                error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
> -                           client_arg_name, "string");
> -                return;
> -            }
> -        break;
> -        case 'i':
> -        case 'l':
> -        case 'M':
> -        case 'o':
> -            if (qobject_type(client_arg) != QTYPE_QINT) {
> -                error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
> -                           client_arg_name, "int");
> -                return;
> -            }
> -            break;
> -        case 'T':
> -            if (qobject_type(client_arg) != QTYPE_QINT &&
> -                qobject_type(client_arg) != QTYPE_QFLOAT) {
> -                error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
> -                           client_arg_name, "number");
> -                return;
> -            }
> -            break;
> -        case 'b':
> -        case '-':
> -            if (qobject_type(client_arg) != QTYPE_QBOOL) {
> -                error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
> -                           client_arg_name, "bool");
> -                return;
> -            }
> -            break;
> -        case 'O':
> -            assert(flags & QMP_ACCEPT_UNKNOWNS);
> -            break;
> -        case 'q':
> -            /* Any QObject can be passed.  */
> -            break;
> -        case '/':
> -        case '.':
> -            /*
> -             * These types are not supported by QMP and thus are not
> -             * handled here. Fall through.
> -             */
> -        default:
> -            abort();
> -        }
> -    }
> -}
> -
> -/*
> - * - Check if the client has passed all mandatory args
> - * - Set special flags for argument validation
> - */
> -static void check_mandatory_args(const QDict *cmd_args,
> -                                 const QDict *client_args, int *flags,
> -                                 Error **errp)
> -{
> -    const QDictEntry *ent;
> -
> -    for (ent = qdict_first(cmd_args); ent; ent = qdict_next(cmd_args, ent))
> {
> -        const char *cmd_arg_name = qdict_entry_key(ent);
> -        QString *type = qobject_to_qstring(qdict_entry_value(ent));
> -        assert(type != NULL);
> -
> -        if (qstring_get_str(type)[0] == 'O') {
> -            assert((*flags & QMP_ACCEPT_UNKNOWNS) == 0);
> -            *flags |= QMP_ACCEPT_UNKNOWNS;
> -        } else if (qstring_get_str(type)[0] != '-' &&
> -                   qstring_get_str(type)[1] != '?' &&
> -                   !qdict_haskey(client_args, cmd_arg_name)) {
> -            error_setg(errp, QERR_MISSING_PARAMETER, cmd_arg_name);
> -            return;
> -        }
> -    }
> -}
> -
> -static QDict *qdict_from_args_type(const char *args_type)
> -{
> -    int i;
> -    QDict *qdict;
> -    QString *key, *type, *cur_qs;
> -
> -    assert(args_type != NULL);
> -
> -    qdict = qdict_new();
> -
> -    if (args_type == NULL || args_type[0] == '\0') {
> -        /* no args, empty qdict */
> -        goto out;
> -    }
> -
> -    key = qstring_new();
> -    type = qstring_new();
> -
> -    cur_qs = key;
> -
> -    for (i = 0;; i++) {
> -        switch (args_type[i]) {
> -            case ',':
> -            case '\0':
> -                qdict_put(qdict, qstring_get_str(key), type);
> -                QDECREF(key);
> -                if (args_type[i] == '\0') {
> -                    goto out;
> -                }
> -                type = qstring_new(); /* qdict has ref */
> -                cur_qs = key = qstring_new();
> -                break;
> -            case ':':
> -                cur_qs = type;
> -                break;
> -            default:
> -                qstring_append_chr(cur_qs, args_type[i]);
> -                break;
> -        }
> -    }
> -
> -out:
> -    return qdict;
> -}
> -
> -/*
> - * Client argument checking rules:
> - *
> - * 1. Client must provide all mandatory arguments
> - * 2. Each argument provided by the client must be expected
> - * 3. Each argument provided by the client must have the type expected
> - *    by the command
> - */
> -static void qmp_check_client_args(const mon_cmd_t *cmd, QDict *client_args,
> -                                  Error **errp)
> -{
> -    Error *err = NULL;
> -    int flags;
> -    QDict *cmd_args;
> -
> -    cmd_args = qdict_from_args_type(cmd->args_type);
> -
> -    flags = 0;
> -    check_mandatory_args(cmd_args, client_args, &flags, &err);
> -    if (err) {
> -        goto out;
> -    }
> -
> -    check_client_args_type(client_args, cmd_args, flags, &err);
> -
> -out:
> -    error_propagate(errp, err);
> -    QDECREF(cmd_args);
> -}
> -
>  /*
>   * Input object checking rules
>   *
> @@ -3941,67 +3692,58 @@ static QDict *qmp_check_input_obj(QObject *input_obj,
> Error **errp)
>  
>  static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens)
>  {
> -    Error *local_err = NULL;
> -    QObject *obj, *data;
> -    QDict *input, *args;
> -    const mon_cmd_t *cmd;
> -    QmpCommand *qcmd;
> +    QObject *req, *rsp = NULL, *id = NULL;
> +    QDict *qdict = NULL;
>      const char *cmd_name;
>      Monitor *mon = cur_mon;
> +    Error *err = NULL;
>  
> -    args = input = NULL;
> -    data = NULL;
> -
> -    obj = json_parser_parse(tokens, NULL);
> -    if (!obj) {
> -        // FIXME: should be triggered in json_parser_parse()
> -        error_setg(&local_err, QERR_JSON_PARSING);
> +    req = json_parser_parse_err(tokens, NULL, &err);
> +    if (err || !req || qobject_type(req) != QTYPE_QDICT) {
> +        if (!err) {
> +            error_setg(&err, QERR_JSON_PARSING);
> +        }
>          goto err_out;
>      }
>  
> -    input = qmp_check_input_obj(obj, &local_err);
> -    if (!input) {
> -        qobject_decref(obj);
> +    qdict = qmp_check_input_obj(req, &err);
> +    if (!qdict) {
>          goto err_out;
>      }
>  
> -    mon->qmp.id = qdict_get(input, "id");
> -    qobject_incref(mon->qmp.id);
> +    id = qdict_get(qdict, "id");
> +    qobject_incref(id);
> +    qdict_del(qdict, "id");
>  
> -    cmd_name = qdict_get_str(input, "execute");
> +    cmd_name = qdict_get_str(qdict, "execute");
>      trace_handle_qmp_command(mon, cmd_name);
> -    cmd = qmp_find_cmd(cmd_name);
> -    qcmd = qmp_find_command(cmd_name);
> -    if (!qcmd || !cmd) {
> -        error_set(&local_err, ERROR_CLASS_COMMAND_NOT_FOUND,
> -                  "The command %s has not been found", cmd_name);
> -        goto err_out;
> -    }
> -    if (invalid_qmp_mode(mon, cmd_name, &local_err)) {
> +
> +    if (invalid_qmp_mode(mon, cmd_name, &err)) {
>          goto err_out;
>      }
>  
> -    obj = qdict_get(input, "arguments");
> -    if (!obj) {
> -        args = qdict_new();
> -    } else {
> -        args = qobject_to_qdict(obj);
> -        QINCREF(args);
> -    }
> +    rsp = qmp_dispatch(req);
>  
> -    qmp_check_client_args(cmd, args, &local_err);
> -    if (local_err) {
> -        goto err_out;
> +err_out:
> +    if (err) {
> +        qdict = qdict_new();
> +        qdict_put_obj(qdict, "error", qmp_build_error_object(err));
> +        error_free(err);
> +        rsp = QOBJECT(qdict);
>      }
>  
> -    qcmd->fn(args, &data, &local_err);
> +    if (rsp) {
> +        if (id) {
> +            qdict_put_obj(qobject_to_qdict(rsp), "id", id);
> +            id = NULL;
> +        }
>  
> -err_out:
> -    monitor_protocol_emitter(mon, data, local_err);
> -    qobject_decref(data);
> -    error_free(local_err);
> -    QDECREF(input);
> -    QDECREF(args);
> +        monitor_json_emitter(mon, rsp);
> +    }
> +
> +    qobject_decref(id);
> +    qobject_decref(rsp);
> +    qobject_decref(req);
>  }
>  
>  static void monitor_qmp_read(void *opaque, const uint8_t *buf, int size)
> diff --git a/trace-events b/trace-events
> index 616cc52..8d59631 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -98,7 +98,6 @@ qemu_co_mutex_unlock_return(void *mutex, void *self) "mutex
> %p self %p"
>  
>  # monitor.c
>  handle_qmp_command(void *mon, const char *cmd_name) "mon %p cmd_name \"%s\""
> -monitor_protocol_emitter(void *mon) "mon %p"
>  monitor_protocol_event_handler(uint32_t event, void *qdict) "event=%d
>  data=%p"
>  monitor_protocol_event_emit(uint32_t event, void *data) "event=%d data=%p"
>  monitor_protocol_event_queue(uint32_t event, void *qdict, uint64_t rate)
>  "event=%d data=%p rate=%" PRId64
> --
> 2.9.0
> 
>