Re: [Qemu-devel] [PATCH 1/3] qapi: Allow QMP/QAPI commands to have array inputs

[Anthony Liguori <anthony@codemonkey.ws>]

On 02/22/2012 10:12 AM, Jeff Cody wrote:
> On 02/22/2012 09:53 AM, Anthony Liguori wrote:
>> On 02/20/2012 11:31 AM, Jeff Cody wrote:
>>> The QAPI scripts allow for generating commands that receive parameter
>>> input consisting of a list of custom structs, but the QMP input paramter
>>> checking did not support receiving a qlist as opposed to a qdict for
>>> input.
>>
>> What are you trying to send on the wire? Something like
>>
>> {"execute": "foo", "arguments": [ "a", "b", "c" ]}
>>
>> ?
>>
>> That's not valid per the QMP protocol. "arguments" must always be a QMP
>> dictionary.
>>
>
> Not a bare list like that (perhaps my wording was poor), but rather an array of
> custom structs, that contain QMP dicts. In this particular case:
>
> {"execute": "blockdev-group-snapshot-sync", "arguments": [{ "device":
> "ide-hd0","snapshot-file":"/some/place/my-image","format": "qcow2" }]}
>
> When specifying this in the schema JSON file as shown below[1], the QAPI scripts
> generate the marshaller & visitor functions that handle everything correctly.
> The monitor code, however, could not deal with the QList container for the input
> parameters, prior to passing the data to the generated functions.
>
>
> [1] JSON schema definition:
>
> { 'type': 'SnapshotDev',
> 'data': {'device': 'str', 'snapshot-file': 'str', '*format': 'str' } }
>
> { 'command': 'blockdev-group-snapshot-sync',
> 'data': { 'dev': [ 'SnapshotDev' ] } }


This will end up looking like:

{ "execute": "blockdev-group-snapshot-sync",
   "arguments": { "dev": [{"device": "ide-hd0"....}] } }

Which should work as expected in QMP.  HMP argument validation doesn't handle 
arguments of lists but IMHO, it's time to kill that code.

Luiz, what do you think?

Regards,

Anthony Liguori

>
>
>
>>>
>>> This patch allows for array input parameters, although no argument
>>> validation
>>> is performed for commands that accept a list input.
>>>
>>> Signed-off-by: Jeff Cody<jcody@redhat.com>
>>> ---
>>> monitor.c | 72
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++----------
>>> monitor.h | 1 +
>>> 2 files changed, 61 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/monitor.c b/monitor.c
>>> index a7df995..98e6017 100644
>>> --- a/monitor.c
>>> +++ b/monitor.c
>>> @@ -125,8 +125,12 @@ typedef struct mon_cmd_t {
>>> void (*info)(Monitor *mon);
>>> void (*cmd)(Monitor *mon, const QDict *qdict);
>>> int (*cmd_new)(Monitor *mon, const QDict *params, QObject **ret_data);
>>> + int (*cmd_new_list)(Monitor *mon, const QList *params,
>>> + QObject **ret_data);
>>> int (*cmd_async)(Monitor *mon, const QDict *params,
>>> MonitorCompletion *cb, void *opaque);
>>> + int (*cmd_async_list)(Monitor *mon, const QList *params,
>>> + MonitorCompletion *cb, void *opaque);
>>> } mhandler;
>>> bool qapi;
>>> int flags;
>>> @@ -353,6 +357,11 @@ static inline bool handler_is_async(const
>>> mon_cmd_t *cmd)
>>> return cmd->flags& MONITOR_CMD_ASYNC;
>>> }
>>>
>>> +static inline bool handler_accepts_array(const mon_cmd_t *cmd)
>>> +{
>>> + return cmd->flags& MONITOR_CMD_ARRAY_INPUT;
>>> +}
>>> +
>>> static inline int monitor_has_error(const Monitor *mon)
>>> {
>>> return mon->error != NULL;
>>> @@ -671,6 +680,12 @@ static int qmp_async_cmd_handler(Monitor *mon,
>>> const mon_cmd_t *cmd,
>>> return cmd->mhandler.cmd_async(mon, params, qmp_monitor_complete, mon);
>>> }
>>>
>>> +static int qmp_async_cmd_handler_array(Monitor *mon, const mon_cmd_t
>>> *cmd,
>>> + const QList *params)
>>> +{
>>> + return cmd->mhandler.cmd_async_list(mon, params,
>>> qmp_monitor_complete, mon);
>>> +}
>>> +
>>> static void user_async_cmd_handler(Monitor *mon, const mon_cmd_t *cmd,
>>> const QDict *params)
>>> {
>>> @@ -4310,7 +4325,8 @@ static QDict *qmp_check_input_obj(QObject
>>> *input_obj)
>>> }
>>> has_exec_key = 1;
>>> } else if (!strcmp(arg_name, "arguments")) {
>>> - if (qobject_type(arg_obj) != QTYPE_QDICT) {
>>> + if ((qobject_type(arg_obj) != QTYPE_QDICT)&&
>>> + (qobject_type(arg_obj) != QTYPE_QLIST)) {
>>> qerror_report(QERR_QMP_BAD_INPUT_OBJECT_MEMBER, "arguments",
>>> "object");
>>> return NULL;
>>> @@ -4345,11 +4361,26 @@ static void qmp_call_cmd(Monitor *mon, const
>>> mon_cmd_t *cmd,
>>> qobject_decref(data);
>>> }
>>>
>>> +static void qmp_call_cmd_array(Monitor *mon, const mon_cmd_t *cmd,
>>> + const QList *params)
>>> +{
>>> + int ret;
>>> + QObject *data = NULL;
>>> +
>>> + mon_print_count_init(mon);
>>> +
>>> + ret = cmd->mhandler.cmd_new_list(mon, params,&data);
>>> + handler_audit(mon, cmd, ret);
>>> + monitor_protocol_emitter(mon, data);
>>> + qobject_decref(data);
>>> +}
>>> +
>>> static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
>>> {
>>> int err;
>>> QObject *obj;
>>> QDict *input, *args;
>>> + QList *args_list = NULL;
>>> const mon_cmd_t *cmd;
>>> const char *cmd_name;
>>> Monitor *mon = cur_mon;
>>> @@ -4386,26 +4417,42 @@ static void
>>> handle_qmp_command(JSONMessageParser *parser, QList *tokens)
>>> }
>>>
>>> obj = qdict_get(input, "arguments");
>>> - if (!obj) {
>>> - args = qdict_new();
>>> + if (handler_accepts_array(cmd)) {
>>> + if (!obj || (qobject_type(obj) != QTYPE_QLIST)) {
>>> + args_list = qlist_new();
>>> + } else {
>>> + args_list = qobject_to_qlist(obj);
>>> + QINCREF(args_list);
>>> + }
>>> } else {
>>> - args = qobject_to_qdict(obj);
>>> - QINCREF(args);
>>> - }
>>> -
>>> - err = qmp_check_client_args(cmd, args);
>>> - if (err< 0) {
>>> - goto err_out;
>>> + if (!obj || (qobject_type(obj) != QTYPE_QDICT)) {
>>> + args = qdict_new();
>>> + } else {
>>> + args = qobject_to_qdict(obj);
>>> + QINCREF(args);
>>> + }
>>> + err = qmp_check_client_args(cmd, args);
>>> + if (err< 0) {
>>> + goto err_out;
>>> + }
>>> }
>>>
>>> if (handler_is_async(cmd)) {
>>> - err = qmp_async_cmd_handler(mon, cmd, args);
>>> + if (handler_accepts_array(cmd)) {
>>> + err = qmp_async_cmd_handler_array(mon, cmd, args_list);
>>> + } else {
>>> + err = qmp_async_cmd_handler(mon, cmd, args);
>>> + }
>>> if (err) {
>>> /* emit the error response */
>>> goto err_out;
>>> }
>>> } else {
>>> - qmp_call_cmd(mon, cmd, args);
>>> + if (handler_accepts_array(cmd)) {
>>> + qmp_call_cmd_array(mon, cmd, args_list);
>>> + } else {
>>> + qmp_call_cmd(mon, cmd, args);
>>> + }
>>> }
>>>
>>> goto out;
>>> @@ -4415,6 +4462,7 @@ err_out:
>>> out:
>>> QDECREF(input);
>>> QDECREF(args);
>>> + QDECREF(args_list);
>>> }
>>>
>>> /**
>>> diff --git a/monitor.h b/monitor.h
>>> index b72ea07..499fc1f 100644
>>> --- a/monitor.h
>>> +++ b/monitor.h
>>> @@ -19,6 +19,7 @@ extern Monitor *default_mon;
>>>
>>> /* flags for monitor commands */
>>> #define MONITOR_CMD_ASYNC 0x0001
>>> +#define MONITOR_CMD_ARRAY_INPUT 0x0002
>>>
>>> /* QMP events */
>>> typedef enum MonitorEvent {
>>
>