tests: Clean up around qmp() and hmp()

[Qemu-devel] [PATCH 2/9] qtest: Document calling conventions

Posted by Markus Armbruster 8 years, 3 months ago

From: Eric Blake <eblake@redhat.com>

We have two flavors of vararg usage in qtest; make it clear that
qmp() has different semantics than hmp(), and let the compiler
enforce that hmp() is used correctly. However, qmp() (and friends)
only accept a subset of printf flags look-alikes (namely, those
that our JSON parser understands), and what is worse, qmp("true")
(the JSON keyword 'true') is different from qmp("%s", "true")
(the JSON string '"true"'), so marking those as printf-like would
produce more harm from bogus warnings than it helps (we may have
made a mistake in previously marking qobject_from_jsonf(), but
this patch is not addressing that).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170720214008.28494-5-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 tests/libqtest.h | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/tests/libqtest.h b/tests/libqtest.h
index 38bc1e9..ae57282 100644
--- a/tests/libqtest.h
+++ b/tests/libqtest.h
@@ -50,7 +50,8 @@ void qtest_quit(QTestState *s);
 /**
  * qtest_qmp_discard_response:
  * @s: #QTestState instance to operate on.
- * @fmt...: QMP message to send to qemu
+ * @fmt...: QMP message to send to qemu; formats arguments through
+ * json-lexer.c (only understands '%((l|ll|I64)?d|[ipsf])').
  *
  * Sends a QMP message to QEMU and consumes the response.
  */
@@ -59,7 +60,8 @@ void qtest_qmp_discard_response(QTestState *s, const char *fmt, ...);
 /**
  * qtest_qmp:
  * @s: #QTestState instance to operate on.
- * @fmt...: QMP message to send to qemu
+ * @fmt...: QMP message to send to qemu; formats arguments through
+ * json-lexer.c (only understands '%((l|ll|I64)?d|[ipsf])').
  *
  * Sends a QMP message to QEMU and returns the response.
  */
@@ -68,7 +70,8 @@ QDict *qtest_qmp(QTestState *s, const char *fmt, ...);
 /**
  * qtest_async_qmp:
  * @s: #QTestState instance to operate on.
- * @fmt...: QMP message to send to qemu
+ * @fmt...: QMP message to send to qemu; formats arguments through
+ * json-lexer.c (only understands '%((l|ll|I64)?d|[ipsf])').
  *
  * Sends a QMP message to QEMU and leaves the response in the stream.
  */
@@ -134,7 +137,7 @@ QDict *qtest_qmp_eventwait_ref(QTestState *s, const char *event);
 /**
  * qtest_hmp:
  * @s: #QTestState instance to operate on.
- * @fmt...: HMP command to send to QEMU
+ * @fmt...: HMP command to send to QEMU, formats arguments like vsprintf().
  *
  * Send HMP command to QEMU via QMP's human-monitor-command.
  * QMP events are discarded.
@@ -535,7 +538,8 @@ static inline void qtest_end(void)
 
 /**
  * qmp:
- * @fmt...: QMP message to send to qemu
+ * @fmt...: QMP message to send to qemu; formats arguments through
+ * json-lexer.c (only understands '%((l|ll|I64)?d|[ipsf])').
  *
  * Sends a QMP message to QEMU and returns the response.
  */
@@ -543,7 +547,8 @@ QDict *qmp(const char *fmt, ...);
 
 /**
  * qmp_async:
- * @fmt...: QMP message to send to qemu
+ * @fmt...: QMP message to send to qemu; formats arguments through
+ * json-lexer.c (only understands '%((l|ll|I64)?d|[ipsf])').
  *
  * Sends a QMP message to QEMU and leaves the response in the stream.
  */
@@ -551,7 +556,8 @@ void qmp_async(const char *fmt, ...);
 
 /**
  * qmp_discard_response:
- * @fmt...: QMP message to send to qemu
+ * @fmt...: QMP message to send to qemu; formats arguments through
+ * json-lexer.c (only understands '%((l|ll|I64)?d|[ipsf])').
  *
  * Sends a QMP message to QEMU and consumes the response.
  */
@@ -592,7 +598,7 @@ static inline QDict *qmp_eventwait_ref(const char *event)
 
 /**
  * hmp:
- * @fmt...: HMP command to send to QEMU
+ * @fmt...: HMP command to send to QEMU, formats arguments like vsprintf().
  *
  * Send HMP command to QEMU via QMP's human-monitor-command.
  *
-- 
2.7.5

Re: [Qemu-devel] [PATCH 2/9] qtest: Document calling conventions

Posted by Eric Blake 8 years, 3 months ago

On 07/21/2017 08:53 AM, Markus Armbruster wrote:
> From: Eric Blake <eblake@redhat.com>
> 
> We have two flavors of vararg usage in qtest; make it clear that
> qmp() has different semantics than hmp(), and let the compiler
> enforce that hmp() is used correctly. However, qmp() (and friends)
> only accept a subset of printf flags look-alikes (namely, those
> that our JSON parser understands), and what is worse, qmp("true")
> (the JSON keyword 'true') is different from qmp("%s", "true")
> (the JSON string '"true"'), so marking those as printf-like would
> produce more harm from bogus warnings than it helps (we may have
> made a mistake in previously marking qobject_from_jsonf(), but
> this patch is not addressing that).
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Message-Id: <20170720214008.28494-5-eblake@redhat.com>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>

As you pointed out on the other thread,

> @@ -134,7 +137,7 @@ QDict *qtest_qmp_eventwait_ref(QTestState *s, const char *event);
>  /**
>   * qtest_hmp:
>   * @s: #QTestState instance to operate on.
> - * @fmt...: HMP command to send to QEMU
> + * @fmt...: HMP command to send to QEMU, formats arguments like vsprintf().
>   *
>   * Send HMP command to QEMU via QMP's human-monitor-command.
>   * QMP events are discarded.

I accidentally killed the attribute here,

> @@ -592,7 +598,7 @@ static inline QDict *qmp_eventwait_ref(const char *event)
>  
>  /**
>   * hmp:
> - * @fmt...: HMP command to send to QEMU
> + * @fmt...: HMP command to send to QEMU, formats arguments like vsprintf().
>   *
>   * Send HMP command to QEMU via QMP's human-monitor-command.
>   *

and here.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH 2/9] qtest: Document calling conventions

Posted by Markus Armbruster 8 years, 3 months ago

Eric Blake <eblake@redhat.com> writes:

> On 07/21/2017 08:53 AM, Markus Armbruster wrote:
>> From: Eric Blake <eblake@redhat.com>
>> 
>> We have two flavors of vararg usage in qtest; make it clear that
>> qmp() has different semantics than hmp(), and let the compiler
>> enforce that hmp() is used correctly. However, qmp() (and friends)
>> only accept a subset of printf flags look-alikes (namely, those
>> that our JSON parser understands), and what is worse, qmp("true")
>> (the JSON keyword 'true') is different from qmp("%s", "true")
>> (the JSON string '"true"'), so marking those as printf-like would
>> produce more harm from bogus warnings than it helps (we may have
>> made a mistake in previously marking qobject_from_jsonf(), but
>> this patch is not addressing that).
>> 
>> Signed-off-by: Eric Blake <eblake@redhat.com>
>> Message-Id: <20170720214008.28494-5-eblake@redhat.com>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>
> As you pointed out on the other thread,
>
>> @@ -134,7 +137,7 @@ QDict *qtest_qmp_eventwait_ref(QTestState *s, const char *event);
>>  /**
>>   * qtest_hmp:
>>   * @s: #QTestState instance to operate on.
>> - * @fmt...: HMP command to send to QEMU
>> + * @fmt...: HMP command to send to QEMU, formats arguments like vsprintf().
>>   *
>>   * Send HMP command to QEMU via QMP's human-monitor-command.
>>   * QMP events are discarded.
>
> I accidentally killed the attribute here,
>
>> @@ -592,7 +598,7 @@ static inline QDict *qmp_eventwait_ref(const char *event)
>>  
>>  /**
>>   * hmp:
>> - * @fmt...: HMP command to send to QEMU
>> + * @fmt...: HMP command to send to QEMU, formats arguments like vsprintf().
>>   *
>>   * Send HMP command to QEMU via QMP's human-monitor-command.
>>   *
>
> and here.

Putting them back is easier than updating commit message 1/9.

Re: [Qemu-devel] [PATCH 2/9] qtest: Document calling conventions

Posted by Stefan Hajnoczi 8 years, 3 months ago

On Fri, Jul 21, 2017 at 03:53:19PM +0200, Markus Armbruster wrote:
> From: Eric Blake <eblake@redhat.com>
> 
> We have two flavors of vararg usage in qtest; make it clear that
> qmp() has different semantics than hmp(), and let the compiler
> enforce that hmp() is used correctly. However, qmp() (and friends)
> only accept a subset of printf flags look-alikes (namely, those
> that our JSON parser understands), and what is worse, qmp("true")
> (the JSON keyword 'true') is different from qmp("%s", "true")
> (the JSON string '"true"'), so marking those as printf-like would
> produce more harm from bogus warnings than it helps (we may have
> made a mistake in previously marking qobject_from_jsonf(), but
> this patch is not addressing that).
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Message-Id: <20170720214008.28494-5-eblake@redhat.com>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  tests/libqtest.h | 22 ++++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>