Re: [Qemu-devel] [Qemu-block] [PATCH 2/2] trace: Forbid event format ending with newline character
On 9/13/19 5:00 PM, Philippe Mathieu-Daudé wrote:
> On 9/13/19 10:01 PM, John Snow wrote:
>> On 9/13/19 6:52 AM, Philippe Mathieu-Daudé wrote:
>>> Event format ending with newlines confuse the trace reports.
>>> Forbid them.
>>>
>>> Add a check to refuse new format added with trailing newline:
>>>
>>> $ make
>>> [...]
>>> GEN hw/misc/trace.h
>>> Traceback (most recent call last):
>>> File "scripts/tracetool.py", line 152, in
>>> main(sys.argv)
>>> File "scripts/tracetool.py", line 143, in main
>>> events.extend(tracetool.read_events(fh, arg))
>>> File "scripts/tracetool/__init__.py", line 367, in read_events
>>> event = Event.build(line)
>>> File "scripts/tracetool/__init__.py", line 281, in build
>>> raise ValueError("Event format can not end with a newline character")
>>> ValueError: Error at hw/misc/trace-events:121: Event format can not end
>>> with a newline character
>>>
>>> Signed-off-by: Philippe Mathieu-Daudé
>>> ---
>>> docs/devel/tracing.txt| 2 ++
>>> scripts/tracetool/__init__.py | 3 +++
>>> 2 files changed, 5 insertions(+)
>>>
>>> diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt
>>> index 76e492a489..8231bbf5d1 100644
>>> --- a/docs/devel/tracing.txt
>>> +++ b/docs/devel/tracing.txt
>>> @@ -112,6 +112,8 @@ Trace events should use types as follows:
>>> Format strings should reflect the types defined in the trace event. Take
>>> special care to use PRId64 and PRIu64 for int64_t and uint64_t types,
>>> respectively. This ensures portability between 32- and 64-bit platforms.
>>> +Format strings must not end with a newline character. It is the
>>> responsibility
>>> +of backends to adapt line ending for proper logging.
>>>
>>> Each event declaration will start with the event name, then its arguments,
>>> finally a format string for pretty-printing. For example:
>>> diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
>>> index 6fca674936..57df74e67c 100644
>>> --- a/scripts/tracetool/__init__.py
>>> +++ b/scripts/tracetool/__init__.py
>>> @@ -277,6 +277,9 @@ class Event(object):
>>> if fmt.find("%m") != -1 or fmt_trans.find("%m") != -1:
>>> raise ValueError("Event format '%m' is forbidden, pass the
>>> error "
>>> "as an explicit trace argument")
>>> +if fmt.endswith("\\n\""):
>>> +raise ValueError("Event format must not end with a newline "
>>
>> It's barely worth mentioning, but you can use r"\n" for cases like this,
>> if it makes it easier to read.
>
> TIL Python r"" :)
>
> This would be r"\n\"", right? We need to match the trailing '"'.
> Same length, not sure which string is easier to review =)
>
Ah, wow, I did misread this. It's confusing!
In this case, you can use r'\n"' to get the job done.
(My r-b stands, anyway.)
--js
Re: [Qemu-devel] [Qemu-block] [PATCH 2/2] trace: Forbid event format ending with newline character
On 9/13/19 10:01 PM, John Snow wrote:
> On 9/13/19 6:52 AM, Philippe Mathieu-Daudé wrote:
>> Event format ending with newlines confuse the trace reports.
>> Forbid them.
>>
>> Add a check to refuse new format added with trailing newline:
>>
>> $ make
>> [...]
>> GEN hw/misc/trace.h
>> Traceback (most recent call last):
>> File "scripts/tracetool.py", line 152, in
>> main(sys.argv)
>> File "scripts/tracetool.py", line 143, in main
>> events.extend(tracetool.read_events(fh, arg))
>> File "scripts/tracetool/__init__.py", line 367, in read_events
>> event = Event.build(line)
>> File "scripts/tracetool/__init__.py", line 281, in build
>> raise ValueError("Event format can not end with a newline character")
>> ValueError: Error at hw/misc/trace-events:121: Event format can not end
>> with a newline character
>>
>> Signed-off-by: Philippe Mathieu-Daudé
>> ---
>> docs/devel/tracing.txt| 2 ++
>> scripts/tracetool/__init__.py | 3 +++
>> 2 files changed, 5 insertions(+)
>>
>> diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt
>> index 76e492a489..8231bbf5d1 100644
>> --- a/docs/devel/tracing.txt
>> +++ b/docs/devel/tracing.txt
>> @@ -112,6 +112,8 @@ Trace events should use types as follows:
>> Format strings should reflect the types defined in the trace event. Take
>> special care to use PRId64 and PRIu64 for int64_t and uint64_t types,
>> respectively. This ensures portability between 32- and 64-bit platforms.
>> +Format strings must not end with a newline character. It is the
>> responsibility
>> +of backends to adapt line ending for proper logging.
>>
>> Each event declaration will start with the event name, then its arguments,
>> finally a format string for pretty-printing. For example:
>> diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
>> index 6fca674936..57df74e67c 100644
>> --- a/scripts/tracetool/__init__.py
>> +++ b/scripts/tracetool/__init__.py
>> @@ -277,6 +277,9 @@ class Event(object):
>> if fmt.find("%m") != -1 or fmt_trans.find("%m") != -1:
>> raise ValueError("Event format '%m' is forbidden, pass the
>> error "
>> "as an explicit trace argument")
>> +if fmt.endswith("\\n\""):
>> +raise ValueError("Event format must not end with a newline "
>
> It's barely worth mentioning, but you can use r"\n" for cases like this,
> if it makes it easier to read.
TIL Python r"" :)
This would be r"\n\"", right? We need to match the trailing '"'.
Same length, not sure which string is easier to review =)
Re: [Qemu-devel] [Qemu-block] [PATCH 2/2] trace: Forbid event format ending with newline character
On 9/13/19 6:52 AM, Philippe Mathieu-Daudé wrote:
> Event format ending with newlines confuse the trace reports.
> Forbid them.
>
> Add a check to refuse new format added with trailing newline:
>
> $ make
> [...]
> GEN hw/misc/trace.h
> Traceback (most recent call last):
> File "scripts/tracetool.py", line 152, in
> main(sys.argv)
> File "scripts/tracetool.py", line 143, in main
> events.extend(tracetool.read_events(fh, arg))
> File "scripts/tracetool/__init__.py", line 367, in read_events
> event = Event.build(line)
> File "scripts/tracetool/__init__.py", line 281, in build
> raise ValueError("Event format can not end with a newline character")
> ValueError: Error at hw/misc/trace-events:121: Event format can not end
> with a newline character
>
> Signed-off-by: Philippe Mathieu-Daudé
> ---
> docs/devel/tracing.txt| 2 ++
> scripts/tracetool/__init__.py | 3 +++
> 2 files changed, 5 insertions(+)
>
> diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt
> index 76e492a489..8231bbf5d1 100644
> --- a/docs/devel/tracing.txt
> +++ b/docs/devel/tracing.txt
> @@ -112,6 +112,8 @@ Trace events should use types as follows:
> Format strings should reflect the types defined in the trace event. Take
> special care to use PRId64 and PRIu64 for int64_t and uint64_t types,
> respectively. This ensures portability between 32- and 64-bit platforms.
> +Format strings must not end with a newline character. It is the
> responsibility
> +of backends to adapt line ending for proper logging.
>
> Each event declaration will start with the event name, then its arguments,
> finally a format string for pretty-printing. For example:
> diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
> index 6fca674936..57df74e67c 100644
> --- a/scripts/tracetool/__init__.py
> +++ b/scripts/tracetool/__init__.py
> @@ -277,6 +277,9 @@ class Event(object):
> if fmt.find("%m") != -1 or fmt_trans.find("%m") != -1:
> raise ValueError("Event format '%m' is forbidden, pass the error
> "
> "as an explicit trace argument")
> +if fmt.endswith("\\n\""):
> +raise ValueError("Event format must not end with a newline "
It's barely worth mentioning, but you can use r"\n" for cases like this,
if it makes it easier to read.
