[pulseaudio-discuss] Logging startup of the first instance...

[rong deng]

2012/6/28 David Henningsson <david.henningsson at canonical.com>:
> On 06/28/2012 09:41 AM, rong deng wrote:
>>
>> Hi David,
>>
>> I've come up with an idea to accommodate this situation, tell me if
>> it's useful for you or there's a better solution. :)
>
>
> I think this solution (to go with .1, .2 etc prefix) is good enough for me.
> A question about the implementation though - is it racy? I'm not completely
> sure if two clients which in parallel try to spawn the server, end up
> choosing the same file name.

Hi David,

I'm afraid that the current implementation suffer the same race issue.
because the second server would just ignore the current existing file
and would be happy to create its own. It should be fixed.

>
> Would opening with O_EXCL work as a test instead, perhaps?

Yes, adding O_EXCL to open()'s flags would help in this situation.

>
>
>>
>> So I've added a new syntax when we specified the file log target. The
>> original one is file:<PATH>, now it's newfile:<PATH>.  This syntax
>> would:
>> 1. check if PATH file exists or not, if it doesn't exist, then
>> everything is OK, we're not overriding anything, we do the original
>> code route.
>> 2. now unfortunately this file exists, then we try PATH.1, PATH.2,
>> PATH.3 .... until we find a non-existent file, let's say it's PATH.5,
>> so we create the PATH.5 as our log file target.
>>
>> Any comments are welcome.
>>
>> The patch is attached.
>>
>> 2012/6/11 David Henningsson <david.henningsson at canonical.com>:
>>>
>>> On 06/11/2012 02:35 AM, rong deng wrote:
>>>>
>>>>
>>>> 2012/6/4 David Henningsson<david.henningsson at canonical.com>:
>>>>>
>>>>>
>>>>> Sometimes I have users who complain about some problem, but after a
>>>>> "pulseaudio -k" the problem is gone. Therefore asking them to restart
>>>>> pulseaudio with -vvvv switch will not give any information about the
>>>>> error.
>>>>>
>>>>>  * I could log to syslog (the default), but once I enable debug level
>>>>> log,
>>>>> the syslog daemon can start to ratelimit, especially during the startup
>>>>> phase of pulseaudio.
>>>>>
>>>>>  * I could log to file, but then that file would quickly get
>>>>> overwritten,
>>>>> as
>>>>> soon as pulseaudio restarts.
>>>>>
>>>>> Is there a trick I'm missing here? Or would it be possible to add some
>>>>> kind
>>>>> of expansion to the log file name to make the files unique?
>>>>
>>>>
>>>>
>>>> Hi David,
>>>>
>>>> I'm doing the GSoC to enhance the logging functionality in pulseaudio,
>>>> I could take a look at this issue and try to improve it a little bit.
>>>> :)
>>>
>>>
>>>
>>> Yes, I was actually thinking the same :-) Thanks!
>>>
>>> Not sure how to do it in the best way though. I'm figuring that at least
>>> a
>>> timestamp and pid should be possible to insert into the log file name in
>>> a
>>> configurable way.
>>> Also we probably don't want to reinvent the wheel but use the expansion
>>> mechanisms provided by ...something around us, or some library we're
>>> already
>>> depending on, if we can find anything of use?
>>> Maybe someone else knows more on the topic.
>>>
>>>
>>> --
>>> David Henningsson, Canonical Ltd.
>>> https://launchpad.net/~diwic
>
>
>
>
> --
> David Henningsson, Canonical Ltd.
> https://launchpad.net/~diwic
>
>