Re: [GIT PULL] kdbus for 4.1-rc1

Richard Weinberger
2015-04-30T12:23:31Z

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Am 30.04.2015 um 14:16 schrieb Łukasz Stelmach:
> It was <2015-04-30 czw 12:40>, when Richard Weinberger wrote:
>> Am 30.04.2015 um 12:19 schrieb Łukasz Stelmach:
>>> It was <2015-04-30 czw 11:12>, when Richard Weinberger wrote:
>>>> Am 30.04.2015 um 11:05 schrieb Łukasz Stelmach:
>>>>> Regardless, of initrd issues I feel there is a need of a local IPC
>>>>> that is more capable than UDS. Linus Torvalds is probably right that
>>>>> dbus-daemon is everything but effictient. I disagree, however, that
>>>>> it can be optimised and therefore solve *all* issues kdbus is trying
>>>>> to address. dbus-deamon, by design, can't some things. It can't
>>>>> transmitt large payloads without copying them. It can't be made
>>>>> race-free.
>>>>
>>>> This is true.
>>>> But as long dbus-deamon is not optimized as much as possible there is
>>>> no reason to force push kdbus.
>>>> As soon dbus-deamon exploits all kernel interfaces as much it can and
>>>> it still needs work (may it performance or other stuff) we can think
>>>> of new kernel features which can help dbus-deamon.
>>>
>>> I may not be well informed about kernel interfaces, but there are
>>> some use cases no dbus-daemon optimisation can make work properly
>>> because of rece-conditons introduced by the user-space based message
>>> router.
>>>
>>> For example, a service can't aquire credentials of a client process that
>>> actually sent a request (it can, but it can't trust them). The service
>>> can't be protected by LSM on a bus that is driven by dbus-daemon. Yes,
>>> dbus-daemon, can check client's and srevice's labels and enforce a
>>> policy but it is going to be the daemon and not the LSM code in the
>>> kernel.
>>
>> That's why I said we can think of new kernel features if they are
>> needed. But they current sink or swim approach of kdbus folks is also
>> not the solution. As I said, if dbus-daemon utilizes the kernel
>> interface as much as possible we can think of new features.
>
> What kernel interfaces do you suggest to use to solve the issues
> I mentioned in the second paragraph: race conditions, LSM support (for
> example)?

The question is whether it makes sense to collect this kind of meta data.
I really like Andy and Alan's idea improve AF_UNIX or revive AF_BUS.

Thanks,
//richard

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