Re: [PATCH 1/3] VFS "stat light" out of fstatat, and fine grained flags

[Oleg Drokin <green@linuxhacker.ru>]

Hello!

On Apr 12, 2009, at 4:50 PM, Jamie Lokier wrote:
>>   Also it adds AT_STAT_SELF flag to mean that the stat should be  
>> executed not
>>   on a path, but on the passed filedecriptor itself.
> Do you think this is more attractive?
>
>    ret = fstatat(fd, 0, &stat, AT_STAT_SELF|AT_STAT_TYPE| 
> AT_STAT_SIZE);
>
> Or this?
>    ret = fstatat(fd, 0, &stat, AT_STAT_TYPE|AT_STAT_SIZE);
> Where 0 in the path automatically means AT_STAT_SELF.
> Or this?
>    ret = fstatat(fd, AT_STAT_SELF, &stat, AT_STAT_TYPE|AT_STAT_SIZE);
> Where AT_STAT_SELF is defined as (const char *)-1 in system headers,
> to better catch null pointer application bugs.

While I think the last one might be attractive, we also need to think
about compatibility, unaware kernels would return -EFAULT if you pass  
some
nonsense as a path, which is much less useful than say nice EINVAL.

Bye,
     Oleg