Re: [RFC] shmgetfd idea

["H. Peter Anvin" <hpa@zytor.com>]

On 01/28/2014 04:14 PM, Kay Sievers wrote:
>>
>> If the "single owner" is determined by the file structure (e.g. via a
>> fcntl as opposed to a ioctl), then presumably we would simply deny an
>> attempt to open the inode and create a new file structure for it.
>>
>> On Linux, /proc/$PID/fd is an open as opposed to a dup (as much as I
>> personally don't like those semantics, they are well set in stone at
>> this point) so it satisfies your requirements.
> 
> If that all could be made working, for the kdbus case we would be fine
> with requiring *any* tmpfs mount, create a new memfd from there with
> O_TMPFILE, and use new fcntl() definitios to protect/seal/unseal and
> identify that fd.
> 
> For the more restricted cases like Android that tmpfs mount could get
> a mount option to not allow the creation of any non-unlinked file, I
> guess.
> 

Right, that would be the idea.

	-hpa


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