Re: [PATCHv4 man-pages 3/3] open.2: describe O_BENEATH flag

From: David Drysdale
Date: Fri Aug 14 2015 - 11:31:08 EST


On Fri, Aug 14, 2015 at 3:17 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> On Fri, Aug 14, 2015 at 2:29 AM, David Drysdale <drysdale@xxxxxxxxxx> wrote:
>> On Fri, Aug 14, 2015 at 6:33 AM, Michael Kerrisk (man-pages)
>> <mtk.manpages@xxxxxxxxx> wrote:
>>> On 13 August 2015 at 19:38, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>>>> On Thu, Aug 13, 2015 at 2:32 AM, David Drysdale <drysdale@xxxxxxxxxx> wrote:
>>>>> Signed-off-by: David Drysdale <drysdale@xxxxxxxxxx>
>>>>
>>>> What's the behavior wrt fcntl(F_GETFL, etc)?
>>>
>>> I would presume that O_BENEATH is one of the so-called "file creation
>>> flags". See this paragraph of the DESCRIPTION:
>>>
>>> In addition, zero or more file creation flags and file status
>>> flags can be bitwise-or'd in flags. The file creation flags are
>>> O_CLOEXEC, O_CREAT, O_DIRECTORY, O_EXCL, O_NOCTTY, O_NOFOLLOW,
>>> O_TMPFILE, O_TRUNC, and O_TTY_INIT. The file status flags are
>>> all of the remaining flags listed below. The distinction between
>>> these two groups of flags is that the file status flags can be
>>> retrieved and (in some cases) modified; see fcntl(2) for details.
>>>
>>> David, presuming this is correct (I can't see how O_BENEATH could be a
>>> "file *status* flag"), your patch should also add O_BENEATH to the
>>> list in that paragraph.
>>
>> Yeah, O_BENEATH makes sense as a file creation flag; I'll add it
>> to that list -- thanks for spotting.
>
> Should there be a test that you can't clear O_BENEATH with F_SETFL?
>
> --Andy

I'll add a test that fcntl(F_SETFL) silently ignores the file creation flags,
including O_BENEATH.
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