[systemd-devel] [RFC PATCH 1/2] Replace mkostemp+unlink with open(O_TMPFILE)

[Kay Sievers]

On Mon, Jan 27, 2014 at 7:50 PM, Zbigniew Jędrzejewski-Szmek
<zbyszek at in.waw.pl> wrote:
> On Mon, Jan 27, 2014 at 07:15:23PM +0100, Kay Sievers wrote:
>> On Mon, Jan 27, 2014 at 6:27 PM, Zbigniew Jędrzejewski-Szmek
>> <zbyszek at in.waw.pl> wrote:
>> > On Mon, Jan 27, 2014 at 05:57:56PM +0100, Kay Sievers wrote:
>>
>> >> Can we expect open(O_TMPFILE) to fail on kernels which do not support it?
>>
>> >> I guess they will just silently ignore it? Then we never unlink?
>>
>> > No, it is supposed to fail properly if it doesn't work. The flags were
>> > changed to be incompatible with old kernels. We should probably have a
>> > unit test for that. I have a small utility I was using for tests, I'll
>> > dig it up.
>>
>> Oh, any idea how this works? I couldn't see any kernel code that
>> checks for currently unused flags and fails.
>
> open("/tmp", O_TMPFILE|O_RDWR, S_IRUSR | S_IWUSR)
>
> returns -1, errno=EISDIR on Linux 3.9.

Yeah, but what happens for a "/tmp/does-not-exist" request? :)

Kay