[LTP] [PATCH] creat05: count opened fds

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> This testcase estimates number of opened fds by opening
> a new one and assuming there are no gaps. This doesn't always
> hold true. There can be gaps if test harness that runs it
> opens couple fds with O_CLOEXEC prior to starting creat05.
> As result, testcase unexpectedly fails in setup.

As far as I understand it the O_CLOEXEC is not the problem here. It may
be reproduced even without it when the test harness leaves an open fd
after some open one, right?

Something as:

fd0 = open("foo", ...);
fd1 = open("bar", ...);
close(fd0);
fork();
if (!pid)
	exec("creat05");


And in that case the testcase can do even without listing the
/proc/self/fd. Since POSIX specifies that we get the smallest unused fd
for each creat() we can just call it in a loop until the resulting
fd == max_fd - 1. We would have to allocate the array to store the fds
so that we can close them in cleanup though.

-- 
Cyril Hrubis
chrubis@suse.cz