It was decided that exposing O_CLOEXEC
flag to fcntl(fd, F_GETFL)
is security leak. Change was made by this commit in kernel 3.6-rc7:
commit c6f3d81115989e274c42a852222b80d2e14ced6f
Author: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun Aug 26 11:01:04 2012 -0400
don't leak O_CLOEXEC into ->f_flags
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In other words, you should not have relied on O_CLOEXEC
being visible in first place.