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    SubjectRe: [PATCH] nextfd(2)
    On Sun, Apr 1, 2012 at 5:57 AM, Alexey Dobriyan <adobriyan@gmail.com> wrote:
    >
    > BSD added closefrom(fd) which is OK for this exact purpose but suboptimal
    > on the bigger scale. closefrom(2) does only close(2) (obviously :-)
    > closefrom(2) siletly ignores errors from close(2) which in theory is not OK
    > for userspace.
    >
    > So, don't add closefrom(2), add nextfd(2).

    I don't disagree with this, but I don't think it's worth a new file of
    its own - I think it should go next to dup() and friends (currently in
    fs/fcntl.h).

    Also, I think you should:

    (a) at a minimum use the bitmap. It's easy:

    struct fdtable *fdt;

    rcu_read_lock();
    fdt = files_fdtable(current->files);
    .. maximum fd in fdt->max_fds ...
    .. you have the bitmap in fdt->open_fds ..

    (b) I'd also suggest you add a "flag" argument and have at least one
    bit option for "search for next *free* file table entry". I'm not sure
    anybody wants it, but it is kind of the same operation, and having a
    "flags" field means that it's extensible in the future if people want
    to find the next cloexec fd or whatever. Or if they just want to find
    the *last* fd, or something.

    But I think the concept makes sense.

    Linus


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