This list contains all per-process used file fdinfo's, sorted by fd number.
Will be used to safely create new artificial file descriptors and also allow
to recreate temporary descriptors with original number, if possible, like
AutoFS tries to preserve original pipe write end descriptor, when it was
closed.
This patch also adds a couple of simple helpers to find unused file
descriptor:
1) fd_is_used() does exactly what it is named
2) find_unused_fd() returns "hint_fd" if unused or last used descriptor plus
one.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>