Re: interrupting `shred -u's renaming: what should it do?

[Paul Jarc]

address@hidden (Bob Proulx) wrote:
> But if a new file appears by the same original name then there is no
> longer any need to hide it with regards to the previous incarnation
> of the name.  At that point the name can just be removed.

Ok, that makes sense.

> My comment pertained to my thought that if you could rename it and
> fail if the name exists then that means in that case the file could be
> removed.  But if the rename succeeded then things were restored as
> much as possible to a sane state after an interrupt.

You can do that, without clobbering the new file with the original
name, and you don't need full atomicity.
result=link("000000", "original name");
if (result==0 || errno==EEXIST) unlink("000000");
else report_the_error_and_keep_the_temp_file();

link() gives us as much atomicity as we need - checking for the
existence of the original name is atomic with allocating the original
name.  We don't need all that to also be atomic with releasing the
temporary name.


paul