svn commit: r256377 - in head: etc/defaults etc/rc.d share/examples/kld/random_adaptor share/man/man4 sys/boot/forth sys/conf sys/dev/glxsb sys/dev/hifn sys/dev/random sys/dev/rndtest sys/dev/safe ...

[Adrian Chadd]

Hi Mark,

Can we make the VFS random seeding stuff a compile time option, so we can
disable it for the embedded platforms where we'll never use it?



Thanks,

-adrian



On 13 October 2013 10:03, Mark R V Murray <mark at grondar.org> wrote:

>
> On 13 Oct 2013, at 17:18, Ian Lepore <ian at FreeBSD.org> wrote:
>
> > On Sun, 2013-10-13 at 16:18 +0100, Mark R V Murray wrote:
> >> On 13 Oct 2013, at 16:13, Konstantin Belousov <kostikbel at gmail.com>
> wrote:
> >>> Surely this works, thank you. The rwfile.c content probably should be
> >>> taken under the #ifdef RANDOM_RWFILE.
> >>
> >> OK - thanks for the feedback!
> >>
> >>> But I do not see much use for the randomdev_read_file() and
> >>> randomdev_write_file() functions. It would be better to directly code
> >>> the VFS calls in the random_harvestq_cache(). For one thing, it would
> >>> eliminate unneccessary close and open of the entropy file.
> >>
> >> There is some uncertainty about the future of that code, so I want
> >> to keep it that way for now. Writing files from the kernel is making so@
> >> very uncomfortable, and there is too much scope for error there.
> >>
> >
> > Indeed, it makes me nervous too, as a heavy user of readonly root
> > filesystems.  If writing this file is so critical that it has to be done
> > by the kernel, then what happens when it fails?  Right now it prints an
> > error and continues -- if it is not so critical that failure means
> > panic, then why is the kernel doing it at all?
>
> Good points all. The intent is not to win the arms-race outright, but to
> win the common-case battles as convincingly as possible. That said, its
> not looking good for the process, but I still want to give it a decent
> look before/if yanking it.
>
> > Why is the file even in the root filesystem?  /var/db seems to be the
> > right place for a transient file needed by the system.
>
> Because that appears to be the best place to put first-boot entropy from
> sysinstall/bsdinstall. /var/db/entropy/... will also be used if possible;
> watch this space.
>
> > Speaking of errors, that might include things like the current code
> > calling vn_close() with the FREAD flag on a file open for writing.
>
>
> Thanks :-( :-)
>
> M
> --
> Mark R V Murray
>
>