Re: swap; sanity checking; list addres change

[Gary Shea <shea@xmission.com> writes:]

>First, I would appreciate it if I could get my list address
>changed to shea@xmission.com... my Novell address is a bit
>unstable.

Done.

>Second, has anyone got swap to work under any conditions?
>I am having real trouble getting vsta built, since it
>apparently needs more than 4 Megs in various places. It
>blows up about 15 times in the course of the build. I have
>tried swap with DOS partitions but it crashes the
>system. I'm making a good faith effort here -- I went out
>and bought 2 more Meg of memory and a 520 Meg disk!

I have a palmtop 486 coming in about a week. I plan on partitioning 10 megs
for swap, at which point I can start trying this for myself.

Dave did some hacking, and we flushed out a couple bugs and a design flaw.
I think the design flaw is in my court.

>Finally, the hard question. I need to map a word into kernel
>space and change it. The user passes the system call
>the address of the word. I need to make sure the user isn't
>passing me something that should not be changed. My guess is
>I should scan through the pview's for that user's process, looking
>for one that applies to the word's address (can there be more
>than one?). If p_prot == 0 I won't be compromising security.
>Then I need to actually change the word. I'm not clear on how
>to do that... I can't find any examples to steal! I'm guessing
>that I need to somehow map the user's page into kernel space,
>do the change, then destroy the mapping. Can anyone point me to
>some code?

Do you really need it *mapped*? If not, copyin/copyout are the way to go.
They do all the sanity checking and catch invalid references.

                                                Andy
Received on Sun Nov 6 17:07:14 1994