doscmd under 8-stable, anyone?
Joerg Wunsch
freebsd-current at uriah.heep.sax.de
Wed Jun 15 14:37:17 UTC 2011
As Kostik Belousov wrote:
> > So does anyone have an idea
> > why this mmap() call:
...
> > yields an EINVAL now under 8-stable?
>
> Do sysctl security.bsd.map_at_zero=1
Ah, thanks! Now it works. Well, at least it doesn't crash anymore (I
somehow have to fix my boot environment, hopefully I'll be able to
perform a fresh installation of FreeDOS there.)
So I guess this should be added to doscmd's documentation then.
As Jeremy Chadwick wrote:
> I'm not sure why a person would need or want MAP_FIXED in this
> situation; why can't they just take the result of mmap() (a void *) and
> use that as a base address offset instead of assuming zero in their
> software?
Because MS-DOS utilities are written in the assumption of running at
address 0 (or only slightly beyond). Remember, this mmap() maps the
MS-DOS emulator base memory (that's why it is fatal if the allocation
fails).
--
cheers, J"org .-.-. --... ...-- -.. . DL8DTL
http://www.sax.de/~joerg/ NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)
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