using /proc/$pid/mem to access vga bios is not portable and crashes
sgi machines when aux/vga is run. instead, try /dev/realmodemem
first (provided by realemu), then #v/vgabios.
this allows extracting tar archives that use longnames extension,
where the real filename is stored in a special entry with
linkflag == 'L' before the file entry. also skip longlink entries
with linkflag == 'K'.
David du Colombier wrote:
> The slowness issue only appears on the loopback, because
> it provides a 16384 MTU.
>
> There is an old bug in the Plan 9 TCP stack, were the TCP
> MSS doesn't take account the MTU for incoming connections.
>
> I originally fixed this issue in January 2015 for the Plan 9
> port on Google Compute Engine. On GCE, there is an unusual
> 1460 MTU.
>
> The Plan 9 TCP stack defines a default 1460 MSS corresponding
> to a 1500 MTU. Then, the MSS is fixed according to the MTU
> for outgoing connections, but not incoming connections.
>
> On GCE, this issue leads to IP fragmentation, but GCE didn't
> handle IP fragmentation properly, so the connections
> were dropped.
>
> On the loopback medium, I suppose this is the opposite issue.
> Since the TCP stack didn't fix the MSS in the incoming
> connection, the programs sent multiple small 1500 bytes
> IP packets instead of large 16384 IP packets, but I don't
> know why it leads to such a slowdown.
i made a mistake here as this change breaks the arm and mips compilers
which lack an optimiation in xcom() that folds constant pointer arithmetic
into the offset. on arm, the a node is a complex expression with op OADD of
type TIND but the test rejected the (valid) pointer arithmetic.
instead, we now test for the operations which cannot be constant instead
of using the type as a proxy.
mischief spotted that the only way for listeners to go away was
truncating (but not removing) a service script. this is wrong and
not as described in the manpage.
this change makes removing (or truncating) a listen script stop
the listener.
scandir() first marks all current announces, then reads the service
directory adding announces which will clear the marks for the ones
already there or add a new unmarked one. finally, we shoot down and
remove all still marked announces.
6c changed "- cmd_lagest_size + 1" into a *unsigned* 32bit constant. which
got added to 64bit pointer making pcb->limit > pcb->end resulting
in errors for partial commands in the buffer. removing the parentesis
propagates the operation to 64bit.
the intend of posting a note to the faulting process is to
interrupt the syscall to give the note handler a chance
to handle it. kernel processes however, have no note handlers
and all the postnote() does is set up->notepending which will
make the next attempt to sleep raise an Eintr[] error. this
is harmless, but usually not what we want.
