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SubjectRe: Linux-1.3.81
Date
In article <m2yboij7gx.fsf@deanna.miranova.com>,
Steven L Baur <steve@miranova.com> wrote:
>
>>>>>> "Linus" == Linus Torvalds <torvalds@cs.helsinki.fi> writes:
>...
>Linus> - named pipes now work the way God intended them to work, the SunOS
>Linus> compat code is disabled by default.
>...
>Linus> Look it over, will you?
>
>Linus> Linus
>
>This appears to have a devastating affect on sysvinit 2.58 (it loops
>on the error message ``error reading initrequest'' upon changing run
>levels), appropriately enough in the routine CheckInitFifo which is
>commented:
>/*
> * Read from the init FIFO. Processes like telnetd and rlogind can
> * ask us to create login processes on their behalf.
> *
> * FIXME: this needs to be finished.
> */
>
>I'm not sure what the fix is.

The fix is that the interface definition needs to be finished. It
isn't about some bug in the code ;) However, I think the new named pipe
code in the kernel breaks a lot of applications.
As I see it, there _is_ a difference between pipes and fifos: you
cannot ever re-open a pipe, but you can re-open a fifo. With the
new code, a server (init) can only accept one request on a named pipe.
After the client (telinit) has closed the fifo, read() keeps returning
0 instead of blocking and select() tells init there is data waiting...

With the old SunOS behaviour it was possible to open a fifo once,
do a select() on it and accept incoming requests from different
clients. Now the server has to keep open()ing and close()ing the fifo,
which is not pretty and will break lots of stuff.

Linus, could you please either explain a way around this or
restore the old behaviour of select() on pipes?

Mike.
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