Re: mmap, SIGBUS, and handling it

Maciej W. Rozycki (macro@ds2.pg.gda.pl)
Fri, 10 May 2002 21:54:06 +0200 (MET DST)


On Fri, 10 May 2002, David S. Miller wrote:

> He's talking about how SIG_IGN should behave.

So do I.

> If you want non-default behavior, specify a signal handler instead
> of SIG_IGN.

Well, SIG_IGN is non-default (user-specified) behavior -- SIG_DFL is.

> Why should we enforce policy on a user? If one wants to ignore such
> signals for whatever reason, let him do that.
>
> We don't specify any policy other than the behavior of SIG_IGN which
> is to kill off the process for SIGBUS.

Making a special exception to well-defined semantics because it seems
less useful for a certain case is policy. SIG_IGN means to ignore a
signal (except from SIGKILL, SIGSTOP, SIGCONT signals that cannot be
ignored, but that's a result of how they work and it is explicitly
specified in standards) -- everything else is unexpected semantics.

> If you specify a handler you can have SIGBUS do whatever you want it
> to. There are no enforced limitations, only a specified behavior
> for SIG_IGN when used for SIGBUS.
>
> The original poster has solved his problem, yet you continue to argue
> one and on and on.

s/argue/discuss/

Anyway, since the code seems to work like I describe/expect, there is
really no problem for me. Haven't you meant SIG_DFL, actually?

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

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