Messages in this thread |  | | Date | Mon, 18 Sep 2000 14:02:26 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] Fix queued SIGIO |
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On Mon, Sep 18, 2000 at 01:44:04PM +0200, Alan Cox wrote: > > On Mon, Sep 18, 2000 at 12:34:03PM +0200, Alan Cox wrote: > > > > The problem is really that SI_SIGIO is negative, but it should be positive > > > > to make SI_FROMUSER return false on it. > > > > > > > > Changing it would unfortunately break binary compatibility. This patch > > > > > > Why ? > > > > If a program checks info->si_code for incoming signals. > > ok now what does the value the kernel passes have to do with the value we > write on the user stack - at the moment we blindly copy but we could just > use a tiny lookup table to 'dekernelize' the ID. In fact if you picked a bitflag > you could just mask it
That would not help much, the user could just still set the non mapped value in sigqueueinfo() [which would need to be forbidden to avoid users faking kernel signals, which my patch exactly does]
-Andi
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