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From: David Schwartz <davids@webmaster.com>
To: <alex@pennace.org>, Neil Brown <neilb@cse.unsw.edu.au>
CC: Bernd Eckenfels <ecki@lina.inka.de>, <linux-kernel@vger.kernel.org>
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Date: Fri, 5 Oct 2001 16:43:09 -0700
In-Reply-To: <20011005193049.A6981@buick.pennace.org>
Subject: Re: Desperately missing a working "pselect()" or similar...
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>> A technique I used in a similar situation once went something like:  

>> tv.tv_sec=bignum;
>> tv.tv_usec = 0;
>> enable_signals();
>> select(nfds, &readfds,&writefds,0,&tv);

>> and have the signal handlers set tv.tv_sec to 0. (tv is a global
>>variable).

>I've thought about that, but I haven't been able to find any guarantee that
>there will be no user space futzing around with &tv, like a library wrapper
>that copies tv to another spot in memory and invokes the syscall with that
>address.

	This will commonly happen if, for example, the user-side timeval structure 
contains seconds and microseconds and the kernel-side structure contains 
seconds and nanoseconds. The signal might occur after the library has 
performed the structure conversion.

	DS


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