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Message-ID:	<436E50DE.3070405@cwilson.fastmail.fm>
Date:	Sun, 06 Nov 2005 13:52:14 -0500
From:	Charles Wilson <cygwin AT cwilson DOT fastmail DOT fm>
User-Agent:	Mozilla Thunderbird 1.0.6 (Windows/20050716)
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To:	cygwin AT cygwin DOT com
Subject:	Re: BUG: alternatives
References:	<436CF5E9 DOT 30106 AT cwilson DOT fastmail DOT fm> <001201c5e244$c9e50490$020aa8c0 AT DFW5RB41> <436D9993 DOT 7050100 AT cwilson DOT fastmail DOT fm> <20051106134339 DOT GA24549 AT trixie DOT casa DOT cgf DOT cx>
In-Reply-To:	<20051106134339.GA24549@trixie.casa.cgf.cx>

Christopher Faylor wrote:

> A signal shouldn't cause a truncated read when retrieving data from
> disk on cygwin or linux.

ACK.

> I think the only sane way to handle this is to put the read in a loop
> and realloc the buffer as needed as long as the read continues to return
> '>0'.

Ok.

> It's obviously pretty racy to get the size of the file and then expect that
> you'll be able to read in exactly that many bytes.

ACK.

Revised patch attached.  I'm wondering, tho, about the advisability of 
using alloca'ed (rather than malloc'ed) memory to hold the contents of a 
file of unrestricted size.  Aren't there limits on the available space 
within a single stack frame?  Does it make sense (is it legal) to alloca 
40k or 50k or 500k? of memory?

Granted, most /var/lib/alternatives files are going to be fairly small 
(< 1k) but there's no guarantee of that...

--
Chuck


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