Re: /proc/$pid/pagemap troubles

From: Andreas Schwab
Date: Tue Jul 31 2007 - 18:58:31 EST


Matt Mackall <mpm@xxxxxxxxxxx> writes:

> On Tue, Jul 31, 2007 at 01:36:14PM -0700, Dave Hansen wrote:
>> Since the pagemap code has a little header on it to help describe the
>> format, I wrote a little c program to parse its output. I get some
>> strange results. If I do this:
>>
>> fd = open("/proc/1/pagemap", O_RDONLY);
>> count = read(fd, &endianness, 1);
>>
>> count will always be 4.
>
> Known bug, fixed in my pending and not-currently-working update. It
> ought to return 0 for short reads.

That's not a good choice. Returning 0 means EOF, but there is actually
data to be read.

Andreas.

--
Andreas Schwab, SuSE Labs, schwab@xxxxxxx
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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