GNU bug report logs - #13391
dd silently ignores lseek error

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Message #13 received at 13391-done <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: Neil Klopfenstein <neil.klopfenstein <at> gmail.com>, 13391-done <at> debbugs.gnu.org
Subject: Re: bug#13391: dd silently ignores lseek error
Date: Wed, 09 Jan 2013 01:14:22 +0000

[Message part 1 (text/plain, inline)]

On 01/08/2013 08:55 PM, Paul Eggert wrote:
> On 01/08/13 10:11, Neil Klopfenstein wrote:
>> Note that it begins reading at the _beginning of the ar file_ -- the 'skip'
>> argument has failed silently.
>
> But the 'skip' hasn't failed.  It's merely being implemented via 'read'
> rather than via 'lseek'.  The records are being skipped correctly.
>
> It might be useful to give dd a new option, which causes it
> to insist on lseeking rather than reading in cases like these,
> and to report an error if the lseek fails.

I had a look around for a tool to verify
that a file/device supports the seek operation
and couldn't find one.
So this seems like useful functionality.
Worth applying the attached?

thanks,
Pádraig.

[dd-flag-seekable.diff (text/x-patch, attachment)]

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