Re: pg_dump's checkSeek() seems inadequate

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: pg_dump's checkSeek() seems inadequate
Date: 2010-06-28 11:32:17
Message-ID: 4C288841.7030601@dunslane.net
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Tom Lane wrote:
> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
>
>> Tom Lane wrote:
>>
>>> A somewhat more plausible scenario is that somebody might hope that
>>> they could do something like this:
>>>
>>> echo 'some custom header' >pg.dump
>>> pg_dump -Fc >>pg.dump
>>>
>
>
>> What would anyone hope to achieve by such a manoeuvre, even if it
>> worked, which I am close the dead sure it would not?
>>
>
> It looks to me like it probably would actually work, so far as pg_dump
> is concerned, but _discoverArchiveFormat() would break it because that
> tries to do an unconditional fseeko(fp, 0, SEEK_SET) (and the position
> counting is screwed up even if the fseeko fails). That could probably
> be fixed if anyone thought this scenario was interesting enough to
> justify work directed specifically at it.
>

IIRC pg_restore expects the archive to begin with the header and TOC
produced by pg_dump. Maybe I'm being dense, but I'm not able to see how
prefixing that with something else could possibly do something useful or
workable.

cheers

andrew

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Robert Haas 2010-06-28 12:09:21 Re: suppress automatic recovery after back crash
Previous Message KaiGai Kohei 2010-06-28 09:21:28 Re: get_whatever_oid, part 1: object types with unqualifed names