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From: Andy Whitcroft <apw@shadowen•org>
To: Junio C Hamano <junkio@cox•net>
Cc: git@vger•kernel.org
Subject: Re: [PATCH] use xread where we are not checking for EAGAIN/EINTR
Date: Fri, 05 Jan 2007 12:20:00 +0000	[thread overview]
Message-ID: <459E4270.9090307@shadowen.org> (raw)
In-Reply-To: <7vvejlg1pg.fsf@assigned-by-dhcp.cox.net>

Junio C Hamano wrote:
> Andy Whitcroft <apw@shadowen•org> writes:
> 
>>     We have an xread() wrapper to help us with those nasty
>>     interrupt returns and yet we fail to use it consistently.
>>     This patch updates those plain read()'s which do not
>>     have any handling for errors, or which treat those errors
>>     as user visible fatal errors.
>>
>>     This feels right to me, but perhaps there is some good
>>     reason that things are done this way ... if so could
>>     someone elighten me.
> 
> Thanks.
> 
> I do not think any of the changes you did introduced new bugs,
> but I think some of them are still wrong.  xread() protects us
> from EINTR happening before any byte is read, but it can still
> give a short read.  Many callers have a loop like this:
> 
> 	do {
>         	size = xread(...);
>                 yet_to_go -= size;
> 	} while (yet_to_go);
> 
> but some are not (e.g. add_excludes_from_file_1() in dir.c
> expects xread() does not return before reading full buffer).

Yes, that is true.  I was going to fix that in the next step with the
writes.  But yes thats likely to involve them becoming 'read_in_full'
style thing and in fact churn us more.

Ignore this one and I'll look to do it 'right'.

-apw

  reply	other threads:[~2007-01-05 12:20 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-05 10:54 [PATCH] use xread where we are not checking for EAGAIN/EINTR Andy Whitcroft
2007-01-05 11:19 ` Junio C Hamano
2007-01-05 12:20   ` Andy Whitcroft [this message]
2007-01-08 15:56     ` Andy Whitcroft
2007-01-08 15:57       ` [PATCH 1/4] short i/o: clean up the naming for the write_{in,or}_xxx family Andy Whitcroft
2007-01-08 15:58       ` [PATCH 2/4] short i/o: fix calls to read to use xread or read_in_full Andy Whitcroft
2007-01-08 15:58       ` [PATCH 3/4] short i/o: fix calls to write to use xwrite or write_in_full Andy Whitcroft
2007-01-08 15:58       ` [PATCH 4/4] short i/o: fix config updates to use write_in_full Andy Whitcroft
2007-01-08 20:13       ` [PATCH] use xread where we are not checking for EAGAIN/EINTR Junio C Hamano
2007-01-11 21:43       ` [PATCH] Avoid errors and warnings when attempting to do I/O on zero bytes Eric Wong

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