Re: [fetchmail-devel] [PATCH] fetchmail workaround for a bug in Zimbra

[Matthias A. <mat...@gm...>]

Am 19.11.2011 00:43, schrieb Mikulas Patocka:
> Hi
> 
> Zimbra occasionally returns this response:
> 
> fetchmail: IMAP> A0007 FETCH 1 RFC822.HEADER
> fetchmail: IMAP< * 1 FETCH ()
> fetchmail: IMAP< A0007 OK FETCH completed
> 
> It happens when there is a corrupted message without a header in the 
> database. (I don't know how this message could be created, I just see it 
> there).
> 
> When fetchmail encounters such resonse, it gives up and disconnects.
> 
> The attached patch changes it so that PS_TRANSIENT is returned in this 
> case and fetchmail continues to fetch following messages correctly.
> 
> Mikulas
> 
> --- imap.c_	2011-11-18 17:28:35.638698000 -0500
> +++ imap.c	2011-11-18 18:04:41.745220000 -0500
> @@ -1166,7 +1166,8 @@
>  
>  	/* try to recover for some responses */
>  	if (!strncmp(buf, "* NO", 4) ||
> -		!strncmp(buf, "* BAD", 5))
> +		!strncmp(buf, "* BAD", 5) ||
> +		strstr(buf, "FETCH ()"))
>  	{
>  	    return(PS_TRANSIENT);
>  	}

Dear Mikulas,

thanks a lot for the contribution.  I have applied the patch, currently
on the legacy_63 branch (gitorious.org), for inclusion in the next 6.3.X
release (6.3.22).  I don't currently foresee a release date, as there
aren't many, or critical, fixes since 6.3.21 yet.  A release might be a
couple of weeks out.

For 7.X and later versions, I have considered rewriting the IMAP reply
parser, but chances are that the behaviour is in violation of RFC3501
and will still need special casing/work arounds.

I'll have to check more places of the RFC than my time currently allows;
Dovecot for one returns

. FETCH 248 RFC822.HEADER
* 248 FETCH (RFC822.HEADER {0}
)

in response to a blank message which seems more useful.

Best regards
Matthias