[ldns-users] ldns-read-zone output not very helpful

Wouter Wijngaards wouter at nlnetlabs.nl
Wed Jul 21 09:21:48 UTC 2021

Hi Anand,

On 21/07/2021 11:01, Anand Buddhdev via ldns-users wrote:
> On 21/07/2021 10:43, Wouter Wijngaards via ldns-users wrote:
> Hi Wouter,
>>> Line 3638 is actually a blank line! Here are the lines before and after it:
>>> 3636 reg01-test.atlas    86400   A
>>> 3637 reg01-test.atlas    86400   AAAA    2001:67c:2e8:11::
>>> 3638
>>> 3639 reg02-test.atlas    86400   A
>>> 3640 reg02-test.atlas    86400   AAAA    2001:67c:2e8:11::
>> So the error happens because the code is trying to read the class but
>> this fails. To be precise: the owner name can be read. The TTL can be
>> read, and if it exists, it parses. But when it then attempts to read the
>> next token, for the class, that token cannot be read.
>> You skip the class token and have a type token. But the token itself
>> cannot be read, I mean it skips spaces and tabs but then fails. So the
>> token fetch failed at the class position.
>> Perhaps there is data there, but there is whitespace on the line. And
>> the empty spaces are read as an owner and TTL, empty values, and then
>> the class token read finds the end of the buffer and this fails with the
>> syntax error.
>> Or there could be invisible unicode characters in the sourcefile. But I
>> do not immediately see what codepath would then print this error.
> I have just checked the file again. Around the line where ldns reports
> this error, I do not see anything strange. Line 3638 is truly blank, as
> in, it contains just a newline character, and nothing else.
> The zone file has several $INCLUDE directives, and some of the included
> files have $GENERATE directives in them. Could ldns be getting confused
> by these? Could it also be reporting the line number *after* including
> the files? That would explain why I can't find anything obvious.

ldns-read-zone does not support the include and should return an error,
in zone.c:262, there it fails for an include directive. Also for the
generate directive, that should have been a syntax error. Is it reading
a different, processed, file?

Best regards, Wouter

> Anand
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