[Dnsmasq-discuss] [PATCH] Logging of dhcp_script output

Simon Kelley simon at thekelleys.org.uk
Tue May 9 23:14:41 BST 2017

On 09/05/17 18:49, Petr Menšík wrote:
> Hi Simon,
> sorry for a delay. We concluded that we do not like die on parse error
> even for dhcp script. It does always start up now unless script returns
> nonzero exit status. With this change, it would never start, until you
> were able to figure out what is wrong with your script. Then fix the
> cause. Until that, no-one will receive any lease as they did before.
> When assigning addresses to dhclient that had his address before,
> dnsmasq will offer requested address if it is not leased. If you start
> with clear leases, many machines will receive correct addresses again.
> Dnsmasq is used as small server for containers or virtual hosts on the
> local machine. I think it is quite useful they will always (try to) start.
> I think it should be possible to disable dying on parse errors. I think
> change from totally ignoring parsing errors to being not able to skip
> them is problematic for real world administrators.
> I would prefer current behavior as default, but with possible
> configuration override. I think it would be useful if return code
> suggested there is problem with lease database. I could then move old
> leases file and retry with empty database from the startup script.
> What do you think?

I think that just logging a warning is best. I don't want to add yet
another obscure config option.



> Dne 29.4.2017 v 00:03 Simon Kelley napsal(a):
>> On 24/04/17 15:42, Petr Mensik wrote:
>>> Thank you for accepting that patches. I agree that some garbage is
>>> far more likely to appear in dhcp-script mode. I would myself welcome
>>> error log from wrong formatted lease file as well. If I understand it
>>> well, that file will be overwritten after the first lease created. If
>>> it contains wrong data, just log an error, but do not terminate.
>> That seems sensible. Change committed.
>>> It should not surprise administrator that just disabled IPv6 support.
>>> Error message would be logged once at startup until the first lease
>>> is created. Then file will be rewritten without any IPv6 leases,
>>> because they were skipped during the reading. I would accept one
>>> error message as notification some leases are gone forever.
>> Agreed.
>>> I will have to ask whether failure to start on database corruption is
>>> considered a problem. It was silently ignoring all problems before.
>>> Now it fails to start the service completely if any error occurs. I
>>> think it relied on auto recovery with empty leases in the same way as
>>> with plain file. I think there should be a way to override default
>>> behavior. I will check for more opinions and get back with results.
>> Any news on this?
>> Cheers,
>> Simon.
>>> Thank you Simon.
>>> Cheers, Petr

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