Re: Minor feature additions

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Hello,
Andreas Schneider a écrit :
> On Tuesday 07 July 2009 21:05:11 Chris Backas wrote:
>   
>> Hello all,
>>     
>
> Hi Chris,
>
>   
>> 1) The known hosts file: Current libssh considers it an error
>> condition if this does not exist. I don't really see why, but it
>> causes us problems on our production machines because typically no
>> one's ever run ssh on them directly before, so the file isn't there to
>> begin with. We see no reason to have to go around to every machine and
>> ensure this file exists first, so I did a simple modification in the
>> 0.2 release that changes "file not found"  in ssh_parse_knownhost()
>> from an error condition to a simple "return NULL", meaning "No match
>> found".
>>     
>
> I think there should be know error if the known_hosts file doesn't exist. At 
> least it should be the choice of the application developer to fail here or 
> not. Feel free to send a git patch.
>
>   
Returning a constant saying "known host file not found" should be
enough. Legacy code (not handling this constant) would not change
behaviour since the previous behaviour was to return an error. I am in
favor of this change (both branches).
>> Could there be a simple option which determines whether not having a
>> known hosts file is a real problem?
>>     
>
> I don't think so and if then the application developer should handle it in 
> this case. Maybe set the errno here.
>
>   
We have a mechanism for this.
>> 2) In getai(), it saves a lot of futile DNS querying time to do
>> something like this:
>> hints.ai_flags |= AI_NUMERICHOST;
>>
>> Obviously, if you know ahead of time that you're supplying a plain IP
>> Address. Could there be a way to tell libssh that this is the case and
>> add that flag to the hints conditionally?
>>     
>
> I think we could add a function for this. Aris?
>
>   
Hmm, I think we don't have to add a function but rather understand why
it tries to make a DNS lookup even when we give out an IP address.
Almost no highlevel framework adds an option to hint the resolver that
we gave a numeric IP, I think it should not be exported to the public
functions.
I'm going to see what we do wrong, in worst case, doing a regexplike
search on [0-9]+\.[0-9]+\.[0-9]+\.[0-9]+ is not that hard. (a bit harder
for ipv6).

Aris