FreeTDS Development Group

["James K. Lowden" <jklowden AT freetds.org>]

Peter C. Norton wrote:
> 
> I've hacked in some simple support for this with very minor edits to
> gssapi.c, tds.h, and config.c.  The support adds a new config option
> to freetds.conf that adds a boolean config option of "enable gssapi
> delegation = <true|false>" by adding a couple of defines in tds.h and an
> additional value to the TDSCONNECTION struct.
> 
> So my first question is: Would this minor addition be accepted into
> the mainline freetds by the maintainers?

Hello Peter, 

Absolutely.  I don't understand the fine points of Kerberos, but I don't
see any downside to the changes you propose.  

> The man page for fprintf only specifies that passing in a non-null
> terminated pointer to the *printf calls will result in "unspecified
> behavior"

We should never pass NULL to any form of printf.  Yes, some
implementations may handle it gracefully, but it's poor form at the very
least.  Your proposed change is fine.  I have also used shortcuts such as

        fprintf(stderr, "Operating-system error:\n\t%s\n", 
                oserrstr? oserrstr : "(none)");

> Test #2 ... actually bothers me more because it seems like the
> expected behavior of setting a SIGALARM handler isn't working properly:

Feh.  We shouldn't do I/O in a signal handler.  It would be hard to
convince me that ct_cancel() can be called in a signal handler, either. 
Safely, I mean.  

http://www.gnu.org/s/libc/manual/html_node/Nonreentrancy.html#Nonreentrancy
http://publications.gbdirect.co.uk/c_book/chapter9/signal_handling.html

The canonical catch_alrm() /* nice, saving one letter, there, eh?! [1] */ 
would look more like this:

static volatile unsigned char ftimed_out = 0;

void
catch_alrm(int sig_num)
{
        signal(SIGALRM, catch_alrm);
        ftimed_out = 1;
}

and the fetch loop (no prize itself) would call ct_cancel() if ftimed_out
is true.  Which of course it could do on row 5 without all the signal
handler stuff.  

I appreciate your thoroughness and look forward to your patch.  

Regards, 

--jkl

[1] I think it was Ken Thompson who, when asked if he'd do anything
differently if he had UNIX to do over again said, "I'd spell creat(2) with
its 'e'".