Re: [Fwd: [FYI] Important bug fix commited]

Hi,

sorry for delay...

On Sunday 28 September 2003 18:54, Andreas Fink wrote:
[snip]

> > Here is the quote from `man gethostbyname`:
> >        The functions gethostbyname() and gethostbyaddr() may return
> >        pointers to static data, which may be overwritten by later
> > calls.
> >        Copying the struct hostent does not suffice, since it contains
> >        pointers- a deep copy is required.
>
> from man gethostbyname on MacOS X:
>
> BUGS
>       These functions use static data storage; if the data is needed for
> future
>       use, it should be copied before any subsequent calls overwrite it.
>   Only
>       the Internet address format is currently understood.

it's the same as for all gethostbyname functions, these uses static data...

> in my eyes it should be sufficient to make a semaphore lock around the
> function, copy the data out and you're done.

yep, this means, "deep-copy". Just look into gwlib/protected.c, but if a
reentrant function supported, we avoid locking then.

> The struct returned on MacOS X is:
>
>      struct  hostent {
>               char    *h_name;        /* official name of host */
>               char    **h_aliases;    /* alias list */
>               int     h_addrtype;     /* host address type */
>               int     h_length;       /* length of address */
>               char    **h_addr_list;  /* list of addresses from name
> server */
>       };
>
> and the function calls are:
>
> struct hostent *	gethostbyname(const char *name);
> struct hostent *	gethostbyname2(const char *name, int af);
>
> > Commited version trying to use reentrant alternatives for
> > gethostbyname,
> > unfortunately it's not a POSIX functions and every OS have a different
> > call.
> > For now we have 3 types supported:
> > 	1) 6 params for call (Linux version)
> > 	2) 5 params for call (Solaris version)
> > 	3) no reentrant function at all , make a deep copy of hostent
> > pointers.
> >
> > gethostbyname_r with 3 params for call doesn't supported yet (deep copy
> >  used), because I can't test it (implementation should be simple).
> >
> > --
> > Best regards / Mit besten Grüßen aus Düsseldorf
> >
> > Dipl.-Ing.
> > Alexander Malysh
> > ___________________________________________
> >
> > Centrium GmbH
> > Vogelsanger Weg 80
> > 40470 Düsseldorf
> >
> > Fon: +49 (0211) 74 84 51 80
> > Fax: +49 (0211) 277 49 109
> >
> > email: [email protected]
> > web: www.centrium.de
> > msn: [email protected]
> > icq: 98063111
> > ___________________________________________
> >
> > Please avoid sending me Word or PowerPoint attachments.
> > See http://www.fsf.org/philosophy/no-word-attachments.html
>
> Andreas Fink
> Global Networks Switzerland AG
>
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-- 
Best regards / Mit besten Grüßen aus Düsseldorf

Dipl.-Ing.
Alexander Malysh
___________________________________

Centrium GmbH
Vogelsanger Weg 80
40470 Düsseldorf

Fon: +49 (0211) 74 84 51 80
Fax: +49 (0211) 277 49 109

email: a.malysh at centrium.de
web: http://www.centrium.de
msn: olek2002 at hotmail.com
icq: 98063111
___________________________________________

Please avoid sending me Word or PowerPoint attachments.
See http://www.fsf.org/philosophy/no-word-attachments.html