Re: [naviserver-devel] Darwin DNS

[Stephen D. <sd...@gm...>]

On 10/8/05, Zoran Vasiljevic <zv...@ar...> wrote:
> No luck: this (NetBSD) system does not have any MT-safe call.
> What I did:
>
> During the configure I emit the warning if compiling under Darwin.
>
> checking for getaddrinfo in -lsocket... no
> checking for getnameinfo in -lsocket... no
> checking for getaddrinfo... yes
> checking for getnameinfo... yes
> checking for gethostbyname_r... no
> checking for gethostbyaddr_r... no
> configure: WARNING: DNS queries will use non-threadsafe calls which
> could result in server instability
>
> In dns.c I added
>
> #ifdef __APPLE__
>     Ns_Cs cs;
>     Ns_CsEnter(&cs);
>     ...
>     Ns_CsLeave(&cs);
> #endif
>
> to cope with this *at least* within our own program. This does not
> guarantee that this is MT-safe because any of the rest of the
> system may call those calls anytime, hence we get problems anyways.



Why can't we fall back to using gethostbyname() on Darwin with it's
mt-unsafe getaddrinfo()?  gethostbyname() is also mt-unsafe, but we
already have a critical section around that.  If we have critical
sections around two separate dns calls which return the same results,
there's really no advantage in choosing one over the other, right?