From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <0fcc387289a4a346cbd5bf450171a0d0@plan9.jp>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] csipinfo
From: Joel “chesky” Salomon <chesky@plan9.jp>
Date: Wed, 18 Oct 2006 14:44:52 -0400
In-Reply-To: <61d9157e8f6994d999d7f257cd2b05b4@coraid.com>
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> had to go around the list ... can't post from here.
>=20
> i think you're making this too hard.  what you want is more
> of a dns query.  this is very easy to do.  something like
> (this might not complie -- i just typed it out.)
>=20
> char*
> gethostbyaddr(char *net, char *addr)
> {
> 	char buf[64];
> 	int fd, l;
>=20
> 	if(net =3D=3D 0)
> 		net=3D"/net";
> 	snprint(buf, sizeof buf, "%s/dns", net);
> 	fd =3D open(buf, ORDWR);
> 	if(fd < 0)
> 		return 0;
> 	snprint(buf, sizeof buf, "%s ptr", addr);
> 	if(write(fd, buf, strlen(buf)) < 0)
> 		return 0;
> 	l =3D read(fd, buf, sizeof buf);
> 	if(l < 0 || l =3D=3D sizeof buf)
> 		return 0;
> 	return strdup(buf);
> }
>=20
> - erik

Thanks, this finally looks like what I need.  Two points though:
1.  Is 64 bytes sufficient for the domain name?  Searching the =E2=80=99n=
et
I=E2=80=99ve found other numbers =E2=80=94 according to <http://tinyurl.c=
om/ykyths> it
should be 1005; <http://tinyurl.com/xdp4> links to a name about 140
bytes long and firefox handles it just fine.
2. Why the second part of =E2=80=9Cif(l < 0 || l =3D=3D sizeof buf)=E2=80=
=9D?

I=E2=80=99ll bang on this a bit and see if I can make it set errstr appro=
priately.

--Joel