netgroup limits on -current ... [mountd(8)]
Vladimir Egorin
vladimir at math.uic.edu
Tue Feb 21 06:17:30 PST 2006
On Tue, Feb 21, 2006 at 12:24:35PM +1030, Wilkinson, Alex wrote:
> OS: FreeBSD 7.0-CURRENT #24: Thu Feb 16 12:28:58 CST 2006
>
> Hi all,
>
> We are currently experiencing problems with FreeBSD -CURRENT and mountd(8).
> When we export a filesystem via NFS to a netgroup with a 'large' number of hosts
> in it we get all sorts of truncation. There looks like a limit on the number of
> hosts in a netgroup FreeBSD's mountd(8) can export to. e.g.
>
> NFS Export
> ----------
>
> /export/home/username my_netgroup
>
> mountd(8) In Debugging Mode
> ---------------------------
>
> Feb 21 12:10:49 host mountd[83451]: can't get address info for host hostname.dsto.defence.g
> Feb 21 12:10:49 host mountd[83451]: bad host host.dsto.defence.g in netgroup my_netgroup, skipping
>
> This happens as mountd(8) builds its exports list via:
>
> mountd: getting export list
> mountd: got line /export/home/username my_netgroup
> mountd: making new ep fs=0x4297314f,0x57f85ac
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
> got host host.dsto.defence.gov.au
>
> ...
>
> relevant code producing this error:
>
> /usr/src/usr.sbin/mountd
>
> get_host(cp, grp, tgrp)
> char *cp;
> struct grouplist *grp;
> struct grouplist *tgrp;
> {
> struct grouplist *checkgrp;
> struct addrinfo *ai, *tai, hints;
> int ecode;
> char host[NI_MAXHOST];
>
> if (grp->gr_type != GT_NULL) {
> syslog(LOG_ERR, "Bad netgroup type for ip host %s", cp);
> return (1);
> }
> memset(&hints, 0, sizeof hints);
> hints.ai_flags = AI_CANONNAME;
> hints.ai_protocol = IPPROTO_UDP;
> ecode = getaddrinfo(cp, NULL, &hints, &ai);
> if (ecode != 0) {
> syslog(LOG_ERR,"can't get address info for host %s", cp);
> return 1;
> }
> grp->gr_ptr.gt_addrinfo = ai;
> while (ai != NULL) {
> if (ai->ai_canonname == NULL) {
> if (getnameinfo(ai->ai_addr, ai->ai_addrlen, host,
> sizeof host, NULL, 0, NI_NUMERICHOST) != 0)
> strlcpy(host, "?", sizeof(host));
> ai->ai_canonname = strdup(host);
> ai->ai_flags |= AI_CANONNAME;
> }
> if (debug)
> fprintf(stderr, "got host %s\n", ai->ai_canonname);
> /*
> * Sanity check: make sure we don't already have an entry
> * for this host in the grouplist.
> */
> for (checkgrp = tgrp; checkgrp != NULL;
> checkgrp = checkgrp->gr_next) {
> if (checkgrp->gr_type != GT_HOST)
> continue;
> for (tai = checkgrp->gr_ptr.gt_addrinfo; tai != NULL;
> tai = tai->ai_next) {
> if (sacmp(tai->ai_addr, ai->ai_addr, NULL) != 0)
> continue;
> if (debug)
> fprintf(stderr,
> "ignoring duplicate host %s\n",
> ai->ai_canonname);
> grp->gr_type = GT_IGNORE;
> return (0);
> }
> }
> ai = ai->ai_next;
> }
>
>
> Can someone please tell me if there is a limit on the number characters or hosts
> that mountd(8) can build an export list from ? And if so can we increase it ?
>
> Cheers
>
> - aW
This reminds me of an old problem I had on a solaris 2.5.1 -- it was not possible
to have a "large" number of hosts in the netgroup and (thus) in the export list.
The solution was to split the large netgroup into a number of smaller netgroups,
and then combine them into a large netgroup using the smaller netgroups' names.
We did that with a C program, you could also do that in a script.
The problem was a limit of 255 characters on the length of the
netgroup list.
I still have the program if you are interested.
--
Vladimir
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