/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <ndb.h>#include <ip.h>#include "dns.h" Area *owned, *delegated; /* *  true if a name is in our area */Area*inmyarea(char *name){	int len;	Area *s, *d; 	len = strlen(name);	for(s = owned; s; s = s->next){		if(s->len > len)			continue;		if(cistrcmp(s->soarr->owner->name, name + len - s->len) == 0)			if(len == s->len || name[len - s->len - 1] == '.')				break;	}	if(s == nil)		return nil; 	/* name is in area `s' */	for(d = delegated; d; d = d->next){		if(d->len > len)			continue;		if(cistrcmp(d->soarr->owner->name, name + len - d->len) == 0)			if(len == d->len || name[len - d->len - 1] == '.')				return nil; /* name is in a delegated subarea */	} 	return s;	/* name is in area `s' and not in a delegated subarea */} /* *  our area is the part of the domain tree that *  we serve */voidaddarea(DN *dp, RR *rp, Ndbtuple *t){	Area *s;	Area **l; 	lock(&dnlock);	if(t->val[0])		l = &delegated;	else		l = &owned; 	for (s = *l; s != nil; s = s->next)		if (strcmp(dp->name, s->soarr->owner->name) == 0) {			unlock(&dnlock);			return;		/* we've already got one */		} 	/*	 *  The area contains a copy of the soa rr that created it.	 *  The owner of the the soa rr should stick around as long	 *  as the area does.	 */	s = emalloc(sizeof(*s));	s->len = strlen(dp->name);	rrcopy(rp, &s->soarr);	s->soarr->owner = dp;	s->soarr->db = 1;	s->soarr->ttl = Hour;	s->neednotify = 1;	s->needrefresh = 0; 	if (debug)		dnslog("new area %s %s", dp->name,			l == &delegated? "delegated": "owned"); 	s->next = *l;	*l = s;	unlock(&dnlock);} voidfreearea(Area **l){	Area *s; 	while(s = *l){		*l = s->next;		lock(&dnlock);		rrfree(s->soarr);		memset(s, 0, sizeof *s);	/* cause trouble */		unlock(&dnlock);		free(s);	}} /* * refresh all areas that need it *  this entails running a command 'zonerefreshprogram'.  This could *  copy over databases from elsewhere or just do a zone transfer. */voidrefresh_areas(Area *s){	int pid;	Waitmsg *w; 	for(; s != nil; s = s->next){		if(!s->needrefresh)			continue; 		if(zonerefreshprogram == nil){			s->needrefresh = 0;			continue;		} 		pid = fork();		if (pid == -1) {			sleep(1000);	/* don't fork again immediately */			continue;		}		if (pid == 0){			execl(zonerefreshprogram, "zonerefresh",				s->soarr->owner->name, nil);			exits("exec zonerefresh failed");		}		while ((w = wait()) != nil && w->pid != pid)			free(w);		if (w && w->pid == pid)			if(w->msg == nil || *w->msg == '\0')				s->needrefresh = 0;		free(w);	}}