if (!_res.options) _res.options = RES_DEFAULT;
if (!(_res.options & RES_INIT)) _res.options |= RES_DEFAULT;
res_init(){	register FILE *fp;	register char *cp, **pp;	register int n, dots;	char buf[BUFSIZ];	int nserv = 0;    /* number of nameserver records read from file */	int haveenv = 0;	int havesearch = 0;#ifdef RESOLVSORT	int nsort = 0;	char *net;#endif	/*	 * These three fields used to be statically initialized.  This made	 * it hard to use this code in a shared library.  It is necessary,	 * now that we're doing dynamic initialization here, that we preserve	 * the old semantics: if an application modifies one of these three	 * fields of _res before res_init() is called, res_init() will not	 * alter them.  Of course, if an application is setting them to	 * _zero_ before calling res_init(), hoping to override what used	 * to be the static default, we can't detect it and unexpected results	 * will follow.  Zero for any of these fields would make no sense,	 * so one can safely assume that the applications were already getting	 * unexpected results.	 */	if (!_res.retrans)		_res.retrans = RES_TIMEOUT;	if (!_res.retry)		_res.retry = 4;	if (!_res.options)		_res.options = RES_DEFAULT;#ifdef USELOOPBACK	_res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);#else	_res.nsaddr.sin_addr.s_addr = INADDR_ANY;#endif	_res.nsaddr.sin_family = AF_INET;	_res.nsaddr.sin_port = htons(NAMESERVER_PORT);	_res.nscount = 1;	_res.ndots = 1;	_res.pfcode = 0;	/* Allow user to override the local domain definition */	if ((cp = getenv("LOCALDOMAIN")) != NULL) {		(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);		haveenv++;		/*		 * Set search list to be blank-separated strings		 * from rest of env value.  Permits users of LOCALDOMAIN		 * to still have a search list, and anyone to set the		 * one that they want to use as an individual (even more		 * important now that the rfc1535 stuff restricts searches)		 */		cp = _res.defdname;		pp = _res.dnsrch;		*pp++ = cp;		for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {			if (*cp == '\n')	/* silly backwards compat */				break;			else if (*cp == ' ' || *cp == '\t') {				*cp = 0;				n = 1;			} else if (n) {				*pp++ = cp;				n = 0;				havesearch = 1;			}		}		/* null terminate last domain if there are excess */		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')			cp++;		*cp = '\0';		*pp++ = 0;	}#define	MATCH(line, name) \	(!strncmp(line, name, sizeof(name) - 1) && \	(line[sizeof(name) - 1] == ' ' || \	 line[sizeof(name) - 1] == '\t'))#ifdef	NeXT	if (netinfo_res_init(&haveenv, &havesearch) == 0)#endif	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {	    /* read the config file */	    while (fgets(buf, sizeof(buf), fp) != NULL) {		/* skip comments */		if (*buf == ';' || *buf == '#')			continue;		/* read default domain name */		if (MATCH(buf, "domain")) {		    if (haveenv)	/* skip if have from environ */			    continue;		    cp = buf + sizeof("domain") - 1;		    while (*cp == ' ' || *cp == '\t')			    cp++;		    if ((*cp == '\0') || (*cp == '\n'))			    continue;		    strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);		    if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)			    *cp = '\0';		    havesearch = 0;		    continue;		}		/* set search list */		if (MATCH(buf, "search")) {		    if (haveenv)	/* skip if have from environ */			    continue;		    cp = buf + sizeof("search") - 1;		    while (*cp == ' ' || *cp == '\t')			    cp++;		    if ((*cp == '\0') || (*cp == '\n'))			    continue;		    strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);		    if ((cp = strchr(_res.defdname, '\n')) != NULL)			    *cp = '\0';		    /*		     * Set search list to be blank-separated strings		     * on rest of line.		     */		    cp = _res.defdname;		    pp = _res.dnsrch;		    *pp++ = cp;		    for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {			    if (*cp == ' ' || *cp == '\t') {				    *cp = 0;				    n = 1;			    } else if (n) {				    *pp++ = cp;				    n = 0;			    }		    }		    /* null terminate last domain if there are excess */		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')			    cp++;		    *cp = '\0';		    *pp++ = 0;		    havesearch = 1;		    continue;		}		/* read nameservers to query */		if (MATCH(buf, "nameserver") && nserv < MAXNS) {		    struct in_addr a;		    cp = buf + sizeof("nameserver") - 1;		    while (*cp == ' ' || *cp == '\t')			cp++;		    if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {			_res.nsaddr_list[nserv].sin_addr = a;			_res.nsaddr_list[nserv].sin_family = AF_INET;			_res.nsaddr_list[nserv].sin_port =				htons(NAMESERVER_PORT);			nserv++;		    }		    continue;		}#ifdef RESOLVSORT		if (MATCH(buf, "sortlist")) {		    struct in_addr a;		    cp = buf + sizeof("sortlist") - 1;		    while (nsort < MAXRESOLVSORT) {			while (*cp == ' ' || *cp == '\t')			    cp++;			if (*cp == '\0' || *cp == '\n' || *cp == ';')			    break;			net = cp;			while (*cp && *cp != '/' &&			       isascii(*cp) && !isspace(*cp))				cp++;			n = *cp;			*cp = 0;			if (inet_aton(net, &a)) {			    _res.sort_list[nsort].addr = a;			    if (n == '/') {				*cp++ = n;				net = cp;				while (*cp && isascii(*cp) && !isspace(*cp))				    cp++;				n = *cp;				*cp = 0;				if (inet_aton(net, &a)) {				    _res.sort_list[nsort].mask = a.s_addr;				} else {				    _res.sort_list[nsort].mask = 					net_mask(_res.sort_list[nsort].addr);				}			    } else {				_res.sort_list[nsort].mask = 				    net_mask(_res.sort_list[nsort].addr);			    }			    nsort++;			}			*cp++ = n;		    }		    continue;		}#endif		if (MATCH(buf, "options")) {		    res_setoptions(buf + sizeof("options") - 1, "conf");		    continue;		}	    }	    if (nserv > 1) 		_res.nscount = nserv;#ifdef RESOLVSORT	    _res.nsort = nsort;#endif	    (void) fclose(fp);	}	if (_res.defdname[0] == 0 &&	    gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&	    (cp = strchr(buf, '.')) != NULL)		strcpy(_res.defdname, cp + 1);	/* find components of local domain that might be searched */	if (havesearch == 0) {		pp = _res.dnsrch;		*pp++ = _res.defdname;		*pp = NULL;#ifndef RFC1535		dots = 0;		for (cp = _res.defdname; *cp; cp++)			dots += (*cp == '.');		cp = _res.defdname;		while (pp < _res.dnsrch + MAXDFLSRCH) {			if (dots < LOCALDOMAINPARTS)				break;			cp = strchr(cp, '.') + 1;    /* we know there is one */			*pp++ = cp;			dots--;		}		*pp = NULL;#ifdef DEBUG		if (_res.options & RES_DEBUG) {			printf(";; res_init()... default dnsrch list:\n");			for (pp = _res.dnsrch; *pp; pp++)				printf(";;\t%s\n", *pp);			printf(";;\t..END..\n");		}#endif /* DEBUG */#endif /* !RFC1535 */	}	if ((cp = getenv("RES_OPTIONS")) != NULL)		res_setoptions(cp, "env");	_res.options |= RES_INIT;	return (0);}