The following reply was made to PR pkg/36853; it has been noted by GNATS.

From: christos@zoulas.com (Christos Zoulas)
To: gnats-bugs@NetBSD.org, martti@NetBSD.org, gnats-admin@netbsd.org,
	pkgsrc-bugs@netbsd.org, carl@bl.echidna.id.au
Cc: 
Subject: Re: pkg/36853: clamav-milter doesn't start - _res is not supported for multi-threaded programs.
Date: Fri, 21 Dec 2007 11:48:16 -0500

 On Dec 21, 11:30am, carl@bl.echidna.id.au (Carl Brewer) wrote:
 -- Subject: Re: pkg/36853: clamav-milter doesn't start - _res is not supporte
 
 Here is an *UNTESTED* patch that fixes the race in res_query for non-bind9
 systems, and uses res_ninit/res_nquery in bind9 systems.
 
 Enjoy,
 
 christos
 
 --- clamav-milter.c.orig	2007-12-12 17:41:25.000000000 -0500
 +++ clamav-milter.c	2007-12-21 11:47:01.000000000 -0500
 @@ -90,6 +90,9 @@
  #if	HAVE_RESOLV_H
  #include <arpa/nameser.h>	/* for HEADER */
  #include <resolv.h>
 +#if __RES >= 20030124
 +#define	HAVE_BIND9
 +#endif
  #endif
  #ifdef	HAVE_UNISTD_H
  #include <unistd.h>
 @@ -505,6 +508,20 @@
  #endif	/*SESSION*/
  
  static	pthread_cond_t	watchdog_cond = PTHREAD_COND_INITIALIZER;
 +#ifndef HAVE_BIND9
 +static	pthread_mutex_t res_mutex = PTHREAD_MUTEX_INITIALIZER;
 +#define RES_QUERY(len, h, c, t, q, s) \
 +	do { \
 +		pthread_mutex_lock(&res_mutex); \
 +		len = res_query((h), (c), (t), (q), (s)); \
 +		pthread_mutex_unlock(&res_mutex); \
 +	} while (/*CONSTCOND*/0)
 +#else
 +static	pthread_key_t res_key;
 +#define RES_QUERY(len, h, c, t, q, s) \
 +	len = res_nquery((res_state)pthread_getspecific(res_key), \
 +	    (h), (c), (t), (q), (s))
 +#endif
  
  #ifndef	SHUT_RD
  #define	SHUT_RD		0
 @@ -2061,12 +2078,19 @@
  	logg(_("Starting %s\n"), clamav_version);
  	logg(_("*Debugging is on\n"));
  
 +#ifndef HAVE_BIND9
  	if(!(_res.options&RES_INIT))
  		if(res_init() < 0) {
  			fprintf(stderr, "%s: Can't initialise the resolver\n",
  				argv[0]);
  			return EX_UNAVAILABLE;
  		}
 +#else
 +	if (pthread_key_create(&res_key, free)) {
 +		perror("pthread_key_create");
 +		return EX_UNAVAILABLE;
 +	}
 +#endif
  
  	if(blacklist_time) {
  		char name[MAXHOSTNAMELEN + 1];
 @@ -2579,6 +2603,18 @@
  	int sock = s->sock;
  	struct sockaddr *server = (struct sockaddr *)s->server;
  	int server_index = s->server_index;
 +#ifdef HAVE_BIND9
 +	res_state res = cli_calloc(1, sizeof(*res));
 +	if (pthread_setspecific(res_key, res)) {
 +		perror("pthread_setspecific");
 +		free(res);
 +		return NULL;
 +	}
 +	if (res_ninit(res) < 0) {
 +		perror("res_ninit");
 +		return NULL;
 +	}
 +#endif
  
  	if(last_failed_pings[server_index]) {
  		s->rc = 0;
 @@ -6150,7 +6186,7 @@
  			return NULL;
  	}
  
 -	len = res_query(host, C_IN, T_MX, (u_char *)&q, sizeof(q));
 +	RES_QUERY(len, host, C_IN, T_MX, (u_char *)&q, sizeof(q));
  	if(len < 0)
  		return t;	/* Host has no MX records */
  
 @@ -6219,7 +6255,7 @@
  	if((host == NULL) || (*host == '\0'))
  		return t;
  
 -	len = res_query(host, C_IN, T_A, (u_char *)&q, sizeof(q));
 +	RES_QUERY(len, host, C_IN, T_A, (u_char *)&q, sizeof(q));
  	if(len < 0)
  		return t;	/* Host has no A records */
  
 @@ -6278,7 +6314,6 @@
   *	an SPF system, we ONLY use SPF records to reduce phish false positives
   * TODO: IPv6?
   * TODO: cache queries?
 - * TODO: check res_query is thread safe
   *
   * INPUT: prevhosts, a list of hosts already searched: stops include loops
   *	e.g. mercado.com includes medrcadosw.com which includes mercado.com,
 @@ -6330,7 +6365,7 @@
  		*ptr = '\0';
  
  	logg("*SPF query '%s'\n", host);
 -	len = res_query(host, C_IN, T_TXT, (u_char *)&q, sizeof(q));
 +	RES_QUERY(len, host, C_IN, T_TXT, (u_char *)&q, sizeof(q));
  	if(len < 0) {
  		free(host);
  		return 0;	/* Host has no TXT records */