Add minimal support for _res setup and update.

Change res_init() to initialize the _res structure on first call, and
udpate the global async context if changes were made by the user. All
resolver functions now call res_init() internally.

fixes issue spotted by otto@

11 files changed, 93 insertions, 45 deletions

diff --git a/lib/libc/asr/asr.c b/lib/libc/asr/asr.c
index 1aea2bd4e7c..a2025ec4af0 100644
--- a/lib/libc/asr/asr.c
+++ b/lib/libc/asr/asr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr.c,v 1.25 2013/04/30 12:02:39 eric Exp $	*/
+/*	$OpenBSD: asr.c,v 1.26 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2010-2012 Eric Faurot <eric@openbsd.org>
  *
@@ -394,9 +394,9 @@ asr_ctx_free(struct asr_ctx *ac)
 
 	if (ac->ac_domain)
 		free(ac->ac_domain);
-	for (i = 0; i < ac->ac_nscount; i++)
+	for (i = 0; i < ASR_MAXNS; i++)
 		free(ac->ac_ns[i]);
-	for (i = 0; i < ac->ac_domcount; i++)
+	for (i = 0; i < ASR_MAXDOM; i++)
 		free(ac->ac_dom[i]);
 
 	free(ac);
@@ -632,7 +632,7 @@ pass0(char **tok, int n, struct asr_ctx *ac)
 		}
 	} else if (!strcmp(tok[0], "search")) {
 		/* resolv.conf says the last line wins */
-		for (i = 0; i < ac->ac_domcount; i++)
+		for (i = 0; i < ASR_MAXDOM; i++)
 			free(ac->ac_dom[i]);
 		ac->ac_domcount = 0;
 		for (i = 1; i < n; i++)
diff --git a/lib/libc/asr/asr_debug.c b/lib/libc/asr/asr_debug.c
index 468c197134e..8cc54e2062f 100644
--- a/lib/libc/asr/asr_debug.c
+++ b/lib/libc/asr/asr_debug.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr_debug.c,v 1.12 2013/04/09 06:42:17 otto Exp $	*/
+/*	$OpenBSD: asr_debug.c,v 1.13 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -302,22 +302,7 @@ asr_dump_config(FILE *f, struct asr *a)
 		fprintf(f, "	%s\n", print_sockaddr(ac->ac_ns[i], buf,
 		    sizeof buf));
 	fprintf(f, "HOSTFILE %s\n", ac->ac_hostfile);
-	fprintf(f, "LOOKUP");
-	for (i = 0; i < ac->ac_dbcount; i++) {
-		switch (ac->ac_db[i]) {
-		case ASR_DB_FILE:
-			fprintf(f, " file");
-			break;
-		case ASR_DB_DNS:
-			fprintf(f, " dns");
-			break;
-		case ASR_DB_YP:
-			fprintf(f, " yp");
-			break;
-		default:
-			fprintf(f, " ?%i", ac->ac_db[i]);
-		}
-	}
+	fprintf(f, "LOOKUP %s", ac->ac_db);
 	fprintf(f, "\n------------------------------------\n");
 }
 
diff --git a/lib/libc/asr/asr_private.h b/lib/libc/asr/asr_private.h
index 275d18eb576..3564e302c6a 100644
--- a/lib/libc/asr/asr_private.h
+++ b/lib/libc/asr/asr_private.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr_private.h,v 1.17 2013/04/30 12:02:39 eric Exp $	*/
+/*	$OpenBSD: asr_private.h,v 1.18 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -121,11 +121,9 @@ enum async_type {
 	ASR_GETNAMEINFO,
 };
 
-enum asr_db_type {
-	ASR_DB_FILE,
-	ASR_DB_DNS,
-	ASR_DB_YP,
-};
+#define	ASR_DB_FILE	'f'
+#define	ASR_DB_DNS	'b'
+#define	ASR_DB_YP	'y'
 
 struct asr_ctx {
 	int		 ac_refcount;
@@ -135,7 +133,7 @@ struct asr_ctx {
 	int		 ac_domcount;
 	char		*ac_dom[ASR_MAXDOM];
 	int		 ac_dbcount;
-	int		 ac_db[ASR_MAXDB];
+	char		 ac_db[ASR_MAXDB + 1];
 	int		 ac_family[3];
 
 	char		*ac_hostfile;
diff --git a/lib/libc/asr/getaddrinfo.c b/lib/libc/asr/getaddrinfo.c
index 84b11ce5b80..9e8ba91c5b2 100644
--- a/lib/libc/asr/getaddrinfo.c
+++ b/lib/libc/asr/getaddrinfo.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getaddrinfo.c,v 1.1 2012/09/08 11:08:21 eric Exp $	*/
+/*	$OpenBSD: getaddrinfo.c,v 1.2 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -31,6 +31,8 @@ getaddrinfo(const char *hostname, const char *servname,
 	struct async_res ar;
 	int		 saved_errno = errno;
 
+	res_init();
+
 	as = getaddrinfo_async(hostname, servname, hints, NULL);
 	if (as == NULL) {
 		if (errno == ENOMEM) {
diff --git a/lib/libc/asr/gethostnamadr.c b/lib/libc/asr/gethostnamadr.c
index 6833166dbf7..363d0a2e527 100644
--- a/lib/libc/asr/gethostnamadr.c
+++ b/lib/libc/asr/gethostnamadr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: gethostnamadr.c,v 1.6 2013/04/14 22:23:08 deraadt Exp $	*/
+/*	$OpenBSD: gethostnamadr.c,v 1.7 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -127,12 +127,22 @@ _gethostbyname(const char *name, int af)
 struct hostent *
 gethostbyname(const char *name)
 {
-	return _gethostbyname(name, -1);
+	struct hostent	*h;
+
+	res_init();
+
+	if (_res.options & RES_USE_INET6 &&
+	    (h = _gethostbyname(name, AF_INET6)))
+			return (h);
+
+	return _gethostbyname(name, AF_INET);
 }
 
 struct hostent *
 gethostbyname2(const char *name, int af)
 {
+	res_init();
+
 	return _gethostbyname(name, af);
 }
 
@@ -142,6 +152,8 @@ gethostbyaddr(const void *addr, socklen_t len, int af)
 	struct async	*as;
 	struct async_res ar;
 
+	res_init();
+
 	as = gethostbyaddr_async(addr, len, af, NULL);
 	if (as == NULL) {
 		h_errno = NETDB_INTERNAL;
diff --git a/lib/libc/asr/getnameinfo.c b/lib/libc/asr/getnameinfo.c
index 0349732ab10..7e2b5d43db4 100644
--- a/lib/libc/asr/getnameinfo.c
+++ b/lib/libc/asr/getnameinfo.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getnameinfo.c,v 1.1 2012/09/08 11:08:21 eric Exp $	*/
+/*	$OpenBSD: getnameinfo.c,v 1.2 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -31,6 +31,8 @@ getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host,
 	struct async_res ar;
 	int		 saved_errno = errno;
 
+	res_init();
+
 	as = getnameinfo_async(sa, salen, host, hostlen, serv, servlen, flags,
 	    NULL);
 	if (as == NULL) {
diff --git a/lib/libc/asr/getnetnamadr.c b/lib/libc/asr/getnetnamadr.c
index 63cc0754f68..5c8781cb2ef 100644
--- a/lib/libc/asr/getnetnamadr.c
+++ b/lib/libc/asr/getnetnamadr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getnetnamadr.c,v 1.4 2013/04/04 17:50:19 eric Exp $	*/
+/*	$OpenBSD: getnetnamadr.c,v 1.5 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -83,6 +83,8 @@ getnetbyname(const char *name)
 	struct async	*as;
 	struct async_res ar;
 
+	res_init();
+
 	as = getnetbyname_async(name, NULL);
 	if (as == NULL) {
 		h_errno = NETDB_INTERNAL;
@@ -108,6 +110,8 @@ getnetbyaddr(in_addr_t net, int type)
 	struct async	*as;
 	struct async_res ar;
 
+	res_init();
+
 	as = getnetbyaddr_async(net, type, NULL);
 	if (as == NULL) {
 		h_errno = NETDB_INTERNAL;
diff --git a/lib/libc/asr/getrrsetbyname.c b/lib/libc/asr/getrrsetbyname.c
index 12bb56b06f8..9cafae80877 100644
--- a/lib/libc/asr/getrrsetbyname.c
+++ b/lib/libc/asr/getrrsetbyname.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getrrsetbyname.c,v 1.1 2012/09/08 11:08:21 eric Exp $	*/
+/*	$OpenBSD: getrrsetbyname.c,v 1.2 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -32,6 +32,8 @@ getrrsetbyname(const char *name, unsigned int class, unsigned int type,
 	struct async_res ar;
 	int		 r, saved_errno = errno;
 
+	res_init();
+
 	as = getrrsetbyname_async(name, class, type, flags, NULL);
 	if (as == NULL) {
 		r = (errno == ENOMEM) ? ERRSET_NOMEMORY : ERRSET_FAIL;
diff --git a/lib/libc/asr/res_init.c b/lib/libc/asr/res_init.c
index 1ba38cd0c24..c8958793b46 100644
--- a/lib/libc/asr/res_init.c
+++ b/lib/libc/asr/res_init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_init.c,v 1.1 2012/09/08 11:08:21 eric Exp $	*/
+/*	$OpenBSD: res_init.c,v 1.2 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -16,18 +16,16 @@
  */
 
 #include <sys/types.h>
+#include <arpa/nameser.h>
 #include <netinet/in.h>
 
 #include <resolv.h>
+#include <string.h>
 
 #include "asr.h"
+#include "asr_private.h"
+#include "thread_private.h"
 
-/*
- * XXX these function is actually internal to asr, but we use it here to force
- * the creation a default resolver context in res_init().
- */
-struct asr_ctx *asr_use_resolver(struct asr *);
-void asr_ctx_unref(struct asr_ctx *);
 
 struct __res_state _res;
 struct __res_state_ext _res_ext;
@@ -37,8 +35,47 @@ int h_errno;
 int
 res_init(void)
 {
-	async_resolver_done(NULL);
-	asr_ctx_unref(asr_use_resolver(NULL));
+	_THREAD_PRIVATE_MUTEX(init);
+	struct asr_ctx	*ac;
+
+	ac = asr_use_resolver(NULL);
+
+	/*
+	 * The first thread to call res_init() will setup the global _res
+	 * structure from the async context, not overriding fields set early
+	 * by the user.
+	 */
+	_THREAD_PRIVATE_MUTEX_LOCK(init);
+	if (!(_res.options & RES_INIT)) {
+		if (_res.retry == 0)
+			_res.retry = ac->ac_nsretries;
+		if (_res.options == 0)
+			_res.options = ac->ac_options;
+		if (_res.lookups[0] == '\0')
+			strlcpy(_res.lookups, ac->ac_db, sizeof(_res.lookups));
+
+		_res.nscount = ac->ac_nscount;
+		_res.options |= RES_INIT;
+	}
+	_THREAD_PRIVATE_MUTEX_UNLOCK(init);
+
+	/*
+	 * If the program is not threaded, we want to reflect (some) changes
+	 * made by the user to the global _res structure.
+	 * This is a bit of a hack: if there is already an async query on
+	 * this context, it might change things in its back.  It is ok
+	 * as long as the user only uses the blocking resolver API.
+	 * If needed we could consider cloning the context if there is
+	 * a running query.
+	 */
+	if (!__isthreaded) {
+		ac->ac_nsretries = _res.retry;
+		ac->ac_options = _res.options;
+		strlcpy(ac->ac_db, _res.lookups, sizeof(ac->ac_db));
+		ac->ac_dbcount = strlen(ac->ac_db);
+	}
+
+	asr_ctx_unref(ac);
 
 	return (0);
 }
diff --git a/lib/libc/asr/res_query.c b/lib/libc/asr/res_query.c
index 7a6a1db0ca4..c30188fae54 100644
--- a/lib/libc/asr/res_query.c
+++ b/lib/libc/asr/res_query.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_query.c,v 1.3 2013/04/30 12:02:39 eric Exp $	*/
+/*	$OpenBSD: res_query.c,v 1.4 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -31,6 +31,8 @@ res_query(const char *name, int class, int type, u_char *ans, int anslen)
 	struct async_res ar;
 	size_t		 len;
 
+	res_init();
+
 	if (ans == NULL || anslen <= 0) {
 		h_errno = NO_RECOVERY;
 		errno = EINVAL;
@@ -71,6 +73,8 @@ res_search(const char *name, int class, int type, u_char *ans, int anslen)
 	struct async_res ar;
 	size_t		 len;
 
+	res_init();
+
 	if (ans == NULL || anslen <= 0) {
 		h_errno = NO_RECOVERY;
 		errno = EINVAL;
diff --git a/lib/libc/asr/res_send.c b/lib/libc/asr/res_send.c
index 5135a8d15da..2353796a080 100644
--- a/lib/libc/asr/res_send.c
+++ b/lib/libc/asr/res_send.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_send.c,v 1.3 2013/04/30 12:02:39 eric Exp $	*/
+/*	$OpenBSD: res_send.c,v 1.4 2013/05/27 17:31:01 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -31,6 +31,8 @@ res_send(const u_char *buf, int buflen, u_char *ans, int anslen)
 	struct async_res ar;
 	size_t		 len;
 
+	res_init();
+
 	if (ans == NULL || anslen <= 0) {
 		errno = EINVAL;
 		return (-1);