Simplify handling of nameserver configuration in resolver

Remove use of ext.nsmap member of struct __res_state and always use an identity mapping betwen the nsaddr_list array and the ext.nsaddrs array. The fact that a nameserver has an IPv6 address is signalled by setting nsaddr_list[].sin_family to zero.
git-mirror · May 21, 2015 · 2212c14 · 2212c14
1 parent f585737
commit 2212c14
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diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,14 @@
+2015-05-21  Andreas Schwab  <schwab@suse.de>
+
+	[BZ #13028]
+	[BZ #17053]
+	* resolv/res_init.c (__res_vinit): Remove use of ext.nsmap member
+	of struct __res_state.
+	* resolv/res_send.c (__libc_res_nsend): Likewise.
+	(get_nsaddr): New function.
+	(res_ourserver_p, send_vc, reopen): Use it instead of accessing
+	statp directly.
+
 2015-05-20  Joseph Myers  <joseph@codesourcery.com>
 
 	* conform/GlibcConform.pm ($CFLAGS{"POSIX"}): Use

diff --git a/NEWS b/NEWS
@@ -9,16 +9,16 @@ Version 2.22
 
 * The following bugs are resolved with this release:
 
-  4719, 6792, 13064, 14094, 14841, 14906, 15319, 15467, 15790, 15969, 16159,
-  16339, 16351, 16352, 16512, 16560, 16704, 16783, 16850, 17090, 17195,
-  17269, 17523, 17542, 17569, 17581, 17588, 17596, 17620, 17621, 17628,
-  17631, 17692, 17711, 17715, 17776, 17779, 17792, 17836, 17912, 17916,
-  17930, 17932, 17944, 17949, 17964, 17965, 17967, 17969, 17978, 17987,
-  17991, 17996, 17998, 17999, 18007, 18019, 18020, 18029, 18030, 18032,
-  18036, 18038, 18039, 18042, 18043, 18046, 18047, 18049, 18068, 18080,
-  18093, 18100, 18104, 18110, 18111, 18125, 18128, 18138, 18185, 18196,
-  18197, 18206, 18210, 18211, 18217, 18220, 18221, 18244, 18247, 18287,
-  18319, 18333, 18346, 18397, 18409, 18418, 18434.
+  4719, 6792, 13028, 13064, 14094, 14841, 14906, 15319, 15467, 15790, 15969,
+  16159, 16339, 16351, 16352, 16512, 16560, 16704, 16783, 16850, 17053,
+  17090, 17195, 17269, 17523, 17542, 17569, 17581, 17588, 17596, 17620,
+  17621, 17628, 17631, 17692, 17711, 17715, 17776, 17779, 17792, 17836,
+  17912, 17916, 17930, 17932, 17944, 17949, 17964, 17965, 17967, 17969,
+  17978, 17987, 17991, 17996, 17998, 17999, 18007, 18019, 18020, 18029,
+  18030, 18032, 18036, 18038, 18039, 18042, 18043, 18046, 18047, 18049,
+  18068, 18080, 18093, 18100, 18104, 18110, 18111, 18125, 18128, 18138,
+  18185, 18196, 18197, 18206, 18210, 18211, 18217, 18220, 18221, 18244,
+  18247, 18287, 18319, 18333, 18346, 18397, 18409, 18418, 18434.
 
 * Cache information can be queried via sysconf() function on s390 e.g. with
   _SC_LEVEL1_ICACHE_SIZE as argument.

diff --git a/resolv/res_init.c b/resolv/res_init.c
@@ -153,10 +153,8 @@ __res_vinit(res_state statp, int preinit) {
 	char *cp, **pp;
 	int n;
 	char buf[BUFSIZ];
-	int nserv = 0;    /* number of IPv4 nameservers read from file */
-#ifdef _LIBC
-	int nservall = 0; /* number of (IPv4 + IPV6) nameservers read from file */
-#endif
+	int nserv = 0;    /* number of nameservers read from file */
+	int have_serv6 = 0;
 	int haveenv = 0;
 	int havesearch = 0;
 #ifdef RESOLVSORT
@@ -184,15 +182,9 @@ __res_vinit(res_state statp, int preinit) {
 	statp->_flags = 0;
 	statp->qhook = NULL;
 	statp->rhook = NULL;
-	statp->_u._ext.nsinit = 0;
 	statp->_u._ext.nscount = 0;
-#ifdef _LIBC
-	statp->_u._ext.nscount6 = 0;
-	for (n = 0; n < MAXNS; n++) {
-		statp->_u._ext.nsaddrs[n] = NULL;
-		statp->_u._ext.nsmap[n] = MAXNS;
-	}
-#endif
+	for (n = 0; n < MAXNS; n++)
+	    statp->_u._ext.nsaddrs[n] = NULL;
 
 	/* Allow user to override the local domain definition */
 	if ((cp = getenv("LOCALDOMAIN")) != NULL) {
@@ -296,25 +288,20 @@ __res_vinit(res_state statp, int preinit) {
 		    continue;
 		}
 		/* read nameservers to query */
-#ifdef _LIBC
-		if (MATCH(buf, "nameserver") && nservall < MAXNS) {
-#else
 		if (MATCH(buf, "nameserver") && nserv < MAXNS) {
-#endif
 		    struct in_addr a;
 
 		    cp = buf + sizeof("nameserver") - 1;
 		    while (*cp == ' ' || *cp == '\t')
 			cp++;
 		    if ((*cp != '\0') && (*cp != '\n')
 			&& __inet_aton(cp, &a)) {
-			statp->nsaddr_list[nservall].sin_addr = a;
-			statp->nsaddr_list[nservall].sin_family = AF_INET;
-			statp->nsaddr_list[nservall].sin_port =
+			statp->nsaddr_list[nserv].sin_addr = a;
+			statp->nsaddr_list[nserv].sin_family = AF_INET;
+			statp->nsaddr_list[nserv].sin_port =
 				htons(NAMESERVER_PORT);
 			nserv++;
 #ifdef _LIBC
-			nservall++;
 		    } else {
 			struct in6_addr a6;
 			char *el;
@@ -356,10 +343,11 @@ __res_vinit(res_state statp, int preinit) {
 				    }
 				}
 
-				statp->_u._ext.nsaddrs[nservall] = sa6;
-				statp->_u._ext.nssocks[nservall] = -1;
-				statp->_u._ext.nsmap[nservall] = MAXNS + 1;
-				nservall++;
+				statp->nsaddr_list[nserv].sin_family = 0;
+				statp->_u._ext.nsaddrs[nserv] = sa6;
+				statp->_u._ext.nssocks[nserv] = -1;
+				have_serv6 = 1;
+				nserv++;
 			    }
 			}
 #endif
@@ -414,10 +402,9 @@ __res_vinit(res_state statp, int preinit) {
 		    continue;
 		}
 	    }
-	    statp->nscount = nservall;
+	    statp->nscount = nserv;
 #ifdef _LIBC
-	    if (nservall - nserv > 0) {
-		statp->_u._ext.nscount6 = nservall - nserv;
+	    if (have_serv6) {
 		/* We try IPv6 servers again.  */
 		statp->ipv6_unavail = false;
 	    }
@@ -606,11 +593,7 @@ __res_iclose(res_state statp, bool free_addr) {
 		statp->_vcsock = -1;
 		statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 	}
-#ifdef _LIBC
-	for (ns = 0; ns < MAXNS; ns++)
-#else
 	for (ns = 0; ns < statp->_u._ext.nscount; ns++)
-#endif
 		if (statp->_u._ext.nsaddrs[ns]) {
 			if (statp->_u._ext.nssocks[ns] != -1) {
 				close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
@@ -621,8 +604,6 @@ __res_iclose(res_state statp, bool free_addr) {
 				statp->_u._ext.nsaddrs[ns] = NULL;
 			}
 		}
-	if (free_addr)
-		statp->_u._ext.nsinit = 0;
 }
 libc_hidden_def (__res_iclose)