Update the resolver part of libc to bind-4.9.3-beta24 level (from beta9p1)

Note that this was done by selective patching from diffs, to not conflict
with the 4.4bsd base code..  This was *not* a trivial task..  I have been
testing this code (apart from cosmetic changes) in my libc for a while now.

Obtained from: Paul Vixie <paul@vix.com>

1 files changed, 71 insertions, 37 deletions

diff --git a/lib/libc/net/res_init.c b/lib/libc/net/res_init.c
index 347e5b6..c6292c8 100644
--- a/lib/libc/net/res_init.c
+++ b/lib/libc/net/res_init.c
@@ -53,11 +53,12 @@
 
 #if defined(LIBC_SCCS) && !defined(lint)
 static char sccsid[] = "@(#)res_init.c	8.1 (Berkeley) 6/7/93";
-static char rcsid[] = "$Id: res_init.c,v 1.3 1994/09/25 17:45:39 pst Exp $";
+static char rcsid[] = "$Id: res_init.c,v 1.4 1995/05/30 05:40:55 rgrimes Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
 #include <sys/socket.h>
+#include <sys/time.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <arpa/nameser.h>
@@ -69,9 +70,13 @@ static char rcsid[] = "$Id: res_init.c,v 1.3 1994/09/25 17:45:39 pst Exp $";
 #include <stdlib.h>
 #include <string.h>
 
+#include <res_config.h>
+
 static void res_setoptions __P((char *, char *));
 
 #ifdef RESOLVSORT
+static const char sort_mask[] = "/&";
+#define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 static u_int32_t net_mask __P((struct in_addr));
 #endif
 
@@ -102,11 +107,12 @@ struct __res_state _res;
  *
  * Return 0 if completes successfully, -1 on error
  */
+int
 res_init()
 {
 	register FILE *fp;
 	register char *cp, **pp;
-	register int n, dots;
+	register int n;
 	char buf[BUFSIZ];
 	int nserv = 0;    /* number of nameserver records read from file */
 	int haveenv = 0;
@@ -115,9 +121,12 @@ res_init()
 	int nsort = 0;
 	char *net;
 #endif
+#ifndef RFC1535
+	int dots;
+#endif
 
 	/*
-	 * These four fields used to be statically initialized.  This made
+	 * 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
@@ -128,14 +137,27 @@ res_init()
 	 * 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.
+	 *
+	 * _res.options is tricky since some apps were known to diddle the bits
+	 * before res_init() was first called. We can't replicate that semantic
+	 * with dynamic initialization (they may have turned bits off that are
+	 * set in RES_DEFAULT).  Our solution is to declare such applications
+	 * "broken".  They could fool us by setting RES_INIT but none do (yet).
 	 */
 	if (!_res.retrans)
 		_res.retrans = RES_TIMEOUT;
 	if (!_res.retry)
 		_res.retry = 4;
-	if (!_res.options)
+	if (!(_res.options & RES_INIT))
 		_res.options = RES_DEFAULT;
 
+	/*
+	 * This one used to initialize implicitly to zero, so unless the app
+	 * has set it to something in particular, we can randomize it now.
+	 */
+	if (!_res.id)
+		_res.id = res_randomid();
+
 #ifdef USELOOPBACK
 	_res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 #else
@@ -181,14 +203,19 @@ res_init()
 		*pp++ = 0;
 	}
 
+#define	MATCH(line, name) \
+	(!strncmp(line, name, sizeof(name) - 1) && \
+	(line[sizeof(name) - 1] == ' ' || \
+	 line[sizeof(name) - 1] == '\t'))
+
 	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 	    /* read the config file */
 	    while (fgets(buf, sizeof(buf), fp) != NULL) {
 		/* skip comments */
-		if ((*buf == ';') || (*buf == '#'))
+		if (*buf == ';' || *buf == '#')
 			continue;
 		/* read default domain name */
-		if (!strncmp(buf, "domain", sizeof("domain") - 1)) {
+		if (MATCH(buf, "domain")) {
 		    if (haveenv)	/* skip if have from environ */
 			    continue;
 		    cp = buf + sizeof("domain") - 1;
@@ -204,7 +231,7 @@ res_init()
 		    continue;
 		}
 		/* set search list */
-		if (!strncmp(buf, "search", sizeof("search") - 1)) {
+		if (MATCH(buf, "search")) {
 		    if (haveenv)	/* skip if have from environ */
 			    continue;
 		    cp = buf + sizeof("search") - 1;
@@ -223,9 +250,7 @@ res_init()
 		    cp = _res.defdname;
 		    pp = _res.dnsrch;
 		    *pp++ = cp;
-		    for (n = 0;
-			 *cp && pp < _res.dnsrch + MAXDNSRCH;
-			 cp++) {
+		    for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 			    if (*cp == ' ' || *cp == '\t') {
 				    *cp = 0;
 				    n = 1;
@@ -243,8 +268,7 @@ res_init()
 		    continue;
 		}
 		/* read nameservers to query */
-		if (!strncmp(buf, "nameserver", sizeof("nameserver") - 1) &&
-		   nserv < MAXNS) {
+		if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 		   struct in_addr a;
 
 		    cp = buf + sizeof("nameserver") - 1;
@@ -260,7 +284,7 @@ res_init()
 		    continue;
 		}
 #ifdef RESOLVSORT
-		if (!strncmp(buf, "sortlist", sizeof("sortlist") -1)) {
+		if (MATCH(buf, "sortlist")) {
 		    struct in_addr a;
 
 		    cp = buf + sizeof("sortlist") - 1;
@@ -270,17 +294,18 @@ res_init()
 			if (*cp == '\0' || *cp == '\n' || *cp == ';')
 			    break;
 			net = cp;
-			while (*cp && *cp != '/' &&
+			while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 			    isascii(*cp) && !isspace(*cp))
 				cp++;
 			n = *cp;
 			*cp = 0;
 			if (inet_aton(net, &a)) {
 			    _res.sort_list[nsort].addr = a;
-			    if (n == '/') {
+			    if (ISSORTMASK(n)) {
 				*cp++ = n;
 				net = cp;
-				while (*cp && isascii(*cp) && !isspace(*cp))
+				while (*cp && *cp != ';' &&
+					isascii(*cp) && !isspace(*cp))
 				    cp++;
 				n = *cp;
 				*cp = 0;
@@ -296,12 +321,12 @@ res_init()
 			    }
 			    nsort++;
 			}
-			*cp++ = n;
+			*cp = n;
 		    }
 		    continue;
 		}
 #endif
-		if (!strncmp(buf, "options", sizeof("options") -1)) {
+		if (MATCH(buf, "options")) {
 		    res_setoptions(buf + sizeof("options") - 1, "conf");
 		    continue;
 		}
@@ -312,13 +337,11 @@ res_init()
 	    _res.nsort = nsort;
 #endif
 	    (void) fclose(fp);
-	} /*if(fopen)*/
-	if (_res.defdname[0] == 0) {
-		if (gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
-		   (cp = strchr(buf, '.'))) {
-			(void)strcpy(_res.defdname, cp + 1);
-		}
 	}
+	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) {
@@ -333,32 +356,30 @@ res_init()
 
 		cp = _res.defdname;
 		while (pp < _res.dnsrch + MAXDFLSRCH) {
-			if (dots < LOCALDOMAINPARTS) {
+			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++) {
+			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) {
+	if ((cp = getenv("RES_OPTIONS")) != NULL)
 		res_setoptions(cp, "env");
-	}
 	_res.options |= RES_INIT;
 	return (0);
 }
 
-
 static void
 res_setoptions(options, source)
 	char *options, *source;
@@ -366,10 +387,11 @@ res_setoptions(options, source)
 	char *cp = options;
 	int i;
 
-	if (_res.options & RES_DEBUG) {
+#ifdef DEBUG
+	if (_res.options & RES_DEBUG)
 		printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 		       options, source);
-	}
+#endif
 	while (*cp) {
 		/* skip leading and inner runs of spaces */
 		while (*cp == ' ' || *cp == '\t')
@@ -381,16 +403,19 @@ res_setoptions(options, source)
 				_res.ndots = i;
 			else
 				_res.ndots = RES_MAXNDOTS;
-			if (_res.options & RES_DEBUG) {
+#ifdef DEBUG
+			if (_res.options & RES_DEBUG)
 				printf(";;\tndots=%d\n", _res.ndots);
-			}
+#endif
 		} else if (!strncmp(cp, "debug", sizeof("debug")-1)) {
+#ifdef DEBUG
 			if (!(_res.options & RES_DEBUG)) {
 				printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 				       options, source);
 				_res.options |= RES_DEBUG;
 			}
 			printf(";;\tdebug\n");
+#endif
 		} else {
 			/* XXX - print a warning here? */
 		}
@@ -401,6 +426,7 @@ res_setoptions(options, source)
 }
 
 #ifdef RESOLVSORT
+/* XXX - should really support CIDR which means explicit masks always. */
 static u_int32_t
 net_mask(in)		/* XXX - should really use system's version of this */
 	struct in_addr in;
@@ -411,7 +437,15 @@ net_mask(in)		/* XXX - should really use system's version of this */
                 return (htonl(IN_CLASSA_NET));
         else if (IN_CLASSB(i))
                 return (htonl(IN_CLASSB_NET));
-        else
-                return (htonl(IN_CLASSC_NET));
+	return (htonl(IN_CLASSC_NET));
 }
 #endif
+
+u_int16_t
+res_randomid()
+{
+	struct timeval now;
+
+	gettimeofday(&now, NULL);
+	return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
+}