initial import

1 files changed, 384 insertions, 0 deletions

diff --git a/resolv/res_query.c b/resolv/res_query.c
new file mode 100644
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--- /dev/null
+++ b/resolv/res_query.c
@@ -0,0 +1,384 @@
+/*
+ * ++Copyright++ 1988, 1993
+ * -
+ * Copyright (c) 1988, 1993
+ *    The Regents of the University of California.  All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ * 	This product includes software developed by the University of
+ * 	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * -
+ * Portions Copyright (c) 1993 by Digital Equipment Corporation.
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies, and that
+ * the name of Digital Equipment Corporation not be used in advertising or
+ * publicity pertaining to distribution of the document or software without
+ * specific, written prior permission.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
+ * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ * -
+ * --Copyright--
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)res_query.c	8.1 (Berkeley) 6/4/93";
+static char rcsid[] = "$Id$";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/param.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <arpa/nameser.h>
+
+#include <stdio.h>
+#include <netdb.h>
+#include <resolv.h>
+#include <ctype.h>
+#include <errno.h>
+#if defined(BSD) && (BSD >= 199306)
+# include <stdlib.h>
+# include <string.h>
+#else
+# include "../conf/portability.h"
+#endif
+
+#if defined(USE_OPTIONS_H)
+# include <../conf/options.h>
+#endif
+
+#if PACKETSZ > 1024
+#define MAXPACKET	PACKETSZ
+#else
+#define MAXPACKET	1024
+#endif
+
+char *__hostalias __P((const char *));
+int h_errno;
+
+/*
+ * Formulate a normal query, send, and await answer.
+ * Returned answer is placed in supplied buffer "answer".
+ * Perform preliminary check of answer, returning success only
+ * if no error is indicated and the answer count is nonzero.
+ * Return the size of the response on success, -1 on error.
+ * Error number is left in h_errno.
+ *
+ * Caller must parse answer and determine whether it answers the question.
+ */
+int
+res_query(name, class, type, answer, anslen)
+	const char *name;	/* domain name */
+	int class, type;	/* class and type of query */
+	u_char *answer;		/* buffer to put answer */
+	int anslen;		/* size of answer buffer */
+{
+	u_char buf[MAXPACKET];
+	register HEADER *hp = (HEADER *) answer;
+	int n;
+
+	hp->rcode = NOERROR;	/* default */
+
+	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+		h_errno = NETDB_INTERNAL;
+		return (-1);
+	}
+#ifdef DEBUG
+	if (_res.options & RES_DEBUG)
+		printf(";; res_query(%s, %d, %d)\n", name, class, type);
+#endif
+
+	n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
+			buf, sizeof(buf));
+	if (n <= 0) {
+#ifdef DEBUG
+		if (_res.options & RES_DEBUG)
+			printf(";; res_query: mkquery failed\n");
+#endif
+		h_errno = NO_RECOVERY;
+		return (n);
+	}
+	n = res_send(buf, n, answer, anslen);
+	if (n < 0) {
+#ifdef DEBUG
+		if (_res.options & RES_DEBUG)
+			printf(";; res_query: send error\n");
+#endif
+		h_errno = TRY_AGAIN;
+		return (n);
+	}
+
+	if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
+#ifdef DEBUG
+		if (_res.options & RES_DEBUG)
+			printf(";; rcode = %d, ancount=%d\n", hp->rcode,
+			    ntohs(hp->ancount));
+#endif
+		switch (hp->rcode) {
+		case NXDOMAIN:
+			h_errno = HOST_NOT_FOUND;
+			break;
+		case SERVFAIL:
+			h_errno = TRY_AGAIN;
+			break;
+		case NOERROR:
+			h_errno = NO_DATA;
+			break;
+		case FORMERR:
+		case NOTIMP:
+		case REFUSED:
+		default:
+			h_errno = NO_RECOVERY;
+			break;
+		}
+		return (-1);
+	}
+	return (n);
+}
+
+/*
+ * Formulate a normal query, send, and retrieve answer in supplied buffer.
+ * Return the size of the response on success, -1 on error.
+ * If enabled, implement search rules until answer or unrecoverable failure
+ * is detected.  Error code, if any, is left in h_errno.
+ */
+int
+res_search(name, class, type, answer, anslen)
+	const char *name;	/* domain name */
+	int class, type;	/* class and type of query */
+	u_char *answer;		/* buffer to put answer */
+	int anslen;		/* size of answer */
+{
+	register const char *cp, * const *domain;
+	HEADER *hp = (HEADER *) answer;
+	u_int dots;
+	int trailing_dot, ret, saved_herrno;
+	int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
+
+	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+		h_errno = NETDB_INTERNAL;
+		return (-1);
+	}
+	errno = 0;
+	h_errno = HOST_NOT_FOUND;	/* default, if we never query */
+	dots = 0;
+	for (cp = name; *cp; cp++)
+		dots += (*cp == '.');
+	trailing_dot = 0;
+	if (cp > name && *--cp == '.')
+		trailing_dot++;
+
+	/*
+	 * if there aren't any dots, it could be a user-level alias
+	 */
+	if (!dots && (cp = __hostalias(name)) != NULL)
+		return (res_query(cp, class, type, answer, anslen));
+
+	/*
+	 * If there are dots in the name already, let's just give it a try
+	 * 'as is'.  The threshold can be set with the "ndots" option.
+	 */
+	saved_herrno = -1;
+	if (dots >= _res.ndots) {
+		ret = res_querydomain(name, NULL, class, type, answer, anslen);
+		if (ret > 0)
+			return (ret);
+		saved_herrno = h_errno;
+		tried_as_is++;
+	}
+
+	/*
+	 * We do at least one level of search if
+	 *	- there is no dot and RES_DEFNAME is set, or
+	 *	- there is at least one dot, there is no trailing dot,
+	 *	  and RES_DNSRCH is set.
+	 */
+	if ((!dots && (_res.options & RES_DEFNAMES)) ||
+	    (dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
+		int done = 0;
+
+		for (domain = (const char * const *)_res.dnsrch;
+		     *domain && !done;
+		     domain++) {
+
+			ret = res_querydomain(name, *domain, class, type,
+					      answer, anslen);
+			if (ret > 0)
+				return (ret);
+
+			/*
+			 * If no server present, give up.
+			 * If name isn't found in this domain,
+			 * keep trying higher domains in the search list
+			 * (if that's enabled).
+			 * On a NO_DATA error, keep trying, otherwise
+			 * a wildcard entry of another type could keep us
+			 * from finding this entry higher in the domain.
+			 * If we get some other error (negative answer or
+			 * server failure), then stop searching up,
+			 * but try the input name below in case it's
+			 * fully-qualified.
+			 */
+			if (errno == ECONNREFUSED) {
+				h_errno = TRY_AGAIN;
+				return (-1);
+			}
+
+			switch (h_errno) {
+			case NO_DATA:
+				got_nodata++;
+				/* FALLTHROUGH */
+			case HOST_NOT_FOUND:
+				/* keep trying */
+				break;
+			case TRY_AGAIN:
+				if (hp->rcode == SERVFAIL) {
+					/* try next search element, if any */
+					got_servfail++;
+					break;
+				}
+				/* FALLTHROUGH */
+			default:
+				/* anything else implies that we're done */
+				done++;
+			}
+
+			/* if we got here for some reason other than DNSRCH,
+			 * we only wanted one iteration of the loop, so stop.
+			 */
+			if (!(_res.options & RES_DNSRCH))
+				done++;
+		}
+	}
+
+	/* if we have not already tried the name "as is", do that now.
+	 * note that we do this regardless of how many dots were in the
+	 * name or whether it ends with a dot.
+	 */
+	if (!tried_as_is) {
+		ret = res_querydomain(name, NULL, class, type, answer, anslen);
+		if (ret > 0)
+			return (ret);
+	}
+
+	/* if we got here, we didn't satisfy the search.
+	 * if we did an initial full query, return that query's h_errno
+	 * (note that we wouldn't be here if that query had succeeded).
+	 * else if we ever got a nodata, send that back as the reason.
+	 * else send back meaningless h_errno, that being the one from
+	 * the last DNSRCH we did.
+	 */
+	if (saved_herrno != -1)
+		h_errno = saved_herrno;
+	else if (got_nodata)
+		h_errno = NO_DATA;
+	else if (got_servfail)
+		h_errno = TRY_AGAIN;
+	return (-1);
+}
+
+/*
+ * Perform a call on res_query on the concatenation of name and domain,
+ * removing a trailing dot from name if domain is NULL.
+ */
+int
+res_querydomain(name, domain, class, type, answer, anslen)
+	const char *name, *domain;
+	int class, type;	/* class and type of query */
+	u_char *answer;		/* buffer to put answer */
+	int anslen;		/* size of answer */
+{
+	char nbuf[2*MAXDNAME+2];
+	const char *longname = nbuf;
+	int n;
+
+#ifdef DEBUG
+	if (_res.options & RES_DEBUG)
+		printf(";; res_querydomain(%s, %s, %d, %d)\n",
+		       name, domain?domain:"<Nil>", class, type);
+#endif
+	if (domain == NULL) {
+		/*
+		 * Check for trailing '.';
+		 * copy without '.' if present.
+		 */
+		n = strlen(name) - 1;
+		if (n != (0 - 1) && name[n] == '.' && n < sizeof(nbuf) - 1) {
+			bcopy(name, nbuf, n);
+			nbuf[n] = '\0';
+		} else
+			longname = name;
+	} else
+		sprintf(nbuf, "%.*s.%.*s", MAXDNAME, name, MAXDNAME, domain);
+
+	return (res_query(longname, class, type, answer, anslen));
+}
+
+char *
+__hostalias(name)
+	register const char *name;
+{
+	register char *cp1, *cp2;
+	FILE *fp;
+	char *file;
+	char buf[BUFSIZ];
+	static char abuf[MAXDNAME];
+
+	file = getenv("HOSTALIASES");
+	if (file == NULL || (fp = fopen(file, "r")) == NULL)
+		return (NULL);
+	buf[sizeof(buf) - 1] = '\0';
+	while (fgets(buf, sizeof(buf), fp)) {
+		for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1)
+			;
+		if (!*cp1)
+			break;
+		*cp1 = '\0';
+		if (!strcasecmp(buf, name)) {
+			while (isspace(*++cp1))
+				;
+			if (!*cp1)
+				break;
+			for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)
+				;
+			abuf[sizeof(abuf) - 1] = *cp2 = '\0';
+			strncpy(abuf, cp1, sizeof(abuf) - 1);
+			fclose(fp);
+			return (abuf);
+		}
+	}
+	fclose(fp);
+	return (NULL);
+}