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-rw-r--r--lib/libc/resolv/res_query.c97
1 files changed, 73 insertions, 24 deletions
diff --git a/lib/libc/resolv/res_query.c b/lib/libc/resolv/res_query.c
index c160e93..c0cf003 100644
--- a/lib/libc/resolv/res_query.c
+++ b/lib/libc/resolv/res_query.c
@@ -10,10 +10,6 @@
* 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.
@@ -70,8 +66,10 @@
#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
-static const char rcsid[] = "$Id: res_query.c,v 1.7.18.1 2005/04/27 05:01:11 sra Exp $";
+static const char rcsid[] = "$Id: res_query.c,v 1.2.2.3.4.2 2004/03/16 12:34:19 marka Exp $";
#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
#include "port_before.h"
#include <sys/types.h>
@@ -86,6 +84,7 @@ static const char rcsid[] = "$Id: res_query.c,v 1.7.18.1 2005/04/27 05:01:11 sra
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <unistd.h>
#include "port_after.h"
/* Options. Leave them on. */
@@ -97,7 +96,7 @@ static const char rcsid[] = "$Id: res_query.c,v 1.7.18.1 2005/04/27 05:01:11 sra
#define MAXPACKET 1024
#endif
-/*%
+/*
* Formulate a normal query, send, and await answer.
* Returned answer is placed in supplied buffer "answer".
* Perform preliminary check of answer, returning success only
@@ -109,10 +108,10 @@ static const char rcsid[] = "$Id: res_query.c,v 1.7.18.1 2005/04/27 05:01:11 sra
*/
int
res_nquery(res_state statp,
- const char *name, /*%< domain name */
- int class, int type, /*%< class and type of query */
- u_char *answer, /*%< buffer to put answer */
- int anslen) /*%< size of answer buffer */
+ const char *name, /* domain name */
+ int class, int type, /* class and type of query */
+ u_char *answer, /* buffer to put answer */
+ int anslen) /* size of answer buffer */
{
u_char buf[MAXPACKET];
HEADER *hp = (HEADER *) answer;
@@ -122,7 +121,8 @@ res_nquery(res_state statp,
oflags = statp->_flags;
again:
- hp->rcode = NOERROR; /*%< default */
+ hp->rcode = NOERROR; /* default */
+
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_query(%s, %d, %d)\n", name, class, type);
@@ -194,7 +194,7 @@ again:
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
@@ -202,10 +202,10 @@ again:
*/
int
res_nsearch(res_state statp,
- const char *name, /*%< domain name */
- int class, int type, /*%< class and type of query */
- u_char *answer, /*%< buffer to put answer */
- int anslen) /*%< size of answer */
+ const char *name, /* domain name */
+ int class, int type, /* class and type of query */
+ u_char *answer, /* buffer to put answer */
+ int anslen) /* size of answer */
{
const char *cp, * const *domain;
HEADER *hp = (HEADER *) answer;
@@ -217,7 +217,8 @@ res_nsearch(res_state statp,
int searched = 0;
errno = 0;
- RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /*%< True if we never query. */
+ RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */
+
dots = 0;
for (cp = name; *cp != '\0'; cp++)
dots += (*cp == '.');
@@ -240,6 +241,21 @@ res_nsearch(res_state statp,
answer, anslen);
if (ret > 0 || trailing_dot)
return (ret);
+ if (errno == ECONNREFUSED) {
+ RES_SET_H_ERRNO(statp, TRY_AGAIN);
+ return (-1);
+ }
+ switch (statp->res_h_errno) {
+ case NO_DATA:
+ case HOST_NOT_FOUND:
+ break;
+ case TRY_AGAIN:
+ if (hp->rcode == SERVFAIL)
+ break;
+ /* FALLTHROUGH */
+ default:
+ return (-1);
+ }
saved_herrno = statp->res_h_errno;
tried_as_is++;
}
@@ -263,6 +279,9 @@ res_nsearch(res_state statp,
(domain[0][0] == '.' && domain[0][1] == '\0'))
root_on_list++;
+ if (root_on_list && tried_as_is)
+ continue;
+
ret = res_nquerydomain(statp, name, *domain,
class, type,
answer, anslen);
@@ -295,9 +314,26 @@ res_nsearch(res_state statp,
/* keep trying */
break;
case TRY_AGAIN:
+ /*
+ * This can occur due to a server failure
+ * (that is, all listed servers have failed),
+ * or all listed servers have timed out.
+ * ((HEADER *)answer)->rcode may not be set
+ * to SERVFAIL in the case of a timeout.
+ *
+ * Either way we must return TRY_AGAIN in
+ * order to avoid non-deterministic
+ * return codes.
+ * For example, loaded name servers or races
+ * against network startup/validation (dhcp,
+ * ppp, etc) can cause the search to timeout
+ * on one search element, e.g. 'fu.bar.com',
+ * and return a definitive failure on the
+ * next search element, e.g. 'fu.'.
+ */
+ got_servfail++;
if (hp->rcode == SERVFAIL) {
/* try next search element, if any */
- got_servfail++;
break;
}
/* FALLTHROUGH */
@@ -314,6 +350,18 @@ res_nsearch(res_state statp,
}
}
+ switch (statp->res_h_errno) {
+ case NO_DATA:
+ case HOST_NOT_FOUND:
+ break;
+ case TRY_AGAIN:
+ if (hp->rcode == SERVFAIL)
+ break;
+ /* FALLTHROUGH */
+ default:
+ goto giveup;
+ }
+
/*
* If the query has not already been tried as is then try it
* unless RES_NOTLDQUERY is set and there were no dots.
@@ -333,6 +381,7 @@ res_nsearch(res_state statp,
* else send back meaningless H_ERRNO, that being the one from
* the last DNSRCH we did.
*/
+giveup:
if (saved_herrno != -1)
RES_SET_H_ERRNO(statp, saved_herrno);
else if (got_nodata)
@@ -342,7 +391,7 @@ res_nsearch(res_state statp,
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.
*/
@@ -350,9 +399,9 @@ int
res_nquerydomain(res_state statp,
const char *name,
const char *domain,
- int class, int type, /*%< class and type of query */
- u_char *answer, /*%< buffer to put answer */
- int anslen) /*%< size of answer */
+ int class, int type, /* class and type of query */
+ u_char *answer, /* buffer to put answer */
+ int anslen) /* size of answer */
{
char nbuf[MAXDNAME];
const char *longname = nbuf;
@@ -399,6 +448,8 @@ res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
if (statp->options & RES_NOALIASES)
return (NULL);
+ if (issetugid())
+ return (NULL);
file = getenv("HOSTALIASES");
if (file == NULL || (fp = fopen(file, "r")) == NULL)
return (NULL);
@@ -428,5 +479,3 @@ res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
fclose(fp);
return (NULL);
}
-
-/*! \file */
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