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Diffstat (limited to 'resolv/res_query.c')
-rw-r--r--resolv/res_query.c119
1 files changed, 88 insertions, 31 deletions
diff --git a/resolv/res_query.c b/resolv/res_query.c
index 968ba8b..ab4e02a 100644
--- a/resolv/res_query.c
+++ b/resolv/res_query.c
@@ -91,6 +91,13 @@ static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vix
#define MAXPACKET 65536
#endif
+#define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1)
+
+static int
+__libc_res_nquerydomain(res_state statp, const char *name, const char *domain,
+ int class, int type, u_char *answer, int anslen,
+ u_char **answerp);
+
/*
* Formulate a normal query, send, and await answer.
* Returned answer is placed in supplied buffer "answer".
@@ -102,11 +109,12 @@ static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vix
* Caller must parse answer and determine whether it answers the question.
*/
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 */
+__libc_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 */
+ u_char **answerp) /* if buffer needs to be enlarged */
{
u_char *buf;
HEADER *hp = (HEADER *) answer;
@@ -114,15 +122,7 @@ res_nquery(res_state statp,
hp->rcode = NOERROR; /* default */
- if (!__libc_use_alloca (MAXPACKET)) {
- buf = malloc (MAXPACKET);
- if (buf == NULL) {
- __set_h_errno (NETDB_INTERNAL);
- return -1;
- }
- use_malloc = 1;
- } else
- buf = alloca (MAXPACKET);
+ buf = alloca (QUERYSIZE);
#ifdef DEBUG
if (statp->options & RES_DEBUG)
@@ -130,8 +130,18 @@ res_nquery(res_state statp,
#endif
n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
- buf, MAXPACKET);
- if (n <= 0) {
+ buf, QUERYSIZE);
+ if (__builtin_expect (n <= 0, 0)) {
+ /* Retry just in case res_nmkquery failed because of too
+ short buffer. Shouldn't happen. */
+ buf = malloc (MAXPACKET);
+ if (buf != NULL) {
+ use_malloc = 1;
+ n = res_nmkquery(statp, QUERY, name, class, type, NULL,
+ 0, NULL, buf, MAXPACKET);
+ }
+ }
+ if (__builtin_expect (n <= 0, 0)) {
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_query: mkquery failed\n");
@@ -141,7 +151,7 @@ res_nquery(res_state statp,
free (buf);
return (n);
}
- n = res_nsend(statp, buf, n, answer, anslen);
+ n = __libc_res_nsend(statp, buf, n, answer, anslen, answerp);
if (use_malloc)
free (buf);
if (n < 0) {
@@ -181,6 +191,17 @@ res_nquery(res_state statp,
return (n);
}
+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 */
+{
+ return __libc_res_nquery(statp, name, class, type, answer, anslen,
+ NULL);
+}
+
/*
* Formulate a normal query, send, and retrieve answer in supplied buffer.
* Return the size of the response on success, -1 on error.
@@ -188,11 +209,12 @@ res_nquery(res_state statp,
* is detected. Error code, if any, is left in H_ERRNO.
*/
int
-res_nsearch(res_state statp,
+__libc_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 */
+ int anslen, /* size of answer */
+ u_char **answerp)
{
const char *cp, * const *domain;
HEADER *hp = (HEADER *) answer;
@@ -214,7 +236,8 @@ res_nsearch(res_state statp,
/* If there aren't any dots, it could be a user-level alias. */
if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
- return (res_nquery(statp, cp, class, type, answer, anslen));
+ return (__libc_res_nquery(statp, cp, class, type, answer,
+ anslen, answerp));
/*
* If there are enough dots in the name, let's just give it a
@@ -223,12 +246,16 @@ res_nsearch(res_state statp,
*/
saved_herrno = -1;
if (dots >= statp->ndots || trailing_dot) {
- ret = res_nquerydomain(statp, name, NULL, class, type,
- answer, anslen);
+ ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
+ answer, anslen, answerp);
if (ret > 0 || trailing_dot)
return (ret);
saved_herrno = h_errno;
tried_as_is++;
+ if (answerp && *answerp != answer) {
+ answer = *answerp;
+ anslen = MAXPACKET;
+ }
}
/*
@@ -249,12 +276,17 @@ res_nsearch(res_state statp,
(domain[0][0] == '.' && domain[0][1] == '\0'))
root_on_list++;
- ret = res_nquerydomain(statp, name, *domain,
- class, type,
- answer, anslen);
+ ret = __libc_res_nquerydomain(statp, name, *domain,
+ class, type,
+ answer, anslen, answerp);
if (ret > 0)
return (ret);
+ if (answerp && *answerp != answer) {
+ answer = *answerp;
+ anslen = MAXPACKET;
+ }
+
/*
* If no server present, give up.
* If name isn't found in this domain,
@@ -306,8 +338,8 @@ res_nsearch(res_state statp,
* query now.
*/
if (statp->ndots && !(tried_as_is || root_on_list)) {
- ret = res_nquerydomain(statp, name, NULL, class, type,
- answer, anslen);
+ ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
+ answer, anslen, answerp);
if (ret > 0)
return (ret);
}
@@ -328,17 +360,29 @@ res_nsearch(res_state statp,
return (-1);
}
+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 */
+{
+ return __libc_res_nsearch(statp, name, class, type, answer,
+ anslen, NULL);
+}
+
/*
* 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_nquerydomain(res_state statp,
+static int
+__libc_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 anslen, /* size of answer */
+ u_char **answerp)
{
char nbuf[MAXDNAME];
const char *longname = nbuf;
@@ -374,7 +418,20 @@ res_nquerydomain(res_state statp,
}
sprintf(nbuf, "%s.%s", name, domain);
}
- return (res_nquery(statp, longname, class, type, answer, anslen));
+ return (__libc_res_nquery(statp, longname, class, type, answer,
+ anslen, answerp));
+}
+
+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 */
+{
+ return __libc_res_nquerydomain(statp, name, domain, class, type,
+ answer, anslen, NULL);
}
const char *
generated by cgit v1.1 at 2024-11-05 03:21:03 +0000