Do not take external buffers for storing DNS responses in the internal

async API.  That is actually useless and it makes the code more
complicated.  The required buffers are always allocated when needed.

1 files changed, 13 insertions, 48 deletions

diff --git a/lib/libc/asr/res_send_async.c b/lib/libc/asr/res_send_async.c
index 7a91d190b83..2a661a12e95 100644
--- a/lib/libc/asr/res_send_async.c
+++ b/lib/libc/asr/res_send_async.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_send_async.c,v 1.16 2013/04/14 22:23:08 deraadt Exp $	*/
+/*	$OpenBSD: res_send_async.c,v 1.17 2013/04/30 12:02:39 eric Exp $	*/
 /*
  * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
  *
@@ -49,8 +49,7 @@ static int ensure_ibuf(struct async *, size_t);
 
 
 struct async *
-res_send_async(const unsigned char *buf, int buflen, unsigned char *ans,
-	int anslen, struct asr *asr)
+res_send_async(const unsigned char *buf, int buflen, struct asr *asr)
 {
 	struct asr_ctx  *ac;
 	struct async	*as;
@@ -67,17 +66,6 @@ res_send_async(const unsigned char *buf, int buflen, unsigned char *ans,
 	}
 	as->as_run = res_send_async_run;
 
-	if (ans) {
-		as->as.dns.flags |= ASYNC_EXTIBUF;
-		as->as.dns.ibuf = ans;
-		as->as.dns.ibufsize = anslen;
-		as->as.dns.ibuflen = 0;
-	} else {
-		as->as.dns.ibuf = NULL;
-		as->as.dns.ibufsize = 0;
-		as->as.dns.ibuflen = 0;
-	}
-
 	as->as.dns.flags |= ASYNC_EXTOBUF;
 	as->as.dns.obuf = (unsigned char *)buf;
 	as->as.dns.obuflen = buflen;
@@ -113,8 +101,7 @@ res_send_async(const unsigned char *buf, int buflen, unsigned char *ans,
  * (ans == NULL).
  */
 struct async *
-res_query_async(const char *name, int class, int type, unsigned char *ans,
-	int anslen, struct asr *asr)
+res_query_async(const char *name, int class, int type, struct asr *asr)
 {
 	struct asr_ctx	*ac;
 	struct async	*as;
@@ -122,15 +109,14 @@ res_query_async(const char *name, int class, int type, unsigned char *ans,
 	DPRINT("asr: res_query_async(\"%s\", %i, %i)\n", name, class, type);
 
 	ac = asr_use_resolver(asr);
-	as = res_query_async_ctx(name, class, type, ans, anslen, ac);
+	as = res_query_async_ctx(name, class, type, ac);
 	asr_ctx_unref(ac);
 
 	return (as);
 }
 
 struct async *
-res_query_async_ctx(const char *name, int class, int type, unsigned char *ans,
-	int anslen, struct asr_ctx *a_ctx)
+res_query_async_ctx(const char *name, int class, int type, struct asr_ctx *a_ctx)
 {
 	struct async	*as;
 
@@ -140,16 +126,6 @@ res_query_async_ctx(const char *name, int class, int type, unsigned char *ans,
 		return (NULL); /* errno set */
 	as->as_run = res_send_async_run;
 
-	if (ans) {
-		as->as.dns.flags |= ASYNC_EXTIBUF;
-		as->as.dns.ibuf = ans;
-		as->as.dns.ibufsize = anslen;
-	} else {
-		as->as.dns.ibuf = NULL;
-		as->as.dns.ibufsize = 0;
-	}
-	as->as.dns.ibuflen = 0;
-
 	/* This adds a "." to name if it doesn't already has one.
 	 * That's how res_query() behaves (through res_mkquery").
 	 */
@@ -478,15 +454,12 @@ udp_recv(struct async *as)
 	ssize_t		 n;
 	int		 save_errno;
 
-	/* Allocate input buf if needed */
-	if (as->as.dns.ibuf == NULL) {
-		if (ensure_ibuf(as, PACKETSZ) == -1) {
-			save_errno = errno;
-			close(as->as_fd);
-			errno = save_errno;
-			as->as_fd = -1;
-			return (-1);
-		}
+	if (ensure_ibuf(as, PACKETSZ) == -1) {
+		save_errno = errno;
+		close(as->as_fd);
+		errno = save_errno;
+		as->as_fd = -1;
+		return (-1);
 	}
 
 	n = recv(as->as_fd, as->as.dns.ibuf, as->as.dns.ibufsize, 0);
@@ -664,22 +637,14 @@ close:
 }
 
 /*
- * Make sure the input buffer is at least "n" bytes long.
- * If not (or not allocated) allocated enough space, unless the
- * buffer is external (owned by the caller), in which case it fails.
+ * Make sure the input buffer is at least "n" bytes long, and allocate or
+ * extend it if necessary. Return 0 on success, or set errno and return -1.
  */
 static int
 ensure_ibuf(struct async *as, size_t n)
 {
 	char	*t;
 
-	if (as->as.dns.flags & ASYNC_EXTIBUF) {
-		if (n <= as->as.dns.ibufsize)
-			return (0);
-		errno = EINVAL;
-		return (-1);
-	}
-
 	if (as->as.dns.ibuf == NULL) {
 		as->as.dns.ibuf = malloc(n);
 		if (as->as.dns.ibuf == NULL)