Curl_resolv() now returns a different struct, and it contains a reference

counter so that the caller needs to decrease that counter when done with
the returned data.

If compiled with MALLOCDEBUG I've added some extra checking that the counter
is decreased before a handle is closed etc.

lib/url.c

@@ -1484,18 +1484,23 @@ static int handleSock5Proxy(
   socksreq[3] = 1; /* IPv4 = 1 */
     
   {
-    Curl_addrinfo *hp;
-    hp = Curl_resolv(conn->data, conn->hostname, conn->remote_port);
+#ifndef ENABLE_IPV6
+    struct Curl_dns_entry *dns;
+    Curl_addrinfo *hp=NULL;
+    dns = Curl_resolv(conn->data, conn->hostname, conn->remote_port);
     /*
      * We cannot use 'hostent' as a struct that Curl_resolv() returns.  It
      * returns a Curl_addrinfo pointer that may not always look the same.
      */
-#ifndef ENABLE_IPV6
+    if(dns)
+      hp=dns->addr;
     if (hp && hp->h_addr_list[0]) {
       socksreq[4] = ((char*)hp->h_addr_list[0])[0];
       socksreq[5] = ((char*)hp->h_addr_list[0])[1];
       socksreq[6] = ((char*)hp->h_addr_list[0])[2];
       socksreq[7] = ((char*)hp->h_addr_list[0])[3];
+
+      dns->inuse--; /* not used anymore from now on */
     }
     else {
       failf(conn->data, "Failed to resolve \"%s\" for SOCKS5 connect.",
@@ -1548,7 +1553,7 @@ static int handleSock5Proxy(
 }
 
 static CURLcode ConnectPlease(struct connectdata *conn,
-                              Curl_addrinfo *hostaddr,
+                              struct Curl_dns_entry *hostaddr,
                               bool *connected)
 {
   CURLcode result;
@@ -1567,6 +1572,8 @@ static CURLcode ConnectPlease(struct connectdata *conn,
     /* All is cool, then we store the current information from the hostaddr
        struct to the serv_addr, as it might be needed later. The address
        returned from the function above is crucial here. */
+    conn->connect_addr = hostaddr;
+
 #ifdef ENABLE_IPV6
     conn->serv_addr = addr;
 #else
@@ -1597,7 +1604,7 @@ static CURLcode ConnectPlease(struct connectdata *conn,
 }
 
 static void verboseconnect(struct connectdata *conn,
-                           Curl_addrinfo *hostaddr)
+                           struct Curl_dns_entry *dns)
 {
 #ifdef HAVE_INET_NTOA_R
   char ntoa_buf[64];
@@ -1606,7 +1613,7 @@ static void verboseconnect(struct connectdata *conn,
 
   /* Figure out the ip-number and display the first host name it shows: */
 #ifdef ENABLE_IPV6
-  (void)hostaddr; /* not used in the IPv6 enabled version */
+  (void)dns; /* not used in the IPv6 enabled version */
   {
     char hbuf[NI_MAXHOST];
 #ifdef NI_WITHSCOPEID
@@ -1629,6 +1636,7 @@ static void verboseconnect(struct connectdata *conn,
   }
 #else
   {
+    Curl_addrinfo *hostaddr=dns->addr;
     struct in_addr in;
     (void) memcpy(&in.s_addr, &conn->serv_addr.sin_addr, sizeof (in.s_addr));
     infof(data, "Connected to %s (%s) port %d\n",
@@ -1654,7 +1662,7 @@ static void verboseconnect(struct connectdata *conn,
  * 'serv_addr' field in the connectdata struct for most of it.
  */
 CURLcode Curl_protocol_connect(struct connectdata *conn,
-                               Curl_addrinfo *hostaddr)
+                               struct Curl_dns_entry *hostaddr)
 {
   struct SessionHandle *data = conn->data;
   CURLcode result=CURLE_OK;
@@ -1689,7 +1697,7 @@ static CURLcode CreateConnection(struct SessionHandle *data,
   struct connectdata *conn;
   struct connectdata *conn_temp;
   int urllen;
-  Curl_addrinfo *hostaddr;
+  struct Curl_dns_entry *hostaddr;
 #ifdef HAVE_ALARM
   unsigned int prev_alarm=0;
 #endif
@@ -2811,7 +2819,6 @@ CURLcode Curl_connect(struct SessionHandle *data,
   return code;
 }
 
-
 CURLcode Curl_done(struct connectdata *conn)
 {
   struct SessionHandle *data=conn->data;
@@ -2829,7 +2836,16 @@ CURLcode Curl_done(struct connectdata *conn)
     free(conn->newurl);
     conn->newurl = NULL;
   }
- 
+
+  if(conn->connect_addr)
+    conn->connect_addr->inuse--; /* done with this */
+
+#ifdef MALLOCDEBUG
+  /* scan for DNS cache entries still marked as in use */
+  Curl_hash_apply(data->hostcache,
+                  NULL, Curl_scan_cache_used);
+#endif
+
   /* this calls the protocol-specific function pointer previously set */
   if(conn->curl_done)
     result = conn->curl_done(conn);