to avoid any possibility of the pipe getting full and blocking we now

only allow one query in the async dns pipe at a time. The others are
queued in the parent.
(This used to be commit f1004dd52adb29d088f0725e2c940ed44d3a764f)

diff --git a/source3/nmbd/asyncdns.c b/source3/nmbd/asyncdns.c
index 4982f7f340fbbe239e03653f51edae75da7339b0..a451f6b6176075d4f2a00498e3dc5d6c60268632 100644 (file)
--- a/source3/nmbd/asyncdns.c
+++ b/source3/nmbd/asyncdns.c
@@ -67,9 +67,11 @@ struct query_record {
        struct in_addr result;
 };
 
-/* a queue of pending requests waiting for DNS responses */
+/* a queue of pending requests waiting to be sent to the DNS child */
 static struct packet_struct *dns_queue;
 
+/* the packet currently being processed by the dns child */
+static struct packet_struct *dns_current;
 
 
 /***************************************************************************
@@ -140,20 +142,26 @@ void start_async_dns(void)
 /***************************************************************************
 check if a particular name is already being queried
   ****************************************************************************/
-static BOOL query_in_queue(struct query_record *r)
+static BOOL query_current(struct query_record *r)
 {
-       struct packet_struct *p;
-       for (p = dns_queue; p; p = p->next) {
-               struct nmb_packet *nmb = &p->packet.nmb;
-               struct nmb_name *question = &nmb->question.question_name;
-
-               if (name_equal(question, &r->name)) 
-                       return True;
-       }
-       return False;
+       return dns_current &&
+               name_equal(&r->name, 
+                          &dns_current->packet.nmb.question.question_name);
 }
 
 
+/***************************************************************************
+  write a query to the child process
+  ****************************************************************************/
+static BOOL write_child(struct packet_struct *p)
+{
+       struct query_record r;
+
+       r.name = p->packet.nmb.question.question_name;
+
+       return write_data(fd_out, (char *)&r, sizeof(r)) == sizeof(r);
+}
+
 /***************************************************************************
   check the DNS queue
   ****************************************************************************/
@@ -173,6 +181,19 @@ void run_dns_queue(void)
 
        add_dns_result(&r.name, r.result);
 
+       if (dns_current) {
+               if (query_current(&r)) {
+                       DEBUG(3,("DNS calling reply_name_query\n"));
+                       in_dns = 1;
+                       reply_name_query(dns_current);
+                       in_dns = 0;
+               }
+
+               dns_current->locked = False;
+               free_packet(dns_current);
+               dns_current = NULL;
+       }
+
        /* loop over the whole dns queue looking for entries that
           match the result we just got */
        for (p = dns_queue; p;) {
@@ -200,6 +221,18 @@ void run_dns_queue(void)
                }
        }
 
+       if (dns_queue) {
+               dns_current = dns_queue;
+               dns_queue = dns_queue->next;
+               if (dns_queue) dns_queue->prev = NULL;
+               dns_current->next = NULL;
+
+               if (!write_child(dns_current)) {
+                       DEBUG(3,("failed to send DNS query to child!\n"));
+                       return;
+               }
+       }
+
 }
 
 /***************************************************************************
@@ -208,27 +241,25 @@ queue a DNS query
 BOOL queue_dns_query(struct packet_struct *p,struct nmb_name *question,
                     struct name_record **n)
 {
-       struct query_record r;
-       
        if (in_dns || fd_in == -1)
                return False;
 
-       r.name = *question;
-
-       if (!query_in_queue(&r) && 
-           !write_data(fd_out, (char *)&r, sizeof(r))) {
-               DEBUG(3,("failed to send DNS query to child!\n"));
-               return False;
+       if (!dns_current) {
+               if (!write_child(p)) {
+                       DEBUG(3,("failed to send DNS query to child!\n"));
+                       return False;
+               }
+               dns_current = p;
+               p->locked = True;
+       } else {
+               p->locked = True;
+               p->next = dns_queue;
+               p->prev = NULL;
+               if (p->next)
+                       p->next->prev = p;
+               dns_queue = p;
        }
 
-       p->locked = True;
-       p->next = dns_queue;
-       p->prev = NULL;
-       if (p->next)
-               p->next->prev = p;
-       dns_queue = p;
-
-
        DEBUG(3,("added DNS query for %s\n", namestr(question)));
        return True;
 }