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authorAndrew Tridgell <tridge@samba.org>1997-11-02 01:25:50 +0000
committerAndrew Tridgell <tridge@samba.org>1997-11-02 01:25:50 +0000
commit4fe3b2ce751806e2add9c021c60c22d22fedbab5 (patch)
treef37046647c29ef8315c99a28fc0355fd55f866a9 /source3
parent60e82110214469dcbd9d134a527fa534f9df33b9 (diff)
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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)
Diffstat (limited to 'source3')
-rw-r--r--source3/nmbd/asyncdns.c85
1 files changed, 58 insertions, 27 deletions
diff --git a/source3/nmbd/asyncdns.c b/source3/nmbd/asyncdns.c
index 4982f7f340..a451f6b617 100644
--- 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;
/***************************************************************************
@@ -140,21 +142,27 @@ 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
****************************************************************************/
void run_dns_queue(void)
@@ -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;
}