DragonFlyBSD

If someone wants to take on this task it would actually be fairly easy
to do, maybe 2 hours of work. And probably quite fun, too. The source
is in /usr/src/usr.sbin/dntpd.

The dntpd state machine includes a DNS-resolution stage. Currently dntpd
blocks because the add_server() tries to resolve the server name prior
to demonization. The add_server() calls must still be made prior to
demonization because we want fatal parsing errors to be reported prior
to going into the background.

However, instead of having add_server() create the initial socket and
do the initial DNS resolution it could instead start the server in the
dns-reresolve state, which is state -1, and not even try to resolve
the server names from inside add_server() itself.

-Matt

If it's fun I'll give it a try then.

I tested the following patch by starting dntpd on a machine
disconnected from the network and set to an incorrect system time.
dntpd goes into background without hanging and, when connected back,
the time is eventually corrected.

Is it as simple as that? Have I missed some corner case?

(I'll include an explanatory comment in the final change)

diff --git a/usr.sbin/dntpd/main.c b/usr.sbin/dntpd/main.c
index 9d15bab..90634bd 100644
--- a/usr.sbin/dntpd/main.c
+++ b/usr.sbin/dntpd/main.c
@ -344,7 +344,6 @ static void
add_server(const char *target) {
server_info_t info;
- const char *ipstr;

if (nservers == maxservers) {
     maxservers = 16;
@ -355,14 +354,9 @ add_server(const char *target)
     servers[nservers] = info;
     bzero(info, sizeof(struct server_info));
     info->sam = (struct sockaddr *)&info->sam_st;
-    info->fd = udp_socket(target, 123, info->sam);
    info->fd = 1;
     info>target = strdup(target);
-    if (info->fd >= 0) {
-    ipstr = myaddr2ascii(info->sam);
-    info->ipstr = strdup(ipstr);
-    } else {
-    client_setserverstate(info, 1, "DNS or IP lookup failure");
    }
+    info->server_state = -1;
     ++nservers;
 }

:If it's fun I'll give it a try then.
:
:I tested the following patch by starting dntpd on a machine
:disconnected from the network and set to an incorrect system time.
:dntpd goes into background without hanging and, when connected back,
:the time is eventually corrected.
:
:Is it as simple as that? Have I missed some corner case?

Just the logging case.  I'm pretty sure with a high enough logging
    level it will log messages that imply a failed connection 
    reconnected when, in fact, it is the initial connection that is
    being handled.

Other then that, well, yah... it's pretty easy :-).  Take a quick
    shot at the logging case and then we'll commit it.

-Matt
                    Matthew Dillon 
                    <dillon@backplane.com>

Ok. I'll check into this and commit it later this week.

Cheers,
Nicolas

Fix committed to crater/master.