Fix problem with domains associated with DHCP hosts at startup.

At startup, the leases file is read by lease_init(), and
in lease_init() undecorated hostnames are expanded into
FQDNs by adding the domain associated with the address
of the lease.

lease_init() happens relavtively early in the startup, party because
if it calls  the dhcp-lease helper script, we don't want that to inherit
a load of sensitive file descriptors. This has implications if domains
are defined using the --domain=example.com,eth0 format since it's long
before we call enumerate_interfaces(), so get_domain fails for such domains.

The patch just moves the hostname expansion function to a seperate
subroutine that gets called later, after enumerate_interfaces().

src/dnsmasq.c

@@ -375,6 +375,13 @@ int main (int argc, char **argv)
   if (!enumerate_interfaces(1) || !enumerate_interfaces(0))
     die(_("failed to find list of interfaces: %s"), NULL, EC_MISC);
 
+#ifdef HAVE_DHCP
+  /* Determine lease FQDNs after enumerate_interfaces() call, since it needs
+     to call get_domain and that's only valid for some domain configs once we
+     have interface addresses. */
+  lease_calc_fqdns();
+#endif
+  
   if (option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND)) 
     {
       create_bound_listeners(1);

src/dnsmasq.h

@@ -1605,6 +1605,7 @@ void lease_update_from_configs(void);
 int do_script_run(time_t now);
 void rerun_scripts(void);
 void lease_find_interfaces(time_t now);
+void lease_calc_fqdns(void);
 #ifdef HAVE_SCRIPT
 void lease_add_extradata(struct dhcp_lease *lease, unsigned char *data, 
 			 unsigned int len, int delim);

src/lease.c

@@ -15,7 +15,6 @@
 */
 
 #include "dnsmasq.h"
-
 #ifdef HAVE_DHCP
 
 static struct dhcp_lease *leases = NULL, *old_leases = NULL;
@@ -28,7 +27,6 @@ static int read_leases(time_t now, FILE *leasestream)
   struct dhcp_lease *lease;
   int clid_len, hw_len, hw_type;
   int items;
-  char *domain = NULL;
  
   *daemon->dhcp_buff3 = *daemon->dhcp_buff2 = '\0';
 
@@ -69,8 +67,8 @@ static int read_leases(time_t now, FILE *leasestream)
 		
 	if (inet_pton(AF_INET, daemon->namebuff, &addr.addr4))
 	  {
-	    if ((lease = lease4_allocate(addr.addr4)))
-	      domain = get_domain(lease->addr);
+	    lease = lease4_allocate(addr.addr4);
+	    
 	    
 	    hw_len = parse_hex(daemon->dhcp_buff2, (unsigned char *)daemon->dhcp_buff2, DHCP_CHADDR_MAX, NULL, &hw_type);
 	    /* For backwards compatibility, no explicit MAC address type means ether. */
@@ -90,10 +88,7 @@ static int read_leases(time_t now, FILE *leasestream)
 	      }
 	    
 	    if ((lease = lease6_allocate(&addr.addr6, lease_type)))
-	      {
-		lease_set_iaid(lease, strtoul(s, NULL, 10));
-		domain = get_domain6(&lease->addr6);
-	      }
+	      lease_set_iaid(lease, strtoul(s, NULL, 10));
 	  }
 #endif
 	else
@@ -114,7 +109,7 @@ static int read_leases(time_t now, FILE *leasestream)
 			 hw_len, hw_type, clid_len, now, 0);
 	
 	if (strcmp(daemon->dhcp_buff, "*") !=  0)
-	  lease_set_hostname(lease, daemon->dhcp_buff, 0, domain, NULL);
+	  lease_set_hostname(lease, daemon->dhcp_buff, 0, NULL, NULL);
 
 	ei = atol(daemon->dhcp_buff3);
 
@@ -946,6 +941,36 @@ static void kill_name(struct dhcp_lease *lease)
   lease->hostname = lease->fqdn = NULL;
 }
 
+void lease_calc_fqdns(void)
+{
+  struct dhcp_lease *lease;
+  
+  for (lease = leases; lease; lease = lease->next)
+    {
+      char *domain;
+
+      if (lease->hostname)
+	{
+#ifdef HAVE_DHCP6
+	  if (lease->flags & (LEASE_TA | LEASE_NA))
+	    domain = get_domain6(&lease->addr6);
+	  else
+#endif
+	    domain = get_domain(lease->addr);
+	  
+	  if (domain)
+	    {
+	      /* This is called only during startup, before forking, hence safe_malloc() */
+	      lease->fqdn = safe_malloc(strlen(lease->hostname) + strlen(domain) + 2);
+	      
+	      strcpy(lease->fqdn, lease->hostname);
+	      strcat(lease->fqdn, ".");
+	      strcat(lease->fqdn, domain);
+	    }
+	}
+    }
+}
+	  
 void lease_set_hostname(struct dhcp_lease *lease, const char *name, int auth, char *domain, char *config_domain)
 {
   struct dhcp_lease *lease_tmp;