samba_dnsupdate: Safely update/create names for Samba3 targets as well

This avoids unlocked writes to the dns_hosts_file, and may fix some of our
issues on the build farm where large numbers of tests fail due to failed name resolution.

Andrew Bartlett

Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Wed Sep 26 05:48:25 CEST 2012 on sn-devel-104

2 files changed, 21 insertions, 8 deletions

diff --git a/selftest/target/Samba3.pm b/selftest/target/Samba3.pm
index ef22b02865..df8b55c613 100755
--- a/selftest/target/Samba3.pm
+++ b/selftest/target/Samba3.pm
@@ -1067,10 +1067,13 @@ domusers:X:$gid_domusers:
         }
 	print "DONE\n";
 
-	open(HOSTS, ">>$ENV{SELFTEST_PREFIX}/dns_host_file") or die("Unable to open $ENV{SELFTEST_PREFIX}/dns_host_file");
-	print HOSTS "A $server. $server_ip
-";
-	close(HOSTS);
+	open(DNS_UPDATE_LIST, ">$prefix/dns_update_list") or die("Unable to open $$prefix/dns_update_list");
+	print DNS_UPDATE_LIST "A $server. $server_ip";
+	close(DNS_UPDATE_LIST);
+
+        if (system("$ENV{SRCDIR_ABS}/source4/scripting/bin/samba_dnsupdate --all-interfaces --use-file=$dns_host_file -s $conffile --update-list=$prefix/dns_update_list --no-substiutions --no-credentials") != 0) {
+                die "Unable to update hostname into $dns_host_file";
+        }
 
 	$ret{SERVER_IP} = $server_ip;
 	$ret{NMBD_TEST_LOG} = "$prefix/nmbd_test.log";
diff --git a/source4/scripting/bin/samba_dnsupdate b/source4/scripting/bin/samba_dnsupdate
index ab87356484..2f2c7b562a 100755
--- a/source4/scripting/bin/samba_dnsupdate
+++ b/source4/scripting/bin/samba_dnsupdate
@@ -65,6 +65,7 @@ parser.add_option("--use-file", type="string", help="Use a file, rather than rea
 parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
 parser.add_option("--fail-immediately", action='store_true', help="Exit on first failure")
 parser.add_option("--no-credentials", dest='nocreds', action='store_true', help="don't try and get credentials")
+parser.add_option("--no-substiutions", dest='nosubs', action='store_true', help="don't try and expands variables in file specified by --update-list")
 
 creds = None
 ccachename = None
@@ -278,7 +279,13 @@ def call_nsupdate(d):
         print "Calling nsupdate for %s" % d
 
     if opts.use_file is not None:
-        rfile = open(opts.use_file, 'r+')
+        try:
+            rfile = open(opts.use_file, 'r+')
+        except IOError:
+            # Perhaps create it
+            rfile = open(opts.use_file, 'w+')
+            # Open it for reading again, in case someone else got to it first
+            rfile = open(opts.use_file, 'r+')
         fcntl.lockf(rfile, fcntl.LOCK_EX)
         (file_dir, file_name) = os.path.split(opts.use_file)
         (tmp_fd, tmpfile) = tempfile.mkstemp(dir=file_dir, prefix=file_name, suffix="XXXXXX")
@@ -432,10 +439,13 @@ os.environ['KRB5_CONFIG'] = krb5conf
 
 file = open(dns_update_list, "r")
 
-samdb = SamDB(url=lp.samdb_url(), session_info=system_session(), lp=lp)
+if opts.nosubs:
+    sub_vars = {}
+else:
+    samdb = SamDB(url=lp.samdb_url(), session_info=system_session(), lp=lp)
 
-# get the substitution dictionary
-sub_vars = get_subst_vars(samdb)
+    # get the substitution dictionary
+    sub_vars = get_subst_vars(samdb)
 
 # build up a list of update commands to pass to nsupdate
 update_list = []