ctdb-failover: Add ctdb_smnotify_helper

statd callout will shortly be updated to use NFS utils' sm-notify.
This tiny helper will be used to create on-disk state files used by
sm-notify.  These state files contain endian-specific fields, so
better to write a simple C implementation than to do crazy things in a
shell script (or call out to Python).

Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

diff --git a/ctdb/failover/smnotify_helper.c b/ctdb/failover/smnotify_helper.c
new file mode 100644 (file)
index 0000000..539537b
--- /dev/null
+++ b/ctdb/failover/smnotify_helper.c
@@ -0,0 +1,81 @@
+/*
+   CTDB SM_NOTIFY helper for NFSv3 statd snippets
+
+   Copyright 2023, DataDirect Networks, Inc. All rights reserved.
+   Author: Martin Schwenke <mschwenke@ddn.com>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/network.h"
+
+#include "lib/util/sys_rw.h"
+
+static void print_monitor_line(const char *client_ip,
+                              const char *server_ip)
+{
+       /*
+        * sm-notify doesn't read priv.  rpc.statd appears to use it
+        * for uniqueness of multi-line files.
+        */
+       const char *priv = "00000000000000000000000000000000";
+       /*
+        * sm_mon_1_svc() takes care to write in this format, so let's
+        * do that too, even though sm-notify ignores this field...
+        */
+       uint32_t inaddr_loopback = htonl(INADDR_LOOPBACK);
+
+       printf("%08x %08x %08x %08x %s %s %s\n",
+              inaddr_loopback,
+              100021, /* NLM_PROG */
+              4, /* SM_VERS */
+              16,
+              priv,
+              client_ip,
+              server_ip);
+}
+
+static void print_state(const char *state_str)
+{
+       int state = atoi(state_str);
+
+       /*
+        * Uncomplicated binary output.  sm-notify just reads this as
+        * an int via nsm_get_state().  This file will always be
+        * created in a local temporary directory and is consumed by
+        * sm-notify locally, so no inter-node endianness issues.
+        */
+       sys_write(STDOUT_FILENO, &state, sizeof(state));
+}
+
+static void usage(const char *prog)
+{
+       printf("usage: %s { monitor <client-ip> <source-ip> | state <state> }\n",
+              prog);
+       exit(1);
+}
+
+int main(int argc, const char *argv[])
+{
+       if (argc == 4 && strcmp(argv[1], "monitor") == 0) {
+               print_monitor_line(argv[2], argv[3]);
+       } else if (argc == 3 && strcmp(argv[1], "state") == 0) {
+               print_state(argv[2]);
+       } else {
+               usage(argv[0]);
+       }
+
+       return 0;
+}

diff --git a/ctdb/wscript b/ctdb/wscript
index 855989a2493df29ee3a8a90b78d8447362d6c0ff..170965ac7743a90f4c335149afc78bed326fa6ae 100644 (file)
--- a/ctdb/wscript
+++ b/ctdb/wscript
@@ -685,6 +685,11 @@ def build(bld):
                      includes='include',
                      install_path='${CTDB_HELPER_BINDIR}')
 
+    bld.SAMBA_BINARY('ctdb_smnotify_helper',
+                     source=('failover/smnotify_helper.c'),
+                     deps='sys_rw replace',
+                     install_path='${CTDB_HELPER_BINDIR}')
+
     bld.SAMBA_GENERATOR('ctdb-smnotify-h',
                         source='utils/smnotify/smnotify.x',
                         target='utils/smnotify/smnotify.h',