1 files changed, 280 insertions, 0 deletions
diff --git a/ctdb/common/srvid.c b/ctdb/common/srvid.c
new file mode 100644
index 0000000..3304994
--- /dev/null
+++ b/ctdb/common/srvid.c
@@ -0,0 +1,280 @@
+/*
+   Message handler database based on srvid
+
+   Copyright (C) Amitay Isaacs  2015
+
+   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/filesys.h"
+
+#include <tdb.h>
+
+#include "lib/util/dlinklist.h"
+#include "common/db_hash.h"
+#include "common/srvid.h"
+
+struct srvid_handler_list;
+
+struct srvid_context {
+	struct db_hash_context *dh;
+	struct srvid_handler_list *list;
+};
+
+struct srvid_handler {
+	struct srvid_handler *prev, *next;
+	struct srvid_handler_list *list;
+	srvid_handler_fn handler;
+	void *private_data;
+};
+
+struct srvid_handler_list {
+	struct srvid_handler_list *prev, *next;
+	struct srvid_context *srv;
+	uint64_t srvid;
+	struct srvid_handler *h;
+};
+
+
+/*
+ * Initialise message srvid context and database
+ */
+int srvid_init(TALLOC_CTX *mem_ctx, struct srvid_context **result)
+{
+	struct srvid_context *srv;
+	int ret;
+
+	srv = talloc_zero(mem_ctx, struct srvid_context);
+	if (srv == NULL) {
+		return ENOMEM;
+	}
+
+	ret = db_hash_init(srv, "messagedb", 8192, DB_HASH_SIMPLE, &srv->dh);
+	if (ret != 0) {
+		talloc_free(srv);
+		return ret;
+	}
+
+	*result = srv;
+	return 0;
+}
+
+/*
+ * Wrapper functions to insert/delete/fetch srvid_hander_list
+ */
+
+static int srvid_insert(struct srvid_context *srv, uint64_t srvid,
+			struct srvid_handler_list *list)
+{
+	return db_hash_insert(srv->dh, (uint8_t *)&srvid, sizeof(uint64_t),
+			      (uint8_t *)&list, sizeof(list));
+}
+
+static int srvid_delete(struct srvid_context *srv, uint64_t srvid)
+{
+	return db_hash_delete(srv->dh, (uint8_t *)&srvid, sizeof(uint64_t));
+}
+
+static int srvid_fetch_parser(uint8_t *keybuf, size_t keylen,
+			      uint8_t *databuf, size_t datalen,
+			      void *private_data)
+{
+	struct srvid_handler_list **list =
+		(struct srvid_handler_list **)private_data;
+
+	if (datalen != sizeof(*list)) {
+		return EIO;
+	}
+
+	*list = *(struct srvid_handler_list **)databuf;
+	return 0;
+}
+
+static int srvid_fetch(struct srvid_context *srv, uint64_t srvid,
+		       struct srvid_handler_list **list)
+{
+	return db_hash_fetch(srv->dh, (uint8_t *)&srvid, sizeof(uint64_t),
+			     srvid_fetch_parser, list);
+}
+
+/*
+ * When a handler is freed, remove it from the list
+ */
+static int srvid_handler_destructor(struct srvid_handler *h)
+{
+	struct srvid_handler_list *list = h->list;
+
+	DLIST_REMOVE(list->h, h);
+	if (list->h == NULL) {
+		talloc_free(list);
+	}
+	return 0;
+}
+
+/*
+ * When a list is freed, remove all handlers and remove db entry
+ */
+static int srvid_handler_list_destructor(struct srvid_handler_list *list)
+{
+	struct srvid_handler *h;
+
+	while (list->h != NULL) {
+		h = list->h;
+		DLIST_REMOVE(list->h, h);
+		TALLOC_FREE(h);
+	}
+
+	srvid_delete(list->srv, list->srvid);
+	DLIST_REMOVE(list->srv->list, list);
+	return 0;
+}
+
+/*
+ * Register a message handler
+ */
+int srvid_register(struct srvid_context *srv, TALLOC_CTX *mem_ctx,
+		   uint64_t srvid, srvid_handler_fn handler,
+		   void *private_data)
+{
+	struct srvid_handler_list *list;
+	struct srvid_handler *h;
+	int ret;
+
+	if (srv == NULL) {
+		return EINVAL;
+	}
+
+	h = talloc_zero(mem_ctx, struct srvid_handler);
+	if (h == NULL) {
+		return ENOMEM;
+	}
+
+	h->handler = handler;
+	h->private_data = private_data;
+
+	ret = srvid_fetch(srv, srvid, &list);
+	if (ret != 0) {
+		/* srvid not yet registered */
+		list = talloc_zero(srv, struct srvid_handler_list);
+		if (list == NULL) {
+			talloc_free(h);
+			return ENOMEM;
+		}
+
+		list->srv = srv;
+		list->srvid = srvid;
+
+		ret = srvid_insert(srv, srvid, list);
+		if (ret != 0) {
+			talloc_free(h);
+			talloc_free(list);
+			return ret;
+		}
+
+		DLIST_ADD(srv->list, list);
+		talloc_set_destructor(list, srvid_handler_list_destructor);
+	}
+
+	h->list = list;
+	DLIST_ADD(list->h, h);
+	talloc_set_destructor(h, srvid_handler_destructor);
+	return 0;
+}
+
+/*
+ * Deregister a message handler
+ */
+int srvid_deregister(struct srvid_context *srv, uint64_t srvid,
+		     void *private_data)
+{
+	struct srvid_handler_list *list;
+	struct srvid_handler *h;
+	int ret;
+
+	ret = srvid_fetch(srv, srvid, &list);
+	if (ret != 0) {
+		return ret;
+	}
+
+	for (h = list->h; h != NULL; h = h->next) {
+		if (h->private_data == private_data) {
+			talloc_free(h);
+			return 0;
+		}
+	}
+
+	return ENOENT;
+}
+
+/*
+ * Check if a message handler exists
+ */
+int srvid_exists(struct srvid_context *srv, uint64_t srvid, void *private_data)
+{
+	struct srvid_handler_list *list;
+	struct srvid_handler *h;
+	int ret;
+
+	ret = srvid_fetch(srv, srvid, &list);
+	if (ret != 0) {
+		return ret;
+	}
+	if (list->h == NULL) {
+		return ENOENT;
+	}
+
+	if (private_data != NULL) {
+		for (h = list->h; h != NULL; h = h->next) {
+			if (h->private_data == private_data) {
+				return 0;
+			}
+		}
+
+		return ENOENT;
+	}
+
+	return 0;
+}
+
+/*
+ * Send a message to registered srvid and srvid_all
+ */
+int srvid_dispatch(struct srvid_context *srv, uint64_t srvid,
+		    uint64_t srvid_all, TDB_DATA data)
+{
+	struct srvid_handler_list *list;
+	struct srvid_handler *h;
+	int ret;
+
+	ret = srvid_fetch(srv, srvid, &list);
+	if (ret == 0) {
+		for (h = list->h; h != NULL; h = h->next) {
+			h->handler(srvid, data, h->private_data);
+		}
+	}
+
+	if (srvid_all == 0) {
+		return ret;
+	}
+
+	ret = srvid_fetch(srv, srvid_all, &list);
+	if (ret == 0) {
+		for (h = list->h; h != NULL; h = h->next) {
+			h->handler(srvid, data, h->private_data);
+		}
+	}
+
+	return ret;
+}