2 * Example program to demonstrate the libctdb api
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 3 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
19 * This program needs to be linked with libtdb and libctdb
20 * (You need these packages installed: libtdb libtdb-devel
21 * ctdb and ctdb-devel)
23 * This program can then be compiled using
24 * gcc -o tst tst.c -ltdb -lctdb
41 void msg_h(struct ctdb_connection *ctdb, uint64_t srvid, TDB_DATA data, void *private_data)
43 printf("Message received on port %d : %s\n", (int)srvid, data.dptr);
46 static void pnn_cb(struct ctdb_connection *ctdb,
47 struct ctdb_request *req, void *private)
52 status = ctdb_getpnn_recv(ctdb, req, &pnn);
53 ctdb_request_free(ctdb, req);
55 printf("Error reading PNN\n");
58 printf("status:%d pnn:%d\n", status, pnn);
61 static void rm_cb(struct ctdb_connection *ctdb,
62 struct ctdb_request *req, void *private)
67 status = ctdb_getrecmaster_recv(ctdb, req, &rm);
68 ctdb_request_free(ctdb, req);
70 printf("Error reading RECMASTER\n");
74 printf("GETRECMASTER ASYNC: status:%d recmaster:%d\n", status, rm);
78 * example on how to first read(non-existing recortds are implicitely created
79 * on demand) a record and change it in the callback.
80 * This forms the atom for the read-modify-write cycle.
82 * Pure read, or pure write are just special cases of this cycle.
84 static void rrl_cb(struct ctdb_db *ctdb_db,
85 struct ctdb_lock *lock, TDB_DATA outdata, void *private)
89 bool *rrl_cb_called = private;
91 *rrl_cb_called = true;
94 printf("rrl_cb returned error\n");
98 printf("rrl size:%d data:%.*s\n", outdata.dsize,
99 outdata.dsize, outdata.dptr);
100 if (outdata.dsize == 0) {
103 strcpy(tmp, outdata.dptr);
108 data.dsize = strlen(tmp) + 1;
109 ctdb_writerecord(lock, data);
111 printf("Wrote new record : %s\n", tmp);
113 ctdb_release_lock(lock);
116 static bool registered = false;
117 void message_handler_cb(struct ctdb_connection *ctdb,
118 struct ctdb_request *req, void *private)
120 if (ctdb_set_message_handler_recv(ctdb, req) != 0) {
121 err(1, "registering message");
123 ctdb_request_free(ctdb, req);
124 printf("Message handler registered\n");
128 int main(int argc, char *argv[])
130 struct ctdb_connection *ctdb_connection;
131 struct ctdb_request *handle;
132 struct ctdb_db *ctdb_db_context;
137 bool rrl_cb_called = false;
140 ctdb_connection = ctdb_connect("/tmp/ctdb.socket");
141 if (!ctdb_connection)
142 err(1, "Connecting to /tmp/ctdb.socket");
144 pfd.fd = ctdb_get_fd(ctdb_connection);
146 handle = ctdb_set_message_handler_send(ctdb_connection, 55, msg_h,
147 message_handler_cb, NULL);
148 if (handle == NULL) {
149 printf("Failed to register message port\n");
153 /* Hack for testing: this makes sure registration goes out. */
154 while (!registered) {
155 ctdb_service(ctdb_connection, POLLIN|POLLOUT);
158 msg.dptr="HelloWorld";
159 msg.dsize = strlen(msg.dptr);
161 ret = ctdb_send_message(ctdb_connection, 0, 55, msg);
163 printf("Failed to send message. Aborting\n");
167 handle = ctdb_getrecmaster_send(ctdb_connection, 0, rm_cb, NULL);
168 if (handle == NULL) {
169 printf("Failed to send get_recmaster control\n");
173 ctdb_db_context = ctdb_attachdb(ctdb_connection, "test_test.tdb", 0, 0);
174 if (!ctdb_db_context) {
175 printf("Failed to attach to database\n");
180 * SYNC call with callback to read the recmaster
181 * calls the blocking sync function.
182 * Avoid this mode for performance critical tasks
184 ret = ctdb_getrecmaster(ctdb_connection, CTDB_CURRENT_NODE, &recmaster);
186 printf("Failed to receive response to getrecmaster\n");
189 printf("GETRECMASTER SYNC: status:%d recmaster:%d\n", ret, recmaster);
192 handle = ctdb_getpnn_send(ctdb_connection, CTDB_CURRENT_NODE,
194 if (handle == NULL) {
195 printf("Failed to send get_pnn control\n");
199 /* In the non-contended case the callback might be invoked
200 * immediately, before ctdb_readrecordlock_async() returns.
201 * In the contended case the callback will be invoked later.
203 * Normally an application would not care whether the callback
204 * has already been invoked here or not, but if the application
205 * needs to know, it can use the *private_data pointer
206 * to pass data through to the callback and back.
208 if (!ctdb_readrecordlock_async(ctdb_db_context, key,
209 rrl_cb, &rrl_cb_called)) {
210 printf("Failed to send READRECORDLOCK\n");
213 if (!rrl_cb_called) {
214 printf("READRECORDLOCK is async\n");
218 pfd.events = ctdb_which_events(ctdb_connection);
219 if (poll(&pfd, 1, -1) < 0) {
220 printf("Poll failed");
223 if (ctdb_service(ctdb_connection, pfd.revents) < 0) {
224 err(1, "Failed to service");