1 /***************** Centralized Mutual Exclusion Algorithm *********************/
2 /* This example implements a centralized mutual exclusion algorithm. */
3 /* There is no bug on it, it is just provided to test the state space */
4 /* reduction of DPOR. */
5 /******************************************************************************/
9 #include "xbt/automaton.h"
10 #include "xbt/automatonparse_promela.h"
11 #include "example_liveness_with_cycle.h"
14 #define AMOUNT_OF_CLIENTS 2
15 #define CS_PER_PROCESS 3
17 XBT_LOG_NEW_DEFAULT_CATEGORY(example_liveness_with_cycle, "my log messages");
32 int coordinator(int argc, char *argv[])
34 xbt_dynar_t requests = xbt_dynar_new(sizeof(char *), NULL); // dynamic vector storing requests (which are char*)
35 int CS_used = 0; // initially the CS is idle
36 int todo = AMOUNT_OF_CLIENTS * CS_PER_PROCESS; // amount of releases we are expecting
39 MSG_task_receive(&task, "coordinator");
40 const char *kind = MSG_task_get_name(task); //is it a request or a release?
41 if (!strcmp(kind, "request")) { // that's a request
42 char *req = MSG_task_get_data(task);
43 if (CS_used) { // need to push the request in the vector
44 XBT_INFO("CS already used. Queue the request of client %d", atoi(req) +1);
45 xbt_dynar_push(requests, &req);
46 } else { // can serve it immediatly
47 if(strcmp(req, "1") == 0){
48 m_task_t answer = MSG_task_create("grant", 0, 1000, NULL);
49 MSG_task_send(answer, req);
51 XBT_INFO("CS idle. Grant immediatly");
54 } else { // that's a release. Check if someone was waiting for the lock
55 if (xbt_dynar_length(requests) > 0) {
56 XBT_INFO("CS release. Grant to queued requests (queue size: %lu)", xbt_dynar_length(requests));
58 xbt_dynar_get_cpy(requests, (xbt_dynar_length(requests) - 1), &req);
59 if(strcmp(req, "1") == 0){
60 xbt_dynar_pop(requests, &req);
61 MSG_task_send(MSG_task_create("grant", 0, 1000, NULL), req);
66 } else { // nobody wants it
67 XBT_INFO("CS release. resource now idle");
72 MSG_task_destroy(task);
74 XBT_INFO("Received all releases, quit now");
78 int client(int argc, char *argv[])
80 int my_pid = MSG_process_get_PID(MSG_process_self());
82 char *my_mailbox = bprintf("%s", argv[1]);
83 // request the CS 3 times, sleeping a bit in between
86 for (i = 0; i < CS_PER_PROCESS; i++) {
88 XBT_INFO("Ask the request");
89 MSG_task_send(MSG_task_create("request", 0, 1000, my_mailbox), "coordinator");
90 if(strcmp(my_mailbox, "2") == 0){
95 m_task_t grant = NULL;
96 MSG_task_receive(&grant, my_mailbox);
98 if(strcmp(my_mailbox, "2") == 0){
103 MSG_task_destroy(grant);
104 XBT_INFO("%s got the answer. Sleep a bit and release it", argv[1]);
105 MSG_process_sleep(1);
106 MSG_task_send(MSG_task_create("release", 0, 1000, NULL), "coordinator");
108 MSG_process_sleep(my_pid);
116 XBT_INFO("Got all the CS I wanted (%s), quit now", my_mailbox);
120 int main(int argc, char *argv[])
124 automaton = get_automaton();
125 xbt_new_propositional_symbol(automaton,"p", &predP);
126 xbt_new_propositional_symbol(automaton,"q", &predQ);
128 MSG_global_init(&argc, argv);
129 MSG_create_environment("../msg_platform.xml");
130 MSG_function_register("coordinator", coordinator);
131 MSG_function_register("client", client);
132 MSG_launch_application("deploy_mutex2.xml");
133 MSG_main_liveness_stateless(automaton);