1 /***************** Centralized Mutual Exclusion Algorithm *********************/
2 /* This example implements a centralized mutual exclusion algorithm. */
3 /* LTL property checked : !(GFcs) */
4 /******************************************************************************/
8 #include "xbt/automaton.h"
9 #include "xbt/automatonparse_promela.h"
10 #include "centralized_liveness.h"
13 XBT_LOG_NEW_DEFAULT_CATEGORY(centralized, "my log messages");
22 int coordinator(int argc, char **argv);
23 int client(int argc, char **argv);
25 int coordinator(int argc, char *argv[])
27 xbt_dynar_t requests = xbt_dynar_new(sizeof(char *), NULL); // dynamic vector storing requests (which are char*)
28 int CS_used = 0; // initially the CS is idle
32 MSG_task_receive(&task, "coordinator");
33 const char *kind = MSG_task_get_name(task); //is it a request or a release?
34 if (!strcmp(kind, "request")) { // that's a request
35 char *req = MSG_task_get_data(task);
36 if (CS_used) { // need to push the request in the vector
37 XBT_INFO("CS already used. Queue the request");
38 xbt_dynar_push(requests, &req);
39 } else { // can serve it immediatly
40 XBT_INFO("CS idle. Grant immediatly");
41 m_task_t answer = MSG_task_create("grant", 0, 1000, NULL);
42 MSG_task_send(answer, req);
45 } else { // that's a release. Check if someone was waiting for the lock
46 if (!xbt_dynar_is_empty(requests)) {
47 XBT_INFO("CS release. Grant to queued requests (queue size: %lu)",
48 xbt_dynar_length(requests));
50 xbt_dynar_pop(requests, &req);
51 MSG_task_send(MSG_task_create("grant", 0, 1000, NULL), req);
52 } else { // nobody wants it
53 XBT_INFO("CS release. resource now idle");
57 MSG_task_destroy(task);
63 int client(int argc, char *argv[])
65 int my_pid = MSG_process_get_PID(MSG_process_self());
66 char *my_mailbox = bprintf("%s", argv[1]);
70 XBT_INFO("Client (%s) asks the request", my_mailbox);
71 MSG_task_send(MSG_task_create("request", 0, 1000, my_mailbox),
74 m_task_t grant = NULL;
75 MSG_task_receive(&grant, my_mailbox);
77 MSG_task_destroy(grant);
78 XBT_INFO("Client (%s) got the answer. Sleep a bit and release it", my_mailbox);
80 if(!strcmp(my_mailbox, "1"))
83 /*MSG_process_sleep(my_pid);
84 MSG_task_send(MSG_task_create("release", 0, 1000, NULL),
86 XBT_INFO("Client (%s) releases the CS", my_mailbox);
88 if(!strcmp(my_mailbox, "1"))
91 MSG_process_sleep(my_pid);
98 int main(int argc, char *argv[])
102 automaton = get_automaton();
103 xbt_new_propositional_symbol(automaton,"cs", &predCS);
105 MSG_global_init(&argc, argv);
106 MSG_create_environment("../msg_platform.xml");
107 MSG_function_register("coordinator", coordinator);
108 MSG_function_register("client", client);
109 MSG_launch_application("deploy_centralized_liveness.xml");
110 MSG_main_liveness(automaton);