1 /***************** Centralized Mutual Exclusion Algorithm *********************/
2 /* This example implements a centralized mutual exclusion algorithm. */
3 /* CS requests of client 2 not satisfied */
4 /******************************************************************************/
8 #include "xbt/automaton.h"
9 #include "xbt/automatonparse_promela.h"
10 #include "example_liveness_with_cycle.h"
13 #define AMOUNT_OF_CLIENTS 2
14 #define CS_PER_PROCESS 2
16 XBT_LOG_NEW_DEFAULT_CATEGORY(example_liveness_with_cycle, "my log messages");
31 int coordinator(int argc, char *argv[])
33 xbt_dynar_t requests = xbt_dynar_new(sizeof(char *), NULL); // dynamic vector storing requests (which are char*)
34 int CS_used = 0; // initially the CS is idle
35 int todo = AMOUNT_OF_CLIENTS * CS_PER_PROCESS; // amount of releases we are expecting
38 MSG_task_receive(&task, "coordinator");
39 const char *kind = MSG_task_get_name(task); //is it a request or a release?
40 if (!strcmp(kind, "request")) { // that's a request
41 char *req = MSG_task_get_data(task);
42 if (CS_used) { // need to push the request in the vector
43 XBT_INFO("CS already used. Queue the request of client %d", atoi(req) +1);
44 xbt_dynar_push(requests, &req);
45 } else { // can serve it immediatly
46 if(strcmp(req, "1") == 0){
47 m_task_t answer = MSG_task_create("grant", 0, 1000, NULL);
48 MSG_task_send(answer, req);
50 XBT_INFO("CS idle. Grant immediatly");
53 } else { // that's a release. Check if someone was waiting for the lock
54 if (xbt_dynar_length(requests) > 0) {
55 XBT_INFO("CS release. Grant to queued requests (queue size: %lu)", xbt_dynar_length(requests));
57 xbt_dynar_get_cpy(requests, (xbt_dynar_length(requests) - 1), &req);
58 if(strcmp(req, "1") == 0){
59 xbt_dynar_pop(requests, &req);
60 MSG_task_send(MSG_task_create("grant", 0, 1000, NULL), req);
65 } else { // nobody wants it
66 XBT_INFO("CS release. resource now idle");
71 MSG_task_destroy(task);
73 XBT_INFO("Received all releases, quit now");
77 int client(int argc, char *argv[])
79 int my_pid = MSG_process_get_PID(MSG_process_self());
81 char *my_mailbox = bprintf("%s", argv[1]);
84 // request the CS 4 times, sleeping a bit in between
85 for (i = 0; i < CS_PER_PROCESS; i++) {
87 XBT_INFO("Ask the request");
88 MSG_task_send(MSG_task_create("request", 0, 1000, my_mailbox), "coordinator");
90 if(strcmp(my_mailbox, "2") == 0){
93 XBT_DEBUG("Propositions changed : p=1, q=0");
97 m_task_t grant = NULL;
98 MSG_task_receive(&grant, my_mailbox);
100 if(strcmp(my_mailbox, "2") == 0){
103 XBT_DEBUG("Propositions changed : p=0, q=1");
107 MSG_task_destroy(grant);
108 XBT_INFO("%s got the answer. Sleep a bit and release it", argv[1]);
109 MSG_process_sleep(1);
110 MSG_task_send(MSG_task_create("release", 0, 1000, NULL), "coordinator");
112 MSG_process_sleep(my_pid);
114 if(strcmp(my_mailbox, "2") == 0){
117 XBT_DEBUG("Propositions changed : p=0, q=0");
122 XBT_INFO("Got all the CS I wanted (%s), quit now", my_mailbox);
126 int main(int argc, char *argv[])
130 automaton = get_automaton();
131 xbt_new_propositional_symbol(automaton,"p", &predP);
132 xbt_new_propositional_symbol(automaton,"q", &predQ);
134 MSG_global_init(&argc, argv);
135 MSG_create_environment("../msg_platform.xml");
136 MSG_function_register("coordinator", coordinator);
137 MSG_function_register("client", client);
138 MSG_launch_application("deploy_mutex2.xml");
139 MSG_main_liveness_stateless(automaton, argv[0]);