1 /* Copyright (c) 2012-2023. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 /***************** Centralized Mutual Exclusion Algorithm *******************/
7 /* This example implements a centralized mutual exclusion algorithm. */
8 /* Bug : CS requests of client 1 not satisfied */
9 /* LTL property checked : G(r->F(cs)); (r=request of CS, cs=CS ok) */
10 /****************************************************************************/
18 #include <simgrid/modelchecker.h>
19 #include <simgrid/s4u.hpp>
20 #include <xbt/dynar.h>
22 XBT_LOG_NEW_DEFAULT_CATEGORY(bugged1_liveness, "my log messages");
23 namespace sg4 = simgrid::s4u;
27 enum class Kind { GRANT, REQUEST, RELEASE };
28 Kind kind = Kind::GRANT;
29 sg4::Mailbox* return_mailbox = nullptr;
30 explicit Message(Message::Kind kind, sg4::Mailbox* mbox) : kind(kind), return_mailbox(mbox) {}
37 /** Do not use a clean stack */
38 static void garbage_stack(void)
40 const size_t size = 256;
41 int fd = open("/dev/urandom", O_RDONLY);
48 static void coordinator()
51 std::queue<sg4::Mailbox*> requests;
53 sg4::Mailbox* mbox = sg4::Mailbox::by_name("coordinator");
56 auto m = mbox->get_unique<Message>();
57 if (m->kind == Message::Kind::REQUEST) {
59 XBT_INFO("CS already used. Queue the request.");
60 requests.push(m->return_mailbox);
62 if (m->return_mailbox->get_name() != "1") {
63 XBT_INFO("CS idle. Grant immediately");
64 m->return_mailbox->put(new Message(Message::Kind::GRANT, mbox), 1000);
69 if (not requests.empty()) {
70 XBT_INFO("CS release. Grant to queued requests (queue size: %zu)", requests.size());
71 sg4::Mailbox* req = requests.front();
73 if (req->get_name() != "1") {
74 req->put(new Message(Message::Kind::GRANT, mbox), 1000);
80 XBT_INFO("CS release. resource now idle");
87 static void client(int id)
89 aid_t my_pid = sg4::this_actor::get_pid();
91 sg4::Mailbox* my_mailbox = sg4::Mailbox::by_name(std::to_string(id));
94 XBT_INFO("Ask the request");
95 sg4::Mailbox::by_name("coordinator")->put(new Message(Message::Kind::REQUEST, my_mailbox), 1000);
100 XBT_INFO("Propositions changed : r=1, cs=0");
103 auto grant = my_mailbox->get_unique<Message>();
104 xbt_assert(grant->kind == Message::Kind::GRANT);
109 XBT_INFO("Propositions changed : r=0, cs=1");
112 XBT_INFO("%d got the answer. Sleep a bit and release it", id);
114 sg4::this_actor::sleep_for(1);
116 sg4::Mailbox::by_name("coordinator")->put(new Message(Message::Kind::RELEASE, my_mailbox), 1000);
118 sg4::this_actor::sleep_for(static_cast<double>(my_pid));
123 XBT_INFO("Propositions changed : r=0, cs=0");
128 static void raw_client(int id)
131 // At this point the stack of the callee (client) is probably filled with
132 // zeros and uninitialized variables will contain 0. This call will place
133 // random byes in the stack of the callee:
139 int main(int argc, char* argv[])
141 sg4::Engine e(&argc, argv);
143 MC_automaton_new_propositional_symbol_pointer("r", &r);
144 MC_automaton_new_propositional_symbol_pointer("cs", &cs);
146 e.load_platform(argv[1]);
148 sg4::Actor::create("coordinator", e.host_by_name("Tremblay"), coordinator)
149 ->set_kill_time(argc > 3 ? std::stod(argv[3]) : -1.0);
150 if (std::stod(argv[2]) == 0) {
151 sg4::Actor::create("client", e.host_by_name("Boivin"), raw_client, 1);
152 sg4::Actor::create("client", e.host_by_name("Fafard"), raw_client, 2);
153 } else { // "Visited" case
154 sg4::Actor::create("client", e.host_by_name("Boivin"), raw_client, 2);
155 sg4::Actor::create("client", e.host_by_name("Fafard"), raw_client, 1);