--- /dev/null
+/* Copyright (c) 2012-2020. The SimGrid Team. All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+/***************** Centralized Mutual Exclusion Algorithm *******************/
+/* This example implements a centralized mutual exclusion algorithm. */
+/* Bug : CS requests of client 1 not satisfied */
+/* LTL property checked : G(r->F(cs)); (r=request of CS, cs=CS ok) */
+/****************************************************************************/
+
+#ifdef GARBAGE_STACK
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#endif
+
+#include <simgrid/modelchecker.h>
+#include <simgrid/s4u.hpp>
+#include <xbt/dynar.h>
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(bugged1_liveness, "my log messages");
+
+class Message {
+public:
+ enum class Kind { GRANT, REQUEST, RELEASE };
+ Kind kind = Kind::GRANT;
+ simgrid::s4u::Mailbox* return_mailbox = nullptr;
+ explicit Message(Message::Kind kind, simgrid::s4u::Mailbox* mbox) : kind(kind), return_mailbox(mbox) {}
+};
+
+int r = 0;
+int cs = 0;
+
+#ifdef GARBAGE_STACK
+/** Do not use a clean stack */
+static void garbage_stack(void)
+{
+ const size_t size = 256;
+ int fd = open("/dev/urandom", O_RDONLY);
+ char foo[size];
+ read(fd, foo, size);
+ close(fd);
+}
+#endif
+
+static void coordinator()
+{
+ int CS_used = 0;
+ Message* m = nullptr;
+ std::queue<simgrid::s4u::Mailbox*> requests;
+
+ simgrid::s4u::Mailbox* mbox = simgrid::s4u::Mailbox::by_name("coordinator");
+
+ while (1) {
+ m = static_cast<Message*>(mbox->get());
+ if (m->kind == Message::Kind::REQUEST) {
+ if (CS_used) {
+ XBT_INFO("CS already used. Queue the request.");
+ requests.push(m->return_mailbox);
+ } else {
+ if (m->return_mailbox->get_name() != "1") {
+ XBT_INFO("CS idle. Grant immediatly");
+ m->return_mailbox->put(new Message(Message::Kind::GRANT, mbox), 1000);
+ CS_used = 1;
+ }
+ }
+ } else {
+ if (not requests.empty()) {
+ XBT_INFO("CS release. Grant to queued requests (queue size: %zu)", requests.size());
+ simgrid::s4u::Mailbox* req = requests.front();
+ requests.pop();
+ if (req->get_name() != "1") {
+ req->put(new Message(Message::Kind::GRANT, mbox), 1000);
+ } else {
+ requests.push(req);
+ CS_used = 0;
+ }
+ } else {
+ XBT_INFO("CS release. resource now idle");
+ CS_used = 0;
+ }
+ }
+ delete m;
+ }
+}
+
+static void client(int id)
+{
+ int my_pid = simgrid::s4u::this_actor::get_pid();
+
+ simgrid::s4u::Mailbox* my_mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(id));
+
+ while (1) {
+ XBT_INFO("Ask the request");
+ simgrid::s4u::Mailbox::by_name("coordinator")->put(new Message(Message::Kind::REQUEST, my_mailbox), 1000);
+
+ if (id == 1) {
+ r = 1;
+ cs = 0;
+ XBT_INFO("Propositions changed : r=1, cs=0");
+ }
+
+ Message* grant = static_cast<Message*>(my_mailbox->get());
+
+ if ((id == 1) && (grant->kind == Message::Kind::GRANT)) {
+ cs = 1;
+ r = 0;
+ XBT_INFO("Propositions changed : r=0, cs=1");
+ }
+
+ delete grant;
+
+ XBT_INFO("%d got the answer. Sleep a bit and release it", id);
+
+ simgrid::s4u::this_actor::sleep_for(1);
+
+ simgrid::s4u::Mailbox::by_name("coordinator")->put(new Message(Message::Kind::RELEASE, my_mailbox), 1000);
+
+ simgrid::s4u::this_actor::sleep_for(my_pid);
+
+ if (id == 1) {
+ cs = 0;
+ r = 0;
+ XBT_INFO("Propositions changed : r=0, cs=0");
+ }
+ }
+}
+
+static void raw_client(int id)
+{
+#ifdef GARBAGE_STACK
+ // At this point the stack of the callee (client) is probably filled with
+ // zeros and uninitialized variables will contain 0. This call will place
+ // random byes in the stack of the callee:
+ garbage_stack();
+#endif
+ client(id);
+}
+
+int main(int argc, char* argv[])
+{
+ simgrid::s4u::Engine e(&argc, argv);
+
+ MC_automaton_new_propositional_symbol_pointer("r", &r);
+ MC_automaton_new_propositional_symbol_pointer("cs", &cs);
+
+ e.load_platform(argv[1]);
+
+ simgrid::s4u::Actor::create("coordinator", simgrid::s4u::Host::by_name("Tremblay"), coordinator);
+ if (std::stod(argv[2]) == 0) {
+ simgrid::s4u::Actor::create("client", simgrid::s4u::Host::by_name("Boivin"), raw_client, 1);
+ simgrid::s4u::Actor::create("client", simgrid::s4u::Host::by_name("Fafard"), raw_client, 2);
+ } else { // "Visited" case
+ simgrid::s4u::Actor::create("client", simgrid::s4u::Host::by_name("Boivin"), raw_client, 2);
+ simgrid::s4u::Actor::create("client", simgrid::s4u::Host::by_name("Fafard"), raw_client, 1);
+ }
+ e.run();
+
+ return 0;
+}
