+ if (socket_only) {
+ signal_event_ = nullptr;
+ } else {
+ signal_event_ = event_new(
+ base, SIGCHLD, EV_SIGNAL | EV_PERSIST,
+ [](evutil_socket_t sig, short events, void* arg) {
+ auto checker = static_cast<simgrid::mc::CheckerSide*>(arg);
+ if (events == EV_SIGNAL) {
+ if (sig == SIGCHLD)
+ checker->handle_waitpid();
+ else
+ xbt_die("Unexpected signal: %d", sig);
+ } else {
+ xbt_die("Unexpected event");
+ }
+ },
+ this);
+ event_add(signal_event_, nullptr);
+ }
+}
+
+/* When this constructor is called, no other checkerside exists */
+CheckerSide::CheckerSide(const std::vector<char*>& args, bool need_memory_info) : running_(true)
+{
+ XBT_DEBUG("Create a CheckerSide. Needs_meminfo: %s", need_memory_info ? "YES" : "no");
+
+ // Create an AF_UNIX socketpair used for exchanging messages between the model-checker process (ancestor)
+ // and the application process (child)
+ int sockets[2];
+ xbt_assert(socketpair(AF_UNIX,
+#ifdef __APPLE__
+ SOCK_STREAM, /* Mac OSX does not have AF_UNIX + SOCK_SEQPACKET, even if that's faster */
+#else
+ SOCK_SEQPACKET,
+#endif
+ 0, sockets) != -1,
+ "Could not create socketpair: %s", strerror(errno));
+
+ pid_ = fork();
+ xbt_assert(pid_ >= 0, "Could not fork application process");
+
+ if (pid_ == 0) { // Child
+ ::close(sockets[1]);
+ run_child_process(sockets[0], args, need_memory_info); // We need ptrace if we need the mem info
+ DIE_IMPOSSIBLE;
+ }
+
+ // Parent (model-checker):
+ ::close(sockets[0]);
+ channel_.reset_socket(sockets[1]);
+
+ setup_events(false); /* we need a signal handler too */
+ if (need_memory_info) {
+#if SIMGRID_HAVE_STATEFUL_MC
+ // setup ptrace and sync with the app
+ wait_application_process(pid_);
+
+ // Request the initial memory on need
+ channel_.send(MessageType::NEED_MEMINFO);
+ s_mc_message_need_meminfo_reply_t answer;
+ ssize_t answer_size = channel_.receive(answer);
+ xbt_assert(answer_size != -1, "Could not receive message");
+ xbt_assert(answer.type == MessageType::NEED_MEMINFO_REPLY,
+ "The received message is not the NEED_MEMINFO_REPLY I was expecting but of type %s",
+ to_c_str(answer.type));
+ xbt_assert(answer_size == sizeof answer, "Broken message (size=%zd; expected %zu)", answer_size, sizeof answer);
+
+ /* We now have enough info to create the memory address space */
+ remote_memory_ = std::make_unique<simgrid::mc::RemoteProcessMemory>(pid_, answer.mmalloc_default_mdp);
+#else
+ xbt_die("Cannot introspect memory without MC support");
+#endif
+ }
+
+ wait_for_requests();
+}
+
+CheckerSide::~CheckerSide()
+{
+ event_del(socket_event_);
+ event_free(socket_event_);
+ if (signal_event_ != nullptr) {
+ event_del(signal_event_);
+ event_free(signal_event_);
+ }
+}
+
+/* This constructor is called when cloning a checkerside to get its application to fork away */
+CheckerSide::CheckerSide(int socket, CheckerSide* child_checker)
+ : channel_(socket, child_checker->channel_), running_(true), child_checker_(child_checker)
+{
+ setup_events(true); // We already have a signal handled in that case
+
+ s_mc_message_int_t answer;
+ ssize_t s = get_channel().receive(answer);
+ xbt_assert(s != -1, "Could not receive answer to FORK_REPLY");
+ xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer);
+ xbt_assert(answer.type == MessageType::FORK_REPLY,
+ "Received unexpected message %s (%i); expected MessageType::FORK_REPLY (%i)", to_c_str(answer.type),
+ (int)answer.type, (int)MessageType::FORK_REPLY);
+ pid_ = answer.value;
+
+ wait_for_requests();
+}
+
+std::unique_ptr<CheckerSide> CheckerSide::clone(int master_socket, const std::string& master_socket_name)
+{
+ s_mc_message_fork_t m = {};
+ m.type = MessageType::FORK;
+ xbt_assert(master_socket_name.size() == MC_SOCKET_NAME_LEN);
+ std::copy_n(begin(master_socket_name), MC_SOCKET_NAME_LEN, begin(m.socket_name));
+ xbt_assert(get_channel().send(m) == 0, "Could not ask the app to fork on need.");
+
+ int sock = accept(master_socket, nullptr /* I know who's connecting*/, nullptr);
+ xbt_assert(sock > 0, "Cannot accept the incomming connection of the forked app: %s.", strerror(errno));
+
+ return std::make_unique<CheckerSide>(sock, this);
+}
+
+void CheckerSide::finalize(bool terminate_asap)
+{
+ s_mc_message_int_t m = {};
+ m.type = MessageType::FINALIZE;
+ m.value = terminate_asap;
+ xbt_assert(get_channel().send(m) == 0, "Could not ask the app to finalize on need");
+
+ s_mc_message_t answer;
+ ssize_t s = get_channel().receive(answer);
+ xbt_assert(s != -1, "Could not receive answer to FINALIZE");
+ xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer);
+ xbt_assert(answer.type == MessageType::FINALIZE_REPLY,
+ "Received unexpected message %s (%i); expected MessageType::FINALIZE_REPLY (%i)", to_c_str(answer.type),
+ (int)answer.type, (int)MessageType::FINALIZE_REPLY);