#include <algorithm>
#include <array>
-#include <boost/tokenizer.hpp>
+#include <limits.h>
#include <memory>
#include <numeric>
#include <string>
-
-#include <fcntl.h>
-#ifdef __linux__
-#include <sys/prctl.h>
-#endif
#include <sys/ptrace.h>
+#include <sys/un.h>
#include <sys/wait.h>
-#ifdef __linux__
-#define WAITPID_CHECKED_FLAGS __WALL
-#else
-#define WAITPID_CHECKED_FLAGS 0
-#endif
-
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_Session, mc, "Model-checker session");
XBT_LOG_EXTERNAL_CATEGORY(mc_global);
-static simgrid::config::Flag<std::string> _sg_mc_setenv{
- "model-check/setenv", "Extra environment variables to pass to the child process (ex: 'AZE=aze;QWE=qwe').", "",
- [](std::string_view value) {
- xbt_assert(value.empty() || value.find('=', 0) != std::string_view::npos,
- "The 'model-check/setenv' parameter must be like 'AZE=aze', but it does not contain an equal sign.");
- }};
-
namespace simgrid::mc {
-XBT_ATTRIB_NORETURN static void run_child_process(int socket, const std::vector<char*>& args)
+static std::string master_socket_name;
+
+RemoteApp::RemoteApp(const std::vector<char*>& args) : app_args_(args)
{
- /* On startup, simix_global_init() calls simgrid::mc::Client::initialize(), which checks whether the MC_ENV_SOCKET_FD
- * env variable is set. If so, MC mode is assumed, and the client is setup from its side
- */
+ master_socket_ = socket(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);
+ xbt_assert(master_socket_ != -1, "Cannot create the master socket: %s", strerror(errno));
+ master_socket_name = "/tmp/simgrid-mc-" + std::to_string(getpid());
+ master_socket_name.resize(MC_SOCKET_NAME_LEN); // truncate socket name if it's too long
+ master_socket_name.back() = '\0'; // ensure the data are null-terminated
#ifdef __linux__
- // Make sure we do not outlive our parent
- sigset_t mask;
- sigemptyset(&mask);
- xbt_assert(sigprocmask(SIG_SETMASK, &mask, nullptr) >= 0, "Could not unblock signals");
- xbt_assert(prctl(PR_SET_PDEATHSIG, SIGHUP) == 0, "Could not PR_SET_PDEATHSIG");
+ master_socket_name[0] = '\0'; // abstract socket, automatically removed after close
+#else
+ unlink(master_socket_name.c_str()); // remove possible stale socket before bind
+ atexit([]() {
+ if (not master_socket_name.empty())
+ unlink(master_socket_name.c_str());
+ master_socket_name.clear();
+ });
#endif
- // Remove CLOEXEC to pass the socket to the application
- int fdflags = fcntl(socket, F_GETFD, 0);
- xbt_assert(fdflags != -1 && fcntl(socket, F_SETFD, fdflags & ~FD_CLOEXEC) != -1,
- "Could not remove CLOEXEC for socket");
-
- setenv(MC_ENV_SOCKET_FD, std::to_string(socket).c_str(), 1);
-
- /* Setup the tokenizer that parses the cfg:model-check/setenv parameter */
- using Tokenizer = boost::tokenizer<boost::char_separator<char>>;
- boost::char_separator<char> semicol_sep(";");
- boost::char_separator<char> equal_sep("=");
- Tokenizer token_vars(_sg_mc_setenv.get(), semicol_sep); /* Iterate over all FOO=foo parts */
- for (const auto& token : token_vars) {
- std::vector<std::string> kv;
- Tokenizer token_kv(token, equal_sep);
- for (const auto& t : token_kv) /* Iterate over 'FOO' and then 'foo' in that 'FOO=foo' */
- kv.push_back(t);
- xbt_assert(kv.size() == 2, "Parse error on 'model-check/setenv' value %s. Does it contain an equal sign?",
- token.c_str());
- XBT_INFO("setenv '%s'='%s'", kv[0].c_str(), kv[1].c_str());
- setenv(kv[0].c_str(), kv[1].c_str(), 1);
- }
-
- /* And now, exec the child process */
- int i = 1;
- while (args[i] != nullptr && args[i][0] == '-')
- i++;
+ struct sockaddr_un serv_addr = {};
+ serv_addr.sun_family = AF_UNIX;
+ master_socket_name.copy(serv_addr.sun_path, MC_SOCKET_NAME_LEN);
- xbt_assert(args[i] != nullptr,
- "Unable to find a binary to exec on the command line. Did you only pass config flags?");
+ xbt_assert(bind(master_socket_, (struct sockaddr*)&serv_addr, sizeof serv_addr) >= 0,
+ "Cannot bind the master socket to %c%s: %s.", (serv_addr.sun_path[0] ? serv_addr.sun_path[0] : '@'),
+ serv_addr.sun_path + 1, strerror(errno));
- execvp(args[i], args.data() + i);
- XBT_CRITICAL("The model-checked process failed to exec(%s): %s.\n"
- " Make sure that your binary exists on disk and is executable.",
- args[i], strerror(errno));
- if (strchr(args[i], '=') != nullptr)
- XBT_CRITICAL("If you want to pass environment variables to the application, please use --cfg=model-check/setenv:%s",
- args[i]);
+ xbt_assert(listen(master_socket_, SOMAXCONN) >= 0, "Cannot listen to the master socket: %s.", strerror(errno));
- xbt_die("Aborting now.");
+ application_factory_ = std::make_unique<simgrid::mc::CheckerSide>(app_args_);
+ checker_side_ = application_factory_->clone(master_socket_, master_socket_name);
}
-RemoteApp::RemoteApp(const std::vector<char*>& args)
+void RemoteApp::restore_initial_state()
{
- // Create an AF_LOCAL socketpair used for exchanging messages
- // between the model-checker process (ourselves) and the model-checked
- // process:
- int sockets[2];
- xbt_assert(socketpair(AF_LOCAL, SOCK_SEQPACKET | SOCK_CLOEXEC, 0, sockets) != -1, "Could not create socketpair");
-
- pid_t pid = fork();
- xbt_assert(pid >= 0, "Could not fork model-checked process");
-
- if (pid == 0) { // Child
- ::close(sockets[1]);
- run_child_process(sockets[0], args);
- DIE_IMPOSSIBLE;
- }
-
- // Parent (model-checker):
- ::close(sockets[0]);
-
- auto memory = std::make_unique<simgrid::mc::RemoteProcessMemory>(pid);
- checker_side_ = std::make_unique<simgrid::mc::CheckerSide>(sockets[1], std::move(memory));
-
- start();
-
- /* Take the initial snapshot */
- wait_for_requests();
- initial_snapshot_ = std::make_shared<simgrid::mc::Snapshot>(0, page_store_, checker_side_->get_remote_memory());
-}
-
-RemoteApp::~RemoteApp()
-{
- initial_snapshot_ = nullptr;
- shutdown();
-}
-void RemoteApp::start()
-{
- XBT_DEBUG("Waiting for the model-checked process");
- int status;
-
- // The model-checked process SIGSTOP itself to signal it's ready:
- const pid_t pid = get_remote_process_memory().pid();
-
- xbt_assert(waitpid(pid, &status, WAITPID_CHECKED_FLAGS) == pid && WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP,
- "Could not wait model-checked process");
-
- errno = 0;
-#ifdef __linux__
- ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
- ptrace(PTRACE_CONT, pid, 0, 0);
-#elif defined BSD
- ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
-#else
-#error "no ptrace equivalent coded for this platform"
-#endif
- xbt_assert(errno == 0,
- "Ptrace does not seem to be usable in your setup (errno: %d). "
- "If you run from within a docker, adding `--cap-add SYS_PTRACE` to the docker line may help. "
- "If it does not help, please report this bug.",
- errno);
-}
-void RemoteApp::restore_initial_state() const
-{
- this->initial_snapshot_->restore(checker_side_->get_remote_memory());
+ checker_side_ = application_factory_->clone(master_socket_, master_socket_name);
}
unsigned long RemoteApp::get_maxpid() const
//
// CheckerSide AppSide
// send ACTORS_STATUS ---->
- // <----- send ACTORS_STATUS_REPLY
- // <----- send `N` `s_mc_message_actors_status_one_t` structs
- // <----- send `M` `s_mc_message_simcall_probe_one_t` structs
+ // <----- send ACTORS_STATUS_REPLY_COUNT
+ // <----- send `N` ACTORS_STATUS_REPLY_TRANSITION (s_mc_message_actors_status_one_t)
+ // <----- send `M` ACTORS_STATUS_REPLY_SIMCALL (s_mc_message_simcall_probe_one_t)
+ //
+ // Note that we also receive disabled transitions, because the guiding strategies need them to decide what could
+ // unlock actors.
+
checker_side_->get_channel().send(MessageType::ACTORS_STATUS);
s_mc_message_actors_status_answer_t answer;
ssize_t answer_size = checker_side_->get_channel().receive(answer);
xbt_assert(answer_size != -1, "Could not receive message");
xbt_assert(answer_size == sizeof answer, "Broken message (size=%zd; expected %zu)", answer_size, sizeof answer);
- xbt_assert(answer.type == MessageType::ACTORS_STATUS_REPLY,
- "Received unexpected message %s (%i); expected MessageType::ACTORS_STATUS_REPLY (%i)",
- to_c_str(answer.type), (int)answer.type, (int)MessageType::ACTORS_STATUS_REPLY);
+ xbt_assert(answer.type == MessageType::ACTORS_STATUS_REPLY_COUNT,
+ "%d Received unexpected message %s (%i); expected MessageType::ACTORS_STATUS_REPLY_COUNT (%i)", getpid(),
+ to_c_str(answer.type), (int)answer.type, (int)MessageType::ACTORS_STATUS_REPLY_COUNT);
// Message sanity checks
- xbt_assert(answer.count >= 0, "Received an ACTOR_STATUS_REPLY message with an actor count of '%d' < 0", answer.count);
- xbt_assert(answer.transition_count >= 0, "Received an ACTOR_STATUS_REPLY message with transition_count '%d' < 0",
- answer.transition_count);
- xbt_assert(answer.transition_count == 0 || answer.count >= 0,
- "Received an ACTOR_STATUS_REPLY message with no actor data "
- "but with transition data nonetheless");
+ xbt_assert(answer.count >= 0, "Received an ACTORS_STATUS_REPLY_COUNT message with an actor count of '%d' < 0",
+ answer.count);
std::vector<s_mc_message_actors_status_one_t> status(answer.count);
if (answer.count > 0) {
xbt_assert(static_cast<size_t>(received) == size);
}
- // Ensures that each actor sends precisely `answer.transition_count` transitions. While technically
- // this doesn't catch the edge case where actor A sends 3 instead of 2 and actor B sends 2 instead
- // of 3 transitions, that is ignored here since that invariant needs to be enforced on the AppSide
- const auto expected_transitions = std::accumulate(
- status.begin(), status.end(), 0, [](int total, const auto& actor) { return total + actor.n_transitions; });
- xbt_assert(expected_transitions == answer.transition_count,
- "Expected to receive %d transition(s) but was only notified of %d by the app side", expected_transitions,
- answer.transition_count);
-
- std::vector<s_mc_message_simcall_probe_one_t> probes(answer.transition_count);
- if (answer.transition_count > 0) {
- for (auto& probe : probes) {
+ whereto.clear();
+
+ for (const auto& actor : status) {
+ std::vector<std::shared_ptr<Transition>> actor_transitions;
+ int n_transitions = actor.max_considered;
+ for (int times_considered = 0; times_considered < n_transitions; times_considered++) {
+ s_mc_message_simcall_probe_one_t probe;
ssize_t received = checker_side_->get_channel().receive(probe);
xbt_assert(received >= 0, "Could not receive response to ACTORS_PROBE message (%s)", strerror(errno));
xbt_assert(static_cast<size_t>(received) == sizeof probe,
"Could not receive response to ACTORS_PROBE message (%zd bytes received != %zu bytes expected",
received, sizeof probe);
- }
- }
- whereto.clear();
- std::move_iterator probes_iter(probes.begin());
-
- for (const auto& actor : status) {
- xbt_assert(actor.n_transitions == 0 || actor.n_transitions == actor.max_considered,
- "If any transitions are serialized for an actor, it must match the "
- "total number of transitions that can be considered for the actor "
- "(currently %d), but only %d transition(s) was/were said to be encoded",
- actor.max_considered, actor.n_transitions);
-
- std::vector<std::shared_ptr<Transition>> actor_transitions;
- for (int times_considered = 0; times_considered < actor.n_transitions; times_considered++, probes_iter++) {
- std::stringstream stream((*probes_iter).buffer.data());
+ std::stringstream stream(probe.buffer.data());
actor_transitions.emplace_back(deserialize_transition(actor.aid, times_considered, stream));
}
- XBT_DEBUG("Received %zu transitions for actor %ld", actor_transitions.size(), actor.aid);
+ XBT_DEBUG("Received %zu transitions for actor %ld. The first one is %s", actor_transitions.size(), actor.aid,
+ (actor_transitions.size() > 0 ? actor_transitions[0]->to_string().c_str() : "null"));
whereto.try_emplace(actor.aid, actor.aid, actor.enabled, actor.max_considered, std::move(actor_transitions));
}
}
"--cfg=model-check/replay:'%s'",
explo->get_record_trace().to_string().c_str());
explo->log_state();
- throw DeadlockError();
+ throw McError(ExitStatus::DEADLOCK);
}
}
void RemoteApp::wait_for_requests()
{
- /* Resume the application */
- if (checker_side_->get_channel().send(MessageType::CONTINUE) != 0)
- throw xbt::errno_error();
- get_remote_process_memory().clear_cache();
-
- if (this->get_remote_process_memory().running())
- checker_side_->dispatch_events();
-}
-
-void RemoteApp::shutdown()
-{
- XBT_DEBUG("Shutting down model-checker");
-
- RemoteProcessMemory& process = get_remote_process_memory();
- if (process.running()) {
- XBT_DEBUG("Killing process");
- finalize_app(true);
- kill(process.pid(), SIGKILL);
- process.terminate();
- }
+ checker_side_->wait_for_requests();
}
Transition* RemoteApp::handle_simcall(aid_t aid, int times_considered, bool new_transition)
m.times_considered_ = times_considered;
checker_side_->get_channel().send(m);
- get_remote_process_memory().clear_cache();
- if (this->get_remote_process_memory().running())
+ if (checker_side_->running())
checker_side_->dispatch_events(); // The app may send messages while processing the transition
s_mc_message_simcall_execute_answer_t answer;
ssize_t s = checker_side_->get_channel().receive(answer);
xbt_assert(s != -1, "Could not receive message");
+ xbt_assert(s > 0 && answer.type == MessageType::SIMCALL_EXECUTE_REPLY,
+ "%d Received unexpected message %s (%i); expected MessageType::SIMCALL_EXECUTE_REPLY (%i)", getpid(),
+ to_c_str(answer.type), (int)answer.type, (int)MessageType::SIMCALL_EXECUTE_REPLY);
xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer);
- xbt_assert(answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
- "Received unexpected message %s (%i); expected MessageType::SIMCALL_EXECUTE_ANSWER (%i)",
- to_c_str(answer.type), (int)answer.type, (int)MessageType::SIMCALL_EXECUTE_ANSWER);
if (new_transition) {
std::stringstream stream(answer.buffer.data());
void RemoteApp::finalize_app(bool terminate_asap)
{
- s_mc_message_int_t m = {};
- m.type = MessageType::FINALIZE;
- m.value = terminate_asap;
- xbt_assert(checker_side_->get_channel().send(m) == 0, "Could not ask the app to finalize on need");
-
- s_mc_message_t answer;
- ssize_t s = checker_side_->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);
+ checker_side_->finalize(terminate_asap);
}
} // namespace simgrid::mc
