1 /* Copyright (c) 2008-2022. 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 #include "src/mc/ModelChecker.hpp"
7 #include "src/mc/explo/Exploration.hpp"
8 #include "src/mc/mc_config.hpp"
9 #include "src/mc/mc_exit.hpp"
10 #include "src/mc/mc_private.hpp"
11 #include "src/mc/remote/RemoteProcess.hpp"
12 #include "src/mc/transition/TransitionComm.hpp"
13 #include "xbt/automaton.hpp"
14 #include "xbt/system_error.hpp"
18 #include <sys/ptrace.h>
21 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_ModelChecker, mc, "ModelChecker");
23 ::simgrid::mc::ModelChecker* mc_model_checker = nullptr;
26 # define WAITPID_CHECKED_FLAGS __WALL
28 # define WAITPID_CHECKED_FLAGS 0
31 namespace simgrid::mc {
33 ModelChecker::ModelChecker(std::unique_ptr<RemoteProcess> remote_simulation, int sockfd)
34 : checker_side_(sockfd), remote_process_(std::move(remote_simulation))
38 void ModelChecker::start()
41 [](evutil_socket_t sig, short events, void* arg) {
42 auto mc = static_cast<simgrid::mc::ModelChecker*>(arg);
43 if (events == EV_READ) {
44 std::array<char, MC_MESSAGE_LENGTH> buffer;
45 ssize_t size = mc->checker_side_.get_channel().receive(buffer.data(), buffer.size(), false);
46 if (size == -1 && errno != EAGAIN)
47 throw simgrid::xbt::errno_error();
49 if (not mc->handle_message(buffer.data(), size))
50 mc->checker_side_.break_loop();
51 } else if (events == EV_SIGNAL) {
55 xbt_die("Unexpected event");
60 XBT_DEBUG("Waiting for the model-checked process");
63 // The model-checked process SIGSTOP itself to signal it's ready:
64 const pid_t pid = remote_process_->pid();
66 xbt_assert(waitpid(pid, &status, WAITPID_CHECKED_FLAGS) == pid && WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP,
67 "Could not wait model-checked process");
69 if (not _sg_mc_dot_output_file.get().empty())
76 ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
77 ptrace(PTRACE_CONT, pid, 0, 0);
79 ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
81 # error "no ptrace equivalent coded for this platform"
83 xbt_assert(errno == 0,
84 "Ptrace does not seem to be usable in your setup (errno: %d). "
85 "If you run from within a docker, adding `--cap-add SYS_PTRACE` to the docker line may help. "
86 "If it does not help, please report this bug.",
90 static constexpr auto ignored_local_variables = {
91 std::make_pair("e", "*"),
92 std::make_pair("_log_ev", "*"),
94 /* Ignore local variable about time used for tracing */
95 std::make_pair("start_time", "*"),
98 void ModelChecker::setup_ignore()
100 const RemoteProcess& process = this->get_remote_process();
101 for (auto const& [var, frame] : ignored_local_variables)
102 process.ignore_local_variable(var, frame);
104 /* Static variable used for tracing */
105 process.ignore_global_variable("counter");
108 void ModelChecker::shutdown()
110 XBT_DEBUG("Shutting down model-checker");
112 RemoteProcess& process = get_remote_process();
113 if (process.running()) {
114 XBT_DEBUG("Killing process");
116 kill(process.pid(), SIGKILL);
121 void ModelChecker::resume()
123 if (checker_side_.get_channel().send(MessageType::CONTINUE) != 0)
124 throw xbt::errno_error();
125 remote_process_->clear_cache();
128 static void MC_report_crash(int status)
130 XBT_INFO("**************************");
131 XBT_INFO("** CRASH IN THE PROGRAM **");
132 XBT_INFO("**************************");
133 if (WIFSIGNALED(status))
134 XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
135 else if (WIFEXITED(status))
136 XBT_INFO("From exit: %i", WEXITSTATUS(status));
137 if (not xbt_log_no_loc)
138 XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
139 if (mc_model_checker->get_exploration()) {
140 XBT_INFO("Counter-example execution trace:");
141 for (auto const& s : mc_model_checker->get_exploration()->get_textual_trace())
142 XBT_INFO(" %s", s.c_str());
143 XBT_INFO("Path = %s", mc_model_checker->get_exploration()->get_record_trace().to_string().c_str());
144 Api::get().get_session().log_state();
145 if (xbt_log_no_loc) {
146 XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
148 XBT_INFO("Stack trace:");
149 mc_model_checker->get_remote_process().dump_stack();
154 bool ModelChecker::handle_message(const char* buffer, ssize_t size)
156 s_mc_message_t base_message;
157 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
158 memcpy(&base_message, buffer, sizeof(base_message));
160 switch(base_message.type) {
161 case MessageType::INITIAL_ADDRESSES: {
162 s_mc_message_initial_addresses_t message;
163 xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size, (int)sizeof(message));
164 memcpy(&message, buffer, sizeof(message));
166 get_remote_process().init(message.mmalloc_default_mdp, message.maxpid, message.actors);
170 case MessageType::IGNORE_HEAP: {
171 s_mc_message_ignore_heap_t message;
172 xbt_assert(size == sizeof(message), "Broken message");
173 memcpy(&message, buffer, sizeof(message));
175 IgnoredHeapRegion region;
176 region.block = message.block;
177 region.fragment = message.fragment;
178 region.address = message.address;
179 region.size = message.size;
180 get_remote_process().ignore_heap(region);
184 case MessageType::UNIGNORE_HEAP: {
185 s_mc_message_ignore_memory_t message;
186 xbt_assert(size == sizeof(message), "Broken message");
187 memcpy(&message, buffer, sizeof(message));
188 get_remote_process().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
192 case MessageType::IGNORE_MEMORY: {
193 s_mc_message_ignore_memory_t message;
194 xbt_assert(size == sizeof(message), "Broken message");
195 memcpy(&message, buffer, sizeof(message));
196 this->get_remote_process().ignore_region(message.addr, message.size);
200 case MessageType::STACK_REGION: {
201 s_mc_message_stack_region_t message;
202 xbt_assert(size == sizeof(message), "Broken message");
203 memcpy(&message, buffer, sizeof(message));
204 this->get_remote_process().stack_areas().push_back(message.stack_region);
207 case MessageType::REGISTER_SYMBOL: {
208 s_mc_message_register_symbol_t message;
209 xbt_assert(size == sizeof(message), "Broken message");
210 memcpy(&message, buffer, sizeof(message));
211 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
212 XBT_DEBUG("Received symbol: %s", message.name.data());
214 if (property_automaton == nullptr)
215 property_automaton = xbt_automaton_new();
217 const RemoteProcess* process = &this->get_remote_process();
218 RemotePtr<int> address = remote((int*)message.data);
219 xbt::add_proposition(property_automaton, message.name.data(),
220 [process, address]() { return process->read(address); });
225 case MessageType::WAITING:
228 case MessageType::ASSERTION_FAILED:
229 XBT_INFO("**************************");
230 XBT_INFO("*** PROPERTY NOT VALID ***");
231 XBT_INFO("**************************");
232 XBT_INFO("Counter-example execution trace:");
233 for (auto const& s : get_exploration()->get_textual_trace())
234 XBT_INFO(" %s", s.c_str());
235 XBT_INFO("Path = %s", get_exploration()->get_record_trace().to_string().c_str());
236 Api::get().get_session().log_state();
238 this->exit(SIMGRID_MC_EXIT_SAFETY);
241 xbt_die("Unexpected message from model-checked application");
246 /** Terminate the model-checker application */
247 void ModelChecker::exit(int status)
253 void ModelChecker::handle_waitpid()
255 XBT_DEBUG("Check for wait event");
258 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
260 if (errno == ECHILD) {
262 xbt_assert(not this->get_remote_process().running(), "Inconsistent state");
265 XBT_ERROR("Could not wait for pid");
266 throw simgrid::xbt::errno_error();
270 if (pid == this->get_remote_process().pid()) {
271 // From PTRACE_O_TRACEEXIT:
273 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
274 xbt_assert(ptrace(PTRACE_GETEVENTMSG, remote_process_->pid(), 0, &status) != -1, "Could not get exit status");
275 if (WIFSIGNALED(status)) {
276 MC_report_crash(status);
277 this->get_remote_process().terminate();
278 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
283 // We don't care about signals, just reinject them:
284 if (WIFSTOPPED(status)) {
285 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
288 ptrace(PTRACE_CONT, remote_process_->pid(), 0, WSTOPSIG(status));
290 ptrace(PT_CONTINUE, remote_process_->pid(), (caddr_t)1, WSTOPSIG(status));
292 xbt_assert(errno == 0, "Could not PTRACE_CONT");
295 else if (WIFSIGNALED(status)) {
296 MC_report_crash(status);
297 this->get_remote_process().terminate();
298 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
299 } else if (WIFEXITED(status)) {
300 XBT_DEBUG("Child process is over");
301 this->get_remote_process().terminate();
307 void ModelChecker::wait_for_requests()
310 if (this->get_remote_process().running())
311 checker_side_.dispatch();
314 Transition* ModelChecker::handle_simcall(aid_t aid, int times_considered, bool new_transition)
316 s_mc_message_simcall_execute_t m;
317 memset(&m, 0, sizeof(m));
318 m.type = MessageType::SIMCALL_EXECUTE;
320 m.times_considered_ = times_considered;
321 checker_side_.get_channel().send(m);
323 this->remote_process_->clear_cache();
324 if (this->remote_process_->running())
325 checker_side_.dispatch(); // The app may send messages while processing the transition
327 s_mc_message_simcall_execute_answer_t answer;
328 ssize_t s = checker_side_.get_channel().receive(answer);
329 xbt_assert(s != -1, "Could not receive message");
330 xbt_assert(s == sizeof(answer) && answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
331 "Received unexpected message %s (%i, size=%i) "
332 "expected MessageType::SIMCALL_EXECUTE_ANSWER (%i, size=%i)",
333 to_c_str(answer.type), (int)answer.type, (int)s, (int)MessageType::SIMCALL_EXECUTE_ANSWER,
334 (int)sizeof(answer));
336 if (new_transition) {
337 std::stringstream stream(answer.buffer.data());
338 return deserialize_transition(aid, times_considered, stream);
343 void ModelChecker::finalize_app(bool terminate_asap)
345 s_mc_message_int_t m;
346 memset(&m, 0, sizeof m);
347 m.type = MessageType::FINALIZE;
348 m.value = terminate_asap;
349 xbt_assert(checker_side_.get_channel().send(m) == 0, "Could not ask the app to finalize on need");
351 s_mc_message_t answer;
352 xbt_assert(checker_side_.get_channel().receive(answer) != -1, "Could not receive answer to FINALIZE");
355 } // namespace simgrid::mc