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
34 ModelChecker::ModelChecker(std::unique_ptr<RemoteProcess> remote_simulation, int sockfd)
35 : checker_side_(sockfd), remote_process_(std::move(remote_simulation))
39 void ModelChecker::start()
42 [](evutil_socket_t sig, short events, void* arg) {
43 auto mc = static_cast<simgrid::mc::ModelChecker*>(arg);
44 if (events == EV_READ) {
45 std::array<char, MC_MESSAGE_LENGTH> buffer;
46 ssize_t size = mc->checker_side_.get_channel().receive(buffer.data(), buffer.size(), false);
47 if (size == -1 && errno != EAGAIN)
48 throw simgrid::xbt::errno_error();
50 if (not mc->handle_message(buffer.data(), size))
51 mc->checker_side_.break_loop();
52 } else if (events == EV_SIGNAL) {
56 xbt_die("Unexpected event");
61 XBT_DEBUG("Waiting for the model-checked process");
64 // The model-checked process SIGSTOP itself to signal it's ready:
65 const pid_t pid = remote_process_->pid();
67 xbt_assert(waitpid(pid, &status, WAITPID_CHECKED_FLAGS) == pid && WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP,
68 "Could not wait model-checked process");
70 if (not _sg_mc_dot_output_file.get().empty())
77 ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
78 ptrace(PTRACE_CONT, pid, 0, 0);
80 ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
82 # error "no ptrace equivalent coded for this platform"
84 xbt_assert(errno == 0,
85 "Ptrace does not seem to be usable in your setup (errno: %d). "
86 "If you run from within a docker, adding `--cap-add SYS_PTRACE` to the docker line may help. "
87 "If it does not help, please report this bug.",
91 static constexpr auto ignored_local_variables = {
92 std::make_pair("e", "*"),
93 std::make_pair("_log_ev", "*"),
95 /* Ignore local variable about time used for tracing */
96 std::make_pair("start_time", "*"),
99 void ModelChecker::setup_ignore()
101 const RemoteProcess& process = this->get_remote_process();
102 for (auto const& [var, frame] : ignored_local_variables)
103 process.ignore_local_variable(var, frame);
105 /* Static variable used for tracing */
106 process.ignore_global_variable("counter");
109 void ModelChecker::shutdown()
111 XBT_DEBUG("Shutting down model-checker");
113 RemoteProcess& process = get_remote_process();
114 if (process.running()) {
115 XBT_DEBUG("Killing process");
117 kill(process.pid(), SIGKILL);
122 void ModelChecker::resume()
124 if (checker_side_.get_channel().send(MessageType::CONTINUE) != 0)
125 throw xbt::errno_error();
126 remote_process_->clear_cache();
129 static void MC_report_crash(int status)
131 XBT_INFO("**************************");
132 XBT_INFO("** CRASH IN THE PROGRAM **");
133 XBT_INFO("**************************");
134 if (WIFSIGNALED(status))
135 XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
136 else if (WIFEXITED(status))
137 XBT_INFO("From exit: %i", WEXITSTATUS(status));
138 if (not xbt_log_no_loc)
139 XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
140 if (mc_model_checker->get_exploration()) {
141 XBT_INFO("Counter-example execution trace:");
142 for (auto const& s : mc_model_checker->get_exploration()->get_textual_trace())
143 XBT_INFO(" %s", s.c_str());
144 XBT_INFO("Path = %s", mc_model_checker->get_exploration()->get_record_trace().to_string().c_str());
145 Api::get().get_session().log_state();
146 if (xbt_log_no_loc) {
147 XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
149 XBT_INFO("Stack trace:");
150 mc_model_checker->get_remote_process().dump_stack();
155 bool ModelChecker::handle_message(const char* buffer, ssize_t size)
157 s_mc_message_t base_message;
158 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
159 memcpy(&base_message, buffer, sizeof(base_message));
161 switch(base_message.type) {
162 case MessageType::INITIAL_ADDRESSES: {
163 s_mc_message_initial_addresses_t message;
164 xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size, (int)sizeof(message));
165 memcpy(&message, buffer, sizeof(message));
167 get_remote_process().init(message.mmalloc_default_mdp, message.maxpid, message.actors);
171 case MessageType::IGNORE_HEAP: {
172 s_mc_message_ignore_heap_t message;
173 xbt_assert(size == sizeof(message), "Broken message");
174 memcpy(&message, buffer, sizeof(message));
176 IgnoredHeapRegion region;
177 region.block = message.block;
178 region.fragment = message.fragment;
179 region.address = message.address;
180 region.size = message.size;
181 get_remote_process().ignore_heap(region);
185 case MessageType::UNIGNORE_HEAP: {
186 s_mc_message_ignore_memory_t message;
187 xbt_assert(size == sizeof(message), "Broken message");
188 memcpy(&message, buffer, sizeof(message));
189 get_remote_process().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
193 case MessageType::IGNORE_MEMORY: {
194 s_mc_message_ignore_memory_t message;
195 xbt_assert(size == sizeof(message), "Broken message");
196 memcpy(&message, buffer, sizeof(message));
197 this->get_remote_process().ignore_region(message.addr, message.size);
201 case MessageType::STACK_REGION: {
202 s_mc_message_stack_region_t message;
203 xbt_assert(size == sizeof(message), "Broken message");
204 memcpy(&message, buffer, sizeof(message));
205 this->get_remote_process().stack_areas().push_back(message.stack_region);
208 case MessageType::REGISTER_SYMBOL: {
209 s_mc_message_register_symbol_t message;
210 xbt_assert(size == sizeof(message), "Broken message");
211 memcpy(&message, buffer, sizeof(message));
212 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
213 XBT_DEBUG("Received symbol: %s", message.name.data());
215 if (property_automaton == nullptr)
216 property_automaton = xbt_automaton_new();
218 const RemoteProcess* process = &this->get_remote_process();
219 RemotePtr<int> address = remote((int*)message.data);
220 xbt::add_proposition(property_automaton, message.name.data(),
221 [process, address]() { return process->read(address); });
226 case MessageType::WAITING:
229 case MessageType::ASSERTION_FAILED:
230 XBT_INFO("**************************");
231 XBT_INFO("*** PROPERTY NOT VALID ***");
232 XBT_INFO("**************************");
233 XBT_INFO("Counter-example execution trace:");
234 for (auto const& s : get_exploration()->get_textual_trace())
235 XBT_INFO(" %s", s.c_str());
236 XBT_INFO("Path = %s", get_exploration()->get_record_trace().to_string().c_str());
237 Api::get().get_session().log_state();
239 this->exit(SIMGRID_MC_EXIT_SAFETY);
242 xbt_die("Unexpected message from model-checked application");
247 /** Terminate the model-checker application */
248 void ModelChecker::exit(int status)
254 void ModelChecker::handle_waitpid()
256 XBT_DEBUG("Check for wait event");
259 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
261 if (errno == ECHILD) {
263 xbt_assert(not this->get_remote_process().running(), "Inconsistent state");
266 XBT_ERROR("Could not wait for pid");
267 throw simgrid::xbt::errno_error();
271 if (pid == this->get_remote_process().pid()) {
272 // From PTRACE_O_TRACEEXIT:
274 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
275 xbt_assert(ptrace(PTRACE_GETEVENTMSG, remote_process_->pid(), 0, &status) != -1, "Could not get exit status");
276 if (WIFSIGNALED(status)) {
277 MC_report_crash(status);
278 this->get_remote_process().terminate();
279 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
284 // We don't care about signals, just reinject them:
285 if (WIFSTOPPED(status)) {
286 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
289 ptrace(PTRACE_CONT, remote_process_->pid(), 0, WSTOPSIG(status));
291 ptrace(PT_CONTINUE, remote_process_->pid(), (caddr_t)1, WSTOPSIG(status));
293 xbt_assert(errno == 0, "Could not PTRACE_CONT");
296 else if (WIFSIGNALED(status)) {
297 MC_report_crash(status);
298 this->get_remote_process().terminate();
299 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
300 } else if (WIFEXITED(status)) {
301 XBT_DEBUG("Child process is over");
302 this->get_remote_process().terminate();
308 void ModelChecker::wait_for_requests()
311 if (this->get_remote_process().running())
312 checker_side_.dispatch();
315 Transition* ModelChecker::handle_simcall(aid_t aid, int times_considered, bool new_transition)
317 s_mc_message_simcall_execute_t m;
318 memset(&m, 0, sizeof(m));
319 m.type = MessageType::SIMCALL_EXECUTE;
321 m.times_considered_ = times_considered;
322 checker_side_.get_channel().send(m);
324 this->remote_process_->clear_cache();
325 if (this->remote_process_->running())
326 checker_side_.dispatch(); // The app may send messages while processing the transition
328 s_mc_message_simcall_execute_answer_t answer;
329 ssize_t s = checker_side_.get_channel().receive(answer);
330 xbt_assert(s != -1, "Could not receive message");
331 xbt_assert(s == sizeof(answer) && answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
332 "Received unexpected message %s (%i, size=%i) "
333 "expected MessageType::SIMCALL_EXECUTE_ANSWER (%i, size=%i)",
334 to_c_str(answer.type), (int)answer.type, (int)s, (int)MessageType::SIMCALL_EXECUTE_ANSWER,
335 (int)sizeof(answer));
337 if (new_transition) {
338 std::stringstream stream(answer.buffer.data());
339 return deserialize_transition(aid, times_considered, stream);
344 void ModelChecker::finalize_app(bool terminate_asap)
346 s_mc_message_int_t m;
347 memset(&m, 0, sizeof m);
348 m.type = MessageType::FINALIZE;
349 m.value = terminate_asap;
350 xbt_assert(checker_side_.get_channel().send(m) == 0, "Could not ask the app to finalize on need");
352 s_mc_message_t answer;
353 xbt_assert(checker_side_.get_channel().receive(answer) != -1, "Could not receive answer to FINALIZE");
357 } // namespace simgrid