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;
25 using simgrid::mc::remote;
28 # define WAITPID_CHECKED_FLAGS __WALL
30 # define WAITPID_CHECKED_FLAGS 0
36 ModelChecker::ModelChecker(std::unique_ptr<RemoteProcess> remote_simulation, int sockfd)
37 : checker_side_(sockfd), remote_process_(std::move(remote_simulation))
41 void ModelChecker::start()
44 [](evutil_socket_t sig, short events, void* arg) {
45 auto mc = static_cast<simgrid::mc::ModelChecker*>(arg);
46 if (events == EV_READ) {
47 std::array<char, MC_MESSAGE_LENGTH> buffer;
48 ssize_t size = mc->checker_side_.get_channel().receive(buffer.data(), buffer.size(), false);
49 if (size == -1 && errno != EAGAIN)
50 throw simgrid::xbt::errno_error();
52 if (not mc->handle_message(buffer.data(), size))
53 mc->checker_side_.break_loop();
54 } else if (events == EV_SIGNAL) {
58 xbt_die("Unexpected event");
63 XBT_DEBUG("Waiting for the model-checked process");
66 // The model-checked process SIGSTOP itself to signal it's ready:
67 const pid_t pid = remote_process_->pid();
69 xbt_assert(waitpid(pid, &status, WAITPID_CHECKED_FLAGS) == pid && WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP,
70 "Could not wait model-checked process");
72 if (not _sg_mc_dot_output_file.get().empty())
79 ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
80 ptrace(PTRACE_CONT, pid, 0, 0);
82 ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
84 # error "no ptrace equivalent coded for this platform"
86 xbt_assert(errno == 0,
87 "Ptrace does not seem to be usable in your setup (errno: %d). "
88 "If you run from within a docker, adding `--cap-add SYS_PTRACE` to the docker line may help. "
89 "If it does not help, please report this bug.",
93 static constexpr auto ignored_local_variables = {
94 std::make_pair("e", "*"),
95 std::make_pair("_log_ev", "*"),
97 /* Ignore local variable about time used for tracing */
98 std::make_pair("start_time", "*"),
101 void ModelChecker::setup_ignore()
103 const RemoteProcess& process = this->get_remote_process();
104 for (auto const& [var, frame] : ignored_local_variables)
105 process.ignore_local_variable(var, frame);
107 /* Static variable used for tracing */
108 process.ignore_global_variable("counter");
111 void ModelChecker::shutdown()
113 XBT_DEBUG("Shutting down model-checker");
115 RemoteProcess& process = get_remote_process();
116 if (process.running()) {
117 XBT_DEBUG("Killing process");
119 kill(process.pid(), SIGKILL);
124 void ModelChecker::resume()
126 int res = checker_side_.get_channel().send(MessageType::CONTINUE);
128 throw xbt::errno_error();
129 remote_process_->clear_cache();
132 static void MC_report_crash(int status)
134 XBT_INFO("**************************");
135 XBT_INFO("** CRASH IN THE PROGRAM **");
136 XBT_INFO("**************************");
137 if (WIFSIGNALED(status))
138 XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
139 else if (WIFEXITED(status))
140 XBT_INFO("From exit: %i", WEXITSTATUS(status));
141 if (not xbt_log_no_loc)
142 XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
143 if (mc_model_checker->get_exploration()) {
144 XBT_INFO("Counter-example execution trace:");
145 for (auto const& s : mc_model_checker->get_exploration()->get_textual_trace())
146 XBT_INFO(" %s", s.c_str());
147 XBT_INFO("Path = %s", mc_model_checker->get_exploration()->get_record_trace().to_string().c_str());
148 Api::get().get_session().log_state();
149 if (xbt_log_no_loc) {
150 XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
152 XBT_INFO("Stack trace:");
153 mc_model_checker->get_remote_process().dump_stack();
158 bool ModelChecker::handle_message(const char* buffer, ssize_t size)
160 s_mc_message_t base_message;
161 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
162 memcpy(&base_message, buffer, sizeof(base_message));
164 switch(base_message.type) {
165 case MessageType::INITIAL_ADDRESSES: {
166 s_mc_message_initial_addresses_t message;
167 xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size, (int)sizeof(message));
168 memcpy(&message, buffer, sizeof(message));
170 get_remote_process().init(message.mmalloc_default_mdp, message.maxpid, message.actors);
174 case MessageType::IGNORE_HEAP: {
175 s_mc_message_ignore_heap_t message;
176 xbt_assert(size == sizeof(message), "Broken message");
177 memcpy(&message, buffer, sizeof(message));
179 IgnoredHeapRegion region;
180 region.block = message.block;
181 region.fragment = message.fragment;
182 region.address = message.address;
183 region.size = message.size;
184 get_remote_process().ignore_heap(region);
188 case MessageType::UNIGNORE_HEAP: {
189 s_mc_message_ignore_memory_t message;
190 xbt_assert(size == sizeof(message), "Broken message");
191 memcpy(&message, buffer, sizeof(message));
192 get_remote_process().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
196 case MessageType::IGNORE_MEMORY: {
197 s_mc_message_ignore_memory_t message;
198 xbt_assert(size == sizeof(message), "Broken message");
199 memcpy(&message, buffer, sizeof(message));
200 this->get_remote_process().ignore_region(message.addr, message.size);
204 case MessageType::STACK_REGION: {
205 s_mc_message_stack_region_t message;
206 xbt_assert(size == sizeof(message), "Broken message");
207 memcpy(&message, buffer, sizeof(message));
208 this->get_remote_process().stack_areas().push_back(message.stack_region);
211 case MessageType::REGISTER_SYMBOL: {
212 s_mc_message_register_symbol_t message;
213 xbt_assert(size == sizeof(message), "Broken message");
214 memcpy(&message, buffer, sizeof(message));
215 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
216 XBT_DEBUG("Received symbol: %s", message.name.data());
218 if (property_automaton == nullptr)
219 property_automaton = xbt_automaton_new();
221 const RemoteProcess* process = &this->get_remote_process();
222 RemotePtr<int> address = remote((int*)message.data);
223 xbt::add_proposition(property_automaton, message.name.data(),
224 [process, address]() { return process->read(address); });
229 case MessageType::WAITING:
232 case MessageType::ASSERTION_FAILED:
233 XBT_INFO("**************************");
234 XBT_INFO("*** PROPERTY NOT VALID ***");
235 XBT_INFO("**************************");
236 XBT_INFO("Counter-example execution trace:");
237 for (auto const& s : get_exploration()->get_textual_trace())
238 XBT_INFO(" %s", s.c_str());
239 XBT_INFO("Path = %s", get_exploration()->get_record_trace().to_string().c_str());
240 Api::get().get_session().log_state();
242 this->exit(SIMGRID_MC_EXIT_SAFETY);
245 xbt_die("Unexpected message from model-checked application");
250 /** Terminate the model-checker application */
251 void ModelChecker::exit(int status)
257 void ModelChecker::handle_waitpid()
259 XBT_DEBUG("Check for wait event");
262 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
264 if (errno == ECHILD) {
266 xbt_assert(not this->get_remote_process().running(), "Inconsistent state");
269 XBT_ERROR("Could not wait for pid");
270 throw simgrid::xbt::errno_error();
274 if (pid == this->get_remote_process().pid()) {
275 // From PTRACE_O_TRACEEXIT:
277 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
278 xbt_assert(ptrace(PTRACE_GETEVENTMSG, remote_process_->pid(), 0, &status) != -1, "Could not get exit status");
279 if (WIFSIGNALED(status)) {
280 MC_report_crash(status);
281 this->get_remote_process().terminate();
282 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
287 // We don't care about signals, just reinject them:
288 if (WIFSTOPPED(status)) {
289 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
292 ptrace(PTRACE_CONT, remote_process_->pid(), 0, WSTOPSIG(status));
294 ptrace(PT_CONTINUE, remote_process_->pid(), (caddr_t)1, WSTOPSIG(status));
296 xbt_assert(errno == 0, "Could not PTRACE_CONT");
299 else if (WIFSIGNALED(status)) {
300 MC_report_crash(status);
301 this->get_remote_process().terminate();
302 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
303 } else if (WIFEXITED(status)) {
304 XBT_DEBUG("Child process is over");
305 this->get_remote_process().terminate();
311 void ModelChecker::wait_for_requests()
314 if (this->get_remote_process().running())
315 checker_side_.dispatch();
318 Transition* ModelChecker::handle_simcall(aid_t aid, int times_considered, bool new_transition)
320 s_mc_message_simcall_execute_t m;
321 memset(&m, 0, sizeof(m));
322 m.type = MessageType::SIMCALL_EXECUTE;
324 m.times_considered_ = times_considered;
325 checker_side_.get_channel().send(m);
327 this->remote_process_->clear_cache();
328 if (this->remote_process_->running())
329 checker_side_.dispatch(); // The app may send messages while processing the transition
331 s_mc_message_simcall_execute_answer_t answer;
332 ssize_t s = checker_side_.get_channel().receive(answer);
333 xbt_assert(s != -1, "Could not receive message");
334 xbt_assert(s == sizeof(answer) && answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
335 "Received unexpected message %s (%i, size=%i) "
336 "expected MessageType::SIMCALL_EXECUTE_ANSWER (%i, size=%i)",
337 to_c_str(answer.type), (int)answer.type, (int)s, (int)MessageType::SIMCALL_EXECUTE_ANSWER,
338 (int)sizeof(answer));
340 if (new_transition) {
341 std::stringstream stream(answer.buffer.data());
342 return deserialize_transition(aid, times_considered, stream);
347 void ModelChecker::finalize_app(bool terminate_asap)
349 s_mc_message_int_t m;
350 memset(&m, 0, sizeof m);
351 m.type = MessageType::FINALIZE;
352 m.value = terminate_asap;
353 xbt_assert(checker_side_.get_channel().send(m) == 0, "Could not ask the app to finalize on need");
355 s_mc_message_t answer;
356 xbt_assert(checker_side_.get_channel().receive(answer) != -1, "Could not receive answer to FINALIZE");
360 } // namespace simgrid