1 /* Copyright (c) 2008-2023. 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/explo/LivenessChecker.hpp"
9 #include "src/mc/mc_config.hpp"
10 #include "src/mc/mc_exit.hpp"
11 #include "src/mc/mc_private.hpp"
12 #include "src/mc/remote/RemoteProcess.hpp"
13 #include "src/mc/transition/TransitionComm.hpp"
14 #include "xbt/automaton.hpp"
15 #include "xbt/system_error.hpp"
19 #include <sys/ptrace.h>
22 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_ModelChecker, mc, "ModelChecker");
24 ::simgrid::mc::ModelChecker* mc_model_checker = nullptr;
27 # define WAITPID_CHECKED_FLAGS __WALL
29 # define WAITPID_CHECKED_FLAGS 0
32 namespace simgrid::mc {
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 signal: %d", sig);
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");
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(Exploration* explorer, 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");
140 XBT_INFO("Counter-example execution trace:");
141 for (auto const& s : explorer->get_textual_trace())
142 XBT_INFO(" %s", s.c_str());
143 XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
144 "--cfg=model-check/replay:'%s'",
145 explorer->get_record_trace().to_string().c_str());
146 explorer->log_state();
147 if (xbt_log_no_loc) {
148 XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
150 XBT_INFO("Stack trace:");
151 explorer->get_remote_app().get_remote_process().dump_stack();
156 bool ModelChecker::handle_message(const char* buffer, ssize_t size)
158 s_mc_message_t base_message;
159 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
160 memcpy(&base_message, buffer, sizeof(base_message));
162 switch(base_message.type) {
163 case MessageType::INITIAL_ADDRESSES: {
164 s_mc_message_initial_addresses_t message;
165 xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size, (int)sizeof(message));
166 memcpy(&message, buffer, sizeof(message));
168 get_remote_process().init(message.mmalloc_default_mdp);
172 case MessageType::IGNORE_HEAP: {
173 s_mc_message_ignore_heap_t message;
174 xbt_assert(size == sizeof(message), "Broken message");
175 memcpy(&message, buffer, sizeof(message));
177 IgnoredHeapRegion region;
178 region.block = message.block;
179 region.fragment = message.fragment;
180 region.address = message.address;
181 region.size = message.size;
182 get_remote_process().ignore_heap(region);
186 case MessageType::UNIGNORE_HEAP: {
187 s_mc_message_ignore_memory_t message;
188 xbt_assert(size == sizeof(message), "Broken message");
189 memcpy(&message, buffer, sizeof(message));
190 get_remote_process().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
194 case MessageType::IGNORE_MEMORY: {
195 s_mc_message_ignore_memory_t message;
196 xbt_assert(size == sizeof(message), "Broken message");
197 memcpy(&message, buffer, sizeof(message));
198 this->get_remote_process().ignore_region(message.addr, message.size);
202 case MessageType::STACK_REGION: {
203 s_mc_message_stack_region_t message;
204 xbt_assert(size == sizeof(message), "Broken message");
205 memcpy(&message, buffer, sizeof(message));
206 this->get_remote_process().stack_areas().push_back(message.stack_region);
209 case MessageType::REGISTER_SYMBOL: {
210 s_mc_message_register_symbol_t message;
211 xbt_assert(size == sizeof(message), "Broken message");
212 memcpy(&message, buffer, sizeof(message));
213 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
214 XBT_DEBUG("Received symbol: %s", message.name.data());
216 LivenessChecker::automaton_register_symbol(get_remote_process(), message.name.data(), remote((int*)message.data));
220 case MessageType::WAITING:
223 case MessageType::ASSERTION_FAILED:
224 XBT_INFO("**************************");
225 XBT_INFO("*** PROPERTY NOT VALID ***");
226 XBT_INFO("**************************");
227 XBT_INFO("Counter-example execution trace:");
228 for (auto const& s : get_exploration()->get_textual_trace())
229 XBT_INFO(" %s", s.c_str());
230 XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
231 "--cfg=model-check/replay:'%s'",
232 get_exploration()->get_record_trace().to_string().c_str());
233 exploration_->log_state();
235 this->exit(SIMGRID_MC_EXIT_SAFETY);
238 xbt_die("Unexpected message from model-checked application");
243 /** Terminate the model-checker application */
244 void ModelChecker::exit(int status)
250 void ModelChecker::handle_waitpid()
252 XBT_DEBUG("Check for wait event");
255 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
257 if (errno == ECHILD) {
259 xbt_assert(not this->get_remote_process().running(), "Inconsistent state");
262 XBT_ERROR("Could not wait for pid");
263 throw simgrid::xbt::errno_error();
267 if (pid == this->get_remote_process().pid()) {
268 // From PTRACE_O_TRACEEXIT:
270 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
271 unsigned long eventmsg;
272 xbt_assert(ptrace(PTRACE_GETEVENTMSG, remote_process_->pid(), 0, &eventmsg) != -1, "Could not get exit status");
273 status = static_cast<int>(eventmsg);
274 if (WIFSIGNALED(status)) {
275 MC_report_crash(exploration_, status);
276 this->get_remote_process().terminate();
277 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
282 // We don't care about signals, just reinject them:
283 if (WIFSTOPPED(status)) {
284 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
287 ptrace(PTRACE_CONT, remote_process_->pid(), 0, WSTOPSIG(status));
289 ptrace(PT_CONTINUE, remote_process_->pid(), (caddr_t)1, WSTOPSIG(status));
291 xbt_assert(errno == 0, "Could not PTRACE_CONT");
294 else if (WIFSIGNALED(status)) {
295 MC_report_crash(exploration_, status);
296 this->get_remote_process().terminate();
297 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
298 } else if (WIFEXITED(status)) {
299 XBT_DEBUG("Child process is over");
300 this->get_remote_process().terminate();
306 void ModelChecker::wait_for_requests()
309 if (this->get_remote_process().running())
310 checker_side_.dispatch();
313 Transition* ModelChecker::handle_simcall(aid_t aid, int times_considered, bool new_transition)
315 s_mc_message_simcall_execute_t m = {};
316 m.type = MessageType::SIMCALL_EXECUTE;
318 m.times_considered_ = times_considered;
319 checker_side_.get_channel().send(m);
321 this->remote_process_->clear_cache();
322 if (this->remote_process_->running())
323 checker_side_.dispatch(); // The app may send messages while processing the transition
325 s_mc_message_simcall_execute_answer_t answer;
326 ssize_t s = checker_side_.get_channel().receive(answer);
327 xbt_assert(s != -1, "Could not receive message");
328 xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer);
329 xbt_assert(answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
330 "Received unexpected message %s (%i); expected MessageType::SIMCALL_EXECUTE_ANSWER (%i)",
331 to_c_str(answer.type), (int)answer.type, (int)MessageType::SIMCALL_EXECUTE_ANSWER);
333 if (new_transition) {
334 std::stringstream stream(answer.buffer.data());
335 return deserialize_transition(aid, times_considered, stream);
340 void ModelChecker::finalize_app(bool terminate_asap)
342 s_mc_message_int_t m = {};
343 m.type = MessageType::FINALIZE;
344 m.value = terminate_asap;
345 xbt_assert(checker_side_.get_channel().send(m) == 0, "Could not ask the app to finalize on need");
347 s_mc_message_t answer;
348 ssize_t s = checker_side_.get_channel().receive(answer);
349 xbt_assert(s != -1, "Could not receive answer to FINALIZE");
350 xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer);
351 xbt_assert(answer.type == MessageType::FINALIZE_REPLY,
352 "Received unexpected message %s (%i); expected MessageType::FINALIZE_REPLY (%i)", to_c_str(answer.type),
353 (int)answer.type, (int)MessageType::FINALIZE_REPLY);
356 } // namespace simgrid::mc