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 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");
74 ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
75 ptrace(PTRACE_CONT, pid, 0, 0);
77 ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
79 # error "no ptrace equivalent coded for this platform"
81 xbt_assert(errno == 0,
82 "Ptrace does not seem to be usable in your setup (errno: %d). "
83 "If you run from within a docker, adding `--cap-add SYS_PTRACE` to the docker line may help. "
84 "If it does not help, please report this bug.",
88 static constexpr auto ignored_local_variables = {
89 std::make_pair("e", "*"),
90 std::make_pair("_log_ev", "*"),
92 /* Ignore local variable about time used for tracing */
93 std::make_pair("start_time", "*"),
96 void ModelChecker::setup_ignore()
98 const RemoteProcess& process = this->get_remote_process();
99 for (auto const& [var, frame] : ignored_local_variables)
100 process.ignore_local_variable(var, frame);
102 /* Static variable used for tracing */
103 process.ignore_global_variable("counter");
106 void ModelChecker::shutdown()
108 XBT_DEBUG("Shutting down model-checker");
110 RemoteProcess& process = get_remote_process();
111 if (process.running()) {
112 XBT_DEBUG("Killing process");
114 kill(process.pid(), SIGKILL);
119 void ModelChecker::resume()
121 if (checker_side_.get_channel().send(MessageType::CONTINUE) != 0)
122 throw xbt::errno_error();
123 remote_process_->clear_cache();
126 static void MC_report_crash(Exploration* explorer, int status)
128 XBT_INFO("**************************");
129 XBT_INFO("** CRASH IN THE PROGRAM **");
130 XBT_INFO("**************************");
131 if (WIFSIGNALED(status))
132 XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
133 else if (WIFEXITED(status))
134 XBT_INFO("From exit: %i", WEXITSTATUS(status));
135 if (not xbt_log_no_loc)
136 XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
138 XBT_INFO("Counter-example execution trace:");
139 for (auto const& s : explorer->get_textual_trace())
140 XBT_INFO(" %s", s.c_str());
141 XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
142 "--cfg=model-check/replay:'%s'",
143 explorer->get_record_trace().to_string().c_str());
144 explorer->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);
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 LivenessChecker::automaton_register_symbol(get_remote_process(), message.name.data(), remote((int*)message.data));
218 case MessageType::WAITING:
221 case MessageType::ASSERTION_FAILED:
222 XBT_INFO("**************************");
223 XBT_INFO("*** PROPERTY NOT VALID ***");
224 XBT_INFO("**************************");
225 XBT_INFO("Counter-example execution trace:");
226 for (auto const& s : get_exploration()->get_textual_trace())
227 XBT_INFO(" %s", s.c_str());
228 XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
229 "--cfg=model-check/replay:'%s'",
230 get_exploration()->get_record_trace().to_string().c_str());
231 exploration_->log_state();
233 this->exit(SIMGRID_MC_EXIT_SAFETY);
236 xbt_die("Unexpected message from model-checked application");
241 /** Terminate the model-checker application */
242 void ModelChecker::exit(int status)
248 void ModelChecker::handle_waitpid()
250 XBT_DEBUG("Check for wait event");
253 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
255 if (errno == ECHILD) {
257 xbt_assert(not this->get_remote_process().running(), "Inconsistent state");
260 XBT_ERROR("Could not wait for pid");
261 throw simgrid::xbt::errno_error();
265 if (pid == this->get_remote_process().pid()) {
266 // From PTRACE_O_TRACEEXIT:
268 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
269 unsigned long eventmsg;
270 xbt_assert(ptrace(PTRACE_GETEVENTMSG, remote_process_->pid(), 0, &eventmsg) != -1, "Could not get exit status");
271 status = static_cast<int>(eventmsg);
272 if (WIFSIGNALED(status)) {
273 MC_report_crash(exploration_, status);
274 this->get_remote_process().terminate();
275 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
280 // We don't care about signals, just reinject them:
281 if (WIFSTOPPED(status)) {
282 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
285 ptrace(PTRACE_CONT, remote_process_->pid(), 0, WSTOPSIG(status));
287 ptrace(PT_CONTINUE, remote_process_->pid(), (caddr_t)1, WSTOPSIG(status));
289 xbt_assert(errno == 0, "Could not PTRACE_CONT");
292 else if (WIFSIGNALED(status)) {
293 MC_report_crash(exploration_, status);
294 this->get_remote_process().terminate();
295 this->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
296 } else if (WIFEXITED(status)) {
297 XBT_DEBUG("Child process is over");
298 this->get_remote_process().terminate();
304 void ModelChecker::wait_for_requests()
307 if (this->get_remote_process().running())
308 checker_side_.dispatch();
311 Transition* ModelChecker::handle_simcall(aid_t aid, int times_considered, bool new_transition)
313 s_mc_message_simcall_execute_t m = {};
314 m.type = MessageType::SIMCALL_EXECUTE;
316 m.times_considered_ = times_considered;
317 checker_side_.get_channel().send(m);
319 this->remote_process_->clear_cache();
320 if (this->remote_process_->running())
321 checker_side_.dispatch(); // The app may send messages while processing the transition
323 s_mc_message_simcall_execute_answer_t answer;
324 ssize_t s = checker_side_.get_channel().receive(answer);
325 xbt_assert(s != -1, "Could not receive message");
326 xbt_assert(s == sizeof(answer) && answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
327 "Received unexpected message %s (%i, size=%i) "
328 "expected MessageType::SIMCALL_EXECUTE_ANSWER (%i, size=%i)",
329 to_c_str(answer.type), (int)answer.type, (int)s, (int)MessageType::SIMCALL_EXECUTE_ANSWER,
330 (int)sizeof(answer));
332 if (new_transition) {
333 std::stringstream stream(answer.buffer.data());
334 return deserialize_transition(aid, times_considered, stream);
339 void ModelChecker::finalize_app(bool terminate_asap)
341 s_mc_message_int_t m = {};
342 m.type = MessageType::FINALIZE;
343 m.value = terminate_asap;
344 xbt_assert(checker_side_.get_channel().send(m) == 0, "Could not ask the app to finalize on need");
346 s_mc_message_t answer;
347 ssize_t s = checker_side_.get_channel().receive(answer);
348 xbt_assert(s != -1, "Could not receive answer to FINALIZE");
349 xbt_assert(s == sizeof(answer) && answer.type == MessageType::FINALIZE_REPLY,
350 "Received unexpected message %s (%i, size=%i) expected MessageType::FINALIZE_REPLY (%i, size=%i)",
351 to_c_str(answer.type), (int)answer.type, (int)s, (int)MessageType::FINALIZE_REPLY, (int)sizeof(answer));
354 } // namespace simgrid::mc