1 /* Copyright (c) 2008-2019. 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/Session.hpp"
8 #include "src/mc/Transition.hpp"
9 #include "src/mc/checker/Checker.hpp"
10 #include "src/mc/mc_config.hpp"
11 #include "src/mc/mc_exit.hpp"
12 #include "src/mc/mc_private.hpp"
13 #include "src/mc/remote/RemoteClient.hpp"
14 #include "xbt/automaton.hpp"
15 #include "xbt/system_error.hpp"
17 #include <sys/ptrace.h>
20 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_ModelChecker, mc, "ModelChecker");
22 ::simgrid::mc::ModelChecker* mc_model_checker = nullptr;
24 using simgrid::mc::remote;
27 # define WAITPID_CHECKED_FLAGS __WALL
29 # define WAITPID_CHECKED_FLAGS 0
35 ModelChecker::ModelChecker(std::unique_ptr<RemoteClient> process)
37 , socket_event_(nullptr)
38 , signal_event_(nullptr)
40 , process_(std::move(process))
44 ModelChecker::~ModelChecker()
46 if (socket_event_ != nullptr)
47 event_free(socket_event_);
48 if (signal_event_ != nullptr)
49 event_free(signal_event_);
51 event_base_free(base_);
54 void ModelChecker::start()
56 base_ = event_base_new();
57 event_callback_fn event_callback = [](evutil_socket_t fd, short events, void *arg)
59 ((ModelChecker *)arg)->handle_events(fd, events);
61 socket_event_ = event_new(base_, process_->get_channel().get_socket(), EV_READ | EV_PERSIST, event_callback, this);
62 event_add(socket_event_, NULL);
63 signal_event_ = event_new(base_,
66 event_callback, this);
67 event_add(signal_event_, NULL);
69 XBT_DEBUG("Waiting for the model-checked process");
72 // The model-checked process SIGSTOP itself to signal it's ready:
73 const pid_t pid = process_->pid();
75 pid_t res = waitpid(pid, &status, WAITPID_CHECKED_FLAGS);
76 if (res < 0 || not WIFSTOPPED(status) || WSTOPSIG(status) != SIGSTOP)
77 xbt_die("Could not wait model-checked process");
81 if (not _sg_mc_dot_output_file.get().empty())
87 ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
88 ptrace(PTRACE_CONT, pid, 0, 0);
90 ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
92 # error "no ptrace equivalent coded for this platform"
96 static const std::pair<const char*, const char*> ignored_local_variables[] = {
97 std::pair<const char*, const char*>{ "e", "*" },
98 std::pair<const char*, const char*>{ "_log_ev", "*" },
100 /* Ignore local variable about time used for tracing */
101 std::pair<const char*, const char*>{ "start_time", "*" },
104 void ModelChecker::setup_ignore()
106 RemoteClient& process = this->process();
107 for (std::pair<const char*, const char*> const& var :
108 ignored_local_variables)
109 process.ignore_local_variable(var.first, var.second);
111 /* Static variable used for tracing */
112 process.ignore_global_variable("counter");
115 void ModelChecker::shutdown()
117 XBT_DEBUG("Shuting down model-checker");
119 RemoteClient* process = &this->process();
120 if (process->running()) {
121 XBT_DEBUG("Killing process");
122 kill(process->pid(), SIGKILL);
123 process->terminate();
127 void ModelChecker::resume(RemoteClient& process)
129 int res = process.get_channel().send(MC_MESSAGE_CONTINUE);
131 throw xbt::errno_error();
132 process.clear_cache();
135 static void MC_report_crash(int status)
137 XBT_INFO("**************************");
138 XBT_INFO("** CRASH IN THE PROGRAM **");
139 XBT_INFO("**************************");
140 if (WIFSIGNALED(status))
141 XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
142 else if (WIFEXITED(status))
143 XBT_INFO("From exit: %i", WEXITSTATUS(status));
144 if (not xbt_log_no_loc)
145 XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
146 XBT_INFO("Counter-example execution trace:");
147 for (auto const& s : mc_model_checker->getChecker()->get_textual_trace())
148 XBT_INFO(" %s", s.c_str());
150 session->log_state();
151 if (xbt_log_no_loc) {
152 XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
154 XBT_INFO("Stack trace:");
155 mc_model_checker->process().dump_stack();
159 static void MC_report_assertion_error()
161 XBT_INFO("**************************");
162 XBT_INFO("*** PROPERTY NOT VALID ***");
163 XBT_INFO("**************************");
164 XBT_INFO("Counter-example execution trace:");
165 for (auto const& s : mc_model_checker->getChecker()->get_textual_trace())
166 XBT_INFO(" %s", s.c_str());
168 session->log_state();
171 bool ModelChecker::handle_message(char* buffer, ssize_t size)
173 s_mc_message_t base_message;
174 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
175 memcpy(&base_message, buffer, sizeof(base_message));
177 switch(base_message.type) {
178 case MC_MESSAGE_IGNORE_HEAP:
180 s_mc_message_ignore_heap_t message;
181 xbt_assert(size == sizeof(message), "Broken messsage");
182 memcpy(&message, buffer, sizeof(message));
184 IgnoredHeapRegion region;
185 region.block = message.block;
186 region.fragment = message.fragment;
187 region.address = message.address;
188 region.size = message.size;
189 process().ignore_heap(region);
193 case MC_MESSAGE_UNIGNORE_HEAP:
195 s_mc_message_ignore_memory_t message;
196 xbt_assert(size == sizeof(message), "Broken messsage");
197 memcpy(&message, buffer, sizeof(message));
198 process().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
202 case MC_MESSAGE_IGNORE_MEMORY:
204 s_mc_message_ignore_memory_t message;
205 xbt_assert(size == sizeof(message), "Broken messsage");
206 memcpy(&message, buffer, sizeof(message));
207 this->process().ignore_region(message.addr, message.size);
211 case MC_MESSAGE_STACK_REGION:
213 s_mc_message_stack_region_t message;
214 xbt_assert(size == sizeof(message), "Broken messsage");
215 memcpy(&message, buffer, sizeof(message));
216 this->process().stack_areas().push_back(message.stack_region);
220 case MC_MESSAGE_REGISTER_SYMBOL:
222 s_mc_message_register_symbol_t message;
223 xbt_assert(size == sizeof(message), "Broken message");
224 memcpy(&message, buffer, sizeof(message));
225 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
226 XBT_DEBUG("Received symbol: %s", message.name);
228 if (property_automaton == nullptr)
229 property_automaton = xbt_automaton_new();
231 RemoteClient* process = &this->process();
232 RemotePtr<int> address = remote((int*)message.data);
233 xbt::add_proposition(property_automaton, message.name, [process, address]() { return process->read(address); });
238 case MC_MESSAGE_WAITING:
241 case MC_MESSAGE_ASSERTION_FAILED:
242 MC_report_assertion_error();
243 this->exit(SIMGRID_MC_EXIT_SAFETY);
246 xbt_die("Unexpected message from model-checked application");
251 /** Terminate the model-checker application */
252 void ModelChecker::exit(int status)
254 // TODO, terminate the model checker politely instead of exiting rudely
255 if (process().running())
256 kill(process().pid(), SIGKILL);
260 void ModelChecker::handle_events(int fd, short events)
262 if (events == EV_READ) {
263 char buffer[MC_MESSAGE_LENGTH];
264 ssize_t size = process_->get_channel().receive(buffer, sizeof(buffer), false);
265 if (size == -1 && errno != EAGAIN)
266 throw simgrid::xbt::errno_error();
267 if (not handle_message(buffer, size)) {
268 event_base_loopbreak(base_);
271 else if (events == EV_SIGNAL) {
275 xbt_die("Unexpected event");
279 void ModelChecker::loop()
281 if (this->process().running())
282 event_base_dispatch(base_);
285 void ModelChecker::handle_waitpid()
287 XBT_DEBUG("Check for wait event");
290 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
292 if (errno == ECHILD) {
294 xbt_assert(not this->process().running(), "Inconsistent state");
297 XBT_ERROR("Could not wait for pid");
298 throw simgrid::xbt::errno_error();
302 if (pid == this->process().pid()) {
303 // From PTRACE_O_TRACEEXIT:
305 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
306 xbt_assert(ptrace(PTRACE_GETEVENTMSG, this->process().pid(), 0, &status) != -1, "Could not get exit status");
307 if (WIFSIGNALED(status)) {
308 MC_report_crash(status);
309 mc_model_checker->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
314 // We don't care about signals, just reinject them:
315 if (WIFSTOPPED(status)) {
316 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
319 ptrace(PTRACE_CONT, this->process().pid(), 0, WSTOPSIG(status));
321 ptrace(PT_CONTINUE, this->process().pid(), (caddr_t)1, WSTOPSIG(status));
323 xbt_assert(errno == 0, "Could not PTRACE_CONT");
326 else if (WIFSIGNALED(status)) {
327 MC_report_crash(status);
328 mc_model_checker->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
329 } else if (WIFEXITED(status)) {
330 XBT_DEBUG("Child process is over");
331 this->process().terminate();
337 void ModelChecker::on_signal(int signo)
339 if (signo == SIGCHLD)
340 this->handle_waitpid();
343 void ModelChecker::wait_for_requests()
345 this->resume(process());
346 if (this->process().running())
347 event_base_dispatch(base_);
350 void ModelChecker::handle_simcall(Transition const& transition)
352 s_mc_message_simcall_handle_t m;
353 memset(&m, 0, sizeof(m));
354 m.type = MC_MESSAGE_SIMCALL_HANDLE;
355 m.pid = transition.pid_;
356 m.value = transition.argument_;
357 this->process_->get_channel().send(m);
358 this->process_->clear_cache();
359 if (this->process_->running())
360 event_base_dispatch(base_);
363 bool ModelChecker::checkDeadlock()
365 int res = this->process().get_channel().send(MC_MESSAGE_DEADLOCK_CHECK);
366 xbt_assert(res == 0, "Could not check deadlock state");
367 s_mc_message_int_t message;
368 ssize_t s = mc_model_checker->process().get_channel().receive(message);
369 xbt_assert(s != -1, "Could not receive message");
370 xbt_assert(s == sizeof(message) && message.type == MC_MESSAGE_DEADLOCK_CHECK_REPLY,
371 "Received unexpected message %s (%i, size=%i) "
372 "expected MC_MESSAGE_DEADLOCK_CHECK_REPLY (%i, size=%i)",
373 MC_message_type_name(message.type), (int)message.type, (int)s, (int)MC_MESSAGE_DEADLOCK_CHECK_REPLY,
374 (int)sizeof(message));
375 return message.value != 0;
379 } // namespace simgrid