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/sosp/RemoteProcessMemory.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<RemoteProcessMemory> remote_memory, int sockfd)
35 : checker_side_(sockfd), remote_process_memory_(std::move(remote_memory))
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_memory_->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 RemoteProcessMemory& process = this->get_remote_process_memory();
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 static void MC_report_crash(Exploration* explorer, int status)
110 XBT_INFO("**************************");
111 XBT_INFO("** CRASH IN THE PROGRAM **");
112 XBT_INFO("**************************");
113 if (WIFSIGNALED(status))
114 XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
115 else if (WIFEXITED(status))
116 XBT_INFO("From exit: %i", WEXITSTATUS(status));
117 if (not xbt_log_no_loc)
118 XBT_INFO("%s core dump was generated by the system.", WCOREDUMP(status) ? "A" : "No");
120 XBT_INFO("Counter-example execution trace:");
121 for (auto const& s : explorer->get_textual_trace())
122 XBT_INFO(" %s", s.c_str());
123 XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
124 "--cfg=model-check/replay:'%s'",
125 explorer->get_record_trace().to_string().c_str());
126 explorer->log_state();
127 if (xbt_log_no_loc) {
128 XBT_INFO("Stack trace not displayed because you passed --log=no_loc");
130 XBT_INFO("Stack trace:");
131 explorer->get_remote_app().get_remote_process_memory().dump_stack();
136 bool ModelChecker::handle_message(const char* buffer, ssize_t size)
138 s_mc_message_t base_message;
139 xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message");
140 memcpy(&base_message, buffer, sizeof(base_message));
142 switch(base_message.type) {
143 case MessageType::INITIAL_ADDRESSES: {
144 s_mc_message_initial_addresses_t message;
145 xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size, (int)sizeof(message));
146 memcpy(&message, buffer, sizeof(message));
148 get_remote_process_memory().init(message.mmalloc_default_mdp);
152 case MessageType::IGNORE_HEAP: {
153 s_mc_message_ignore_heap_t message;
154 xbt_assert(size == sizeof(message), "Broken message");
155 memcpy(&message, buffer, sizeof(message));
157 IgnoredHeapRegion region;
158 region.block = message.block;
159 region.fragment = message.fragment;
160 region.address = message.address;
161 region.size = message.size;
162 get_remote_process_memory().ignore_heap(region);
166 case MessageType::UNIGNORE_HEAP: {
167 s_mc_message_ignore_memory_t message;
168 xbt_assert(size == sizeof(message), "Broken message");
169 memcpy(&message, buffer, sizeof(message));
170 get_remote_process_memory().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
174 case MessageType::IGNORE_MEMORY: {
175 s_mc_message_ignore_memory_t message;
176 xbt_assert(size == sizeof(message), "Broken message");
177 memcpy(&message, buffer, sizeof(message));
178 this->get_remote_process_memory().ignore_region(message.addr, message.size);
182 case MessageType::STACK_REGION: {
183 s_mc_message_stack_region_t message;
184 xbt_assert(size == sizeof(message), "Broken message");
185 memcpy(&message, buffer, sizeof(message));
186 this->get_remote_process_memory().stack_areas().push_back(message.stack_region);
189 case MessageType::REGISTER_SYMBOL: {
190 s_mc_message_register_symbol_t message;
191 xbt_assert(size == sizeof(message), "Broken message");
192 memcpy(&message, buffer, sizeof(message));
193 xbt_assert(not message.callback, "Support for client-side function proposition is not implemented.");
194 XBT_DEBUG("Received symbol: %s", message.name.data());
196 LivenessChecker::automaton_register_symbol(get_remote_process_memory(), message.name.data(),
197 remote((int*)message.data));
201 case MessageType::WAITING:
204 case MessageType::ASSERTION_FAILED:
205 XBT_INFO("**************************");
206 XBT_INFO("*** PROPERTY NOT VALID ***");
207 XBT_INFO("**************************");
208 XBT_INFO("Counter-example execution trace:");
209 for (auto const& s : get_exploration()->get_textual_trace())
210 XBT_INFO(" %s", s.c_str());
211 XBT_INFO("You can debug the problem (and see the whole details) by rerunning out of simgrid-mc with "
212 "--cfg=model-check/replay:'%s'",
213 get_exploration()->get_record_trace().to_string().c_str());
214 exploration_->log_state();
216 exploration_->system_exit(SIMGRID_MC_EXIT_SAFETY);
219 xbt_die("Unexpected message from model-checked application");
224 void ModelChecker::handle_waitpid()
226 XBT_DEBUG("Check for wait event");
229 while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
231 if (errno == ECHILD) {
233 xbt_assert(not this->get_remote_process_memory().running(), "Inconsistent state");
236 XBT_ERROR("Could not wait for pid");
237 throw simgrid::xbt::errno_error();
241 if (pid == this->get_remote_process_memory().pid()) {
242 // From PTRACE_O_TRACEEXIT:
244 if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
245 unsigned long eventmsg;
246 xbt_assert(ptrace(PTRACE_GETEVENTMSG, get_remote_process_memory().pid(), 0, &eventmsg) != -1,
247 "Could not get exit status");
248 status = static_cast<int>(eventmsg);
249 if (WIFSIGNALED(status)) {
250 MC_report_crash(exploration_, status);
251 this->get_remote_process_memory().terminate();
252 exploration_->system_exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
257 // We don't care about non-lethal signals, just reinject them:
258 if (WIFSTOPPED(status)) {
259 XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
262 ptrace(PTRACE_CONT, get_remote_process_memory().pid(), 0, WSTOPSIG(status));
264 ptrace(PT_CONTINUE, get_remote_process_memory().pid(), (caddr_t)1, WSTOPSIG(status));
266 xbt_assert(errno == 0, "Could not PTRACE_CONT");
269 else if (WIFSIGNALED(status)) {
270 MC_report_crash(exploration_, status);
271 this->get_remote_process_memory().terminate();
272 exploration_->system_exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
273 } else if (WIFEXITED(status)) {
274 XBT_DEBUG("Child process is over");
275 this->get_remote_process_memory().terminate();
281 Transition* ModelChecker::handle_simcall(aid_t aid, int times_considered, bool new_transition)
283 s_mc_message_simcall_execute_t m = {};
284 m.type = MessageType::SIMCALL_EXECUTE;
286 m.times_considered_ = times_considered;
287 checker_side_.get_channel().send(m);
289 this->remote_process_memory_->clear_cache();
290 if (this->remote_process_memory_->running())
291 checker_side_.dispatch(); // The app may send messages while processing the transition
293 s_mc_message_simcall_execute_answer_t answer;
294 ssize_t s = checker_side_.get_channel().receive(answer);
295 xbt_assert(s != -1, "Could not receive message");
296 xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer);
297 xbt_assert(answer.type == MessageType::SIMCALL_EXECUTE_ANSWER,
298 "Received unexpected message %s (%i); expected MessageType::SIMCALL_EXECUTE_ANSWER (%i)",
299 to_c_str(answer.type), (int)answer.type, (int)MessageType::SIMCALL_EXECUTE_ANSWER);
301 if (new_transition) {
302 std::stringstream stream(answer.buffer.data());
303 return deserialize_transition(aid, times_considered, stream);
308 } // namespace simgrid::mc