-/* Copyright (c) 2008-2015. The SimGrid Team.
+/* Copyright (c) 2008-2017. The SimGrid Team.
* All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
#include <cassert>
-#include "ModelChecker.hpp"
-#include "PageStore.hpp"
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+#include <sys/ptrace.h>
-::simgrid::mc::ModelChecker* mc_model_checker = NULL;
+#include <memory>
+#include <system_error>
+
+#include "xbt/automaton.h"
+#include "xbt/automaton.hpp"
+#include "xbt/log.h"
+#include "xbt/system_error.hpp"
+
+#include "simgrid/sg_config.h"
+
+#include "src/mc/ModelChecker.hpp"
+#include "src/mc/ModelChecker.hpp"
+#include "src/mc/PageStore.hpp"
+#include "src/mc/Transition.hpp"
+#include "src/mc/checker/Checker.hpp"
+#include "src/mc/mc_exit.hpp"
+#include "src/mc/mc_private.hpp"
+#include "src/mc/mc_record.hpp"
+#include "src/mc/remote/mc_protocol.h"
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_ModelChecker, mc, "ModelChecker");
+
+::simgrid::mc::ModelChecker* mc_model_checker = nullptr;
+extern std::string _sg_mc_dot_output_file;
+
+using simgrid::mc::remote;
+
+#ifdef __linux__
+# define WAITPID_CHECKED_FLAGS __WALL
+#else
+# define WAITPID_CHECKED_FLAGS 0
+#endif
namespace simgrid {
namespace mc {
-ModelChecker::ModelChecker(pid_t pid, int socket) :
- hostnames_(xbt_dict_new()),
- page_store_(500),
- process_(pid, socket),
- parent_snapshot_(nullptr)
+ModelChecker::ModelChecker(std::unique_ptr<RemoteClient> process)
+ : base_(nullptr)
+ , socket_event_(nullptr)
+ , signal_event_(nullptr)
+ , page_store_(500)
+ , process_(std::move(process))
+ , parent_snapshot_(nullptr)
+{
+
+}
+
+ModelChecker::~ModelChecker() {
+ if (socket_event_ != nullptr)
+ event_free(socket_event_);
+ if (signal_event_ != nullptr)
+ event_free(signal_event_);
+ if (base_ != nullptr)
+ event_base_free(base_);
+}
+
+void ModelChecker::start()
+{
+ const pid_t pid = process_->pid();
+
+ base_ = event_base_new();
+ event_callback_fn event_callback = [](evutil_socket_t fd, short events, void *arg)
+ {
+ ((ModelChecker *)arg)->handle_events(fd, events);
+ };
+ socket_event_ = event_new(base_,
+ process_->getChannel().getSocket(),
+ EV_READ|EV_PERSIST,
+ event_callback, this);
+ event_add(socket_event_, NULL);
+ signal_event_ = event_new(base_,
+ SIGCHLD,
+ EV_SIGNAL|EV_PERSIST,
+ event_callback, this);
+ event_add(signal_event_, NULL);
+
+ XBT_DEBUG("Waiting for the model-checked process");
+ int status;
+
+ // The model-checked process SIGSTOP itself to signal it's ready:
+ pid_t res = waitpid(pid, &status, WAITPID_CHECKED_FLAGS);
+ if (res < 0 || not WIFSTOPPED(status) || WSTOPSIG(status) != SIGSTOP)
+ xbt_die("Could not wait model-checked process");
+
+ process_->init();
+
+ if (not _sg_mc_dot_output_file.empty())
+ MC_init_dot_output();
+
+ setup_ignore();
+
+#ifdef __linux__
+ ptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXIT);
+ ptrace(PTRACE_CONT, pid, 0, 0);
+#elif defined BSD
+ ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
+#else
+# error "no ptrace equivalent coded for this platform"
+#endif
+}
+
+static const std::pair<const char*, const char*> ignored_local_variables[] = {
+ std::pair<const char*, const char*>{ "e", "*" },
+ std::pair<const char*, const char*>{ "__ex_cleanup", "*" },
+ std::pair<const char*, const char*>{ "__ex_mctx_en", "*" },
+ std::pair<const char*, const char*>{ "__ex_mctx_me", "*" },
+ std::pair<const char*, const char*>{ "__xbt_ex_ctx_ptr", "*" },
+ std::pair<const char*, const char*>{ "_log_ev", "*" },
+ std::pair<const char*, const char*>{ "_throw_ctx", "*" },
+ std::pair<const char*, const char*>{ "ctx", "*" },
+
+ std::pair<const char*, const char*>{ "self", "simcall_BODY_mc_snapshot" },
+ std::pair<const char*, const char*>{ "next_context", "smx_ctx_sysv_suspend_serial" },
+ std::pair<const char*, const char*>{ "i", "smx_ctx_sysv_suspend_serial" },
+
+ /* Ignore local variable about time used for tracing */
+ std::pair<const char*, const char*>{ "start_time", "*" },
+};
+
+void ModelChecker::setup_ignore()
+{
+ RemoteClient& process = this->process();
+ for (std::pair<const char*, const char*> const& var :
+ ignored_local_variables)
+ process.ignore_local_variable(var.first, var.second);
+
+ /* Static variable used for tracing */
+ process.ignore_global_variable("counter");
+}
+
+void ModelChecker::shutdown()
+{
+ XBT_DEBUG("Shuting down model-checker");
+
+ simgrid::mc::RemoteClient* process = &this->process();
+ if (process->running()) {
+ XBT_DEBUG("Killing process");
+ kill(process->pid(), SIGKILL);
+ process->terminate();
+ }
+}
+
+void ModelChecker::resume(simgrid::mc::RemoteClient& process)
+{
+ int res = process.getChannel().send(MC_MESSAGE_CONTINUE);
+ if (res)
+ throw simgrid::xbt::errno_error();
+ process.clear_cache();
+}
+
+static void MC_report_crash(int status)
+{
+ XBT_INFO("**************************");
+ XBT_INFO("** CRASH IN THE PROGRAM **");
+ XBT_INFO("**************************");
+ if (WIFSIGNALED(status))
+ XBT_INFO("From signal: %s", strsignal(WTERMSIG(status)));
+ else if (WIFEXITED(status))
+ XBT_INFO("From exit: %i", WEXITSTATUS(status));
+ if (WCOREDUMP(status))
+ XBT_INFO("A core dump was generated by the system.");
+ else
+ XBT_INFO("No core dump was generated by the system.");
+ XBT_INFO("Counter-example execution trace:");
+ simgrid::mc::dumpRecordPath();
+ for (auto const& s : mc_model_checker->getChecker()->getTextualTrace())
+ XBT_INFO("%s", s.c_str());
+ simgrid::mc::session->logState();
+ XBT_INFO("Stack trace:");
+ mc_model_checker->process().dumpStack();
+}
+
+static void MC_report_assertion_error()
+{
+ XBT_INFO("**************************");
+ XBT_INFO("*** PROPERTY NOT VALID ***");
+ XBT_INFO("**************************");
+ XBT_INFO("Counter-example execution trace:");
+ simgrid::mc::dumpRecordPath();
+ for (auto const& s : mc_model_checker->getChecker()->getTextualTrace())
+ XBT_INFO("%s", s.c_str());
+ simgrid::mc::session->logState();
+}
+
+bool ModelChecker::handle_message(char* buffer, ssize_t size)
+{
+ s_mc_message_t base_message;
+ if (size < (ssize_t) sizeof(base_message))
+ xbt_die("Broken message");
+ memcpy(&base_message, buffer, sizeof(base_message));
+
+ switch(base_message.type) {
+
+ case MC_MESSAGE_IGNORE_HEAP:
+ {
+ s_mc_message_ignore_heap_t message;
+ if (size != sizeof(message))
+ xbt_die("Broken messsage");
+ memcpy(&message, buffer, sizeof(message));
+
+ IgnoredHeapRegion region;
+ region.block = message.block;
+ region.fragment = message.fragment;
+ region.address = message.address;
+ region.size = message.size;
+ process().ignore_heap(region);
+ break;
+ }
+
+ case MC_MESSAGE_UNIGNORE_HEAP:
+ {
+ s_mc_message_ignore_memory_t message;
+ if (size != sizeof(message))
+ xbt_die("Broken messsage");
+ memcpy(&message, buffer, sizeof(message));
+ process().unignore_heap((void*)(std::uintptr_t)message.addr, message.size);
+ break;
+ }
+
+ case MC_MESSAGE_IGNORE_MEMORY:
+ {
+ s_mc_message_ignore_memory_t message;
+ if (size != sizeof(message))
+ xbt_die("Broken messsage");
+ memcpy(&message, buffer, sizeof(message));
+ this->process().ignore_region(message.addr, message.size);
+ break;
+ }
+
+ case MC_MESSAGE_STACK_REGION:
+ {
+ s_mc_message_stack_region_t message;
+ if (size != sizeof(message))
+ xbt_die("Broken messsage");
+ memcpy(&message, buffer, sizeof(message));
+ this->process().stack_areas().push_back(message.stack_region);
+ }
+ break;
+
+ case MC_MESSAGE_REGISTER_SYMBOL:
+ {
+ s_mc_message_register_symbol_t message;
+ if (size != sizeof(message))
+ xbt_die("Broken message");
+ memcpy(&message, buffer, sizeof(message));
+ if (message.callback)
+ xbt_die("Support for client-side function proposition is not implemented.");
+ XBT_DEBUG("Received symbol: %s", message.name);
+
+ if (simgrid::mc::property_automaton == nullptr)
+ simgrid::mc::property_automaton = xbt_automaton_new();
+
+ simgrid::mc::RemoteClient* process = &this->process();
+ simgrid::mc::RemotePtr<int> address = simgrid::mc::remote((int*)message.data);
+ simgrid::xbt::add_proposition(simgrid::mc::property_automaton, message.name,
+ [process, address]() { return process->read(address); });
+
+ break;
+ }
+
+ case MC_MESSAGE_WAITING:
+ return false;
+
+ case MC_MESSAGE_ASSERTION_FAILED:
+ MC_report_assertion_error();
+ this->exit(SIMGRID_MC_EXIT_SAFETY);
+ break;
+
+ default:
+ xbt_die("Unexpected message from model-checked application");
+
+ }
+ return true;
+}
+
+/** Terminate the model-checker application */
+void ModelChecker::exit(int status)
+{
+ // TODO, terminate the model checker politely instead of exiting rudely
+ if (process().running())
+ kill(process().pid(), SIGKILL);
+ ::exit(status);
+}
+
+void ModelChecker::handle_events(int fd, short events)
{
+ if (events == EV_READ) {
+ char buffer[MC_MESSAGE_LENGTH];
+ ssize_t size = process_->getChannel().receive(buffer, sizeof(buffer), false);
+ if (size == -1 && errno != EAGAIN)
+ throw simgrid::xbt::errno_error();
+ if (not handle_message(buffer, size)) {
+ event_base_loopbreak(base_);
+ }
+ }
+ else if (events == EV_SIGNAL) {
+ on_signal(fd);
+ }
+ else {
+ xbt_die("Unexpected event");
+ }
}
-ModelChecker::~ModelChecker()
+void ModelChecker::loop()
{
- xbt_dict_free(&this->hostnames_);
+ if (this->process().running())
+ event_base_dispatch(base_);
}
-const char* ModelChecker::get_host_name(const char* hostname)
+void ModelChecker::handle_waitpid()
{
- // Lookup the host name in the dictionary (or create it):
- xbt_dictelm_t elt = xbt_dict_get_elm_or_null(this->hostnames_, hostname);
- if (!elt) {
- xbt_dict_set(this->hostnames_, hostname, NULL, NULL);
- elt = xbt_dict_get_elm_or_null(this->hostnames_, hostname);
- assert(elt);
+ XBT_DEBUG("Check for wait event");
+ int status;
+ pid_t pid;
+ while ((pid = waitpid(-1, &status, WNOHANG)) != 0) {
+ if (pid == -1) {
+ if (errno == ECHILD) {
+ // No more children:
+ if (this->process().running())
+ xbt_die("Inconsistent state");
+ else
+ break;
+ } else {
+ XBT_ERROR("Could not wait for pid");
+ throw simgrid::xbt::errno_error();
+ }
+ }
+
+ if (pid == this->process().pid()) {
+
+ // From PTRACE_O_TRACEEXIT:
+#ifdef __linux__
+ if (status>>8 == (SIGTRAP | (PTRACE_EVENT_EXIT<<8))) {
+ if (ptrace(PTRACE_GETEVENTMSG, this->process().pid(), 0, &status) == -1)
+ xbt_die("Could not get exit status");
+ if (WIFSIGNALED(status)) {
+ MC_report_crash(status);
+ mc_model_checker->exit(SIMGRID_MC_EXIT_PROGRAM_CRASH);
+ }
+ }
+#endif
+
+ // We don't care about signals, just reinject them:
+ if (WIFSTOPPED(status)) {
+ XBT_DEBUG("Stopped with signal %i", (int) WSTOPSIG(status));
+ errno = 0;
+#ifdef __linux__
+ ptrace(PTRACE_CONT, this->process().pid(), 0, WSTOPSIG(status));
+#elif defined BSD
+ ptrace(PT_CONTINUE, this->process().pid(), (caddr_t)1, WSTOPSIG(status));
+#endif
+ if (errno != 0)
+ xbt_die("Could not PTRACE_CONT");
+ }
+
+ else if (WIFEXITED(status) || WIFSIGNALED(status)) {
+ XBT_DEBUG("Child process is over");
+ this->process().terminate();
+ }
+ }
}
- return elt->key;
+}
+
+void ModelChecker::on_signal(int signo)
+{
+ if (signo == SIGCHLD)
+ this->handle_waitpid();
+}
+
+void ModelChecker::wait_for_requests()
+{
+ this->resume(process());
+ if (this->process().running())
+ event_base_dispatch(base_);
+}
+
+void ModelChecker::handle_simcall(Transition const& transition)
+{
+ s_mc_message_simcall_handle_t m;
+ memset(&m, 0, sizeof(m));
+ m.type = MC_MESSAGE_SIMCALL_HANDLE;
+ m.pid = transition.pid;
+ m.value = transition.argument;
+ this->process_->getChannel().send(m);
+ this->process_->clear_cache();
+ if (this->process_->running())
+ event_base_dispatch(base_);
+}
+
+bool ModelChecker::checkDeadlock()
+{
+ int res;
+ if ((res = this->process().getChannel().send(MC_MESSAGE_DEADLOCK_CHECK)))
+ xbt_die("Could not check deadlock state");
+ s_mc_message_int_t message;
+ ssize_t s = mc_model_checker->process().getChannel().receive(message);
+ if (s == -1)
+ xbt_die("Could not receive message");
+ if (s != sizeof(message) || message.type != MC_MESSAGE_DEADLOCK_CHECK_REPLY)
+ xbt_die("Received unexpected message %s (%i, size=%i) "
+ "expected MC_MESSAGE_DEADLOCK_CHECK_REPLY (%i, size=%i)",
+ MC_message_type_name(message.type), (int) message.type, (int) s,
+ (int) MC_MESSAGE_DEADLOCK_CHECK_REPLY, (int) sizeof(message)
+ );
+ return message.value != 0;
}
}
