X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/a78e55a602586cf557968132c2d8c30af758af25..fa22f462594acff6e8eaab9fb39453ae1927e51c:/src/mc/remote/CheckerSide.cpp diff --git a/src/mc/remote/CheckerSide.cpp b/src/mc/remote/CheckerSide.cpp index 1660265aef..9d8287990b 100644 --- a/src/mc/remote/CheckerSide.cpp +++ b/src/mc/remote/CheckerSide.cpp @@ -9,25 +9,126 @@ #include "src/mc/sosp/RemoteProcessMemory.hpp" #include "xbt/system_error.hpp" +#ifdef __linux__ +#include +#endif + +#include #include +#include #include #include +#ifdef __linux__ +#define WAITPID_CHECKED_FLAGS __WALL +#else +#define WAITPID_CHECKED_FLAGS 0 +#endif + XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_checkerside, mc, "MC communication with the application"); +static simgrid::config::Flag _sg_mc_setenv{ + "model-check/setenv", "Extra environment variables to pass to the child process (ex: 'AZE=aze;QWE=qwe').", "", + [](std::string_view value) { + xbt_assert(value.empty() || value.find('=', 0) != std::string_view::npos, + "The 'model-check/setenv' parameter must be like 'AZE=aze', but it does not contain an equal sign."); + }}; + namespace simgrid::mc { -CheckerSide::CheckerSide(int sockfd, pid_t pid) - : remote_memory_(std::make_unique(pid)) - , channel_(sockfd) - , running_(true) - , pid_(pid) + +XBT_ATTRIB_NORETURN static void run_child_process(int socket, const std::vector& args, bool need_ptrace) { + /* On startup, simix_global_init() calls simgrid::mc::Client::initialize(), which checks whether the MC_ENV_SOCKET_FD + * env variable is set. If so, MC mode is assumed, and the client is setup from its side + */ + +#ifdef __linux__ + // Make sure we do not outlive our parent + sigset_t mask; + sigemptyset(&mask); + xbt_assert(sigprocmask(SIG_SETMASK, &mask, nullptr) >= 0, "Could not unblock signals"); + xbt_assert(prctl(PR_SET_PDEATHSIG, SIGHUP) == 0, "Could not PR_SET_PDEATHSIG"); +#endif + + // Remove CLOEXEC to pass the socket to the application + int fdflags = fcntl(socket, F_GETFD, 0); + xbt_assert(fdflags != -1 && fcntl(socket, F_SETFD, fdflags & ~FD_CLOEXEC) != -1, + "Could not remove CLOEXEC for socket"); + + setenv(MC_ENV_SOCKET_FD, std::to_string(socket).c_str(), 1); + if (need_ptrace) + setenv("MC_NEED_PTRACE", "1", 1); + + /* Setup the tokenizer that parses the cfg:model-check/setenv parameter */ + using Tokenizer = boost::tokenizer>; + boost::char_separator semicol_sep(";"); + boost::char_separator equal_sep("="); + Tokenizer token_vars(_sg_mc_setenv.get(), semicol_sep); /* Iterate over all FOO=foo parts */ + for (const auto& token : token_vars) { + std::vector kv; + Tokenizer token_kv(token, equal_sep); + for (const auto& t : token_kv) /* Iterate over 'FOO' and then 'foo' in that 'FOO=foo' */ + kv.push_back(t); + xbt_assert(kv.size() == 2, "Parse error on 'model-check/setenv' value %s. Does it contain an equal sign?", + token.c_str()); + XBT_INFO("setenv '%s'='%s'", kv[0].c_str(), kv[1].c_str()); + setenv(kv[0].c_str(), kv[1].c_str(), 1); + } + + /* And now, exec the child process */ + int i = 1; + while (args[i] != nullptr && args[i][0] == '-') + i++; + + xbt_assert(args[i] != nullptr, + "Unable to find a binary to exec on the command line. Did you only pass config flags?"); + + execvp(args[i], args.data() + i); + XBT_CRITICAL("The model-checked process failed to exec(%s): %s.\n" + " Make sure that your binary exists on disk and is executable.", + args[i], strerror(errno)); + if (strchr(args[i], '=') != nullptr) + XBT_CRITICAL("If you want to pass environment variables to the application, please use --cfg=model-check/setenv:%s", + args[i]); + + xbt_die("Aborting now."); +} + +static void wait_application_process(pid_t pid) +{ + XBT_DEBUG("Waiting for the model-checked process"); + int status; + + // The model-checked process SIGSTOP itself to signal it's ready: + xbt_assert(waitpid(pid, &status, WAITPID_CHECKED_FLAGS) == pid && WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP, + "Could not wait model-checked process"); + + errno = 0; +#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 + xbt_assert(errno == 0, + "Ptrace does not seem to be usable in your setup (errno: %d). " + "If you run from within a docker, adding `--cap-add SYS_PTRACE` to the docker line may help. " + "If it does not help, please report this bug.", + errno); +} + +void CheckerSide::setup_events() +{ + if (base_ != nullptr) + event_base_free(base_.get()); auto* base = event_base_new(); base_.reset(base); - auto* socket_event = event_new( + socket_event_ = event_new( base, get_channel().get_socket(), EV_READ | EV_PERSIST, - [](evutil_socket_t sig, short events, void* arg) { + [](evutil_socket_t, short events, void* arg) { auto checker = static_cast(arg); if (events == EV_READ) { std::array buffer; @@ -38,17 +139,18 @@ CheckerSide::CheckerSide(int sockfd, pid_t pid) throw simgrid::xbt::errno_error(); } - if (not checker->handle_message(buffer.data(), size)) + if (size == 0) // The app closed the socket. It must be dead by now. + checker->handle_waitpid(); + else if (not checker->handle_message(buffer.data(), size)) checker->break_loop(); } else { xbt_die("Unexpected event"); } }, this); - event_add(socket_event, nullptr); - socket_event_.reset(socket_event); + event_add(socket_event_, nullptr); - auto* signal_event = event_new( + signal_event_ = event_new( base, SIGCHLD, EV_SIGNAL | EV_PERSIST, [](evutil_socket_t sig, short events, void* arg) { auto checker = static_cast(arg); @@ -62,8 +164,73 @@ CheckerSide::CheckerSide(int sockfd, pid_t pid) } }, this); - event_add(signal_event, nullptr); - signal_event_.reset(signal_event); + event_add(signal_event_, nullptr); +} + +CheckerSide::CheckerSide(const std::vector& args, bool need_memory_info) : running_(true) +{ + // Create an AF_LOCAL socketpair used for exchanging messages between the model-checker process (ancestor) + // and the application process (child) + int sockets[2]; + xbt_assert(socketpair(AF_LOCAL, SOCK_SEQPACKET | SOCK_CLOEXEC, 0, sockets) != -1, "Could not create socketpair"); + + pid_ = fork(); + xbt_assert(pid_ >= 0, "Could not fork model-checked process"); + + if (pid_ == 0) { // Child + ::close(sockets[1]); + run_child_process(sockets[0], args, need_memory_info); // We need ptrace if we need the mem info + DIE_IMPOSSIBLE; + } + + // Parent (model-checker): + ::close(sockets[0]); + channel_.reset_socket(sockets[1]); + + setup_events(); + if (need_memory_info) + wait_application_process(pid_); + + // Request the initial memory on need + if (need_memory_info) { + channel_.send(MessageType::NEED_MEMINFO); + s_mc_message_need_meminfo_reply_t answer; + ssize_t answer_size = channel_.receive(answer); + xbt_assert(answer_size != -1, "Could not receive message"); + xbt_assert(answer.type == MessageType::NEED_MEMINFO_REPLY, + "The received message is not the NEED_MEMINFO_REPLY I was expecting but of type %s", + to_c_str(answer.type)); + xbt_assert(answer_size == sizeof answer, "Broken message (size=%zd; expected %zu)", answer_size, sizeof answer); + + /* We now have enough info to create the memory address space */ + remote_memory_ = std::make_unique(pid_, answer.mmalloc_default_mdp); + } + + wait_for_requests(); +} + +CheckerSide::~CheckerSide() +{ + event_del(socket_event_); + event_free(socket_event_); + event_del(signal_event_); + event_free(signal_event_); +} + +void CheckerSide::finalize(bool terminate_asap) +{ + s_mc_message_int_t m = {}; + m.type = MessageType::FINALIZE; + m.value = terminate_asap; + xbt_assert(get_channel().send(m) == 0, "Could not ask the app to finalize on need"); + + s_mc_message_t answer; + ssize_t s = get_channel().receive(answer); + xbt_assert(s != -1, "Could not receive answer to FINALIZE"); + xbt_assert(s == sizeof answer, "Broken message (size=%zd; expected %zu)", s, sizeof answer); + xbt_assert(answer.type == MessageType::FINALIZE_REPLY, + "Received unexpected message %s (%i); expected MessageType::FINALIZE_REPLY (%i)", to_c_str(answer.type), + (int)answer.type, (int)MessageType::FINALIZE_REPLY); } void CheckerSide::dispatch_events() const @@ -79,56 +246,63 @@ void CheckerSide::break_loop() const bool CheckerSide::handle_message(const char* buffer, ssize_t size) { s_mc_message_t base_message; - xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message"); + xbt_assert(size >= (ssize_t)sizeof(base_message), "Broken message. Got only %ld bytes.", size); memcpy(&base_message, buffer, sizeof(base_message)); switch (base_message.type) { - case MessageType::INITIAL_ADDRESSES: { - s_mc_message_initial_addresses_t message; - xbt_assert(size == sizeof(message), "Broken message. Got %d bytes instead of %d.", (int)size, - (int)sizeof(message)); - memcpy(&message, buffer, sizeof(message)); - - get_remote_memory().init(message.mmalloc_default_mdp); - break; - } - case MessageType::IGNORE_HEAP: { - s_mc_message_ignore_heap_t message; - xbt_assert(size == sizeof(message), "Broken message"); - memcpy(&message, buffer, sizeof(message)); + if (remote_memory_ != nullptr) { + s_mc_message_ignore_heap_t message; + xbt_assert(size == sizeof(message), "Broken message"); + memcpy(&message, buffer, sizeof(message)); - IgnoredHeapRegion region; - region.block = message.block; - region.fragment = message.fragment; - region.address = message.address; - region.size = message.size; - get_remote_memory().ignore_heap(region); + IgnoredHeapRegion region; + region.block = message.block; + region.fragment = message.fragment; + region.address = message.address; + region.size = message.size; + get_remote_memory()->ignore_heap(region); + } else { + XBT_INFO("Ignoring a IGNORE_HEAP message because we don't need to introspect memory."); + } break; } case MessageType::UNIGNORE_HEAP: { - s_mc_message_ignore_memory_t message; - xbt_assert(size == sizeof(message), "Broken message"); - memcpy(&message, buffer, sizeof(message)); - get_remote_memory().unignore_heap((void*)(std::uintptr_t)message.addr, message.size); + if (remote_memory_ != nullptr) { + s_mc_message_ignore_memory_t message; + xbt_assert(size == sizeof(message), "Broken message"); + memcpy(&message, buffer, sizeof(message)); + get_remote_memory()->unignore_heap((void*)message.addr, message.size); + } else { + XBT_INFO("Ignoring an UNIGNORE_HEAP message because we don't need to introspect memory."); + } break; } case MessageType::IGNORE_MEMORY: { - s_mc_message_ignore_memory_t message; - xbt_assert(size == sizeof(message), "Broken message"); - memcpy(&message, buffer, sizeof(message)); - get_remote_memory().ignore_region(message.addr, message.size); + if (remote_memory_ != nullptr) { + s_mc_message_ignore_memory_t message; + xbt_assert(size == sizeof(message), "Broken message"); + memcpy(&message, buffer, sizeof(message)); + get_remote_memory()->ignore_region(message.addr, message.size); + } else { + XBT_INFO("Ignoring an IGNORE_MEMORY message because we don't need to introspect memory."); + } break; } case MessageType::STACK_REGION: { - s_mc_message_stack_region_t message; - xbt_assert(size == sizeof(message), "Broken message"); - memcpy(&message, buffer, sizeof(message)); - get_remote_memory().stack_areas().push_back(message.stack_region); - } break; + if (remote_memory_ != nullptr) { + s_mc_message_stack_region_t message; + xbt_assert(size == sizeof(message), "Broken message"); + memcpy(&message, buffer, sizeof(message)); + get_remote_memory()->stack_areas().push_back(message.stack_region); + } else { + XBT_INFO("Ignoring an STACK_REGION message because we don't need to introspect memory."); + } + break; + } case MessageType::REGISTER_SYMBOL: { s_mc_message_register_symbol_t message; @@ -137,7 +311,7 @@ bool CheckerSide::handle_message(const char* buffer, ssize_t size) xbt_assert(not message.callback, "Support for client-side function proposition is not implemented."); XBT_DEBUG("Received symbol: %s", message.name.data()); - LivenessChecker::automaton_register_symbol(get_remote_memory(), message.name.data(), remote((int*)message.data)); + LivenessChecker::automaton_register_symbol(*get_remote_memory(), message.name.data(), remote((int*)message.data)); break; } @@ -154,6 +328,23 @@ bool CheckerSide::handle_message(const char* buffer, ssize_t size) return true; } +void CheckerSide::wait_for_requests() +{ + /* Resume the application */ + if (get_channel().send(MessageType::CONTINUE) != 0) + throw xbt::errno_error(); + clear_memory_cache(); + + if (running()) + dispatch_events(); +} + +void CheckerSide::clear_memory_cache() +{ + if (remote_memory_) + remote_memory_->clear_cache(); +} + void CheckerSide::handle_waitpid() { XBT_DEBUG("Check for wait event"); @@ -165,8 +356,7 @@ void CheckerSide::handle_waitpid() xbt_assert(not this->running(), "Inconsistent state"); break; } else { - XBT_ERROR("Could not wait for pid"); - throw simgrid::xbt::errno_error(); + xbt_die("Could not wait for pid: %s", strerror(errno)); } }