//===-- NativeProcessLinux.cpp --------------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #include "NativeProcessLinux.h" #include #include #include #include #include #include #include #include #include #include #include "NativeThreadLinux.h" #include "Plugins/Process/POSIX/ProcessPOSIXLog.h" #include "Plugins/Process/Utility/LinuxProcMaps.h" #include "Procfs.h" #include "lldb/Core/ModuleSpec.h" #include "lldb/Host/Host.h" #include "lldb/Host/HostProcess.h" #include "lldb/Host/ProcessLaunchInfo.h" #include "lldb/Host/PseudoTerminal.h" #include "lldb/Host/ThreadLauncher.h" #include "lldb/Host/common/NativeRegisterContext.h" #include "lldb/Host/linux/Host.h" #include "lldb/Host/linux/Ptrace.h" #include "lldb/Host/linux/Uio.h" #include "lldb/Host/posix/ProcessLauncherPosixFork.h" #include "lldb/Symbol/ObjectFile.h" #include "lldb/Target/Process.h" #include "lldb/Target/Target.h" #include "lldb/Utility/LLDBAssert.h" #include "lldb/Utility/LLDBLog.h" #include "lldb/Utility/State.h" #include "lldb/Utility/Status.h" #include "lldb/Utility/StringExtractor.h" #include "llvm/ADT/ScopeExit.h" #include "llvm/Support/Errno.h" #include "llvm/Support/Error.h" #include "llvm/Support/FileSystem.h" #include "llvm/Support/Threading.h" #include #include #include #include #include #include #ifdef __aarch64__ #include #include #endif // Support hardware breakpoints in case it has not been defined #ifndef TRAP_HWBKPT #define TRAP_HWBKPT 4 #endif #ifndef HWCAP2_MTE #define HWCAP2_MTE (1 << 18) #endif using namespace lldb; using namespace lldb_private; using namespace lldb_private::process_linux; using namespace llvm; // Private bits we only need internally. static bool ProcessVmReadvSupported() { static bool is_supported; static llvm::once_flag flag; llvm::call_once(flag, [] { Log *log = GetLog(POSIXLog::Process); uint32_t source = 0x47424742; uint32_t dest = 0; struct iovec local, remote; remote.iov_base = &source; local.iov_base = &dest; remote.iov_len = local.iov_len = sizeof source; // We shall try if cross-process-memory reads work by attempting to read a // value from our own process. ssize_t res = process_vm_readv(getpid(), &local, 1, &remote, 1, 0); is_supported = (res == sizeof(source) && source == dest); if (is_supported) LLDB_LOG(log, "Detected kernel support for process_vm_readv syscall. " "Fast memory reads enabled."); else LLDB_LOG(log, "syscall process_vm_readv failed (error: {0}). Fast memory " "reads disabled.", llvm::sys::StrError()); }); return is_supported; } static void MaybeLogLaunchInfo(const ProcessLaunchInfo &info) { Log *log = GetLog(POSIXLog::Process); if (!log) return; if (const FileAction *action = info.GetFileActionForFD(STDIN_FILENO)) LLDB_LOG(log, "setting STDIN to '{0}'", action->GetFileSpec()); else LLDB_LOG(log, "leaving STDIN as is"); if (const FileAction *action = info.GetFileActionForFD(STDOUT_FILENO)) LLDB_LOG(log, "setting STDOUT to '{0}'", action->GetFileSpec()); else LLDB_LOG(log, "leaving STDOUT as is"); if (const FileAction *action = info.GetFileActionForFD(STDERR_FILENO)) LLDB_LOG(log, "setting STDERR to '{0}'", action->GetFileSpec()); else LLDB_LOG(log, "leaving STDERR as is"); int i = 0; for (const char **args = info.GetArguments().GetConstArgumentVector(); *args; ++args, ++i) LLDB_LOG(log, "arg {0}: '{1}'", i, *args); } static void DisplayBytes(StreamString &s, void *bytes, uint32_t count) { uint8_t *ptr = (uint8_t *)bytes; const uint32_t loop_count = std::min(DEBUG_PTRACE_MAXBYTES, count); for (uint32_t i = 0; i < loop_count; i++) { s.Printf("[%x]", *ptr); ptr++; } } static void PtraceDisplayBytes(int &req, void *data, size_t data_size) { Log *log = GetLog(POSIXLog::Ptrace); if (!log) return; StreamString buf; switch (req) { case PTRACE_POKETEXT: { DisplayBytes(buf, &data, 8); LLDB_LOGV(log, "PTRACE_POKETEXT {0}", buf.GetData()); break; } case PTRACE_POKEDATA: { DisplayBytes(buf, &data, 8); LLDB_LOGV(log, "PTRACE_POKEDATA {0}", buf.GetData()); break; } case PTRACE_POKEUSER: { DisplayBytes(buf, &data, 8); LLDB_LOGV(log, "PTRACE_POKEUSER {0}", buf.GetData()); break; } case PTRACE_SETREGS: { DisplayBytes(buf, data, data_size); LLDB_LOGV(log, "PTRACE_SETREGS {0}", buf.GetData()); break; } case PTRACE_SETFPREGS: { DisplayBytes(buf, data, data_size); LLDB_LOGV(log, "PTRACE_SETFPREGS {0}", buf.GetData()); break; } case PTRACE_SETSIGINFO: { DisplayBytes(buf, data, sizeof(siginfo_t)); LLDB_LOGV(log, "PTRACE_SETSIGINFO {0}", buf.GetData()); break; } case PTRACE_SETREGSET: { // Extract iov_base from data, which is a pointer to the struct iovec DisplayBytes(buf, *(void **)data, data_size); LLDB_LOGV(log, "PTRACE_SETREGSET {0}", buf.GetData()); break; } default: {} } } static constexpr unsigned k_ptrace_word_size = sizeof(void *); static_assert(sizeof(long) >= k_ptrace_word_size, "Size of long must be larger than ptrace word size"); // Simple helper function to ensure flags are enabled on the given file // descriptor. static Status EnsureFDFlags(int fd, int flags) { Status error; int status = fcntl(fd, F_GETFL); if (status == -1) { error = Status::FromErrno(); return error; } if (fcntl(fd, F_SETFL, status | flags) == -1) { error = Status::FromErrno(); return error; } return error; } static llvm::Error AddPtraceScopeNote(llvm::Error original_error) { Expected ptrace_scope = GetPtraceScope(); if (auto E = ptrace_scope.takeError()) { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "error reading value of ptrace_scope: {0}", E); // The original error is probably more interesting than not being able to // read or interpret ptrace_scope. return original_error; } // We only have suggestions to provide for 1-3. switch (*ptrace_scope) { case 1: case 2: return llvm::createStringError( std::error_code(errno, std::generic_category()), "The current value of ptrace_scope is %d, which can cause ptrace to " "fail to attach to a running process. To fix this, run:\n" "\tsudo sysctl -w kernel.yama.ptrace_scope=0\n" "For more information, see: " "https://www.kernel.org/doc/Documentation/security/Yama.txt.", *ptrace_scope); case 3: return llvm::createStringError( std::error_code(errno, std::generic_category()), "The current value of ptrace_scope is 3, which will cause ptrace to " "fail to attach to a running process. This value cannot be changed " "without rebooting.\n" "For more information, see: " "https://www.kernel.org/doc/Documentation/security/Yama.txt."); case 0: default: return original_error; } } NativeProcessLinux::Manager::Manager(MainLoop &mainloop) : NativeProcessProtocol::Manager(mainloop) { Status status; m_sigchld_handle = mainloop.RegisterSignal( SIGCHLD, [this](MainLoopBase &) { SigchldHandler(); }, status); assert(m_sigchld_handle && status.Success()); } llvm::Expected> NativeProcessLinux::Manager::Launch(ProcessLaunchInfo &launch_info, NativeDelegate &native_delegate) { Log *log = GetLog(POSIXLog::Process); MaybeLogLaunchInfo(launch_info); Status status; ::pid_t pid = ProcessLauncherPosixFork() .LaunchProcess(launch_info, status) .GetProcessId(); LLDB_LOG(log, "pid = {0:x}", pid); if (status.Fail()) { LLDB_LOG(log, "failed to launch process: {0}", status); return status.ToError(); } // Wait for the child process to trap on its call to execve. int wstatus = 0; ::pid_t wpid = llvm::sys::RetryAfterSignal(-1, ::waitpid, pid, &wstatus, 0); assert(wpid == pid); UNUSED_IF_ASSERT_DISABLED(wpid); if (!WIFSTOPPED(wstatus)) { LLDB_LOG(log, "Could not sync with inferior process: wstatus={1}", WaitStatus::Decode(wstatus)); return llvm::make_error("Could not sync with inferior process", llvm::inconvertibleErrorCode()); } LLDB_LOG(log, "inferior started, now in stopped state"); status = SetDefaultPtraceOpts(pid); if (status.Fail()) { LLDB_LOG(log, "failed to set default ptrace options: {0}", status); return status.ToError(); } llvm::Expected arch_or = NativeRegisterContextLinux::DetermineArchitecture(pid); if (!arch_or) return arch_or.takeError(); return std::unique_ptr(new NativeProcessLinux( pid, launch_info.GetPTY().ReleasePrimaryFileDescriptor(), native_delegate, *arch_or, *this, {pid})); } llvm::Expected> NativeProcessLinux::Manager::Attach( lldb::pid_t pid, NativeProcessProtocol::NativeDelegate &native_delegate) { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "pid = {0:x}", pid); auto tids_or = NativeProcessLinux::Attach(pid); if (!tids_or) return tids_or.takeError(); ArrayRef<::pid_t> tids = *tids_or; llvm::Expected arch_or = NativeRegisterContextLinux::DetermineArchitecture(tids[0]); if (!arch_or) return arch_or.takeError(); return std::unique_ptr( new NativeProcessLinux(pid, -1, native_delegate, *arch_or, *this, tids)); } NativeProcessLinux::Extension NativeProcessLinux::Manager::GetSupportedExtensions() const { NativeProcessLinux::Extension supported = Extension::multiprocess | Extension::fork | Extension::vfork | Extension::pass_signals | Extension::auxv | Extension::libraries_svr4 | Extension::siginfo_read; #ifdef __aarch64__ // At this point we do not have a process so read auxv directly. if ((getauxval(AT_HWCAP2) & HWCAP2_MTE)) supported |= Extension::memory_tagging; #endif return supported; } static std::optional> WaitPid() { Log *log = GetLog(POSIXLog::Process); int status; ::pid_t wait_pid = llvm::sys::RetryAfterSignal( -1, ::waitpid, -1, &status, __WALL | __WNOTHREAD | WNOHANG); if (wait_pid == 0) return std::nullopt; if (wait_pid == -1) { Status error(errno, eErrorTypePOSIX); LLDB_LOG(log, "waitpid(-1, &status, _) failed: {0}", error); return std::nullopt; } WaitStatus wait_status = WaitStatus::Decode(status); LLDB_LOG(log, "waitpid(-1, &status, _) = {0}, status = {1}", wait_pid, wait_status); return std::make_pair(wait_pid, wait_status); } void NativeProcessLinux::Manager::SigchldHandler() { Log *log = GetLog(POSIXLog::Process); while (true) { auto wait_result = WaitPid(); if (!wait_result) return; lldb::pid_t pid = wait_result->first; WaitStatus status = wait_result->second; // Ask each process whether it wants to handle the event. Each event should // be handled by exactly one process, but thread creation events require // special handling. // Thread creation consists of two events (one on the parent and one on the // child thread) and they can arrive in any order nondeterministically. The // parent event carries the information about the child thread, but not // vice-versa. This means that if the child event arrives first, it may not // be handled by any process (because it doesn't know the thread belongs to // it). bool handled = llvm::any_of(m_processes, [&](NativeProcessLinux *process) { return process->TryHandleWaitStatus(pid, status); }); if (!handled) { if (status.type == WaitStatus::Stop && status.status == SIGSTOP) { // Store the thread creation event for later collection. m_unowned_threads.insert(pid); } else { LLDB_LOG(log, "Ignoring waitpid event {0} for pid {1}", status, pid); } } } } void NativeProcessLinux::Manager::CollectThread(::pid_t tid) { Log *log = GetLog(POSIXLog::Process); if (m_unowned_threads.erase(tid)) return; // We've encountered this thread already. // The TID is not tracked yet, let's wait for it to appear. int status = -1; LLDB_LOG(log, "received clone event for tid {0}. tid not tracked yet, " "waiting for it to appear...", tid); ::pid_t wait_pid = llvm::sys::RetryAfterSignal(-1, ::waitpid, tid, &status, __WALL); // It's theoretically possible to get other events if the entire process was // SIGKILLed before we got a chance to check this. In that case, we'll just // clean everything up when we get the process exit event. LLDB_LOG(log, "waitpid({0}, &status, __WALL) => {1} (errno: {2}, status = {3})", tid, wait_pid, errno, WaitStatus::Decode(status)); } // Public Instance Methods NativeProcessLinux::NativeProcessLinux(::pid_t pid, int terminal_fd, NativeDelegate &delegate, const ArchSpec &arch, Manager &manager, llvm::ArrayRef<::pid_t> tids) : NativeProcessELF(pid, terminal_fd, delegate), m_manager(manager), m_arch(arch), m_intel_pt_collector(*this) { manager.AddProcess(*this); if (m_terminal_fd != -1) { Status status = EnsureFDFlags(m_terminal_fd, O_NONBLOCK); assert(status.Success()); } for (const auto &tid : tids) { NativeThreadLinux &thread = AddThread(tid, /*resume*/ false); ThreadWasCreated(thread); } // Let our process instance know the thread has stopped. SetCurrentThreadID(tids[0]); SetState(StateType::eStateStopped, false); } llvm::Expected> NativeProcessLinux::Attach(::pid_t pid) { Log *log = GetLog(POSIXLog::Process); Status status; // Use a map to keep track of the threads which we have attached/need to // attach. Host::TidMap tids_to_attach; while (Host::FindProcessThreads(pid, tids_to_attach)) { for (Host::TidMap::iterator it = tids_to_attach.begin(); it != tids_to_attach.end();) { if (it->second == false) { lldb::tid_t tid = it->first; // Attach to the requested process. // An attach will cause the thread to stop with a SIGSTOP. if ((status = PtraceWrapper(PTRACE_ATTACH, tid)).Fail()) { // No such thread. The thread may have exited. More error handling // may be needed. if (status.GetError() == ESRCH) { it = tids_to_attach.erase(it); continue; } if (status.GetError() == EPERM) { // Depending on the value of ptrace_scope, we can return a different // error that suggests how to fix it. return AddPtraceScopeNote(status.ToError()); } return status.ToError(); } int wpid = llvm::sys::RetryAfterSignal(-1, ::waitpid, tid, nullptr, __WALL); // Need to use __WALL otherwise we receive an error with errno=ECHLD At // this point we should have a thread stopped if waitpid succeeds. if (wpid < 0) { // No such thread. The thread may have exited. More error handling // may be needed. if (errno == ESRCH) { it = tids_to_attach.erase(it); continue; } return llvm::errorCodeToError( std::error_code(errno, std::generic_category())); } if ((status = SetDefaultPtraceOpts(tid)).Fail()) return status.ToError(); LLDB_LOG(log, "adding tid = {0}", tid); it->second = true; } // move the loop forward ++it; } } size_t tid_count = tids_to_attach.size(); if (tid_count == 0) return llvm::make_error("No such process", llvm::inconvertibleErrorCode()); std::vector<::pid_t> tids; tids.reserve(tid_count); for (const auto &p : tids_to_attach) tids.push_back(p.first); return std::move(tids); } Status NativeProcessLinux::SetDefaultPtraceOpts(lldb::pid_t pid) { long ptrace_opts = 0; // Have the child raise an event on exit. This is used to keep the child in // limbo until it is destroyed. ptrace_opts |= PTRACE_O_TRACEEXIT; // Have the tracer trace threads which spawn in the inferior process. ptrace_opts |= PTRACE_O_TRACECLONE; // Have the tracer notify us before execve returns (needed to disable legacy // SIGTRAP generation) ptrace_opts |= PTRACE_O_TRACEEXEC; // Have the tracer trace forked children. ptrace_opts |= PTRACE_O_TRACEFORK; // Have the tracer trace vforks. ptrace_opts |= PTRACE_O_TRACEVFORK; // Have the tracer trace vfork-done in order to restore breakpoints after // the child finishes sharing memory. ptrace_opts |= PTRACE_O_TRACEVFORKDONE; return PtraceWrapper(PTRACE_SETOPTIONS, pid, nullptr, (void *)ptrace_opts); } bool NativeProcessLinux::TryHandleWaitStatus(lldb::pid_t pid, WaitStatus status) { if (pid == GetID() && (status.type == WaitStatus::Exit || status.type == WaitStatus::Signal)) { // The process exited. We're done monitoring. Report to delegate. SetExitStatus(status, true); return true; } if (NativeThreadLinux *thread = GetThreadByID(pid)) { MonitorCallback(*thread, status); return true; } return false; } void NativeProcessLinux::MonitorCallback(NativeThreadLinux &thread, WaitStatus status) { Log *log = GetLog(LLDBLog::Process); // Certain activities differ based on whether the pid is the tid of the main // thread. const bool is_main_thread = (thread.GetID() == GetID()); // Handle when the thread exits. if (status.type == WaitStatus::Exit || status.type == WaitStatus::Signal) { LLDB_LOG(log, "got exit status({0}) , tid = {1} ({2} main thread), process " "state = {3}", status, thread.GetID(), is_main_thread ? "is" : "is not", GetState()); // This is a thread that exited. Ensure we're not tracking it anymore. StopTrackingThread(thread); assert(!is_main_thread && "Main thread exits handled elsewhere"); return; } siginfo_t info; const auto info_err = GetSignalInfo(thread.GetID(), &info); // Get details on the signal raised. if (info_err.Success()) { // We have retrieved the signal info. Dispatch appropriately. if (info.si_signo == SIGTRAP) MonitorSIGTRAP(info, thread); else MonitorSignal(info, thread); } else { if (info_err.GetError() == EINVAL) { // This is a group stop reception for this tid. We can reach here if we // reinject SIGSTOP, SIGSTP, SIGTTIN or SIGTTOU into the tracee, // triggering the group-stop mechanism. Normally receiving these would // stop the process, pending a SIGCONT. Simulating this state in a // debugger is hard and is generally not needed (one use case is // debugging background task being managed by a shell). For general use, // it is sufficient to stop the process in a signal-delivery stop which // happens before the group stop. This done by MonitorSignal and works // correctly for all signals. LLDB_LOG(log, "received a group stop for pid {0} tid {1}. Transparent " "handling of group stops not supported, resuming the " "thread.", GetID(), thread.GetID()); ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER); } else { // ptrace(GETSIGINFO) failed (but not due to group-stop). // A return value of ESRCH means the thread/process has died in the mean // time. This can (e.g.) happen when another thread does an exit_group(2) // or the entire process get SIGKILLed. // We can't do anything with this thread anymore, but we keep it around // until we get the WIFEXITED event. LLDB_LOG(log, "GetSignalInfo({0}) failed: {1}, status = {2}, main_thread = " "{3}. Expecting WIFEXITED soon.", thread.GetID(), info_err, status, is_main_thread); } } } void NativeProcessLinux::MonitorSIGTRAP(const siginfo_t &info, NativeThreadLinux &thread) { Log *log = GetLog(POSIXLog::Process); const bool is_main_thread = (thread.GetID() == GetID()); assert(info.si_signo == SIGTRAP && "Unexpected child signal!"); switch (info.si_code) { case (SIGTRAP | (PTRACE_EVENT_FORK << 8)): case (SIGTRAP | (PTRACE_EVENT_VFORK << 8)): case (SIGTRAP | (PTRACE_EVENT_CLONE << 8)): { // This can either mean a new thread or a new process spawned via // clone(2) without SIGCHLD or CLONE_VFORK flag. Note that clone(2) // can also cause PTRACE_EVENT_FORK and PTRACE_EVENT_VFORK if one // of these flags are passed. unsigned long event_message = 0; if (GetEventMessage(thread.GetID(), &event_message).Fail()) { LLDB_LOG(log, "pid {0} received clone() event but GetEventMessage failed " "so we don't know the new pid/tid", thread.GetID()); ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER); } else { MonitorClone(thread, event_message, info.si_code >> 8); } break; } case (SIGTRAP | (PTRACE_EVENT_EXEC << 8)): { LLDB_LOG(log, "received exec event, code = {0}", info.si_code ^ SIGTRAP); // Exec clears any pending notifications. m_pending_notification_tid = LLDB_INVALID_THREAD_ID; // Remove all but the main thread here. Linux fork creates a new process // which only copies the main thread. LLDB_LOG(log, "exec received, stop tracking all but main thread"); llvm::erase_if(m_threads, [&](std::unique_ptr &t) { return t->GetID() != GetID(); }); assert(m_threads.size() == 1); auto *main_thread = static_cast(m_threads[0].get()); SetCurrentThreadID(main_thread->GetID()); main_thread->SetStoppedByExec(); // Tell coordinator about the "new" (since exec) stopped main thread. ThreadWasCreated(*main_thread); // Let our delegate know we have just exec'd. NotifyDidExec(); // Let the process know we're stopped. StopRunningThreads(main_thread->GetID()); break; } case (SIGTRAP | (PTRACE_EVENT_EXIT << 8)): { // The inferior process or one of its threads is about to exit. We don't // want to do anything with the thread so we just resume it. In case we // want to implement "break on thread exit" functionality, we would need to // stop here. unsigned long data = 0; if (GetEventMessage(thread.GetID(), &data).Fail()) data = -1; LLDB_LOG(log, "received PTRACE_EVENT_EXIT, data = {0:x}, WIFEXITED={1}, " "WIFSIGNALED={2}, pid = {3}, main_thread = {4}", data, WIFEXITED(data), WIFSIGNALED(data), thread.GetID(), is_main_thread); StateType state = thread.GetState(); if (!StateIsRunningState(state)) { // Due to a kernel bug, we may sometimes get this stop after the inferior // gets a SIGKILL. This confuses our state tracking logic in // ResumeThread(), since normally, we should not be receiving any ptrace // events while the inferior is stopped. This makes sure that the // inferior is resumed and exits normally. state = eStateRunning; } ResumeThread(thread, state, LLDB_INVALID_SIGNAL_NUMBER); if (is_main_thread) { // Main thread report the read (WIFEXITED) event only after all threads in // the process exit, so we need to stop tracking it here instead of in // MonitorCallback StopTrackingThread(thread); } break; } case (SIGTRAP | (PTRACE_EVENT_VFORK_DONE << 8)): { if (bool(m_enabled_extensions & Extension::vfork)) { thread.SetStoppedByVForkDone(); StopRunningThreads(thread.GetID()); } else ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER); break; } case 0: case TRAP_TRACE: // We receive this on single stepping. case TRAP_HWBKPT: // We receive this on watchpoint hit { // If a watchpoint was hit, report it uint32_t wp_index; Status error = thread.GetRegisterContext().GetWatchpointHitIndex( wp_index, (uintptr_t)info.si_addr); if (error.Fail()) LLDB_LOG(log, "received error while checking for watchpoint hits, pid = " "{0}, error = {1}", thread.GetID(), error); if (wp_index != LLDB_INVALID_INDEX32) { MonitorWatchpoint(thread, wp_index); break; } // If a breakpoint was hit, report it uint32_t bp_index; error = thread.GetRegisterContext().GetHardwareBreakHitIndex( bp_index, (uintptr_t)info.si_addr); if (error.Fail()) LLDB_LOG(log, "received error while checking for hardware " "breakpoint hits, pid = {0}, error = {1}", thread.GetID(), error); if (bp_index != LLDB_INVALID_INDEX32) { MonitorBreakpoint(thread); break; } // Otherwise, report step over MonitorTrace(thread); break; } case SI_KERNEL: #if defined __mips__ // For mips there is no special signal for watchpoint So we check for // watchpoint in kernel trap { // If a watchpoint was hit, report it uint32_t wp_index; Status error = thread.GetRegisterContext().GetWatchpointHitIndex( wp_index, LLDB_INVALID_ADDRESS); if (error.Fail()) LLDB_LOG(log, "received error while checking for watchpoint hits, pid = " "{0}, error = {1}", thread.GetID(), error); if (wp_index != LLDB_INVALID_INDEX32) { MonitorWatchpoint(thread, wp_index); break; } } // NO BREAK #endif case TRAP_BRKPT: MonitorBreakpoint(thread); break; case SIGTRAP: case (SIGTRAP | 0x80): LLDB_LOG( log, "received unknown SIGTRAP stop event ({0}, pid {1} tid {2}, resuming", info.si_code, GetID(), thread.GetID()); // Ignore these signals until we know more about them. ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER); break; default: LLDB_LOG(log, "received unknown SIGTRAP stop event ({0}, pid {1} tid {2}", info.si_code, GetID(), thread.GetID()); MonitorSignal(info, thread); break; } } void NativeProcessLinux::MonitorTrace(NativeThreadLinux &thread) { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "received trace event, pid = {0}", thread.GetID()); // This thread is currently stopped. thread.SetStoppedByTrace(); StopRunningThreads(thread.GetID()); } void NativeProcessLinux::MonitorBreakpoint(NativeThreadLinux &thread) { Log *log = GetLog(LLDBLog::Process | LLDBLog::Breakpoints); LLDB_LOG(log, "received breakpoint event, pid = {0}", thread.GetID()); // Mark the thread as stopped at breakpoint. thread.SetStoppedByBreakpoint(); FixupBreakpointPCAsNeeded(thread); NativeRegisterContextLinux ®_ctx = thread.GetRegisterContext(); auto stepping_with_bp_it = m_threads_stepping_with_breakpoint.find(thread.GetID()); if (stepping_with_bp_it != m_threads_stepping_with_breakpoint.end() && stepping_with_bp_it->second == reg_ctx.GetPC()) thread.SetStoppedByTrace(); StopRunningThreads(thread.GetID()); } void NativeProcessLinux::MonitorWatchpoint(NativeThreadLinux &thread, uint32_t wp_index) { Log *log = GetLog(LLDBLog::Process | LLDBLog::Watchpoints); LLDB_LOG(log, "received watchpoint event, pid = {0}, wp_index = {1}", thread.GetID(), wp_index); // Mark the thread as stopped at watchpoint. The address is at // (lldb::addr_t)info->si_addr if we need it. thread.SetStoppedByWatchpoint(wp_index); // We need to tell all other running threads before we notify the delegate // about this stop. StopRunningThreads(thread.GetID()); } void NativeProcessLinux::MonitorSignal(const siginfo_t &info, NativeThreadLinux &thread) { const int signo = info.si_signo; const bool is_from_llgs = info.si_pid == getpid(); Log *log = GetLog(POSIXLog::Process); // POSIX says that process behaviour is undefined after it ignores a SIGFPE, // SIGILL, SIGSEGV, or SIGBUS *unless* that signal was generated by a kill(2) // or raise(3). Similarly for tgkill(2) on Linux. // // IOW, user generated signals never generate what we consider to be a // "crash". // // Similarly, ACK signals generated by this monitor. // Handle the signal. LLDB_LOG(log, "received signal {0} ({1}) with code {2}, (siginfo pid = {3}, " "waitpid pid = {4})", Host::GetSignalAsCString(signo), signo, info.si_code, info.si_pid, thread.GetID()); // Check for thread stop notification. if (is_from_llgs && (info.si_code == SI_TKILL) && (signo == SIGSTOP)) { // This is a tgkill()-based stop. LLDB_LOG(log, "pid {0} tid {1}, thread stopped", GetID(), thread.GetID()); // Check that we're not already marked with a stop reason. Note this thread // really shouldn't already be marked as stopped - if we were, that would // imply that the kernel signaled us with the thread stopping which we // handled and marked as stopped, and that, without an intervening resume, // we received another stop. It is more likely that we are missing the // marking of a run state somewhere if we find that the thread was marked // as stopped. const StateType thread_state = thread.GetState(); if (!StateIsStoppedState(thread_state, false)) { // An inferior thread has stopped because of a SIGSTOP we have sent it. // Generally, these are not important stops and we don't want to report // them as they are just used to stop other threads when one thread (the // one with the *real* stop reason) hits a breakpoint (watchpoint, // etc...). However, in the case of an asynchronous Interrupt(), this // *is* the real stop reason, so we leave the signal intact if this is // the thread that was chosen as the triggering thread. if (m_pending_notification_tid != LLDB_INVALID_THREAD_ID) { if (m_pending_notification_tid == thread.GetID()) thread.SetStoppedBySignal(SIGSTOP, &info); else thread.SetStoppedWithNoReason(); SetCurrentThreadID(thread.GetID()); SignalIfAllThreadsStopped(); } else { // We can end up here if stop was initiated by LLGS but by this time a // thread stop has occurred - maybe initiated by another event. Status error = ResumeThread(thread, thread.GetState(), 0); if (error.Fail()) LLDB_LOG(log, "failed to resume thread {0}: {1}", thread.GetID(), error); } } else { LLDB_LOG(log, "pid {0} tid {1}, thread was already marked as a stopped " "state (state={2}), leaving stop signal as is", GetID(), thread.GetID(), thread_state); SignalIfAllThreadsStopped(); } // Done handling. return; } // Check if debugger should stop at this signal or just ignore it and resume // the inferior. if (m_signals_to_ignore.contains(signo)) { ResumeThread(thread, thread.GetState(), signo); return; } // This thread is stopped. LLDB_LOG(log, "received signal {0}", Host::GetSignalAsCString(signo)); thread.SetStoppedBySignal(signo, &info); // Send a stop to the debugger after we get all other threads to stop. StopRunningThreads(thread.GetID()); } bool NativeProcessLinux::MonitorClone(NativeThreadLinux &parent, lldb::pid_t child_pid, int event) { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "parent_tid={0}, child_pid={1}, event={2}", parent.GetID(), child_pid, event); m_manager.CollectThread(child_pid); switch (event) { case PTRACE_EVENT_CLONE: { // PTRACE_EVENT_CLONE can either mean a new thread or a new process. // Try to grab the new process' PGID to figure out which one it is. // If PGID is the same as the PID, then it's a new process. Otherwise, // it's a thread. auto tgid_ret = getPIDForTID(child_pid); if (tgid_ret != child_pid) { // A new thread should have PGID matching our process' PID. assert(!tgid_ret || *tgid_ret == GetID()); NativeThreadLinux &child_thread = AddThread(child_pid, /*resume*/ true); ThreadWasCreated(child_thread); // Resume the parent. ResumeThread(parent, parent.GetState(), LLDB_INVALID_SIGNAL_NUMBER); break; } } [[fallthrough]]; case PTRACE_EVENT_FORK: case PTRACE_EVENT_VFORK: { bool is_vfork = event == PTRACE_EVENT_VFORK; std::unique_ptr child_process{new NativeProcessLinux( static_cast<::pid_t>(child_pid), m_terminal_fd, m_delegate, m_arch, m_manager, {static_cast<::pid_t>(child_pid)})}; if (!is_vfork) child_process->m_software_breakpoints = m_software_breakpoints; Extension expected_ext = is_vfork ? Extension::vfork : Extension::fork; if (bool(m_enabled_extensions & expected_ext)) { m_delegate.NewSubprocess(this, std::move(child_process)); // NB: non-vfork clone() is reported as fork parent.SetStoppedByFork(is_vfork, child_pid); StopRunningThreads(parent.GetID()); } else { child_process->Detach(); ResumeThread(parent, parent.GetState(), LLDB_INVALID_SIGNAL_NUMBER); } break; } default: llvm_unreachable("unknown clone_info.event"); } return true; } bool NativeProcessLinux::SupportHardwareSingleStepping() const { if (m_arch.IsMIPS() || m_arch.GetMachine() == llvm::Triple::arm || m_arch.GetTriple().isRISCV() || m_arch.GetTriple().isLoongArch()) return false; return true; } Status NativeProcessLinux::Resume(const ResumeActionList &resume_actions) { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "pid {0}", GetID()); NotifyTracersProcessWillResume(); bool software_single_step = !SupportHardwareSingleStepping(); if (software_single_step) { for (const auto &thread : m_threads) { assert(thread && "thread list should not contain NULL threads"); const ResumeAction *const action = resume_actions.GetActionForThread(thread->GetID(), true); if (action == nullptr) continue; if (action->state == eStateStepping) { Status error = SetupSoftwareSingleStepping( static_cast(*thread)); if (error.Fail()) return error; } } } for (const auto &thread : m_threads) { assert(thread && "thread list should not contain NULL threads"); const ResumeAction *const action = resume_actions.GetActionForThread(thread->GetID(), true); if (action == nullptr) { LLDB_LOG(log, "no action specified for pid {0} tid {1}", GetID(), thread->GetID()); continue; } LLDB_LOG(log, "processing resume action state {0} for pid {1} tid {2}", action->state, GetID(), thread->GetID()); switch (action->state) { case eStateRunning: case eStateStepping: { // Run the thread, possibly feeding it the signal. const int signo = action->signal; Status error = ResumeThread(static_cast(*thread), action->state, signo); if (error.Fail()) return Status::FromErrorStringWithFormat( "NativeProcessLinux::%s: failed to resume thread " "for pid %" PRIu64 ", tid %" PRIu64 ", error = %s", __FUNCTION__, GetID(), thread->GetID(), error.AsCString()); break; } case eStateSuspended: case eStateStopped: break; default: return Status::FromErrorStringWithFormat( "NativeProcessLinux::%s (): unexpected state %s specified " "for pid %" PRIu64 ", tid %" PRIu64, __FUNCTION__, StateAsCString(action->state), GetID(), thread->GetID()); } } return Status(); } Status NativeProcessLinux::Halt() { Status error; if (kill(GetID(), SIGSTOP) != 0) error = Status::FromErrno(); return error; } Status NativeProcessLinux::Detach() { Status error; // Tell ptrace to detach from the process. if (GetID() == LLDB_INVALID_PROCESS_ID) return error; // Cancel out any SIGSTOPs we may have sent while stopping the process. // Otherwise, the process may stop as soon as we detach from it. kill(GetID(), SIGCONT); for (const auto &thread : m_threads) { Status e = Detach(thread->GetID()); // Save the error, but still attempt to detach from other threads. if (e.Fail()) error = e.Clone(); } m_intel_pt_collector.Clear(); return error; } Status NativeProcessLinux::Signal(int signo) { Status error; Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "sending signal {0} ({1}) to pid {1}", signo, Host::GetSignalAsCString(signo), GetID()); if (kill(GetID(), signo)) error = Status::FromErrno(); return error; } Status NativeProcessLinux::Interrupt() { // Pick a running thread (or if none, a not-dead stopped thread) as the // chosen thread that will be the stop-reason thread. Log *log = GetLog(POSIXLog::Process); NativeThreadProtocol *running_thread = nullptr; NativeThreadProtocol *stopped_thread = nullptr; LLDB_LOG(log, "selecting running thread for interrupt target"); for (const auto &thread : m_threads) { // If we have a running or stepping thread, we'll call that the target of // the interrupt. const auto thread_state = thread->GetState(); if (thread_state == eStateRunning || thread_state == eStateStepping) { running_thread = thread.get(); break; } else if (!stopped_thread && StateIsStoppedState(thread_state, true)) { // Remember the first non-dead stopped thread. We'll use that as a // backup if there are no running threads. stopped_thread = thread.get(); } } if (!running_thread && !stopped_thread) { Status error("found no running/stepping or live stopped threads as target " "for interrupt"); LLDB_LOG(log, "skipping due to error: {0}", error); return error; } NativeThreadProtocol *deferred_signal_thread = running_thread ? running_thread : stopped_thread; LLDB_LOG(log, "pid {0} {1} tid {2} chosen for interrupt target", GetID(), running_thread ? "running" : "stopped", deferred_signal_thread->GetID()); StopRunningThreads(deferred_signal_thread->GetID()); return Status(); } Status NativeProcessLinux::Kill() { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "pid {0}", GetID()); Status error; switch (m_state) { case StateType::eStateInvalid: case StateType::eStateExited: case StateType::eStateCrashed: case StateType::eStateDetached: case StateType::eStateUnloaded: // Nothing to do - the process is already dead. LLDB_LOG(log, "ignored for PID {0} due to current state: {1}", GetID(), m_state); return error; case StateType::eStateConnected: case StateType::eStateAttaching: case StateType::eStateLaunching: case StateType::eStateStopped: case StateType::eStateRunning: case StateType::eStateStepping: case StateType::eStateSuspended: // We can try to kill a process in these states. break; } if (kill(GetID(), SIGKILL) != 0) { error = Status::FromErrno(); return error; } return error; } Status NativeProcessLinux::GetMemoryRegionInfo(lldb::addr_t load_addr, MemoryRegionInfo &range_info) { // FIXME review that the final memory region returned extends to the end of // the virtual address space, // with no perms if it is not mapped. // Use an approach that reads memory regions from /proc/{pid}/maps. Assume // proc maps entries are in ascending order. // FIXME assert if we find differently. if (m_supports_mem_region == LazyBool::eLazyBoolNo) { // We're done. return Status::FromErrorString("unsupported"); } Status error = PopulateMemoryRegionCache(); if (error.Fail()) { return error; } lldb::addr_t prev_base_address = 0; // FIXME start by finding the last region that is <= target address using // binary search. Data is sorted. // There can be a ton of regions on pthreads apps with lots of threads. for (auto it = m_mem_region_cache.begin(); it != m_mem_region_cache.end(); ++it) { MemoryRegionInfo &proc_entry_info = it->first; // Sanity check assumption that /proc/{pid}/maps entries are ascending. assert((proc_entry_info.GetRange().GetRangeBase() >= prev_base_address) && "descending /proc/pid/maps entries detected, unexpected"); prev_base_address = proc_entry_info.GetRange().GetRangeBase(); UNUSED_IF_ASSERT_DISABLED(prev_base_address); // If the target address comes before this entry, indicate distance to next // region. if (load_addr < proc_entry_info.GetRange().GetRangeBase()) { range_info.GetRange().SetRangeBase(load_addr); range_info.GetRange().SetByteSize( proc_entry_info.GetRange().GetRangeBase() - load_addr); range_info.SetReadable(MemoryRegionInfo::OptionalBool::eNo); range_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo); range_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo); range_info.SetMapped(MemoryRegionInfo::OptionalBool::eNo); return error; } else if (proc_entry_info.GetRange().Contains(load_addr)) { // The target address is within the memory region we're processing here. range_info = proc_entry_info; return error; } // The target memory address comes somewhere after the region we just // parsed. } // If we made it here, we didn't find an entry that contained the given // address. Return the load_addr as start and the amount of bytes betwwen // load address and the end of the memory as size. range_info.GetRange().SetRangeBase(load_addr); range_info.GetRange().SetRangeEnd(LLDB_INVALID_ADDRESS); range_info.SetReadable(MemoryRegionInfo::OptionalBool::eNo); range_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo); range_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo); range_info.SetMapped(MemoryRegionInfo::OptionalBool::eNo); return error; } Status NativeProcessLinux::PopulateMemoryRegionCache() { Log *log = GetLog(POSIXLog::Process); // If our cache is empty, pull the latest. There should always be at least // one memory region if memory region handling is supported. if (!m_mem_region_cache.empty()) { LLDB_LOG(log, "reusing {0} cached memory region entries", m_mem_region_cache.size()); return Status(); } Status Result; LinuxMapCallback callback = [&](llvm::Expected Info) { if (Info) { FileSpec file_spec(Info->GetName().GetCString()); FileSystem::Instance().Resolve(file_spec); m_mem_region_cache.emplace_back(*Info, file_spec); return true; } Result = Status::FromError(Info.takeError()); m_supports_mem_region = LazyBool::eLazyBoolNo; LLDB_LOG(log, "failed to parse proc maps: {0}", Result); return false; }; // Linux kernel since 2.6.14 has /proc/{pid}/smaps // if CONFIG_PROC_PAGE_MONITOR is enabled auto BufferOrError = getProcFile(GetID(), GetCurrentThreadID(), "smaps"); if (BufferOrError) ParseLinuxSMapRegions(BufferOrError.get()->getBuffer(), callback); else { BufferOrError = getProcFile(GetID(), GetCurrentThreadID(), "maps"); if (!BufferOrError) { m_supports_mem_region = LazyBool::eLazyBoolNo; return BufferOrError.getError(); } ParseLinuxMapRegions(BufferOrError.get()->getBuffer(), callback); } if (Result.Fail()) return Result; if (m_mem_region_cache.empty()) { // No entries after attempting to read them. This shouldn't happen if // /proc/{pid}/maps is supported. Assume we don't support map entries via // procfs. m_supports_mem_region = LazyBool::eLazyBoolNo; LLDB_LOG(log, "failed to find any procfs maps entries, assuming no support " "for memory region metadata retrieval"); return Status::FromErrorString("not supported"); } LLDB_LOG(log, "read {0} memory region entries from /proc/{1}/maps", m_mem_region_cache.size(), GetID()); // We support memory retrieval, remember that. m_supports_mem_region = LazyBool::eLazyBoolYes; return Status(); } void NativeProcessLinux::DoStopIDBumped(uint32_t newBumpId) { Log *log = GetLog(POSIXLog::Process); LLDB_LOG(log, "newBumpId={0}", newBumpId); LLDB_LOG(log, "clearing {0} entries from memory region cache", m_mem_region_cache.size()); m_mem_region_cache.clear(); } llvm::Expected NativeProcessLinux::Syscall(llvm::ArrayRef args) { PopulateMemoryRegionCache(); auto region_it = llvm::find_if(m_mem_region_cache, [](const auto &pair) { return pair.first.GetExecutable() == MemoryRegionInfo::eYes && pair.first.GetShared() != MemoryRegionInfo::eYes; }); if (region_it == m_mem_region_cache.end()) return llvm::createStringError(llvm::inconvertibleErrorCode(), "No executable memory region found!"); addr_t exe_addr = region_it->first.GetRange().GetRangeBase(); NativeThreadLinux &thread = *GetCurrentThread(); assert(thread.GetState() == eStateStopped); NativeRegisterContextLinux ®_ctx = thread.GetRegisterContext(); NativeRegisterContextLinux::SyscallData syscall_data = *reg_ctx.GetSyscallData(); WritableDataBufferSP registers_sp; if (llvm::Error Err = reg_ctx.ReadAllRegisterValues(registers_sp).ToError()) return std::move(Err); auto restore_regs = llvm::make_scope_exit( [&] { reg_ctx.WriteAllRegisterValues(registers_sp); }); llvm::SmallVector memory(syscall_data.Insn.size()); size_t bytes_read; if (llvm::Error Err = ReadMemory(exe_addr, memory.data(), memory.size(), bytes_read) .ToError()) { return std::move(Err); } auto restore_mem = llvm::make_scope_exit( [&] { WriteMemory(exe_addr, memory.data(), memory.size(), bytes_read); }); if (llvm::Error Err = reg_ctx.SetPC(exe_addr).ToError()) return std::move(Err); for (const auto &zip : llvm::zip_first(args, syscall_data.Args)) { if (llvm::Error Err = reg_ctx .WriteRegisterFromUnsigned(std::get<1>(zip), std::get<0>(zip)) .ToError()) { return std::move(Err); } } if (llvm::Error Err = WriteMemory(exe_addr, syscall_data.Insn.data(), syscall_data.Insn.size(), bytes_read) .ToError()) return std::move(Err); m_mem_region_cache.clear(); // With software single stepping the syscall insn buffer must also include a // trap instruction to stop the process. int req = SupportHardwareSingleStepping() ? PTRACE_SINGLESTEP : PTRACE_CONT; if (llvm::Error Err = PtraceWrapper(req, thread.GetID(), nullptr, nullptr).ToError()) return std::move(Err); int status; ::pid_t wait_pid = llvm::sys::RetryAfterSignal(-1, ::waitpid, thread.GetID(), &status, __WALL); if (wait_pid == -1) { return llvm::errorCodeToError( std::error_code(errno, std::generic_category())); } assert((unsigned)wait_pid == thread.GetID()); uint64_t result = reg_ctx.ReadRegisterAsUnsigned(syscall_data.Result, -ESRCH); // Values larger than this are actually negative errno numbers. uint64_t errno_threshold = (uint64_t(-1) >> (64 - 8 * m_arch.GetAddressByteSize())) - 0x1000; if (result > errno_threshold) { return llvm::errorCodeToError( std::error_code(-result & 0xfff, std::generic_category())); } return result; } llvm::Expected NativeProcessLinux::AllocateMemory(size_t size, uint32_t permissions) { std::optional mmap_data = GetCurrentThread()->GetRegisterContext().GetMmapData(); if (!mmap_data) return llvm::make_error(); unsigned prot = PROT_NONE; assert((permissions & (ePermissionsReadable | ePermissionsWritable | ePermissionsExecutable)) == permissions && "Unknown permission!"); if (permissions & ePermissionsReadable) prot |= PROT_READ; if (permissions & ePermissionsWritable) prot |= PROT_WRITE; if (permissions & ePermissionsExecutable) prot |= PROT_EXEC; llvm::Expected Result = Syscall({mmap_data->SysMmap, 0, size, prot, MAP_ANONYMOUS | MAP_PRIVATE, uint64_t(-1), 0}); if (Result) m_allocated_memory.try_emplace(*Result, size); return Result; } llvm::Error NativeProcessLinux::DeallocateMemory(lldb::addr_t addr) { std::optional mmap_data = GetCurrentThread()->GetRegisterContext().GetMmapData(); if (!mmap_data) return llvm::make_error(); auto it = m_allocated_memory.find(addr); if (it == m_allocated_memory.end()) return llvm::createStringError(llvm::errc::invalid_argument, "Memory not allocated by the debugger."); llvm::Expected Result = Syscall({mmap_data->SysMunmap, addr, it->second}); if (!Result) return Result.takeError(); m_allocated_memory.erase(it); return llvm::Error::success(); } Status NativeProcessLinux::ReadMemoryTags(int32_t type, lldb::addr_t addr, size_t len, std::vector &tags) { llvm::Expected details = GetCurrentThread()->GetRegisterContext().GetMemoryTaggingDetails(type); if (!details) return Status::FromError(details.takeError()); // Ignore 0 length read if (!len) return Status(); // lldb will align the range it requests but it is not required to by // the protocol so we'll do it again just in case. // Remove tag bits too. Ptrace calls may work regardless but that // is not a guarantee. MemoryTagManager::TagRange range(details->manager->RemoveTagBits(addr), len); range = details->manager->ExpandToGranule(range); // Allocate enough space for all tags to be read size_t num_tags = range.GetByteSize() / details->manager->GetGranuleSize(); tags.resize(num_tags * details->manager->GetTagSizeInBytes()); struct iovec tags_iovec; uint8_t *dest = tags.data(); lldb::addr_t read_addr = range.GetRangeBase(); // This call can return partial data so loop until we error or // get all tags back. while (num_tags) { tags_iovec.iov_base = dest; tags_iovec.iov_len = num_tags; Status error = NativeProcessLinux::PtraceWrapper( details->ptrace_read_req, GetCurrentThreadID(), reinterpret_cast(read_addr), static_cast(&tags_iovec), 0, nullptr); if (error.Fail()) { // Discard partial reads tags.resize(0); return error; } size_t tags_read = tags_iovec.iov_len; assert(tags_read && (tags_read <= num_tags)); dest += tags_read * details->manager->GetTagSizeInBytes(); read_addr += details->manager->GetGranuleSize() * tags_read; num_tags -= tags_read; } return Status(); } Status NativeProcessLinux::WriteMemoryTags(int32_t type, lldb::addr_t addr, size_t len, const std::vector &tags) { llvm::Expected details = GetCurrentThread()->GetRegisterContext().GetMemoryTaggingDetails(type); if (!details) return Status::FromError(details.takeError()); // Ignore 0 length write if (!len) return Status(); // lldb will align the range it requests but it is not required to by // the protocol so we'll do it again just in case. // Remove tag bits too. Ptrace calls may work regardless but that // is not a guarantee. MemoryTagManager::TagRange range(details->manager->RemoveTagBits(addr), len); range = details->manager->ExpandToGranule(range); // Not checking number of tags here, we may repeat them below llvm::Expected> unpacked_tags_or_err = details->manager->UnpackTagsData(tags); if (!unpacked_tags_or_err) return Status::FromError(unpacked_tags_or_err.takeError()); llvm::Expected> repeated_tags_or_err = details->manager->RepeatTagsForRange(*unpacked_tags_or_err, range); if (!repeated_tags_or_err) return Status::FromError(repeated_tags_or_err.takeError()); // Repack them for ptrace to use llvm::Expected> final_tag_data = details->manager->PackTags(*repeated_tags_or_err); if (!final_tag_data) return Status::FromError(final_tag_data.takeError()); struct iovec tags_vec; uint8_t *src = final_tag_data->data(); lldb::addr_t write_addr = range.GetRangeBase(); // unpacked tags size because the number of bytes per tag might not be 1 size_t num_tags = repeated_tags_or_err->size(); // This call can partially write tags, so we loop until we // error or all tags have been written. while (num_tags > 0) { tags_vec.iov_base = src; tags_vec.iov_len = num_tags; Status error = NativeProcessLinux::PtraceWrapper( details->ptrace_write_req, GetCurrentThreadID(), reinterpret_cast(write_addr), static_cast(&tags_vec), 0, nullptr); if (error.Fail()) { // Don't attempt to restore the original values in the case of a partial // write return error; } size_t tags_written = tags_vec.iov_len; assert(tags_written && (tags_written <= num_tags)); src += tags_written * details->manager->GetTagSizeInBytes(); write_addr += details->manager->GetGranuleSize() * tags_written; num_tags -= tags_written; } return Status(); } size_t NativeProcessLinux::UpdateThreads() { // The NativeProcessLinux monitoring threads are always up to date with // respect to thread state and they keep the thread list populated properly. // All this method needs to do is return the thread count. return m_threads.size(); } Status NativeProcessLinux::SetBreakpoint(lldb::addr_t addr, uint32_t size, bool hardware) { if (hardware) return SetHardwareBreakpoint(addr, size); else return SetSoftwareBreakpoint(addr, size); } Status NativeProcessLinux::RemoveBreakpoint(lldb::addr_t addr, bool hardware) { if (hardware) return RemoveHardwareBreakpoint(addr); else return NativeProcessProtocol::RemoveBreakpoint(addr); } llvm::Expected> NativeProcessLinux::GetSoftwareBreakpointTrapOpcode(size_t size_hint) { // The ARM reference recommends the use of 0xe7fddefe and 0xdefe but the // linux kernel does otherwise. static const uint8_t g_arm_opcode[] = {0xf0, 0x01, 0xf0, 0xe7}; static const uint8_t g_thumb_opcode[] = {0x01, 0xde}; switch (GetArchitecture().GetMachine()) { case llvm::Triple::arm: switch (size_hint) { case 2: return llvm::ArrayRef(g_thumb_opcode); case 4: return llvm::ArrayRef(g_arm_opcode); default: return llvm::createStringError(llvm::inconvertibleErrorCode(), "Unrecognised trap opcode size hint!"); } default: return NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode(size_hint); } } Status NativeProcessLinux::ReadMemory(lldb::addr_t addr, void *buf, size_t size, size_t &bytes_read) { Log *log = GetLog(POSIXLog::Memory); LLDB_LOG(log, "addr = {0}, buf = {1}, size = {2}", addr, buf, size); bytes_read = 0; if (ProcessVmReadvSupported()) { // The process_vm_readv path is about 50 times faster than ptrace api. We // want to use this syscall if it is supported. struct iovec local_iov, remote_iov; local_iov.iov_base = buf; local_iov.iov_len = size; remote_iov.iov_base = reinterpret_cast(addr); remote_iov.iov_len = size; ssize_t read_result = process_vm_readv(GetCurrentThreadID(), &local_iov, 1, &remote_iov, 1, 0); int error = 0; if (read_result < 0) error = errno; else bytes_read = read_result; LLDB_LOG(log, "process_vm_readv({0}, [iovec({1}, {2})], [iovec({3:x}, {2})], 1, " "0) => {4} ({5})", GetCurrentThreadID(), buf, size, addr, read_result, error > 0 ? llvm::sys::StrError(errno) : "sucesss"); } unsigned char *dst = static_cast(buf); size_t remainder; long data; for (; bytes_read < size; bytes_read += remainder) { Status error = NativeProcessLinux::PtraceWrapper( PTRACE_PEEKDATA, GetCurrentThreadID(), reinterpret_cast(addr + bytes_read), nullptr, 0, &data); if (error.Fail()) return error; remainder = size - bytes_read; remainder = remainder > k_ptrace_word_size ? k_ptrace_word_size : remainder; // Copy the data into our buffer memcpy(dst + bytes_read, &data, remainder); } return Status(); } Status NativeProcessLinux::WriteMemory(lldb::addr_t addr, const void *buf, size_t size, size_t &bytes_written) { const unsigned char *src = static_cast(buf); size_t remainder; Status error; Log *log = GetLog(POSIXLog::Memory); LLDB_LOG(log, "addr = {0}, buf = {1}, size = {2}", addr, buf, size); for (bytes_written = 0; bytes_written < size; bytes_written += remainder) { remainder = size - bytes_written; remainder = remainder > k_ptrace_word_size ? k_ptrace_word_size : remainder; if (remainder == k_ptrace_word_size) { unsigned long data = 0; memcpy(&data, src, k_ptrace_word_size); LLDB_LOG(log, "[{0:x}]:{1:x}", addr, data); error = NativeProcessLinux::PtraceWrapper( PTRACE_POKEDATA, GetCurrentThreadID(), (void *)addr, (void *)data); if (error.Fail()) return error; } else { unsigned char buff[8]; size_t bytes_read; error = ReadMemory(addr, buff, k_ptrace_word_size, bytes_read); if (error.Fail()) return error; memcpy(buff, src, remainder); size_t bytes_written_rec; error = WriteMemory(addr, buff, k_ptrace_word_size, bytes_written_rec); if (error.Fail()) return error; LLDB_LOG(log, "[{0:x}]:{1:x} ({2:x})", addr, *(const unsigned long *)src, *(unsigned long *)buff); } addr += k_ptrace_word_size; src += k_ptrace_word_size; } return error; } Status NativeProcessLinux::GetSignalInfo(lldb::tid_t tid, void *siginfo) const { return PtraceWrapper(PTRACE_GETSIGINFO, tid, nullptr, siginfo); } Status NativeProcessLinux::GetEventMessage(lldb::tid_t tid, unsigned long *message) { return PtraceWrapper(PTRACE_GETEVENTMSG, tid, nullptr, message); } Status NativeProcessLinux::Detach(lldb::tid_t tid) { if (tid == LLDB_INVALID_THREAD_ID) return Status(); return PtraceWrapper(PTRACE_DETACH, tid); } bool NativeProcessLinux::HasThreadNoLock(lldb::tid_t thread_id) { for (const auto &thread : m_threads) { assert(thread && "thread list should not contain NULL threads"); if (thread->GetID() == thread_id) { // We have this thread. return true; } } // We don't have this thread. return false; } void NativeProcessLinux::StopTrackingThread(NativeThreadLinux &thread) { Log *const log = GetLog(POSIXLog::Thread); lldb::tid_t thread_id = thread.GetID(); LLDB_LOG(log, "tid: {0}", thread_id); auto it = llvm::find_if(m_threads, [&](const auto &thread_up) { return thread_up.get() == &thread; }); assert(it != m_threads.end()); m_threads.erase(it); NotifyTracersOfThreadDestroyed(thread_id); SignalIfAllThreadsStopped(); } void NativeProcessLinux::NotifyTracersProcessDidStop() { m_intel_pt_collector.ProcessDidStop(); } void NativeProcessLinux::NotifyTracersProcessWillResume() { m_intel_pt_collector.ProcessWillResume(); } Status NativeProcessLinux::NotifyTracersOfNewThread(lldb::tid_t tid) { Log *log = GetLog(POSIXLog::Thread); Status error = Status::FromError(m_intel_pt_collector.OnThreadCreated(tid)); if (error.Fail()) LLDB_LOG(log, "Failed to trace a new thread with intel-pt, tid = {0}. {1}", tid, error.AsCString()); return error; } Status NativeProcessLinux::NotifyTracersOfThreadDestroyed(lldb::tid_t tid) { Log *log = GetLog(POSIXLog::Thread); Status error = Status::FromError(m_intel_pt_collector.OnThreadDestroyed(tid)); if (error.Fail()) LLDB_LOG(log, "Failed to stop a destroyed thread with intel-pt, tid = {0}. {1}", tid, error.AsCString()); return error; } NativeThreadLinux &NativeProcessLinux::AddThread(lldb::tid_t thread_id, bool resume) { Log *log = GetLog(POSIXLog::Thread); LLDB_LOG(log, "pid {0} adding thread with tid {1}", GetID(), thread_id); assert(!HasThreadNoLock(thread_id) && "attempted to add a thread by id that already exists"); // If this is the first thread, save it as the current thread if (m_threads.empty()) SetCurrentThreadID(thread_id); m_threads.push_back(std::make_unique(*this, thread_id)); NativeThreadLinux &thread = static_cast(*m_threads.back()); Status tracing_error = NotifyTracersOfNewThread(thread.GetID()); if (tracing_error.Fail()) { thread.SetStoppedByProcessorTrace(tracing_error.AsCString()); StopRunningThreads(thread.GetID()); } else if (resume) ResumeThread(thread, eStateRunning, LLDB_INVALID_SIGNAL_NUMBER); else thread.SetStoppedBySignal(SIGSTOP); return thread; } Status NativeProcessLinux::GetLoadedModuleFileSpec(const char *module_path, FileSpec &file_spec) { Status error = PopulateMemoryRegionCache(); if (error.Fail()) return error; FileSpec module_file_spec(module_path); FileSystem::Instance().Resolve(module_file_spec); file_spec.Clear(); for (const auto &it : m_mem_region_cache) { if (it.second.GetFilename() == module_file_spec.GetFilename()) { file_spec = it.second; return Status(); } } return Status::FromErrorStringWithFormat( "Module file (%s) not found in /proc/%" PRIu64 "/maps file!", module_file_spec.GetFilename().AsCString(), GetID()); } Status NativeProcessLinux::GetFileLoadAddress(const llvm::StringRef &file_name, lldb::addr_t &load_addr) { load_addr = LLDB_INVALID_ADDRESS; Status error = PopulateMemoryRegionCache(); if (error.Fail()) return error; FileSpec file(file_name); for (const auto &it : m_mem_region_cache) { if (it.second == file) { load_addr = it.first.GetRange().GetRangeBase(); return Status(); } } return Status::FromErrorString("No load address found for specified file."); } NativeThreadLinux *NativeProcessLinux::GetThreadByID(lldb::tid_t tid) { return static_cast( NativeProcessProtocol::GetThreadByID(tid)); } NativeThreadLinux *NativeProcessLinux::GetCurrentThread() { return static_cast( NativeProcessProtocol::GetCurrentThread()); } Status NativeProcessLinux::ResumeThread(NativeThreadLinux &thread, lldb::StateType state, int signo) { Log *const log = GetLog(POSIXLog::Thread); LLDB_LOG(log, "tid: {0}", thread.GetID()); // Before we do the resume below, first check if we have a pending stop // notification that is currently waiting for all threads to stop. This is // potentially a buggy situation since we're ostensibly waiting for threads // to stop before we send out the pending notification, and here we are // resuming one before we send out the pending stop notification. if (m_pending_notification_tid != LLDB_INVALID_THREAD_ID) { LLDB_LOG(log, "about to resume tid {0} per explicit request but we have a " "pending stop notification (tid {1}) that is actively " "waiting for this thread to stop. Valid sequence of events?", thread.GetID(), m_pending_notification_tid); } // Request a resume. We expect this to be synchronous and the system to // reflect it is running after this completes. switch (state) { case eStateRunning: { Status resume_result = thread.Resume(signo); if (resume_result.Success()) SetState(eStateRunning, true); return resume_result; } case eStateStepping: { Status step_result = thread.SingleStep(signo); if (step_result.Success()) SetState(eStateRunning, true); return step_result; } default: LLDB_LOG(log, "Unhandled state {0}.", state); llvm_unreachable("Unhandled state for resume"); } } //===----------------------------------------------------------------------===// void NativeProcessLinux::StopRunningThreads(const lldb::tid_t triggering_tid) { Log *const log = GetLog(POSIXLog::Thread); LLDB_LOG(log, "about to process event: (triggering_tid: {0})", triggering_tid); m_pending_notification_tid = triggering_tid; // Request a stop for all the thread stops that need to be stopped and are // not already known to be stopped. for (const auto &thread : m_threads) { if (StateIsRunningState(thread->GetState())) static_cast(thread.get())->RequestStop(); } SignalIfAllThreadsStopped(); LLDB_LOG(log, "event processing done"); } void NativeProcessLinux::SignalIfAllThreadsStopped() { if (m_pending_notification_tid == LLDB_INVALID_THREAD_ID) return; // No pending notification. Nothing to do. for (const auto &thread_sp : m_threads) { if (StateIsRunningState(thread_sp->GetState())) return; // Some threads are still running. Don't signal yet. } // We have a pending notification and all threads have stopped. Log *log = GetLog(LLDBLog::Process | LLDBLog::Breakpoints); // Clear any temporary breakpoints we used to implement software single // stepping. for (const auto &thread_info : m_threads_stepping_with_breakpoint) { Status error = RemoveBreakpoint(thread_info.second); if (error.Fail()) LLDB_LOG(log, "pid = {0} remove stepping breakpoint: {1}", thread_info.first, error); } m_threads_stepping_with_breakpoint.clear(); // Notify the delegate about the stop SetCurrentThreadID(m_pending_notification_tid); SetState(StateType::eStateStopped, true); m_pending_notification_tid = LLDB_INVALID_THREAD_ID; } void NativeProcessLinux::ThreadWasCreated(NativeThreadLinux &thread) { Log *const log = GetLog(POSIXLog::Thread); LLDB_LOG(log, "tid: {0}", thread.GetID()); if (m_pending_notification_tid != LLDB_INVALID_THREAD_ID && StateIsRunningState(thread.GetState())) { // We will need to wait for this new thread to stop as well before firing // the notification. thread.RequestStop(); } } // Wrapper for ptrace to catch errors and log calls. Note that ptrace sets // errno on error because -1 can be a valid result (i.e. for PTRACE_PEEK*) Status NativeProcessLinux::PtraceWrapper(int req, lldb::pid_t pid, void *addr, void *data, size_t data_size, long *result) { Status error; long int ret; Log *log = GetLog(POSIXLog::Ptrace); PtraceDisplayBytes(req, data, data_size); errno = 0; if (req == PTRACE_GETREGSET || req == PTRACE_SETREGSET) ret = ptrace(static_cast<__ptrace_request>(req), static_cast<::pid_t>(pid), *(unsigned int *)addr, data); else ret = ptrace(static_cast<__ptrace_request>(req), static_cast<::pid_t>(pid), addr, data); if (ret == -1) error = Status::FromErrno(); if (result) *result = ret; LLDB_LOG(log, "ptrace({0}, {1}, {2}, {3}, {4})={5:x}", req, pid, addr, data, data_size, ret); PtraceDisplayBytes(req, data, data_size); if (error.Fail()) LLDB_LOG(log, "ptrace() failed: {0}", error); return error; } llvm::Expected NativeProcessLinux::TraceSupported() { if (IntelPTCollector::IsSupported()) return TraceSupportedResponse{"intel-pt", "Intel Processor Trace"}; return NativeProcessProtocol::TraceSupported(); } Error NativeProcessLinux::TraceStart(StringRef json_request, StringRef type) { if (type == "intel-pt") { if (Expected request = json::parse(json_request, "TraceIntelPTStartRequest")) { return m_intel_pt_collector.TraceStart(*request); } else return request.takeError(); } return NativeProcessProtocol::TraceStart(json_request, type); } Error NativeProcessLinux::TraceStop(const TraceStopRequest &request) { if (request.type == "intel-pt") return m_intel_pt_collector.TraceStop(request); return NativeProcessProtocol::TraceStop(request); } Expected NativeProcessLinux::TraceGetState(StringRef type) { if (type == "intel-pt") return m_intel_pt_collector.GetState(); return NativeProcessProtocol::TraceGetState(type); } Expected> NativeProcessLinux::TraceGetBinaryData( const TraceGetBinaryDataRequest &request) { if (request.type == "intel-pt") return m_intel_pt_collector.GetBinaryData(request); return NativeProcessProtocol::TraceGetBinaryData(request); }