llvm-project/lldb/source/Host/common/NativeProcessProtocol.cpp

//===-- NativeProcessProtocol.cpp -------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/Host/common/NativeProcessProtocol.h"

#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/State.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/common/NativeRegisterContext.h"
#include "lldb/Host/common/NativeThreadProtocol.h"
#include "lldb/Host/common/SoftwareBreakpoint.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/Process.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/lldb-enumerations.h"

using namespace lldb;
using namespace lldb_private;

// -----------------------------------------------------------------------------
// NativeProcessProtocol Members
// -----------------------------------------------------------------------------

NativeProcessProtocol::NativeProcessProtocol(lldb::pid_t pid)
    : m_pid(pid), m_threads(), m_current_thread_id(LLDB_INVALID_THREAD_ID),
      m_threads_mutex(), m_state(lldb::eStateInvalid), m_state_mutex(),
      m_exit_type(eExitTypeInvalid), m_exit_status(0), m_exit_description(),
      m_delegates_mutex(), m_delegates(), m_breakpoint_list(),
      m_watchpoint_list(), m_terminal_fd(-1), m_stop_id(0) {}

lldb_private::Error NativeProcessProtocol::Interrupt() {
  Error error;
#if !defined(SIGSTOP)
  error.SetErrorString("local host does not support signaling");
  return error;
#else
  return Signal(SIGSTOP);
#endif
}

lldb_private::Error
NativeProcessProtocol::GetMemoryRegionInfo(lldb::addr_t load_addr,
                                           MemoryRegionInfo &range_info) {
  // Default: not implemented.
  return Error("not implemented");
}

bool NativeProcessProtocol::GetExitStatus(ExitType *exit_type, int *status,
                                          std::string &exit_description) {
  if (m_state == lldb::eStateExited) {
    *exit_type = m_exit_type;
    *status = m_exit_status;
    exit_description = m_exit_description;
    return true;
  }

  *status = 0;
  return false;
}

bool NativeProcessProtocol::SetExitStatus(ExitType exit_type, int status,
                                          const char *exit_description,
                                          bool bNotifyStateChange) {
  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
  if (log)
    log->Printf("NativeProcessProtocol::%s(%d, %d, %s, %s) called",
                __FUNCTION__, exit_type, status,
                exit_description ? exit_description : "nullptr",
                bNotifyStateChange ? "true" : "false");

  // Exit status already set
  if (m_state == lldb::eStateExited) {
    if (log)
      log->Printf("NativeProcessProtocol::%s exit status already set to %d, "
                  "ignoring new set to %d",
                  __FUNCTION__, m_exit_status, status);
    return false;
  }

  m_state = lldb::eStateExited;

  m_exit_type = exit_type;
  m_exit_status = status;
  if (exit_description && exit_description[0])
    m_exit_description = exit_description;
  else
    m_exit_description.clear();

  if (bNotifyStateChange)
    SynchronouslyNotifyProcessStateChanged(lldb::eStateExited);

  return true;
}

NativeThreadProtocolSP NativeProcessProtocol::GetThreadAtIndex(uint32_t idx) {
  std::lock_guard<std::recursive_mutex> guard(m_threads_mutex);
  if (idx < m_threads.size())
    return m_threads[idx];
  return NativeThreadProtocolSP();
}

NativeThreadProtocolSP
NativeProcessProtocol::GetThreadByIDUnlocked(lldb::tid_t tid) {
  for (auto thread_sp : m_threads) {
    if (thread_sp->GetID() == tid)
      return thread_sp;
  }
  return NativeThreadProtocolSP();
}

NativeThreadProtocolSP NativeProcessProtocol::GetThreadByID(lldb::tid_t tid) {
  std::lock_guard<std::recursive_mutex> guard(m_threads_mutex);
  return GetThreadByIDUnlocked(tid);
}

bool NativeProcessProtocol::IsAlive() const {
  return m_state != eStateDetached && m_state != eStateExited &&
         m_state != eStateInvalid && m_state != eStateUnloaded;
}

bool NativeProcessProtocol::GetByteOrder(lldb::ByteOrder &byte_order) const {
  ArchSpec process_arch;
  if (!GetArchitecture(process_arch))
    return false;
  byte_order = process_arch.GetByteOrder();
  return true;
}

const NativeWatchpointList::WatchpointMap &
NativeProcessProtocol::GetWatchpointMap() const {
  return m_watchpoint_list.GetWatchpointMap();
}

uint32_t NativeProcessProtocol::GetMaxWatchpoints() const {
  // This default implementation will return the number of
  // *hardware* breakpoints available.  MacOSX and other OS
  // implementations that support software breakpoints will want to
  // override this correctly for their implementation.
  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));

  // get any thread
  NativeThreadProtocolSP thread_sp(
      const_cast<NativeProcessProtocol *>(this)->GetThreadAtIndex(0));
  if (!thread_sp) {
    if (log)
      log->Warning("NativeProcessProtocol::%s (): failed to find a thread to "
                   "grab a NativeRegisterContext!",
                   __FUNCTION__);
    return 0;
  }

  NativeRegisterContextSP reg_ctx_sp(thread_sp->GetRegisterContext());
  if (!reg_ctx_sp) {
    if (log)
      log->Warning("NativeProcessProtocol::%s (): failed to get a "
                   "RegisterContextNativeProcess from the first thread!",
                   __FUNCTION__);
    return 0;
  }

  return reg_ctx_sp->NumSupportedHardwareWatchpoints();
}

Error NativeProcessProtocol::SetWatchpoint(lldb::addr_t addr, size_t size,
                                           uint32_t watch_flags,
                                           bool hardware) {
  // This default implementation assumes setting the watchpoint for
  // the process will require setting the watchpoint for each of the
  // threads.  Furthermore, it will track watchpoints set for the
  // process and will add them to each thread that is attached to
  // via the (FIXME implement) OnThreadAttached () method.

  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));

  // Update the thread list
  UpdateThreads();

  // Keep track of the threads we successfully set the watchpoint
  // for.  If one of the thread watchpoint setting operations fails,
  // back off and remove the watchpoint for all the threads that
  // were successfully set so we get back to a consistent state.
  std::vector<NativeThreadProtocolSP> watchpoint_established_threads;

  // Tell each thread to set a watchpoint.  In the event that
  // hardware watchpoints are requested but the SetWatchpoint fails,
  // try to set a software watchpoint as a fallback.  It's
  // conceivable that if there are more threads than hardware
  // watchpoints available, some of the threads will fail to set
  // hardware watchpoints while software ones may be available.
  std::lock_guard<std::recursive_mutex> guard(m_threads_mutex);
  for (auto thread_sp : m_threads) {
    assert(thread_sp && "thread list should not have a NULL thread!");
    if (!thread_sp)
      continue;

    Error thread_error =
        thread_sp->SetWatchpoint(addr, size, watch_flags, hardware);
    if (thread_error.Fail() && hardware) {
      // Try software watchpoints since we failed on hardware watchpoint setting
      // and we may have just run out of hardware watchpoints.
      thread_error = thread_sp->SetWatchpoint(addr, size, watch_flags, false);
      if (thread_error.Success()) {
        if (log)
          log->Warning(
              "hardware watchpoint requested but software watchpoint set");
      }
    }

    if (thread_error.Success()) {
      // Remember that we set this watchpoint successfully in
      // case we need to clear it later.
      watchpoint_established_threads.push_back(thread_sp);
    } else {
      // Unset the watchpoint for each thread we successfully
      // set so that we get back to a consistent state of "not
      // set" for the watchpoint.
      for (auto unwatch_thread_sp : watchpoint_established_threads) {
        Error remove_error = unwatch_thread_sp->RemoveWatchpoint(addr);
        if (remove_error.Fail() && log) {
          log->Warning("NativeProcessProtocol::%s (): RemoveWatchpoint failed "
                       "for pid=%" PRIu64 ", tid=%" PRIu64 ": %s",
                       __FUNCTION__, GetID(), unwatch_thread_sp->GetID(),
                       remove_error.AsCString());
        }
      }

      return thread_error;
    }
  }
  return m_watchpoint_list.Add(addr, size, watch_flags, hardware);
}

Error NativeProcessProtocol::RemoveWatchpoint(lldb::addr_t addr) {
  // Update the thread list
  UpdateThreads();

  Error overall_error;

  std::lock_guard<std::recursive_mutex> guard(m_threads_mutex);
  for (auto thread_sp : m_threads) {
    assert(thread_sp && "thread list should not have a NULL thread!");
    if (!thread_sp)
      continue;

    const Error thread_error = thread_sp->RemoveWatchpoint(addr);
    if (thread_error.Fail()) {
      // Keep track of the first thread error if any threads
      // fail. We want to try to remove the watchpoint from
      // every thread, though, even if one or more have errors.
      if (!overall_error.Fail())
        overall_error = thread_error;
    }
  }
  const Error error = m_watchpoint_list.Remove(addr);
  return overall_error.Fail() ? overall_error : error;
}

bool NativeProcessProtocol::RegisterNativeDelegate(
    NativeDelegate &native_delegate) {
  std::lock_guard<std::recursive_mutex> guard(m_delegates_mutex);
  if (std::find(m_delegates.begin(), m_delegates.end(), &native_delegate) !=
      m_delegates.end())
    return false;

  m_delegates.push_back(&native_delegate);
  native_delegate.InitializeDelegate(this);
  return true;
}

bool NativeProcessProtocol::UnregisterNativeDelegate(
    NativeDelegate &native_delegate) {
  std::lock_guard<std::recursive_mutex> guard(m_delegates_mutex);

  const auto initial_size = m_delegates.size();
  m_delegates.erase(
      remove(m_delegates.begin(), m_delegates.end(), &native_delegate),
      m_delegates.end());

  // We removed the delegate if the count of delegates shrank after
  // removing all copies of the given native_delegate from the vector.
  return m_delegates.size() < initial_size;
}

void NativeProcessProtocol::SynchronouslyNotifyProcessStateChanged(
    lldb::StateType state) {
  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));

  std::lock_guard<std::recursive_mutex> guard(m_delegates_mutex);
  for (auto native_delegate : m_delegates)
    native_delegate->ProcessStateChanged(this, state);

  if (log) {
    if (!m_delegates.empty()) {
      log->Printf("NativeProcessProtocol::%s: sent state notification [%s] "
                  "from process %" PRIu64,
                  __FUNCTION__, lldb_private::StateAsCString(state), GetID());
    } else {
      log->Printf("NativeProcessProtocol::%s: would send state notification "
                  "[%s] from process %" PRIu64 ", but no delegates",
                  __FUNCTION__, lldb_private::StateAsCString(state), GetID());
    }
  }
}

void NativeProcessProtocol::NotifyDidExec() {
  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
  if (log)
    log->Printf("NativeProcessProtocol::%s - preparing to call delegates",
                __FUNCTION__);

  {
    std::lock_guard<std::recursive_mutex> guard(m_delegates_mutex);
    for (auto native_delegate : m_delegates)
      native_delegate->DidExec(this);
  }
}

Error NativeProcessProtocol::SetSoftwareBreakpoint(lldb::addr_t addr,
                                                   uint32_t size_hint) {
  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_BREAKPOINTS));
  if (log)
    log->Printf("NativeProcessProtocol::%s addr = 0x%" PRIx64, __FUNCTION__,
                addr);

  return m_breakpoint_list.AddRef(
      addr, size_hint, false,
      [this](lldb::addr_t addr, size_t size_hint, bool /* hardware */,
             NativeBreakpointSP &breakpoint_sp) -> Error {
        return SoftwareBreakpoint::CreateSoftwareBreakpoint(
            *this, addr, size_hint, breakpoint_sp);
      });
}

Error NativeProcessProtocol::RemoveBreakpoint(lldb::addr_t addr) {
  return m_breakpoint_list.DecRef(addr);
}

Error NativeProcessProtocol::EnableBreakpoint(lldb::addr_t addr) {
  return m_breakpoint_list.EnableBreakpoint(addr);
}

Error NativeProcessProtocol::DisableBreakpoint(lldb::addr_t addr) {
  return m_breakpoint_list.DisableBreakpoint(addr);
}

lldb::StateType NativeProcessProtocol::GetState() const {
  std::lock_guard<std::recursive_mutex> guard(m_state_mutex);
  return m_state;
}

void NativeProcessProtocol::SetState(lldb::StateType state,
                                     bool notify_delegates) {
  std::lock_guard<std::recursive_mutex> guard(m_state_mutex);

  if (state == m_state)
    return;

  m_state = state;

  if (StateIsStoppedState(state, false)) {
    ++m_stop_id;

    // Give process a chance to do any stop id bump processing, such as
    // clearing cached data that is invalidated each time the process runs.
    // Note if/when we support some threads running, we'll end up needing
    // to manage this per thread and per process.
    DoStopIDBumped(m_stop_id);
  }

  // Optionally notify delegates of the state change.
  if (notify_delegates)
    SynchronouslyNotifyProcessStateChanged(state);
}

uint32_t NativeProcessProtocol::GetStopID() const {
  std::lock_guard<std::recursive_mutex> guard(m_state_mutex);
  return m_stop_id;
}

void NativeProcessProtocol::DoStopIDBumped(uint32_t /* newBumpId */) {
  // Default implementation does nothing.
}

Error NativeProcessProtocol::ResolveProcessArchitecture(lldb::pid_t pid,
                                                        ArchSpec &arch) {
  // Grab process info for the running process.
  ProcessInstanceInfo process_info;
  if (!Host::GetProcessInfo(pid, process_info))
    return Error("failed to get process info");

  // Resolve the executable module.
  ModuleSpecList module_specs;
  if (!ObjectFile::GetModuleSpecifications(process_info.GetExecutableFile(), 0,
                                           0, module_specs))
    return Error("failed to get module specifications");
  lldbassert(module_specs.GetSize() == 1);

  arch = module_specs.GetModuleSpecRefAtIndex(0).GetArchitecture();
  if (arch.IsValid())
    return Error();
  else
    return Error("failed to retrieve a valid architecture from the exe module");
}

#ifndef __linux__
// These need to be implemented to support lldb-gdb-server on a given platform.
// Stubs are
// provided to make the rest of the code link on non-supported platforms.

Error NativeProcessProtocol::Launch(ProcessLaunchInfo &launch_info,
                                    NativeDelegate &native_delegate,
                                    MainLoop &mainloop,
                                    NativeProcessProtocolSP &process_sp) {
  llvm_unreachable("Platform has no NativeProcessProtocol support");
}

Error NativeProcessProtocol::Attach(lldb::pid_t pid,
                                    NativeDelegate &native_delegate,
                                    MainLoop &mainloop,
                                    NativeProcessProtocolSP &process_sp) {
  llvm_unreachable("Platform has no NativeProcessProtocol support");
}

#endif