예제 #1
0
파일: Host.cpp 프로젝트: JuliaLang/lldb
Error
Host::LaunchProcessPosixSpawn(const char *exe_path, const ProcessLaunchInfo &launch_info, lldb::pid_t &pid)
{
    Error error;
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_HOST | LIBLLDB_LOG_PROCESS));

    posix_spawnattr_t attr;
    error.SetError( ::posix_spawnattr_init (&attr), eErrorTypePOSIX);

    if (error.Fail() || log)
        error.PutToLog(log, "::posix_spawnattr_init ( &attr )");
    if (error.Fail())
        return error;

    // Make a quick class that will cleanup the posix spawn attributes in case
    // we return in the middle of this function.
    lldb_utility::CleanUp <posix_spawnattr_t *, int> posix_spawnattr_cleanup(&attr, posix_spawnattr_destroy);

    sigset_t no_signals;
    sigset_t all_signals;
    sigemptyset (&no_signals);
    sigfillset (&all_signals);
    ::posix_spawnattr_setsigmask(&attr, &no_signals);
#if defined (__linux__)  || defined (__FreeBSD__)
    ::posix_spawnattr_setsigdefault(&attr, &no_signals);
#else
    ::posix_spawnattr_setsigdefault(&attr, &all_signals);
#endif

    short flags = GetPosixspawnFlags(launch_info);

    error.SetError( ::posix_spawnattr_setflags (&attr, flags), eErrorTypePOSIX);
    if (error.Fail() || log)
        error.PutToLog(log, "::posix_spawnattr_setflags ( &attr, flags=0x%8.8x )", flags);
    if (error.Fail())
        return error;

    // posix_spawnattr_setbinpref_np appears to be an Apple extension per:
    // http://www.unix.com/man-page/OSX/3/posix_spawnattr_setbinpref_np/
#if defined (__APPLE__) && !defined (__arm__)
    
    // Don't set the binpref if a shell was provided.  After all, that's only going to affect what version of the shell
    // is launched, not what fork of the binary is launched.  We insert "arch --arch <ARCH> as part of the shell invocation
    // to do that job on OSX.
    
    if (launch_info.GetShell() == nullptr)
    {
        // We don't need to do this for ARM, and we really shouldn't now that we
        // have multiple CPU subtypes and no posix_spawnattr call that allows us
        // to set which CPU subtype to launch...
        const ArchSpec &arch_spec = launch_info.GetArchitecture();
        cpu_type_t cpu = arch_spec.GetMachOCPUType();
        cpu_type_t sub = arch_spec.GetMachOCPUSubType();
        if (cpu != 0 &&
            cpu != static_cast<cpu_type_t>(UINT32_MAX) &&
            cpu != static_cast<cpu_type_t>(LLDB_INVALID_CPUTYPE) &&
            !(cpu == 0x01000007 && sub == 8)) // If haswell is specified, don't try to set the CPU type or we will fail 
        {
            size_t ocount = 0;
            error.SetError( ::posix_spawnattr_setbinpref_np (&attr, 1, &cpu, &ocount), eErrorTypePOSIX);
            if (error.Fail() || log)
                error.PutToLog(log, "::posix_spawnattr_setbinpref_np ( &attr, 1, cpu_type = 0x%8.8x, count => %llu )", cpu, (uint64_t)ocount);

            if (error.Fail() || ocount != 1)
                return error;
        }
    }

#endif

    const char *tmp_argv[2];
    char * const *argv = (char * const*)launch_info.GetArguments().GetConstArgumentVector();
    char * const *envp = (char * const*)launch_info.GetEnvironmentEntries().GetConstArgumentVector();
    if (argv == NULL)
    {
        // posix_spawn gets very unhappy if it doesn't have at least the program
        // name in argv[0]. One of the side affects I have noticed is the environment
        // variables don't make it into the child process if "argv == NULL"!!!
        tmp_argv[0] = exe_path;
        tmp_argv[1] = NULL;
        argv = (char * const*)tmp_argv;
    }

#if !defined (__APPLE__)
    // manage the working directory
    char current_dir[PATH_MAX];
    current_dir[0] = '\0';
#endif

    FileSpec working_dir{launch_info.GetWorkingDirectory()};
    if (working_dir)
    {
#if defined (__APPLE__)
        // Set the working directory on this thread only
        if (__pthread_chdir(working_dir.GetCString()) < 0) {
            if (errno == ENOENT) {
                error.SetErrorStringWithFormat("No such file or directory: %s",
                        working_dir.GetCString());
            } else if (errno == ENOTDIR) {
                error.SetErrorStringWithFormat("Path doesn't name a directory: %s",
                        working_dir.GetCString());
            } else {
                error.SetErrorStringWithFormat("An unknown error occurred when changing directory for process execution.");
            }
            return error;
        }
#else
        if (::getcwd(current_dir, sizeof(current_dir)) == NULL)
        {
            error.SetError(errno, eErrorTypePOSIX);
            error.LogIfError(log, "unable to save the current directory");
            return error;
        }

        if (::chdir(working_dir.GetCString()) == -1)
        {
            error.SetError(errno, eErrorTypePOSIX);
            error.LogIfError(log, "unable to change working directory to %s",
                    working_dir.GetCString());
            return error;
        }
#endif
    }

    ::pid_t result_pid = LLDB_INVALID_PROCESS_ID;
    const size_t num_file_actions = launch_info.GetNumFileActions ();
    if (num_file_actions > 0)
    {
        posix_spawn_file_actions_t file_actions;
        error.SetError( ::posix_spawn_file_actions_init (&file_actions), eErrorTypePOSIX);
        if (error.Fail() || log)
            error.PutToLog(log, "::posix_spawn_file_actions_init ( &file_actions )");
        if (error.Fail())
            return error;

        // Make a quick class that will cleanup the posix spawn attributes in case
        // we return in the middle of this function.
        lldb_utility::CleanUp <posix_spawn_file_actions_t *, int> posix_spawn_file_actions_cleanup (&file_actions, posix_spawn_file_actions_destroy);

        for (size_t i=0; i<num_file_actions; ++i)
        {
            const FileAction *launch_file_action = launch_info.GetFileActionAtIndex(i);
            if (launch_file_action)
            {
                if (!AddPosixSpawnFileAction(&file_actions, launch_file_action, log, error))
                    return error;
            }
        }

        error.SetError(::posix_spawnp(&result_pid, exe_path, &file_actions, &attr, argv, envp), eErrorTypePOSIX);

        if (error.Fail() || log)
        {
            error.PutToLog(log, "::posix_spawnp ( pid => %i, path = '%s', file_actions = %p, attr = %p, argv = %p, envp = %p )", result_pid,
                           exe_path, static_cast<void *>(&file_actions), static_cast<void *>(&attr), reinterpret_cast<const void *>(argv),
                           reinterpret_cast<const void *>(envp));
            if (log)
            {
                for (int ii=0; argv[ii]; ++ii)
                    log->Printf("argv[%i] = '%s'", ii, argv[ii]);
            }
        }

    }
    else
    {
        error.SetError(::posix_spawnp(&result_pid, exe_path, NULL, &attr, argv, envp), eErrorTypePOSIX);

        if (error.Fail() || log)
        {
            error.PutToLog(log, "::posix_spawnp ( pid => %i, path = '%s', file_actions = NULL, attr = %p, argv = %p, envp = %p )",
                           result_pid, exe_path, static_cast<void *>(&attr), reinterpret_cast<const void *>(argv),
                           reinterpret_cast<const void *>(envp));
            if (log)
            {
                for (int ii=0; argv[ii]; ++ii)
                    log->Printf("argv[%i] = '%s'", ii, argv[ii]);
            }
        }
    }
    pid = result_pid;

    if (working_dir)
    {
#if defined (__APPLE__)
        // No more thread specific current working directory
        __pthread_fchdir (-1);
#else
        if (::chdir(current_dir) == -1 && error.Success())
        {
            error.SetError(errno, eErrorTypePOSIX);
            error.LogIfError(log, "unable to change current directory back to %s",
                    current_dir);
        }
#endif
    }

    return error;
}
static void LLVM_ATTRIBUTE_NORETURN ChildFunc(int error_fd,
                                              const ProcessLaunchInfo &info) {
  if (info.GetFlags().Test(eLaunchFlagLaunchInSeparateProcessGroup)) {
    if (setpgid(0, 0) != 0)
      ExitWithError(error_fd, "setpgid");
  }

  for (size_t i = 0; i < info.GetNumFileActions(); ++i) {
    const FileAction &action = *info.GetFileActionAtIndex(i);
    switch (action.GetAction()) {
    case FileAction::eFileActionClose:
      if (close(action.GetFD()) != 0)
        ExitWithError(error_fd, "close");
      break;
    case FileAction::eFileActionDuplicate:
      if (dup2(action.GetFD(), action.GetActionArgument()) == -1)
        ExitWithError(error_fd, "dup2");
      break;
    case FileAction::eFileActionOpen:
      DupDescriptor(error_fd, action.GetFileSpec(), action.GetFD(),
                    action.GetActionArgument());
      break;
    case FileAction::eFileActionNone:
      break;
    }
  }

  const char **argv = info.GetArguments().GetConstArgumentVector();

  // Change working directory
  if (info.GetWorkingDirectory() &&
      0 != ::chdir(info.GetWorkingDirectory().GetCString()))
    ExitWithError(error_fd, "chdir");

  DisableASLRIfRequested(error_fd, info);
  Environment env = info.GetEnvironment();
  FixupEnvironment(env);
  Environment::Envp envp = env.getEnvp();

  // Clear the signal mask to prevent the child from being affected by any
  // masking done by the parent.
  sigset_t set;
  if (sigemptyset(&set) != 0 ||
      pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0)
    ExitWithError(error_fd, "pthread_sigmask");

  if (info.GetFlags().Test(eLaunchFlagDebug)) {
    // Do not inherit setgid powers.
    if (setgid(getgid()) != 0)
      ExitWithError(error_fd, "setgid");

    // HACK:
    // Close everything besides stdin, stdout, and stderr that has no file
    // action to avoid leaking. Only do this when debugging, as elsewhere we
    // actually rely on passing open descriptors to child processes.
    for (int fd = 3; fd < sysconf(_SC_OPEN_MAX); ++fd)
      if (!info.GetFileActionForFD(fd) && fd != error_fd)
        close(fd);

    // Start tracing this child that is about to exec.
    if (ptrace(PT_TRACE_ME, 0, nullptr, 0) == -1)
      ExitWithError(error_fd, "ptrace");
  }

  // Execute.  We should never return...
  execve(argv[0], const_cast<char *const *>(argv), envp);

#if defined(__linux__)
  if (errno == ETXTBSY) {
    // On android M and earlier we can get this error because the adb daemon
    // can hold a write handle on the executable even after it has finished
    // uploading it. This state lasts only a short time and happens only when
    // there are many concurrent adb commands being issued, such as when
    // running the test suite. (The file remains open when someone does an "adb
    // shell" command in the fork() child before it has had a chance to exec.)
    // Since this state should clear up quickly, wait a while and then give it
    // one more go.
    usleep(50000);
    execve(argv[0], const_cast<char *const *>(argv), envp);
  }
#endif

  // ...unless exec fails.  In which case we definitely need to end the child
  // here.
  ExitWithError(error_fd, "execve");
}
Error
PlatformRemoteGDBServer::LaunchProcess (ProcessLaunchInfo &launch_info)
{
    Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_PLATFORM));
    Error error;

    if (log)
        log->Printf ("PlatformRemoteGDBServer::%s() called", __FUNCTION__);

    auto num_file_actions = launch_info.GetNumFileActions ();
    for (decltype(num_file_actions) i = 0; i < num_file_actions; ++i)
    {
        const auto file_action = launch_info.GetFileActionAtIndex (i);
        if (file_action->GetAction () != FileAction::eFileActionOpen)
            continue;
        switch(file_action->GetFD())
        {
        case STDIN_FILENO:
            m_gdb_client.SetSTDIN(file_action->GetFileSpec());
            break;
        case STDOUT_FILENO:
            m_gdb_client.SetSTDOUT(file_action->GetFileSpec());
            break;
        case STDERR_FILENO:
            m_gdb_client.SetSTDERR(file_action->GetFileSpec());
            break;
        }
    }

    m_gdb_client.SetDisableASLR (launch_info.GetFlags().Test (eLaunchFlagDisableASLR));
    m_gdb_client.SetDetachOnError (launch_info.GetFlags().Test (eLaunchFlagDetachOnError));
    
    FileSpec working_dir = launch_info.GetWorkingDirectory();
    if (working_dir)
    {
        m_gdb_client.SetWorkingDir(working_dir);
    }
    
    // Send the environment and the program + arguments after we connect
    const char **envp = launch_info.GetEnvironmentEntries().GetConstArgumentVector();

    if (envp)
    {
        const char *env_entry;
        for (int i=0; (env_entry = envp[i]); ++i)
        {
            if (m_gdb_client.SendEnvironmentPacket(env_entry) != 0)
                break;
        }
    }
    
    ArchSpec arch_spec = launch_info.GetArchitecture();
    const char *arch_triple = arch_spec.GetTriple().str().c_str();
    
    m_gdb_client.SendLaunchArchPacket(arch_triple);
    if (log)
        log->Printf ("PlatformRemoteGDBServer::%s() set launch architecture triple to '%s'", __FUNCTION__, arch_triple ? arch_triple : "<NULL>");

    int arg_packet_err;
    {
        // Scope for the scoped timeout object
        process_gdb_remote::GDBRemoteCommunication::ScopedTimeout timeout(m_gdb_client, 5);
        arg_packet_err = m_gdb_client.SendArgumentsPacket (launch_info);
    }

    if (arg_packet_err == 0)
    {
        std::string error_str;
        if (m_gdb_client.GetLaunchSuccess (error_str))
        {
            const auto pid = m_gdb_client.GetCurrentProcessID (false);
            if (pid != LLDB_INVALID_PROCESS_ID)
            {
                launch_info.SetProcessID (pid);
                if (log)
                    log->Printf ("PlatformRemoteGDBServer::%s() pid %" PRIu64 " launched successfully", __FUNCTION__, pid);
            }
            else
            {
                if (log)
                    log->Printf ("PlatformRemoteGDBServer::%s() launch succeeded but we didn't get a valid process id back!", __FUNCTION__);
                error.SetErrorString ("failed to get PID");
            }
        }
        else
        {
            error.SetErrorString (error_str.c_str());
            if (log)
                log->Printf ("PlatformRemoteGDBServer::%s() launch failed: %s", __FUNCTION__, error.AsCString ());
        }
    }
    else
    {
        error.SetErrorStringWithFormat("'A' packet returned an error: %i", arg_packet_err);
    }
    return error;
}
// For local debugging, Linux will override the debug logic to use llgs-launch rather than
// lldb-launch, llgs-attach.  This differs from current lldb-launch, debugserver-attach
// approach on MacOSX.
lldb::ProcessSP
PlatformLinux::DebugProcess (ProcessLaunchInfo &launch_info,
                             Debugger &debugger,
                             Target *target,       // Can be NULL, if NULL create a new target, else use existing one
                             Error &error)
{
    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_PLATFORM));
    if (log)
        log->Printf ("PlatformLinux::%s entered (target %p)", __FUNCTION__, static_cast<void*>(target));

    // If we're a remote host, use standard behavior from parent class.
    if (!IsHost ())
        return PlatformPOSIX::DebugProcess (launch_info, debugger, target, error);

    //
    // For local debugging, we'll insist on having ProcessGDBRemote create the process.
    //

    ProcessSP process_sp;

    // Ensure we're using llgs for local debugging.
    if (!UseLlgsForLocalDebugging ())
    {
        assert (false && "we're trying to debug a local process but platform.plugin.linux.use-llgs-for-local is false, should never get here");
        error.SetErrorString ("attempted to start gdb-remote-based debugging for local process but platform.plugin.linux.use-llgs-for-local is false");
        return process_sp;
    }

    // Make sure we stop at the entry point
    launch_info.GetFlags ().Set (eLaunchFlagDebug);

    // We always launch the process we are going to debug in a separate process
    // group, since then we can handle ^C interrupts ourselves w/o having to worry
    // about the target getting them as well.
    launch_info.SetLaunchInSeparateProcessGroup(true);

    // Ensure we have a target.
    if (target == nullptr)
    {
        if (log)
            log->Printf ("PlatformLinux::%s creating new target", __FUNCTION__);

        TargetSP new_target_sp;
        error = debugger.GetTargetList().CreateTarget (debugger,
                                                       nullptr,
                                                       nullptr,
                                                       false,
                                                       nullptr,
                                                       new_target_sp);
        if (error.Fail ())
        {
            if (log)
                log->Printf ("PlatformLinux::%s failed to create new target: %s", __FUNCTION__, error.AsCString ());
            return process_sp;
        }

        target = new_target_sp.get();
        if (!target)
        {
            error.SetErrorString ("CreateTarget() returned nullptr");
            if (log)
                log->Printf ("PlatformLinux::%s failed: %s", __FUNCTION__, error.AsCString ());
            return process_sp;
        }
    }
    else
    {
        if (log)
            log->Printf ("PlatformLinux::%s using provided target", __FUNCTION__);
    }

    // Mark target as currently selected target.
    debugger.GetTargetList().SetSelectedTarget(target);

    // Now create the gdb-remote process.
    if (log)
        log->Printf ("PlatformLinux::%s having target create process with gdb-remote plugin", __FUNCTION__);
    process_sp = target->CreateProcess (launch_info.GetListenerForProcess(debugger), "gdb-remote", nullptr);

    if (!process_sp)
    {
        error.SetErrorString ("CreateProcess() failed for gdb-remote process");
        if (log)
            log->Printf ("PlatformLinux::%s failed: %s", __FUNCTION__, error.AsCString ());
        return process_sp;
    }
    else
    {
        if (log)
            log->Printf ("PlatformLinux::%s successfully created process", __FUNCTION__);
    }

    // Set the unix signals properly.
    process_sp->SetUnixSignals (Host::GetUnixSignals ());

    // Adjust launch for a hijacker.
    ListenerSP listener_sp;
    if (!launch_info.GetHijackListener ())
    {
        if (log)
            log->Printf ("PlatformLinux::%s setting up hijacker", __FUNCTION__);

        listener_sp.reset (new Listener("lldb.PlatformLinux.DebugProcess.hijack"));
        launch_info.SetHijackListener (listener_sp);
        process_sp->HijackProcessEvents (listener_sp.get ());
    }

    // Log file actions.
    if (log)
    {
        log->Printf ("PlatformLinux::%s launching process with the following file actions:", __FUNCTION__);

        StreamString stream;
        size_t i = 0;
        const FileAction *file_action;
        while ((file_action = launch_info.GetFileActionAtIndex (i++)) != nullptr)
        {
            file_action->Dump (stream);
            log->PutCString (stream.GetString().c_str ());
            stream.Clear();
        }
    }

    // Do the launch.
    error = process_sp->Launch(launch_info);
    if (error.Success ())
    {
        // Handle the hijacking of process events.
        if (listener_sp)
        {
            const StateType state = process_sp->WaitForProcessToStop (NULL, NULL, false, listener_sp.get());
            process_sp->RestoreProcessEvents();

            if (state == eStateStopped)
            {
                if (log)
                    log->Printf ("PlatformLinux::%s pid %" PRIu64 " state %s\n",
                                 __FUNCTION__, process_sp->GetID (), StateAsCString (state));
            }
            else
            {
                if (log)
                    log->Printf ("PlatformLinux::%s pid %" PRIu64 " state is not stopped - %s\n",
                                 __FUNCTION__, process_sp->GetID (), StateAsCString (state));
            }
        }

        // Hook up process PTY if we have one (which we should for local debugging with llgs).
        int pty_fd = launch_info.GetPTY().ReleaseMasterFileDescriptor();
        if (pty_fd != lldb_utility::PseudoTerminal::invalid_fd)
        {
            process_sp->SetSTDIOFileDescriptor(pty_fd);
            if (log)
                log->Printf ("PlatformLinux::%s pid %" PRIu64 " hooked up STDIO pty to process", __FUNCTION__, process_sp->GetID ());
        }
        else
        {
            if (log)
                log->Printf ("PlatformLinux::%s pid %" PRIu64 " not using process STDIO pty", __FUNCTION__, process_sp->GetID ());
        }
    }
    else
    {
        if (log)
            log->Printf ("PlatformLinux::%s process launch failed: %s", __FUNCTION__, error.AsCString ());
        // FIXME figure out appropriate cleanup here.  Do we delete the target? Do we delete the process?  Does our caller do that?
    }

    return process_sp;
}
예제 #5
0
static void LLVM_ATTRIBUTE_NORETURN ChildFunc(int error_fd,
                                              const ProcessLaunchInfo &info) {
  // First, make sure we disable all logging. If we are logging to stdout, our
  // logs can be
  // mistaken for inferior output.
  Log::DisableAllLogChannels(nullptr);

  // Do not inherit setgid powers.
  if (setgid(getgid()) != 0)
    ExitWithError(error_fd, "setgid");

  if (info.GetFlags().Test(eLaunchFlagLaunchInSeparateProcessGroup)) {
    if (setpgid(0, 0) != 0)
      ExitWithError(error_fd, "setpgid");
  }

  for (size_t i = 0; i < info.GetNumFileActions(); ++i) {
    const FileAction &action = *info.GetFileActionAtIndex(i);
    switch (action.GetAction()) {
    case FileAction::eFileActionClose:
      if (close(action.GetFD()) != 0)
        ExitWithError(error_fd, "close");
      break;
    case FileAction::eFileActionDuplicate:
      if (dup2(action.GetFD(), action.GetActionArgument()) == -1)
        ExitWithError(error_fd, "dup2");
      break;
    case FileAction::eFileActionOpen:
      DupDescriptor(error_fd, action.GetFileSpec(), action.GetFD(),
                    action.GetActionArgument());
      break;
    case FileAction::eFileActionNone:
      break;
    }
  }

  const char **argv = info.GetArguments().GetConstArgumentVector();

  // Change working directory
  if (info.GetWorkingDirectory() &&
      0 != ::chdir(info.GetWorkingDirectory().GetCString()))
    ExitWithError(error_fd, "chdir");

  // Disable ASLR if requested.
  if (info.GetFlags().Test(lldb::eLaunchFlagDisableASLR)) {
    const unsigned long personality_get_current = 0xffffffff;
    int value = personality(personality_get_current);
    if (value == -1)
      ExitWithError(error_fd, "personality get");

    value = personality(ADDR_NO_RANDOMIZE | value);
    if (value == -1)
      ExitWithError(error_fd, "personality set");
  }

  Args env = info.GetEnvironmentEntries();
  FixupEnvironment(env);
  const char **envp = env.GetConstArgumentVector();

  // Clear the signal mask to prevent the child from being affected by
  // any masking done by the parent.
  sigset_t set;
  if (sigemptyset(&set) != 0 ||
      pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0)
    ExitWithError(error_fd, "pthread_sigmask");

  if (info.GetFlags().Test(eLaunchFlagDebug)) {
    // HACK:
    // Close everything besides stdin, stdout, and stderr that has no file
    // action to avoid leaking. Only do this when debugging, as elsewhere we
    // actually rely on
    // passing open descriptors to child processes.
    for (int fd = 3; fd < sysconf(_SC_OPEN_MAX); ++fd)
      if (!info.GetFileActionForFD(fd) && fd != error_fd)
        close(fd);

    // Start tracing this child that is about to exec.
    if (ptrace(PTRACE_TRACEME, 0, nullptr, nullptr) == -1)
      ExitWithError(error_fd, "ptrace");
  }

  // Execute.  We should never return...
  execve(argv[0], const_cast<char *const *>(argv),
         const_cast<char *const *>(envp));

  if (errno == ETXTBSY) {
    // On android M and earlier we can get this error because the adb deamon can
    // hold a write
    // handle on the executable even after it has finished uploading it. This
    // state lasts
    // only a short time and happens only when there are many concurrent adb
    // commands being
    // issued, such as when running the test suite. (The file remains open when
    // someone does
    // an "adb shell" command in the fork() child before it has had a chance to
    // exec.) Since
    // this state should clear up quickly, wait a while and then give it one
    // more go.
    usleep(50000);
    execve(argv[0], const_cast<char *const *>(argv),
           const_cast<char *const *>(envp));
  }

  // ...unless exec fails.  In which case we definitely need to end the child
  // here.
  ExitWithError(error_fd, "execve");
}
예제 #6
0
// For local debugging, NetBSD will override the debug logic to use llgs-launch
// rather than lldb-launch, llgs-attach.  This differs from current lldb-
// launch, debugserver-attach approach on MacOSX.
lldb::ProcessSP
PlatformNetBSD::DebugProcess(ProcessLaunchInfo &launch_info, Debugger &debugger,
                             Target *target, // Can be NULL, if NULL create a new
                                             // target, else use existing one
                             Status &error) {
  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
  LLDB_LOG(log, "target {0}", target);

  // If we're a remote host, use standard behavior from parent class.
  if (!IsHost())
    return PlatformPOSIX::DebugProcess(launch_info, debugger, target, error);

  //
  // For local debugging, we'll insist on having ProcessGDBRemote create the
  // process.
  //

  ProcessSP process_sp;

  // Make sure we stop at the entry point
  launch_info.GetFlags().Set(eLaunchFlagDebug);

  // We always launch the process we are going to debug in a separate process
  // group, since then we can handle ^C interrupts ourselves w/o having to
  // worry about the target getting them as well.
  launch_info.SetLaunchInSeparateProcessGroup(true);

  // Ensure we have a target.
  if (target == nullptr) {
    LLDB_LOG(log, "creating new target");
    TargetSP new_target_sp;
    error = debugger.GetTargetList().CreateTarget(
        debugger, "", "", eLoadDependentsNo, nullptr, new_target_sp);
    if (error.Fail()) {
      LLDB_LOG(log, "failed to create new target: {0}", error);
      return process_sp;
    }

    target = new_target_sp.get();
    if (!target) {
      error.SetErrorString("CreateTarget() returned nullptr");
      LLDB_LOG(log, "error: {0}", error);
      return process_sp;
    }
  }

  // Mark target as currently selected target.
  debugger.GetTargetList().SetSelectedTarget(target);

  // Now create the gdb-remote process.
  LLDB_LOG(log, "having target create process with gdb-remote plugin");
  process_sp =
      target->CreateProcess(launch_info.GetListener(), "gdb-remote", nullptr);

  if (!process_sp) {
    error.SetErrorString("CreateProcess() failed for gdb-remote process");
    LLDB_LOG(log, "error: {0}", error);
    return process_sp;
  }

  LLDB_LOG(log, "successfully created process");
  // Adjust launch for a hijacker.
  ListenerSP listener_sp;
  if (!launch_info.GetHijackListener()) {
    LLDB_LOG(log, "setting up hijacker");
    listener_sp =
        Listener::MakeListener("lldb.PlatformNetBSD.DebugProcess.hijack");
    launch_info.SetHijackListener(listener_sp);
    process_sp->HijackProcessEvents(listener_sp);
  }

  // Log file actions.
  if (log) {
    LLDB_LOG(log, "launching process with the following file actions:");
    StreamString stream;
    size_t i = 0;
    const FileAction *file_action;
    while ((file_action = launch_info.GetFileActionAtIndex(i++)) != nullptr) {
      file_action->Dump(stream);
      LLDB_LOG(log, "{0}", stream.GetData());
      stream.Clear();
    }
  }

  // Do the launch.
  error = process_sp->Launch(launch_info);
  if (error.Success()) {
    // Handle the hijacking of process events.
    if (listener_sp) {
      const StateType state = process_sp->WaitForProcessToStop(
          llvm::None, NULL, false, listener_sp);

      LLDB_LOG(log, "pid {0} state {0}", process_sp->GetID(), state);
    }

    // Hook up process PTY if we have one (which we should for local debugging
    // with llgs).
    int pty_fd = launch_info.GetPTY().ReleaseMasterFileDescriptor();
    if (pty_fd != PseudoTerminal::invalid_fd) {
      process_sp->SetSTDIOFileDescriptor(pty_fd);
      LLDB_LOG(log, "hooked up STDIO pty to process");
    } else
      LLDB_LOG(log, "not using process STDIO pty");
  } else {
    LLDB_LOG(log, "process launch failed: {0}", error);
    // FIXME figure out appropriate cleanup here.  Do we delete the target? Do
    // we delete the process?  Does our caller do that?
  }

  return process_sp;
}