xref: /llvm-project-15.0.7/lldb/source/Plugins/Platform/POSIX/PlatformPOSIX.cpp (revision a47464b2)

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

#include "PlatformPOSIX.h"

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes

#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Expression/UserExpression.h"
#include "lldb/Host/File.h"
#include "lldb/Host/FileCache.h"
#include "lldb/Host/FileSpec.h"
#include "lldb/Host/FileSystem.h"
#include "lldb/Host/Host.h"
#include "lldb/Target/DynamicLoader.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/ProcessLaunchInfo.h"
#include "lldb/Target/Thread.h"

using namespace lldb;
using namespace lldb_private;

//------------------------------------------------------------------
/// Default Constructor
//------------------------------------------------------------------
PlatformPOSIX::PlatformPOSIX(bool is_host)
    : Platform(is_host), // This is the local host platform
      m_option_group_platform_rsync(new OptionGroupPlatformRSync()),
      m_option_group_platform_ssh(new OptionGroupPlatformSSH()),
      m_option_group_platform_caching(new OptionGroupPlatformCaching()),
      m_remote_platform_sp() {}

//------------------------------------------------------------------
/// Destructor.
///
/// The destructor is virtual since this class is designed to be
/// inherited from by the plug-in instance.
//------------------------------------------------------------------
PlatformPOSIX::~PlatformPOSIX() {}

bool PlatformPOSIX::GetModuleSpec(const FileSpec &module_file_spec,
                                  const ArchSpec &arch,
                                  ModuleSpec &module_spec) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetModuleSpec(module_file_spec, arch,
                                               module_spec);

  return Platform::GetModuleSpec(module_file_spec, arch, module_spec);
}

lldb_private::OptionGroupOptions *PlatformPOSIX::GetConnectionOptions(
    lldb_private::CommandInterpreter &interpreter) {
  auto iter = m_options.find(&interpreter), end = m_options.end();
  if (iter == end) {
    std::unique_ptr<lldb_private::OptionGroupOptions> options(
        new OptionGroupOptions());
    options->Append(m_option_group_platform_rsync.get());
    options->Append(m_option_group_platform_ssh.get());
    options->Append(m_option_group_platform_caching.get());
    m_options[&interpreter] = std::move(options);
  }

  return m_options.at(&interpreter).get();
}

bool PlatformPOSIX::IsConnected() const {
  if (IsHost())
    return true;
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->IsConnected();
  return false;
}

lldb_private::Error PlatformPOSIX::RunShellCommand(
    const char *command, // Shouldn't be NULL
    const FileSpec &
        working_dir, // Pass empty FileSpec to use the current working directory
    int *status_ptr, // Pass NULL if you don't want the process exit status
    int *signo_ptr,  // Pass NULL if you don't want the signal that caused the
                     // process to exit
    std::string
        *command_output, // Pass NULL if you don't want the command output
    uint32_t
        timeout_sec) // Timeout in seconds to wait for shell program to finish
{
  if (IsHost())
    return Host::RunShellCommand(command, working_dir, status_ptr, signo_ptr,
                                 command_output, timeout_sec);
  else {
    if (m_remote_platform_sp)
      return m_remote_platform_sp->RunShellCommand(command, working_dir,
                                                   status_ptr, signo_ptr,
                                                   command_output, timeout_sec);
    else
      return Error("unable to run a remote command without a platform");
  }
}

Error PlatformPOSIX::MakeDirectory(const FileSpec &file_spec,
                                   uint32_t file_permissions) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->MakeDirectory(file_spec, file_permissions);
  else
    return Platform::MakeDirectory(file_spec, file_permissions);
}

Error PlatformPOSIX::GetFilePermissions(const FileSpec &file_spec,
                                        uint32_t &file_permissions) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetFilePermissions(file_spec,
                                                    file_permissions);
  else
    return Platform::GetFilePermissions(file_spec, file_permissions);
}

Error PlatformPOSIX::SetFilePermissions(const FileSpec &file_spec,
                                        uint32_t file_permissions) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->SetFilePermissions(file_spec,
                                                    file_permissions);
  else
    return Platform::SetFilePermissions(file_spec, file_permissions);
}

lldb::user_id_t PlatformPOSIX::OpenFile(const FileSpec &file_spec,
                                        uint32_t flags, uint32_t mode,
                                        Error &error) {
  if (IsHost())
    return FileCache::GetInstance().OpenFile(file_spec, flags, mode, error);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->OpenFile(file_spec, flags, mode, error);
  else
    return Platform::OpenFile(file_spec, flags, mode, error);
}

bool PlatformPOSIX::CloseFile(lldb::user_id_t fd, Error &error) {
  if (IsHost())
    return FileCache::GetInstance().CloseFile(fd, error);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->CloseFile(fd, error);
  else
    return Platform::CloseFile(fd, error);
}

uint64_t PlatformPOSIX::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst,
                                 uint64_t dst_len, Error &error) {
  if (IsHost())
    return FileCache::GetInstance().ReadFile(fd, offset, dst, dst_len, error);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->ReadFile(fd, offset, dst, dst_len, error);
  else
    return Platform::ReadFile(fd, offset, dst, dst_len, error);
}

uint64_t PlatformPOSIX::WriteFile(lldb::user_id_t fd, uint64_t offset,
                                  const void *src, uint64_t src_len,
                                  Error &error) {
  if (IsHost())
    return FileCache::GetInstance().WriteFile(fd, offset, src, src_len, error);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->WriteFile(fd, offset, src, src_len, error);
  else
    return Platform::WriteFile(fd, offset, src, src_len, error);
}

static uint32_t chown_file(Platform *platform, const char *path,
                           uint32_t uid = UINT32_MAX,
                           uint32_t gid = UINT32_MAX) {
  if (!platform || !path || *path == 0)
    return UINT32_MAX;

  if (uid == UINT32_MAX && gid == UINT32_MAX)
    return 0; // pretend I did chown correctly - actually I just didn't care

  StreamString command;
  command.PutCString("chown ");
  if (uid != UINT32_MAX)
    command.Printf("%d", uid);
  if (gid != UINT32_MAX)
    command.Printf(":%d", gid);
  command.Printf("%s", path);
  int status;
  platform->RunShellCommand(command.GetData(), NULL, &status, NULL, NULL, 10);
  return status;
}

lldb_private::Error
PlatformPOSIX::PutFile(const lldb_private::FileSpec &source,
                       const lldb_private::FileSpec &destination, uint32_t uid,
                       uint32_t gid) {
  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PLATFORM));

  if (IsHost()) {
    if (FileSpec::Equal(source, destination, true))
      return Error();
    // cp src dst
    // chown uid:gid dst
    std::string src_path(source.GetPath());
    if (src_path.empty())
      return Error("unable to get file path for source");
    std::string dst_path(destination.GetPath());
    if (dst_path.empty())
      return Error("unable to get file path for destination");
    StreamString command;
    command.Printf("cp %s %s", src_path.c_str(), dst_path.c_str());
    int status;
    RunShellCommand(command.GetData(), NULL, &status, NULL, NULL, 10);
    if (status != 0)
      return Error("unable to perform copy");
    if (uid == UINT32_MAX && gid == UINT32_MAX)
      return Error();
    if (chown_file(this, dst_path.c_str(), uid, gid) != 0)
      return Error("unable to perform chown");
    return Error();
  } else if (m_remote_platform_sp) {
    if (GetSupportsRSync()) {
      std::string src_path(source.GetPath());
      if (src_path.empty())
        return Error("unable to get file path for source");
      std::string dst_path(destination.GetPath());
      if (dst_path.empty())
        return Error("unable to get file path for destination");
      StreamString command;
      if (GetIgnoresRemoteHostname()) {
        if (!GetRSyncPrefix())
          command.Printf("rsync %s %s %s", GetRSyncOpts(), src_path.c_str(),
                         dst_path.c_str());
        else
          command.Printf("rsync %s %s %s%s", GetRSyncOpts(), src_path.c_str(),
                         GetRSyncPrefix(), dst_path.c_str());
      } else
        command.Printf("rsync %s %s %s:%s", GetRSyncOpts(), src_path.c_str(),
                       GetHostname(), dst_path.c_str());
      if (log)
        log->Printf("[PutFile] Running command: %s\n", command.GetData());
      int retcode;
      Host::RunShellCommand(command.GetData(), NULL, &retcode, NULL, NULL, 60);
      if (retcode == 0) {
        // Don't chown a local file for a remote system
        //                if (chown_file(this,dst_path.c_str(),uid,gid) != 0)
        //                    return Error("unable to perform chown");
        return Error();
      }
      // if we are still here rsync has failed - let's try the slow way before
      // giving up
    }
  }
  return Platform::PutFile(source, destination, uid, gid);
}

lldb::user_id_t PlatformPOSIX::GetFileSize(const FileSpec &file_spec) {
  if (IsHost())
    return FileSystem::GetFileSize(file_spec);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->GetFileSize(file_spec);
  else
    return Platform::GetFileSize(file_spec);
}

Error PlatformPOSIX::CreateSymlink(const FileSpec &src, const FileSpec &dst) {
  if (IsHost())
    return FileSystem::Symlink(src, dst);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->CreateSymlink(src, dst);
  else
    return Platform::CreateSymlink(src, dst);
}

bool PlatformPOSIX::GetFileExists(const FileSpec &file_spec) {
  if (IsHost())
    return file_spec.Exists();
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->GetFileExists(file_spec);
  else
    return Platform::GetFileExists(file_spec);
}

Error PlatformPOSIX::Unlink(const FileSpec &file_spec) {
  if (IsHost())
    return FileSystem::Unlink(file_spec);
  else if (m_remote_platform_sp)
    return m_remote_platform_sp->Unlink(file_spec);
  else
    return Platform::Unlink(file_spec);
}

lldb_private::Error PlatformPOSIX::GetFile(
    const lldb_private::FileSpec &source,      // remote file path
    const lldb_private::FileSpec &destination) // local file path
{
  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PLATFORM));

  // Check the args, first.
  std::string src_path(source.GetPath());
  if (src_path.empty())
    return Error("unable to get file path for source");
  std::string dst_path(destination.GetPath());
  if (dst_path.empty())
    return Error("unable to get file path for destination");
  if (IsHost()) {
    if (FileSpec::Equal(source, destination, true))
      return Error("local scenario->source and destination are the same file "
                   "path: no operation performed");
    // cp src dst
    StreamString cp_command;
    cp_command.Printf("cp %s %s", src_path.c_str(), dst_path.c_str());
    int status;
    RunShellCommand(cp_command.GetData(), NULL, &status, NULL, NULL, 10);
    if (status != 0)
      return Error("unable to perform copy");
    return Error();
  } else if (m_remote_platform_sp) {
    if (GetSupportsRSync()) {
      StreamString command;
      if (GetIgnoresRemoteHostname()) {
        if (!GetRSyncPrefix())
          command.Printf("rsync %s %s %s", GetRSyncOpts(), src_path.c_str(),
                         dst_path.c_str());
        else
          command.Printf("rsync %s %s%s %s", GetRSyncOpts(), GetRSyncPrefix(),
                         src_path.c_str(), dst_path.c_str());
      } else
        command.Printf("rsync %s %s:%s %s", GetRSyncOpts(),
                       m_remote_platform_sp->GetHostname(), src_path.c_str(),
                       dst_path.c_str());
      if (log)
        log->Printf("[GetFile] Running command: %s\n", command.GetData());
      int retcode;
      Host::RunShellCommand(command.GetData(), NULL, &retcode, NULL, NULL, 60);
      if (retcode == 0)
        return Error();
      // If we are here, rsync has failed - let's try the slow way before giving
      // up
    }
    // open src and dst
    // read/write, read/write, read/write, ...
    // close src
    // close dst
    if (log)
      log->Printf("[GetFile] Using block by block transfer....\n");
    Error error;
    user_id_t fd_src = OpenFile(source, File::eOpenOptionRead,
                                lldb::eFilePermissionsFileDefault, error);

    if (fd_src == UINT64_MAX)
      return Error("unable to open source file");

    uint32_t permissions = 0;
    error = GetFilePermissions(source, permissions);

    if (permissions == 0)
      permissions = lldb::eFilePermissionsFileDefault;

    user_id_t fd_dst = FileCache::GetInstance().OpenFile(
        destination, File::eOpenOptionCanCreate | File::eOpenOptionWrite |
                         File::eOpenOptionTruncate,
        permissions, error);

    if (fd_dst == UINT64_MAX) {
      if (error.Success())
        error.SetErrorString("unable to open destination file");
    }

    if (error.Success()) {
      lldb::DataBufferSP buffer_sp(new DataBufferHeap(1024, 0));
      uint64_t offset = 0;
      error.Clear();
      while (error.Success()) {
        const uint64_t n_read = ReadFile(fd_src, offset, buffer_sp->GetBytes(),
                                         buffer_sp->GetByteSize(), error);
        if (error.Fail())
          break;
        if (n_read == 0)
          break;
        if (FileCache::GetInstance().WriteFile(fd_dst, offset,
                                               buffer_sp->GetBytes(), n_read,
                                               error) != n_read) {
          if (!error.Fail())
            error.SetErrorString("unable to write to destination file");
          break;
        }
        offset += n_read;
      }
    }
    // Ignore the close error of src.
    if (fd_src != UINT64_MAX)
      CloseFile(fd_src, error);
    // And close the dst file descriptot.
    if (fd_dst != UINT64_MAX &&
        !FileCache::GetInstance().CloseFile(fd_dst, error)) {
      if (!error.Fail())
        error.SetErrorString("unable to close destination file");
    }
    return error;
  }
  return Platform::GetFile(source, destination);
}

std::string PlatformPOSIX::GetPlatformSpecificConnectionInformation() {
  StreamString stream;
  if (GetSupportsRSync()) {
    stream.PutCString("rsync");
    if ((GetRSyncOpts() && *GetRSyncOpts()) ||
        (GetRSyncPrefix() && *GetRSyncPrefix()) || GetIgnoresRemoteHostname()) {
      stream.Printf(", options: ");
      if (GetRSyncOpts() && *GetRSyncOpts())
        stream.Printf("'%s' ", GetRSyncOpts());
      stream.Printf(", prefix: ");
      if (GetRSyncPrefix() && *GetRSyncPrefix())
        stream.Printf("'%s' ", GetRSyncPrefix());
      if (GetIgnoresRemoteHostname())
        stream.Printf("ignore remote-hostname ");
    }
  }
  if (GetSupportsSSH()) {
    stream.PutCString("ssh");
    if (GetSSHOpts() && *GetSSHOpts())
      stream.Printf(", options: '%s' ", GetSSHOpts());
  }
  if (GetLocalCacheDirectory() && *GetLocalCacheDirectory())
    stream.Printf("cache dir: %s", GetLocalCacheDirectory());
  if (stream.GetSize())
    return stream.GetString();
  else
    return "";
}

bool PlatformPOSIX::CalculateMD5(const FileSpec &file_spec, uint64_t &low,
                                 uint64_t &high) {
  if (IsHost())
    return Platform::CalculateMD5(file_spec, low, high);
  if (m_remote_platform_sp)
    return m_remote_platform_sp->CalculateMD5(file_spec, low, high);
  return false;
}

const lldb::UnixSignalsSP &PlatformPOSIX::GetRemoteUnixSignals() {
  if (IsRemote() && m_remote_platform_sp)
    return m_remote_platform_sp->GetRemoteUnixSignals();
  return Platform::GetRemoteUnixSignals();
}

FileSpec PlatformPOSIX::GetRemoteWorkingDirectory() {
  if (IsRemote() && m_remote_platform_sp)
    return m_remote_platform_sp->GetRemoteWorkingDirectory();
  else
    return Platform::GetRemoteWorkingDirectory();
}

bool PlatformPOSIX::SetRemoteWorkingDirectory(const FileSpec &working_dir) {
  if (IsRemote() && m_remote_platform_sp)
    return m_remote_platform_sp->SetRemoteWorkingDirectory(working_dir);
  else
    return Platform::SetRemoteWorkingDirectory(working_dir);
}

bool PlatformPOSIX::GetRemoteOSVersion() {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetOSVersion(
        m_major_os_version, m_minor_os_version, m_update_os_version);
  return false;
}

bool PlatformPOSIX::GetRemoteOSBuildString(std::string &s) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetRemoteOSBuildString(s);
  s.clear();
  return false;
}

size_t PlatformPOSIX::GetEnvironment(StringList &env) {
  if (IsRemote()) {
    if (m_remote_platform_sp)
      return m_remote_platform_sp->GetEnvironment(env);
    return 0;
  }
  return Host::GetEnvironment(env);
}

bool PlatformPOSIX::GetRemoteOSKernelDescription(std::string &s) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetRemoteOSKernelDescription(s);
  s.clear();
  return false;
}

// Remote Platform subclasses need to override this function
ArchSpec PlatformPOSIX::GetRemoteSystemArchitecture() {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetRemoteSystemArchitecture();
  return ArchSpec();
}

const char *PlatformPOSIX::GetHostname() {
  if (IsHost())
    return Platform::GetHostname();

  if (m_remote_platform_sp)
    return m_remote_platform_sp->GetHostname();
  return NULL;
}

const char *PlatformPOSIX::GetUserName(uint32_t uid) {
  // Check the cache in Platform in case we have already looked this uid up
  const char *user_name = Platform::GetUserName(uid);
  if (user_name)
    return user_name;

  if (IsRemote() && m_remote_platform_sp)
    return m_remote_platform_sp->GetUserName(uid);
  return NULL;
}

const char *PlatformPOSIX::GetGroupName(uint32_t gid) {
  const char *group_name = Platform::GetGroupName(gid);
  if (group_name)
    return group_name;

  if (IsRemote() && m_remote_platform_sp)
    return m_remote_platform_sp->GetGroupName(gid);
  return NULL;
}

Error PlatformPOSIX::ConnectRemote(Args &args) {
  Error error;
  if (IsHost()) {
    error.SetErrorStringWithFormat(
        "can't connect to the host platform '%s', always connected",
        GetPluginName().GetCString());
  } else {
    if (!m_remote_platform_sp)
      m_remote_platform_sp =
          Platform::Create(ConstString("remote-gdb-server"), error);

    if (m_remote_platform_sp && error.Success())
      error = m_remote_platform_sp->ConnectRemote(args);
    else
      error.SetErrorString("failed to create a 'remote-gdb-server' platform");

    if (error.Fail())
      m_remote_platform_sp.reset();
  }

  if (error.Success() && m_remote_platform_sp) {
    if (m_option_group_platform_rsync.get() &&
        m_option_group_platform_ssh.get() &&
        m_option_group_platform_caching.get()) {
      if (m_option_group_platform_rsync->m_rsync) {
        SetSupportsRSync(true);
        SetRSyncOpts(m_option_group_platform_rsync->m_rsync_opts.c_str());
        SetRSyncPrefix(m_option_group_platform_rsync->m_rsync_prefix.c_str());
        SetIgnoresRemoteHostname(
            m_option_group_platform_rsync->m_ignores_remote_hostname);
      }
      if (m_option_group_platform_ssh->m_ssh) {
        SetSupportsSSH(true);
        SetSSHOpts(m_option_group_platform_ssh->m_ssh_opts.c_str());
      }
      SetLocalCacheDirectory(
          m_option_group_platform_caching->m_cache_dir.c_str());
    }
  }

  return error;
}

Error PlatformPOSIX::DisconnectRemote() {
  Error error;

  if (IsHost()) {
    error.SetErrorStringWithFormat(
        "can't disconnect from the host platform '%s', always connected",
        GetPluginName().GetCString());
  } else {
    if (m_remote_platform_sp)
      error = m_remote_platform_sp->DisconnectRemote();
    else
      error.SetErrorString("the platform is not currently connected");
  }
  return error;
}

Error PlatformPOSIX::LaunchProcess(ProcessLaunchInfo &launch_info) {
  Error error;

  if (IsHost()) {
    error = Platform::LaunchProcess(launch_info);
  } else {
    if (m_remote_platform_sp)
      error = m_remote_platform_sp->LaunchProcess(launch_info);
    else
      error.SetErrorString("the platform is not currently connected");
  }
  return error;
}

lldb_private::Error PlatformPOSIX::KillProcess(const lldb::pid_t pid) {
  if (IsHost())
    return Platform::KillProcess(pid);

  if (m_remote_platform_sp)
    return m_remote_platform_sp->KillProcess(pid);

  return Error("the platform is not currently connected");
}

lldb::ProcessSP PlatformPOSIX::Attach(ProcessAttachInfo &attach_info,
                                      Debugger &debugger, Target *target,
                                      Error &error) {
  lldb::ProcessSP process_sp;
  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PLATFORM));

  if (IsHost()) {
    if (target == NULL) {
      TargetSP new_target_sp;

      error = debugger.GetTargetList().CreateTarget(debugger, "", "", false,
                                                    NULL, new_target_sp);
      target = new_target_sp.get();
      if (log)
        log->Printf("PlatformPOSIX::%s created new target", __FUNCTION__);
    } else {
      error.Clear();
      if (log)
        log->Printf("PlatformPOSIX::%s target already existed, setting target",
                    __FUNCTION__);
    }

    if (target && error.Success()) {
      debugger.GetTargetList().SetSelectedTarget(target);
      if (log) {
        ModuleSP exe_module_sp = target->GetExecutableModule();
        log->Printf("PlatformPOSIX::%s set selected target to %p %s",
                    __FUNCTION__, (void *)target,
                    exe_module_sp
                        ? exe_module_sp->GetFileSpec().GetPath().c_str()
                        : "<null>");
      }

      process_sp =
          target->CreateProcess(attach_info.GetListenerForProcess(debugger),
                                attach_info.GetProcessPluginName(), NULL);

      if (process_sp) {
        ListenerSP listener_sp = attach_info.GetHijackListener();
        if (listener_sp == nullptr) {
          listener_sp =
              Listener::MakeListener("lldb.PlatformPOSIX.attach.hijack");
          attach_info.SetHijackListener(listener_sp);
        }
        process_sp->HijackProcessEvents(listener_sp);
        error = process_sp->Attach(attach_info);
      }
    }
  } else {
    if (m_remote_platform_sp)
      process_sp =
          m_remote_platform_sp->Attach(attach_info, debugger, target, error);
    else
      error.SetErrorString("the platform is not currently connected");
  }
  return process_sp;
}

lldb::ProcessSP
PlatformPOSIX::DebugProcess(ProcessLaunchInfo &launch_info, Debugger &debugger,
                            Target *target, // Can be NULL, if NULL create a new
                                            // target, else use existing one
                            Error &error) {
  ProcessSP process_sp;

  if (IsHost()) {
    // We are going to hand this process off to debugserver which will be in
    // charge of setting the exit status.
    // We still need to reap it from lldb but if we let the monitor thread also
    // set the exit status, we set up a
    // race between debugserver & us for who will find out about the debugged
    // process's death.
    launch_info.GetFlags().Set(eLaunchFlagDontSetExitStatus);
    process_sp = Platform::DebugProcess(launch_info, debugger, target, error);
  } else {
    if (m_remote_platform_sp)
      process_sp = m_remote_platform_sp->DebugProcess(launch_info, debugger,
                                                      target, error);
    else
      error.SetErrorString("the platform is not currently connected");
  }
  return process_sp;
}

void PlatformPOSIX::CalculateTrapHandlerSymbolNames() {
  m_trap_handlers.push_back(ConstString("_sigtramp"));
}

Error PlatformPOSIX::EvaluateLibdlExpression(
    lldb_private::Process *process, const char *expr_cstr,
    const char *expr_prefix, lldb::ValueObjectSP &result_valobj_sp) {
  DynamicLoader *loader = process->GetDynamicLoader();
  if (loader) {
    Error error = loader->CanLoadImage();
    if (error.Fail())
      return error;
  }

  ThreadSP thread_sp(process->GetThreadList().GetExpressionExecutionThread());
  if (!thread_sp)
    return Error("Selected thread isn't valid");

  StackFrameSP frame_sp(thread_sp->GetStackFrameAtIndex(0));
  if (!frame_sp)
    return Error("Frame 0 isn't valid");

  ExecutionContext exe_ctx;
  frame_sp->CalculateExecutionContext(exe_ctx);
  EvaluateExpressionOptions expr_options;
  expr_options.SetUnwindOnError(true);
  expr_options.SetIgnoreBreakpoints(true);
  expr_options.SetExecutionPolicy(eExecutionPolicyAlways);
  expr_options.SetLanguage(eLanguageTypeC_plus_plus);
  expr_options.SetTrapExceptions(false); // dlopen can't throw exceptions, so
                                         // don't do the work to trap them.
  expr_options.SetTimeoutUsec(2000000);  // 2 seconds

  Error expr_error;
  ExpressionResults result =
      UserExpression::Evaluate(exe_ctx, expr_options, expr_cstr, expr_prefix,
                               result_valobj_sp, expr_error);
  if (result != eExpressionCompleted)
    return expr_error;

  if (result_valobj_sp->GetError().Fail())
    return result_valobj_sp->GetError();
  return Error();
}

uint32_t PlatformPOSIX::DoLoadImage(lldb_private::Process *process,
                                    const lldb_private::FileSpec &remote_file,
                                    lldb_private::Error &error) {
  char path[PATH_MAX];
  remote_file.GetPath(path, sizeof(path));

  StreamString expr;
  expr.Printf(R"(
                   struct __lldb_dlopen_result { void *image_ptr; const char *error_str; } the_result;
                   the_result.image_ptr = dlopen ("%s", 2);
                   if (the_result.image_ptr == (void *) 0x0)
                   {
                       the_result.error_str = dlerror();
                   }
                   else
                   {
                       the_result.error_str = (const char *) 0x0;
                   }
                   the_result;
                  )",
              path);
  const char *prefix = GetLibdlFunctionDeclarations();
  lldb::ValueObjectSP result_valobj_sp;
  error = EvaluateLibdlExpression(process, expr.GetData(), prefix,
                                  result_valobj_sp);
  if (error.Fail())
    return LLDB_INVALID_IMAGE_TOKEN;

  error = result_valobj_sp->GetError();
  if (error.Fail())
    return LLDB_INVALID_IMAGE_TOKEN;

  Scalar scalar;
  ValueObjectSP image_ptr_sp = result_valobj_sp->GetChildAtIndex(0, true);
  if (!image_ptr_sp || !image_ptr_sp->ResolveValue(scalar)) {
    error.SetErrorStringWithFormat("unable to load '%s'", path);
    return LLDB_INVALID_IMAGE_TOKEN;
  }

  addr_t image_ptr = scalar.ULongLong(LLDB_INVALID_ADDRESS);
  if (image_ptr != 0 && image_ptr != LLDB_INVALID_ADDRESS)
    return process->AddImageToken(image_ptr);

  if (image_ptr == 0) {
    ValueObjectSP error_str_sp = result_valobj_sp->GetChildAtIndex(1, true);
    if (error_str_sp) {
      DataBufferSP buffer_sp(new DataBufferHeap(10240, 0));
      size_t num_chars =
          error_str_sp->ReadPointedString(buffer_sp, error, 10240).first;
      if (error.Success() && num_chars > 0)
        error.SetErrorStringWithFormat("dlopen error: %s",
                                       buffer_sp->GetBytes());
      else
        error.SetErrorStringWithFormat("dlopen failed for unknown reasons.");
      return LLDB_INVALID_IMAGE_TOKEN;
    }
  }
  error.SetErrorStringWithFormat("unable to load '%s'", path);
  return LLDB_INVALID_IMAGE_TOKEN;
}

Error PlatformPOSIX::UnloadImage(lldb_private::Process *process,
                                 uint32_t image_token) {
  const addr_t image_addr = process->GetImagePtrFromToken(image_token);
  if (image_addr == LLDB_INVALID_ADDRESS)
    return Error("Invalid image token");

  StreamString expr;
  expr.Printf("dlclose((void *)0x%" PRIx64 ")", image_addr);
  const char *prefix = GetLibdlFunctionDeclarations();
  lldb::ValueObjectSP result_valobj_sp;
  Error error = EvaluateLibdlExpression(process, expr.GetData(), prefix,
                                        result_valobj_sp);
  if (error.Fail())
    return error;

  if (result_valobj_sp->GetError().Fail())
    return result_valobj_sp->GetError();

  Scalar scalar;
  if (result_valobj_sp->ResolveValue(scalar)) {
    if (scalar.UInt(1))
      return Error("expression failed: \"%s\"", expr.GetData());
    process->ResetImageToken(image_token);
  }
  return Error();
}

lldb::ProcessSP PlatformPOSIX::ConnectProcess(llvm::StringRef connect_url,
                                              llvm::StringRef plugin_name,
                                              lldb_private::Debugger &debugger,
                                              lldb_private::Target *target,
                                              lldb_private::Error &error) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->ConnectProcess(connect_url, plugin_name,
                                                debugger, target, error);

  return Platform::ConnectProcess(connect_url, plugin_name, debugger, target,
                                  error);
}

const char *PlatformPOSIX::GetLibdlFunctionDeclarations() const {
  return R"(
              extern "C" void* dlopen(const char*, int);
              extern "C" void* dlsym(void*, const char*);
              extern "C" int   dlclose(void*);
              extern "C" char* dlerror(void);
             )";
}

size_t PlatformPOSIX::ConnectToWaitingProcesses(Debugger &debugger,
                                                Error &error) {
  if (m_remote_platform_sp)
    return m_remote_platform_sp->ConnectToWaitingProcesses(debugger, error);
  return Platform::ConnectToWaitingProcesses(debugger, error);
}