//===-- lldb-platform.cpp ---------------------------------------*- C++ -*-===//

//

// 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 <cerrno>

#if defined(__APPLE__)

#include <netinet/in.h>

#endif

#include <csignal>

#include <cstdint>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#if !defined(_WIN32)

#include <sys/wait.h>

#endif

#include <fstream>

#include <optional>

#include "llvm/Support/FileSystem.h"

#include "llvm/Support/WithColor.h"

#include "llvm/Support/raw_ostream.h"

#include "Acceptor.h"

#include "LLDBServerUtilities.h"

#include "Plugins/Process/gdb-remote/GDBRemoteCommunicationServerPlatform.h"

#include "Plugins/Process/gdb-remote/ProcessGDBRemoteLog.h"

#include "lldb/Host/ConnectionFileDescriptor.h"

#include "lldb/Host/HostGetOpt.h"

#include "lldb/Host/OptionParser.h"

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

#include "lldb/Utility/FileSpec.h"

#include "lldb/Utility/Status.h"

using namespace lldb;

using namespace lldb_private;

using namespace lldb_private::lldb_server;

using namespace lldb_private::process_gdb_remote;

using namespace llvm;

// option descriptors for getopt_long_only()

static int g_debug = 0;

static int g_verbose = 0;

static int g_server = 0;

static struct option g_long_options[] = {

    {"debug", no_argument, &g_debug, 1},

    {"verbose", no_argument, &g_verbose, 1},

    {"log-file", required_argument, nullptr, 'l'},

    {"log-channels", required_argument, nullptr, 'c'},

    {"listen", required_argument, nullptr, 'L'},

    {"port-offset", required_argument, nullptr, 'p'},

    {"gdbserver-port", required_argument, nullptr, 'P'},

    {"min-gdbserver-port", required_argument, nullptr, 'm'},

    {"max-gdbserver-port", required_argument, nullptr, 'M'},

    {"socket-file", required_argument, nullptr, 'f'},

    {"server", no_argument, &g_server, 1},

    {nullptr, 0, nullptr, 0}};

#if defined(__APPLE__)

#define LOW_PORT (IPPORT_RESERVED)

#define HIGH_PORT (IPPORT_HIFIRSTAUTO)

#else

#define LOW_PORT (1024u)

#define HIGH_PORT (49151u)

#endif

#if !defined(_WIN32)

// Watch for signals

static void signal_handler(int signo) {

  switch (signo) {

  case SIGHUP:

    // Use SIGINT first, if that does not work, use SIGHUP as a last resort.

    // And we should not call exit() here because it results in the global

    // destructors to be invoked and wreaking havoc on the threads still

    // running.

    llvm::errs() << "SIGHUP received, exiting lldb-server...\n";

    abort();

    break;

  }

}

#endif

static void display_usage(const char *progname, const char *subcommand) {

  fprintf(stderr, "Usage:\n  %s %s [--log-file log-file-name] [--log-channels "

                  "log-channel-list] [--port-file port-file-path] --server "

                  "--listen port\n",

          progname, subcommand);

  exit(0);

}

static Status save_socket_id_to_file(const std::string &socket_id,

                                     const FileSpec &file_spec) {

  FileSpec temp_file_spec(file_spec.GetDirectory().GetStringRef());

  Status error(llvm::sys::fs::create_directory(temp_file_spec.GetPath()));

  if (error.Fail())

    return Status("Failed to create directory %s: %s",

                  temp_file_spec.GetPath().c_str(), error.AsCString());

  Status status;

  if (auto Err = llvm::writeToOutput(file_spec.GetPath(),

                                     [&socket_id](llvm::raw_ostream &OS) {

                                       OS << socket_id;

                                       return llvm::Error::success();

                                     }))

    return Status("Failed to atomically write file %s: %s",

                  file_spec.GetPath().c_str(),

                  llvm::toString(std::move(Err)).c_str());

  return status;

}

// main

int main_platform(int argc, char *argv[]) {

  const char *progname = argv[0];

  const char *subcommand = argv[1];

  argc--;

  argv++;

#if !defined(_WIN32)

  signal(SIGPIPE, SIG_IGN);

  signal(SIGHUP, signal_handler);

#endif

  int long_option_index = 0;

  Status error;

  std::string listen_host_port;

  int ch;

  std::string log_file;

  StringRef

      log_channels; // e.g. "lldb process threads:gdb-remote default:linux all"

  GDBRemoteCommunicationServerPlatform::PortMap gdbserver_portmap;

  int min_gdbserver_port = 0;

  int max_gdbserver_port = 0;

  uint16_t port_offset = 0;

  FileSpec socket_file;

  bool show_usage = false;

  int option_error = 0;

  int socket_error = -1;

  std::string short_options(OptionParser::GetShortOptionString(g_long_options));

#if __GLIBC__

  optind = 0;

#else

  optreset = 1;

  optind = 1;

#endif

  while ((ch = getopt_long_only(argc, argv, short_options.c_str(),

                                g_long_options, &long_option_index)) != -1) {

    switch (ch) {

    case 0: // Any optional that auto set themselves will return 0

      break;

    case 'L':

      listen_host_port.append(optarg);

      break;

    case 'l': // Set Log File

      if (optarg && optarg[0])

        log_file.assign(optarg);

      break;

    case 'c': // Log Channels

      if (optarg && optarg[0])

        log_channels = StringRef(optarg);

      break;

    case 'f': // Socket file

      if (optarg && optarg[0])

        socket_file.SetFile(optarg, FileSpec::Style::native);

      break;

    case 'p': {

      if (!llvm::to_integer(optarg, port_offset)) {

        WithColor::error() << "invalid port offset string " << optarg << "\n";

        option_error = 4;

        break;

      }

      if (port_offset < LOW_PORT || port_offset > HIGH_PORT) {

        WithColor::error() << llvm::formatv(

            "port offset {0} is not in the "

            "valid user port range of {1} - {2}\n",

            port_offset, LOW_PORT, HIGH_PORT);

        option_error = 5;

      }

    } break;

    case 'P':

    case 'm':

    case 'M': {

      uint16_t portnum;

      if (!llvm::to_integer(optarg, portnum)) {

        WithColor::error() << "invalid port number string " << optarg << "\n";

        option_error = 2;

        break;

      }

      if (portnum < LOW_PORT || portnum > HIGH_PORT) {

        WithColor::error() << llvm::formatv(

            "port number {0} is not in the "

            "valid user port range of {1} - {2}\n",

            portnum, LOW_PORT, HIGH_PORT);

        option_error = 1;

        break;

      }

      if (ch == 'P')

        gdbserver_portmap.AllowPort(portnum);

      else if (ch == 'm')

        min_gdbserver_port = portnum;

      else

        max_gdbserver_port = portnum;

    } break;

    case 'h': /* fall-through is intentional */

    case '?':

      show_usage = true;

      break;

    }

  }

  if (!LLDBServerUtilities::SetupLogging(log_file, log_channels, 0))

    return -1;

  // Make a port map for a port range that was specified.

  if (min_gdbserver_port && min_gdbserver_port < max_gdbserver_port) {

    gdbserver_portmap = GDBRemoteCommunicationServerPlatform::PortMap(

        min_gdbserver_port, max_gdbserver_port);

  } else if (min_gdbserver_port || 
max_gdbserver_port0
) {

    WithColor::error() << llvm::formatv(

        "--min-gdbserver-port ({0}) is not lower than "

        "--max-gdbserver-port ({1})\n",

        min_gdbserver_port, max_gdbserver_port);

    option_error = 3;

  }

  // Print usage and exit if no listening port is specified.

  if (listen_host_port.empty())

    show_usage = true;

  if (show_usage || option_error) {

    display_usage(progname, subcommand);

    exit(option_error);

  }

  // Skip any options we consumed with getopt_long_only.

  argc -= optind;

  argv += optind;

  lldb_private::Args inferior_arguments;

  inferior_arguments.SetArguments(argc, const_cast<const char **>(argv));

  const bool children_inherit_listen_socket = false;

  // the test suite makes many connections in parallel, let's not miss any.

  // The highest this should get reasonably is a function of the number

  // of target CPUs. For now, let's just use 100.

  const int backlog = 100;

  std::unique_ptr<Acceptor> acceptor_up(Acceptor::Create(

      listen_host_port, children_inherit_listen_socket, error));

  if (error.Fail()) {

    fprintf(stderr, "failed to create acceptor: %s", error.AsCString());

    exit(socket_error);

  }

  error = acceptor_up->Listen(backlog);

  if (error.Fail()) {

    printf("failed to listen: %s\n", error.AsCString());

    exit(socket_error);

  }

  if (socket_file) {

    error =

        save_socket_id_to_file(acceptor_up->GetLocalSocketId(), socket_file);

    if (error.Fail()) {

      fprintf(stderr, "failed to write socket id to %s: %s\n",

              socket_file.GetPath().c_str(), error.AsCString());

      return 1;

    }

  }

  do {

    GDBRemoteCommunicationServerPlatform platform(

        acceptor_up->GetSocketProtocol(), acceptor_up->GetSocketScheme());

    if (port_offset > 0)

      platform.SetPortOffset(port_offset);

    if (!gdbserver_portmap.empty()) {

      platform.SetPortMap(std::move(gdbserver_portmap));

    }

    const bool children_inherit_accept_socket = true;

    Connection *conn = nullptr;

    error = acceptor_up->Accept(children_inherit_accept_socket, conn);

    if (error.Fail()) {

      WithColor::error() << error.AsCString() << '\n';

      exit(socket_error);

    }

    printf("Connection established.\n");

    if (g_server) {

      // Collect child zombie processes.

#if !defined(_WIN32)

      while (waitpid(-1, nullptr, WNOHANG) > 0)

        ;

#endif

      if (fork()) {

        // Parent doesn't need a connection to the lldb client

        delete conn;

        // Parent will continue to listen for new connections.

        continue;

      } else {

        // Child process will handle the connection and exit.

        g_server = 0;

        // Listening socket is owned by parent process.

        acceptor_up.release();

      }

    } else {

      // If not running as a server, this process will not accept

      // connections while a connection is active.

      acceptor_up.reset();

    }

    platform.SetConnection(std::unique_ptr<Connection>(conn));

    if (platform.IsConnected()) {

      if (inferior_arguments.GetArgumentCount() > 0) {

        lldb::pid_t pid = LLDB_INVALID_PROCESS_ID;

        std::optional<uint16_t> port = 0;

        std::string socket_name;

        Status error = platform.LaunchGDBServer(inferior_arguments,

                                                "", // hostname

                                                pid, port, socket_name);

        if (error.Success())

          platform.SetPendingGdbServer(pid, *port, socket_name);

        else

          fprintf(stderr, "failed to start gdbserver: %s\n", error.AsCString());

      }

      bool interrupt = false;

      bool done = false;

      while (!interrupt && !done) {

        if (platform.GetPacketAndSendResponse(std::nullopt, error, interrupt,

                                              done) !=

            GDBRemoteCommunication::PacketResult::Success)

          break;

      }

      if (error.Fail())

        WithColor::error() << error.AsCString() << '\n';

    }

  } while (g_server);

  fprintf(stderr, "lldb-server exiting...\n");

  return 0;

}