Update LLDB Host to support IPv6 over TCP

Summary:
This patch adds IPv6 support to LLDB/Host's TCP socket implementation. Supporting IPv6 involved a few significant changes to the implementation of the socket layers, and I have performed some significant code cleanup along the way.

This patch changes the Socket constructors for all types of sockets to not create sockets until first use. This is required for IPv6 support because the socket type will vary based on the address you are connecting to. This also has the benefit of removing code that could have errors from the Socket subclass constructors (which seems like a win to me).

The patch also slightly changes the API and behaviors of the Listen/Accept pattern. Previously both Listen and Accept calls took an address specified as a string. Now only listen does. This change was made because the Listen call can result in opening more than one socket. In order to support listening for both IPv4 and IPv6 connections we need to open one AF_INET socket and one AF_INET6 socket. During the listen call we construct a map of file descriptors to addrin structures which represent the allowable incoming connection address. This map removes the need for taking an address into the Accept call.

This does have a change in functionality. Previously you could Listen for connections based on one address, and Accept connections from a different address. This is no longer supported. I could not find anywhere in LLDB where we actually used the APIs in that way. The new API does still support AnyAddr for allowing incoming connections from any address.

The Listen implementation is implemented using kqueue on FreeBSD and Darwin, WSAPoll on Windows and poll(2) everywhere else.

Reviewers: zturner, clayborg

Subscribers: jasonmolenda, labath, lldb-commits, emaste

Differential Revision: https://reviews.llvm.org/D31823

llvm-svn: 300579

1 files changed, 0 insertions, 182 deletions

diff --git a/lldb/source/Host/posix/MainLoopPosix.cpp b/lldb/source/Host/posix/MainLoopPosix.cpp
deleted file mode 100644
index a73187e730f..00000000000
--- a/lldb/source/Host/posix/MainLoopPosix.cpp
+++ /dev/null
@@ -1,182 +0,0 @@
-//===-- MainLoopPosix.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/posix/MainLoopPosix.h"
-#include "lldb/Utility/Error.h"
-#include <algorithm>
-#include <cassert>
-#include <cerrno>
-#include <csignal>
-#include <sys/select.h>
-#include <vector>
-
-using namespace lldb;
-using namespace lldb_private;
-
-static sig_atomic_t g_signal_flags[NSIG];
-
-static void SignalHandler(int signo, siginfo_t *info, void *) {
-  assert(signo < NSIG);
-  g_signal_flags[signo] = 1;
-}
-
-MainLoopPosix::~MainLoopPosix() {
-  assert(m_read_fds.size() == 0);
-  assert(m_signals.size() == 0);
-}
-
-MainLoopPosix::ReadHandleUP
-MainLoopPosix::RegisterReadObject(const IOObjectSP &object_sp,
-                                  const Callback &callback, Error &error) {
-  if (!object_sp || !object_sp->IsValid()) {
-    error.SetErrorString("IO object is not valid.");
-    return nullptr;
-  }
-
-  const bool inserted =
-      m_read_fds.insert({object_sp->GetWaitableHandle(), callback}).second;
-  if (!inserted) {
-    error.SetErrorStringWithFormat("File descriptor %d already monitored.",
-                                   object_sp->GetWaitableHandle());
-    return nullptr;
-  }
-
-  return CreateReadHandle(object_sp);
-}
-
-// We shall block the signal, then install the signal handler. The signal will
-// be unblocked in
-// the Run() function to check for signal delivery.
-MainLoopPosix::SignalHandleUP
-MainLoopPosix::RegisterSignal(int signo, const Callback &callback,
-                              Error &error) {
-  if (m_signals.find(signo) != m_signals.end()) {
-    error.SetErrorStringWithFormat("Signal %d already monitored.", signo);
-    return nullptr;
-  }
-
-  SignalInfo info;
-  info.callback = callback;
-  struct sigaction new_action;
-  new_action.sa_sigaction = &SignalHandler;
-  new_action.sa_flags = SA_SIGINFO;
-  sigemptyset(&new_action.sa_mask);
-  sigaddset(&new_action.sa_mask, signo);
-
-  sigset_t old_set;
-  if (int ret = pthread_sigmask(SIG_BLOCK, &new_action.sa_mask, &old_set)) {
-    error.SetErrorStringWithFormat("pthread_sigmask failed with error %d\n",
-                                   ret);
-    return nullptr;
-  }
-
-  info.was_blocked = sigismember(&old_set, signo);
-  if (sigaction(signo, &new_action, &info.old_action) == -1) {
-    error.SetErrorToErrno();
-    if (!info.was_blocked)
-      pthread_sigmask(SIG_UNBLOCK, &new_action.sa_mask, nullptr);
-    return nullptr;
-  }
-
-  m_signals.insert({signo, info});
-  g_signal_flags[signo] = 0;
-
-  return SignalHandleUP(new SignalHandle(*this, signo));
-}
-
-void MainLoopPosix::UnregisterReadObject(IOObject::WaitableHandle handle) {
-  bool erased = m_read_fds.erase(handle);
-  UNUSED_IF_ASSERT_DISABLED(erased);
-  assert(erased);
-}
-
-void MainLoopPosix::UnregisterSignal(int signo) {
-  // We undo the actions of RegisterSignal on a best-effort basis.
-  auto it = m_signals.find(signo);
-  assert(it != m_signals.end());
-
-  sigaction(signo, &it->second.old_action, nullptr);
-
-  sigset_t set;
-  sigemptyset(&set);
-  sigaddset(&set, signo);
-  pthread_sigmask(it->second.was_blocked ? SIG_BLOCK : SIG_UNBLOCK, &set,
-                  nullptr);
-
-  m_signals.erase(it);
-}
-
-Error MainLoopPosix::Run() {
-  std::vector<int> signals;
-  sigset_t sigmask;
-  std::vector<int> read_fds;
-  fd_set read_fd_set;
-  m_terminate_request = false;
-
-  // run until termination or until we run out of things to listen to
-  while (!m_terminate_request && (!m_read_fds.empty() || !m_signals.empty())) {
-    // To avoid problems with callbacks changing the things we're supposed to
-    // listen to, we
-    // will store the *real* list of events separately.
-    signals.clear();
-    read_fds.clear();
-    FD_ZERO(&read_fd_set);
-    int nfds = 0;
-
-    if (int ret = pthread_sigmask(SIG_SETMASK, nullptr, &sigmask))
-      return Error("pthread_sigmask failed with error %d\n", ret);
-
-    for (const auto &fd : m_read_fds) {
-      read_fds.push_back(fd.first);
-      FD_SET(fd.first, &read_fd_set);
-      nfds = std::max(nfds, fd.first + 1);
-    }
-
-    for (const auto &sig : m_signals) {
-      signals.push_back(sig.first);
-      sigdelset(&sigmask, sig.first);
-    }
-
-    if (pselect(nfds, &read_fd_set, nullptr, nullptr, nullptr, &sigmask) ==
-            -1 &&
-        errno != EINTR)
-      return Error(errno, eErrorTypePOSIX);
-
-    for (int sig : signals) {
-      if (g_signal_flags[sig] == 0)
-        continue; // No signal
-      g_signal_flags[sig] = 0;
-
-      auto it = m_signals.find(sig);
-      if (it == m_signals.end())
-        continue; // Signal must have gotten unregistered in the meantime
-
-      it->second.callback(*this); // Do the work
-
-      if (m_terminate_request)
-        return Error();
-    }
-
-    for (int fd : read_fds) {
-      if (!FD_ISSET(fd, &read_fd_set))
-        continue; // Not ready
-
-      auto it = m_read_fds.find(fd);
-      if (it == m_read_fds.end())
-        continue; // File descriptor must have gotten unregistered in the
-                  // meantime
-
-      it->second(*this); // Do the work
-
-      if (m_terminate_request)
-        return Error();
-    }
-  }
-  return Error();
-}