Forwarder 2 implementation

tools/android/forwarder2/socket.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tools/android/forwarder2/socket.h"
+
+#include <arpa/inet.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include "base/eintr_wrapper.h"
+#include "base/logging.h"
+#include "base/safe_strerror_posix.h"
+#include "tools/android/common/net.h"
+
+// This is used in Close and Shutdown.
+// Preserving errno for Close() is important because the function is very often
+// used in cleanup code, after an error occurred, and it is very easy to pass an
+// invalid file descriptor to close() in this context, or more rarely, a
+// spurious signal might make close() return -1 + setting errno to EINTR,
+// masking the real reason for the original error. This leads to very unpleasant
+// debugging sessions.
+#define PRESERVE_ERRNO_HANDLE_EINTR(Func)                     \
+  do {                                                        \
+    int local_errno = errno;                                  \
+    (void) HANDLE_EINTR(Func);                                \
+    errno = local_errno;                                      \
+  } while (false);
+
+
+namespace forwarder2 {
+
+bool Socket::BindUnix(const std::string& path, bool abstract) {
+  errno = 0;
+  if (!InitUnixSocket(path, abstract) || !BindAndListen()) {
+    Close();
+    return false;
+  }
+  return true;
+}
+
+bool Socket::BindTcp(const std::string& host, int port) {
+  errno = 0;
+  if (!InitTcpSocket(host, port) || !BindAndListen()) {
+    Close();
+    return false;
+  }
+  return true;
+}
+
+bool Socket::ConnectUnix(const std::string& path, bool abstract) {
+  errno = 0;
+  if (!InitUnixSocket(path, abstract) || !Connect()) {
+    Close();
+    return false;
+  }
+  return true;
+}
+
+bool Socket::ConnectTcp(const std::string& host, int port) {
+  errno = 0;
+  if (!InitTcpSocket(host, port) || !Connect()) {
+    Close();
+    return false;
+  }
+  return true;
+}
+
+Socket::Socket()
+    : socket_(-1),
+      port_(0),
+      socket_error_(false),
+      family_(AF_INET),
+      abstract_(false),
+      addr_ptr_(reinterpret_cast<sockaddr*>(&addr_.addr4)),
+      addr_len_(sizeof(sockaddr)),
+      exit_notifier_fd_(-1) {
+  memset(&addr_, 0, sizeof(addr_));
+}
+
+Socket::~Socket() {
+  CHECK(IsClosed());
+}
+
+void Socket::Shutdown() {
+  if (!IsClosed()) {
+    PRESERVE_ERRNO_HANDLE_EINTR(shutdown(socket_, SHUT_RDWR));
+  }
+}
+
+void Socket::Close() {
+  if (!IsClosed()) {
+    PRESERVE_ERRNO_HANDLE_EINTR(close(socket_));
+    socket_ = -1;
+  }
+}
+
+bool Socket::InitSocketInternal() {
+  socket_ = socket(family_, SOCK_STREAM, 0);
+  if (socket_ < 0)
+    return false;
+  tools::DisableNagle(socket_);
+  int reuse_addr = 1;
+  setsockopt(socket_, SOL_SOCKET, SO_REUSEADDR,
+             &reuse_addr, sizeof(reuse_addr));
+  tools::DeferAccept(socket_);
+  return true;
+}
+
+bool Socket::InitUnixSocket(const std::string& path, bool abstract) {
+  static const size_t kPathMax = sizeof(addr_.addr_un.sun_path);
+  // For abstract sockets we need one extra byte for the leading zero.
+  if (abstract && path.size() + 2 /* '\0' */ > kPathMax ||
+      !abstract && path.size() + 1 /* '\0' */ > kPathMax) {
+    LOG(ERROR) << "The provided path is too big to create a unix "
+               << "domain socket: " << path;
+    return false;
+  }
+  abstract_ = abstract;
+  family_ = PF_UNIX;
+  addr_.addr_un.sun_family = family_;
+
+  if (abstract) {
+    // Copied from net/base/unix_domain_socket_posix.cc
+    // Convert the path given into abstract socket name. It must start with
+    // the '\0' character, so we are adding it. |addr_len| must specify the
+    // length of the structure exactly, as potentially the socket name may
+    // have '\0' characters embedded (although we don't support this).
+    // Note that addr_.addr_un.sun_path is already zero initialized.
+    memcpy(addr_.addr_un.sun_path + 1, path.c_str(), path.size());
+    addr_len_ = path.size() + offsetof(struct sockaddr_un, sun_path) + 1;
+  } else {
+    memcpy(addr_.addr_un.sun_path, path.c_str(), path.size());
+    addr_len_ = sizeof(sockaddr_un);
+  }
+
+  addr_ptr_ = reinterpret_cast<sockaddr*>(&addr_.addr_un);
+  return InitSocketInternal();
+}
+
+bool Socket::InitTcpSocket(const std::string& host, int port) {
+  port_ = port;
+
+  if (host.empty()) {
+    // Use localhost: INADDR_LOOPBACK
+    family_ = AF_INET;
+    addr_.addr4.sin_family = family_;
+    addr_.addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  } else if (!Resolve(host)) {
+    return false;
+  }
+  CHECK(family_ == AF_INET || family_ == AF_INET6)
+      << "Invalid socket family.";
+  if (family_ == AF_INET) {
+    addr_.addr4.sin_port = htons(port_);
+    addr_ptr_ = reinterpret_cast<sockaddr*>(&addr_.addr4);
+    addr_len_ = sizeof(addr_.addr4);
+  } else if (family_ == AF_INET6) {
+    addr_.addr6.sin6_port = htons(port_);
+    addr_ptr_ = reinterpret_cast<sockaddr*>(&addr_.addr6);
+    addr_len_ = sizeof(addr_.addr6);
+  }
+  return InitSocketInternal();
+}
+
+bool Socket::BindAndListen() {
+  errno = 0;
+  if (HANDLE_EINTR(bind(socket_, addr_ptr_, addr_len_)) < 0 ||
+      HANDLE_EINTR(listen(socket_, 5)) < 0) {
+    SetSocketError();
+    return false;
+  }
+  return true;
+}
+
+bool Socket::Accept(Socket* new_socket) {
+  DCHECK(new_socket != NULL);
+  if (!WaitForEvent()) {
+    SetSocketError();
+    return false;
+  }
+  errno = 0;
+  int new_socket_fd = HANDLE_EINTR(accept(socket_, NULL, NULL));
+  if (new_socket_fd < 0) {
+    SetSocketError();
+    return false;
+  }
+
+  tools::DisableNagle(new_socket_fd);
+  new_socket->socket_ = new_socket_fd;
+  return true;
+}
+
+bool Socket::Connect() {
+  errno = 0;
+  if (HANDLE_EINTR(connect(socket_, addr_ptr_, addr_len_)) < 0) {
+    SetSocketError();
+    return false;
+  }
+  return true;
+}
+
+bool Socket::Resolve(const std::string& host) {
+  struct addrinfo hints;
+  struct addrinfo* res;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_flags |= AI_CANONNAME;
+
+  int errcode = getaddrinfo(host.c_str(), NULL, &hints, &res);
+  if (errcode != 0) {
+    SetSocketError();
+    return false;
+  }
+  family_ = res->ai_family;
+  switch (res->ai_family) {
+    case AF_INET:
+      memcpy(&addr_.addr4,
+             reinterpret_cast<sockaddr_in*>(res->ai_addr),
+             sizeof(sockaddr_in));
+      break;
+    case AF_INET6:
+      memcpy(&addr_.addr6,
+             reinterpret_cast<sockaddr_in6*>(res->ai_addr),
+             sizeof(sockaddr_in6));
+      break;
+  }
+  return true;
+}
+
+bool Socket::IsFdInSet(const fd_set& fds) const {
+  if (IsClosed())
+    return false;
+  return FD_ISSET(socket_, &fds);
+}
+
+bool Socket::AddFdToSet(fd_set* fds) const {
+  if (IsClosed())
+    return false;
+  FD_SET(socket_, fds);
+  return true;
+}
+
+int Socket::ReadNumBytes(char* buffer, size_t num_bytes) {
+  int bytes_read = 0;
+  int ret = 1;
+  while (bytes_read < num_bytes && ret > 0) {
+    ret = Read(buffer + bytes_read, num_bytes - bytes_read);
+    if (ret >= 0)
+      bytes_read += ret;
+  }
+  return bytes_read;
+}
+
+void Socket::SetSocketError() {
+  socket_error_ = true;
+  // We never use non-blocking socket.
+  DCHECK(errno != EAGAIN && errno != EWOULDBLOCK);
+  Close();
+}
+
+int Socket::Read(char* buffer, size_t buffer_size) {
+  if (!WaitForEvent()) {
+    SetSocketError();
+    return 0;
+  }
+  int ret = HANDLE_EINTR(read(socket_, buffer, buffer_size));
+  if (ret < 0)
+    SetSocketError();
+  return ret;
+}
+
+int Socket::Write(const char* buffer, size_t count) {
+  int ret = HANDLE_EINTR(send(socket_, buffer, count, MSG_NOSIGNAL));
+  if (ret < 0)
+    SetSocketError();
+  return ret;
+}
+
+int Socket::WriteString(const std::string& buffer) {
+  return WriteNumBytes(buffer.c_str(), buffer.size());
+}
+
+int Socket::WriteNumBytes(const char* buffer, size_t num_bytes) {
+  int bytes_written = 0;
+  int ret = 1;
+  while (bytes_written < num_bytes && ret > 0) {
+    ret = Write(buffer + bytes_written, num_bytes - bytes_written);
+    if (ret >= 0)
+      bytes_written += ret;
+  }
+  return bytes_written;
+}
+
+bool Socket::WaitForEvent() const {
+  if (exit_notifier_fd_ == -1 || socket_ == -1)
+    return true;
+  const int nfds = std::max(socket_, exit_notifier_fd_) + 1;
+  fd_set read_fds;
+  FD_ZERO(&read_fds);
+  FD_SET(socket_, &read_fds);
+  FD_SET(exit_notifier_fd_, &read_fds);
+  if (HANDLE_EINTR(select(nfds, &read_fds, NULL, NULL, NULL)) <= 0)
+    return false;
+  return !FD_ISSET(exit_notifier_fd_, &read_fds);
+}
+
+// static
+int Socket::GetHighestFileDescriptor(
+    const Socket& s1, const Socket& s2) {
+  return std::max(s1.socket_, s2.socket_);
+}
+
+}  // namespace forwarder