arc-networkd/helper_process.cc

// Copyright 2016 The Chromium OS 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 "arc-networkd/helper_process.h"

#include <signal.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

#include <utility>
#include <vector>

#include <base/logging.h>
#include <base/process/launch.h>
#include <brillo/syslog_logging.h>

namespace arc_networkd {

void HelperProcess::Start(int argc, char* argv[], const std::string& fd_arg) {
  int control[2];

  if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, control) != 0) {
    PLOG(FATAL) << "socketpair failed";
  }

  control_fd_.reset(control[0]);
  const int subprocess_fd = control[1];

  CHECK_GE(argc, 1);
  std::vector<std::string> child_argv;
  for (int i = 0; i < argc; i++) {
    child_argv.push_back(argv[i]);
  }
  child_argv.push_back(fd_arg + "=" + std::to_string(subprocess_fd));

  base::FileHandleMappingVector fd_mapping;
  fd_mapping.push_back({subprocess_fd, subprocess_fd});

  base::LaunchOptions options;
  options.fds_to_remap = &fd_mapping;

  base::Process p = base::LaunchProcess(child_argv, options);
  CHECK(p.IsValid());
  pid_ = p.Pid();
}

void HelperProcess::SendMessage(const google::protobuf::MessageLite& proto) {
  std::string str;
  if (!proto.SerializeToString(&str)) {
    LOG(FATAL) << "error serializing protobuf";
  }
  if (write(control_fd_.get(), str.data(), str.size()) !=
      static_cast<ssize_t>(str.size())) {
    LOG(FATAL) << "short write on protobuf";
  }
}

}  // namespace arc_networkd