Method runExecutable

src/CLI/IPCSignalWatcher.cpp:206–270

  }

  void IPCSignalWatcher::runExecutable(const std::map<std::string, std::string>& environment)
  {
    /*
     * Fork child process, that will fork again and exec.
     */
    const ::pid_t pid_fork1 = fork();

    if (pid_fork1 == -1) {
      std::cerr << "ERROR: runExecutable: " << strerror(errno) << std::endl;
      return;
    }

    if (pid_fork1 > 0) {
      /*
       * Wait for the intermediary process to fork and exit. In case something
       * fails in the intermediary process, we can retrieve the error code from
       * the return status.
       */
      int fork1_status = -1;
      const ::pid_t pid_waited = ::waitpid(pid_fork1, &fork1_status, 0);

      if (pid_waited == -1) {
        std::cerr << "ERROR: runExecutable: "  << strerror(errno) << std::endl;
      }
      else if (WIFEXITED(fork1_status)) {
        const int fork1_errno = WEXITSTATUS(fork1_status);

        if (fork1_errno != 0) {
          std::cerr << "ERROR: runExecutable: " << strerror(errno) << std::endl;
        }
      }
      else if (WIFSIGNALED(fork1_status)) {
        const int fork1_signal = WTERMSIG(fork1_status);
        std::cerr << "ERROR: runExecutable: terminated by signal " << fork1_signal << std::endl;
      }

      return;
    }

    /*
     * Intermediary process.
     */
    const ::pid_t sid = ::setsid();

    if (sid == (::pid_t)-1) {
      ::_exit(errno);
    }

    const ::pid_t pid_fork2 = fork();

    if (pid_fork2 == (::pid_t)-1) {
      ::_exit(errno);
    }

    if (pid_fork2 > 0) {
      ::_exit(0);
    }