daemon_lin.cpp

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#include "daemon.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <syslog.h>
#include <string.h>

#include <mutex>
#include <condition_variable>
#include <iostream>
#include <signal.h>

namespace
{

OpcUa::Daemon * DaemonInstance = 0;

void TerminateSignal(int signum)
{
  std::cout << "terminating.." << std::endl;

  if (DaemonInstance)
    {
      DaemonInstance->Terminate();
      DaemonInstance = nullptr;
    }
}

}

namespace OpcUa
{
void Daemon::SetTerminateHandlers()
{
  if (signal(SIGTERM, TerminateSignal) == SIG_ERR)
    {
      std::cerr << "unable to set SIGTERM handler" << std::endl;
    }

  if (signal(SIGINT, TerminateSignal) == SIG_ERR)
    {
      std::cerr << "unable to set SIGINT handler" << std::endl;
    }

  if (signal(SIGSTOP, TerminateSignal) == SIG_ERR)
    {
      std::cerr << "unable to set SIGSTOP handler" << std::endl;
    }

  DaemonInstance = this;
}

void Daemon::Daemonize(const std::string & logFile)
{
  pid_t pid, sid;

  pid = fork();

  if (pid < 0)
    {
      std::cerr << "Failed to fork: " << strerror(errno) << std::endl;
      exit(EXIT_FAILURE);
    }

  if (pid > 0)
    {
      exit(EXIT_SUCCESS);
    }

  umask(0);

  sid = setsid();

  if (sid < 0)
    {
      std::cerr << "setsid() failed: " << strerror(errno) << std::endl;
      exit(EXIT_FAILURE);
    }

  if ((chdir("/")) < 0)
    {
      std::cerr << "Cannot change dir. " << strerror(errno) << std::endl;
      exit(EXIT_FAILURE);
    }

  if (!logFile.empty())
    {
      FILE * tmp = fopen(logFile.c_str(), "w");

      if (!tmp)
        {
          std::cerr << "Cannot open log file " << logFile << ". " << strerror(errno) << std::endl;
          exit(EXIT_FAILURE);
        }

      close(STDIN_FILENO);
      close(STDOUT_FILENO);
      close(STDERR_FILENO);

      dup2(fileno(tmp), STDOUT_FILENO);
      dup2(fileno(tmp), STDERR_FILENO);
    }
}
}