trAvis - MANAGER

Edit File: pidfile.cc

/*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
 * 
 *  DataDifferential Utility Library
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 *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
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 */

#include "mem_config.h"

#include "util/pidfile.hpp"

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cerrno>
#include <fcntl.h>
#include <iostream>
#include <sstream>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

extern "C" {

char pid_file[1024 * 4]= { 0 };

static void remove_pidfile(void)
  {
    if (pid_file[0])
    {
      if (unlink(pid_file) == -1)
      {
        std::cerr << "Could not remove pidfile: " << pid_file << "(" << strerror(errno) << ")" << std::endl;
      }

pid_file[0]= 0;
    }
  }

}

namespace datadifferential {
namespace util {

Pidfile::Pidfile(const std::string &arg) :
  _last_errno(0),
  _filename(arg)
{
}

Pidfile::~Pidfile()
{
  if (not _filename.empty())
  {
    if (access(_filename.c_str(), F_OK) == -1)
    {
      std::stringstream error_stream;
      error_stream << "Could not access the pid file: " << _filename << "(" << strerror(errno) << ")";
      _error_message= error_stream.str();
    }
    else if (unlink(_filename.c_str()) == -1)
    {
      std::stringstream error_stream;
      error_stream << "Could not remove the pid file: " << _filename << "(" << strerror(errno) << ")";
      _error_message= error_stream.str();
    }
  }
  pid_file[0]= 0;
}

bool Pidfile::create()
{
  if (_filename.empty())
  {
    return true;
  }

if (access(_filename.c_str(), F_OK) == 0)
  {
    if (unlink(_filename.c_str()) == -1)
    {
      std::stringstream error_stream;
      error_stream << "Unable to remove exisiting file:" << _filename << "(" << strerror(errno) << ")";
      _error_message= error_stream.str();

return false;
    }
  }

int oflags= O_CREAT|O_WRONLY|O_TRUNC;
#ifdef HAVE_O_CLOEXEC
  oflags= oflags | O_CLOEXEC;
#endif

int file;
  if ((file = open(_filename.c_str(), oflags, S_IRWXU|S_IRGRP|S_IROTH)) < 0)
  {
    std::stringstream error_stream;
    error_stream << "Could not open pid file for writing: " << _filename << "(" << strerror(errno) << ")";
    _error_message= error_stream.str();
    
    return false;
  }

char buffer[BUFSIZ];
  unsigned long temp= static_cast<unsigned long>(getpid());
  int length= snprintf(buffer, sizeof(buffer), "%lu\n", temp);
  if (write(file, buffer, length) != length)
  { 
    std::stringstream error_stream;
    error_stream << "Could not write pid to file: " << _filename << "(" << strerror(errno) << ")";
    _error_message= error_stream.str();
    close(file);

return false;
  }

if (close(file) < 0)
  {
    _error_message+= "Could not close() file after writing pid to it: "; 
    _error_message+= _filename;
    return false;
  }
  snprintf(pid_file, sizeof(pid_file), "%s", _filename.c_str());
  atexit(remove_pidfile);

return true;
}

} /* namespace util */
} /* namespace datadifferential */