git.m6w6.name Git - m6w6/libmemcached/blob - util/pidfile.cc

   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  DataDifferential Utility Library
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
   6  *  All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions are
  10  *  met:
  11  *
  12  *      * Redistributions of source code must retain the above copyright
  13  *  notice, this list of conditions and the following disclaimer.
  14  *
  15  *      * Redistributions in binary form must reproduce the above
  16  *  copyright notice, this list of conditions and the following disclaimer
  17  *  in the documentation and/or other materials provided with the
  18  *  distribution.
  19  *
  20  *      * The names of its contributors may not be used to endorse or
  21  *  promote products derived from this software without specific prior
  22  *  written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  28  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  30  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  34  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  */
  37
  38 #include "config.h"
  39
  40 #include "util/pidfile.hpp"
  41
  42 #include <cstdio>
  43 #include <cstdlib>
  44 #include <cstring>
  45 #include <cerrno>
  46 #include <fcntl.h>
  47 #include <iostream>
  48 #include <sstream>
  49 #include <sys/stat.h>
  50 #include <sys/types.h>
  51 #include <unistd.h>
  52
  53 extern "C" {
  54
  55   char pid_file[1024 * 4]= { 0 };
  56
  57   static void remove_pidfile(void)
  58   {
  59     if (pid_file[0])
  60     {
  61       if (unlink(pid_file) == -1)
  62       {
  63         std::cerr << "Could not remove pidfile: " << pid_file << "(" << strerror(errno) << ")" << std::endl;
  64       }
  65
  66       pid_file[0]= 0;
  67     }
  68   }
  69
  70 }
  71
  72 namespace datadifferential {
  73 namespace util {
  74
  75 Pidfile::Pidfile(const std::string &arg) :
  76   _last_errno(0),
  77   _filename(arg)
  78 {
  79 }
  80
  81
  82 Pidfile::~Pidfile()
  83 {
  84   if (not _filename.empty())
  85   {
  86     if (access(_filename.c_str(), F_OK) == -1)
  87     {
  88       std::stringstream error_stream;
  89       error_stream << "Could not access the pid file: " << _filename << "(" << strerror(errno) << ")";
  90       _error_message= error_stream.str();
  91     }
  92     else if (unlink(_filename.c_str()) == -1)
  93     {
  94       std::stringstream error_stream;
  95       error_stream << "Could not remove the pid file: " << _filename << "(" << strerror(errno) << ")";
  96       _error_message= error_stream.str();
  97     }
  98   }
  99   pid_file[0]= 0;
 100 }
 101
 102 bool Pidfile::create()
 103 {
 104   if (_filename.empty())
 105   {
 106     return true;
 107   }
 108
 109   if (access(_filename.c_str(), F_OK) == 0)
 110   {
 111     if (unlink(_filename.c_str()) == -1)
 112     {
 113       std::stringstream error_stream;
 114       error_stream << "Unable to remove exisiting file:" << _filename << "(" << strerror(errno) << ")";
 115       _error_message= error_stream.str();
 116
 117       return false;
 118     }
 119   }
 120
 121   int file;
 122   if ((file = open(_filename.c_str(), O_CREAT|O_WRONLY|O_TRUNC, S_IRWXU|S_IRGRP|S_IROTH)) < 0)
 123   {
 124     std::stringstream error_stream;
 125     error_stream << "Could not open pid file for writing: " << _filename << "(" << strerror(errno) << ")";
 126     _error_message= error_stream.str();
 127
 128     return false;
 129   }
 130
 131   char buffer[BUFSIZ];
 132   unsigned long temp= static_cast<unsigned long>(getpid());
 133   int length= snprintf(buffer, sizeof(buffer), "%lu\n", temp);
 134   if (write(file, buffer, length) != length)
 135   {
 136     std::stringstream error_stream;
 137     error_stream << "Could not write pid to file: " << _filename << "(" << strerror(errno) << ")";
 138     _error_message= error_stream.str();
 139     close(file);
 140
 141     return false;
 142   }
 143
 144   if (close(file) < 0)
 145   {
 146     _error_message+= "Could not close() file after writing pid to it: ";
 147     _error_message+= _filename;
 148     return false;
 149   }
 150   snprintf(pid_file, sizeof(pid_file), "%s", _filename.c_str());
 151   atexit(remove_pidfile);
 152
 153   return true;
 154 }
 155
 156 } /* namespace util */
 157 } /* namespace datadifferential */