src/daemon.hpp

   1 #ifndef _DAEMON_HPP
   2 #define _DAEMON_HPP
   3 #ifndef NODAEMON
   4
   5 #include <poll.h>
   6 #include <fcntl.h>
   7 #include <pwd.h>
   8 #include <grp.h>
   9 #include <sys/wait.h>
  10 #include <sys/stat.h>
  11 #include <unistd.h>
  12
  13 void chrootAndDrop(std::string const& chrootdir, std::string const& username)
  14 {
  15   if (getuid() != 0)
  16   {
  17     std::cerr << "this programm has to be run as root in order to run in a chroot" << std::endl;
  18     exit(-1);
  19   }
  20
  21   struct passwd *pw = getpwnam(username.c_str());
  22   if(pw) {
  23     if(chroot(chrootdir.c_str()))
  24     {
  25       std::cerr << "can't chroot to " << chrootdir << std::endl;
  26       exit(-1);
  27     }
  28     cLog.msg(Log::PRIO_NOTICE) << "we are in chroot jail (" << chrootdir << ") now" << std::endl;
  29     if(chdir("/"))
  30     {
  31       std::cerr << "can't change to /" << std::endl;
  32       exit(-1);
  33     }
  34     if (initgroups(pw->pw_name, pw->pw_gid) || setgid(pw->pw_gid) || setuid(pw->pw_uid))
  35     {
  36       std::cerr << "can't drop to user " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
  37       exit(-1);
  38     }
  39     cLog.msg(Log::PRIO_NOTICE) << "dropped user to " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
  40   }
  41   else
  42   {
  43     std::cerr << "unknown user " << username << std::endl;
  44     exit(-1);
  45   }
  46 }
  47
  48 void daemonize()
  49 {
  50   pid_t pid;
  51
  52   pid = fork();
  53   if(pid) exit(0);
  54   setsid();
  55   pid = fork();
  56   if(pid) exit(0);
  57
  58 //  std::cout << "running in background now..." << std::endl;
  59
  60   int fd;
  61 //  for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
  62   for (fd=0;fd<=2;fd++) // close all file descriptors
  63     close(fd);
  64   fd = open("/dev/null",O_RDWR);        // stdin
  65   if(fd == -1)
  66     cLog.msg(Log::PRIO_WARNING) << "can't open stdin";
  67   else {
  68     if(dup(fd) == -1)   // stdout
  69       cLog.msg(Log::PRIO_WARNING) << "can't open stdout";
  70     if(dup(fd) == -1)   // stderr
  71       cLog.msg(Log::PRIO_WARNING) << "can't open stderr";
  72   }
  73   umask(027);
  74 }
  75 #endif
  76 #endif
  77