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     chdir("/");
  30     if (initgroups(pw->pw_name, pw->pw_gid) || setgid(pw->pw_gid) || setuid(pw->pw_uid))
  31     {
  32       std::cerr << "can't drop to user " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
  33       exit(-1);
  34     }
  35     cLog.msg(Log::PRIO_NOTICE) << "dropped user to " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
  36   }
  37   else
  38   {
  39     std::cerr << "unknown user " << username << std::endl;
  40     exit(-1);
  41   }
  42 }
  43
  44 void daemonize()
  45 {
  46   pid_t pid;
  47
  48   pid = fork();
  49   if(pid) exit(0);
  50   setsid();
  51   pid = fork();
  52   if(pid) exit(0);
  53
  54 //  std::cout << "running in background now..." << std::endl;
  55
  56   int fd;
  57 //  for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
  58   for (fd=0;fd<=2;fd++) // close all file descriptors
  59     close(fd);
  60   fd=open("/dev/null",O_RDWR);        // stdin
  61   dup(fd);                            // stdout
  62   dup(fd);                            // stderr
  63   umask(027);
  64 }
  65 #endif
  66 #endif
  67