lanbrowsing/lisa/main.cpp

   1 /*    main.cpp
   2  *
   3  *    Copyright (c) 1998-2000 Alexander Neundorf
   4  *    neundorf@kde.org
   5  *
   6  *    You may distribute under the terms of the GNU General Public
   7  *    License as specified in the COPYING file.
   8  *
   9  *    This program is distributed in the hope that it will be useful,
  10  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *    GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include "lisadefines.h"
  17 #include "netmanager.h"
  18
  19 #ifdef LISA_DEBUG
  20 #undef LISA_DEBUG
  21 #endif
  22
  23 #ifdef dcerr
  24 #undef dcerr
  25 #endif
  26
  27 #define LISA_DEBUG 0
  28 #define dcerr if (LISA_DEBUG==1) std::cerr<<"main "
  29
  30 #include <iostream>
  31 #include <signal.h>
  32 #include <unistd.h>
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35 #include <sys/socket.h>
  36 #include <netinet/in.h>
  37
  38 // detect linux/glibc for the gnu style --args
  39 #if defined(__linux__) || defined(__linux) || defined(linux)
  40 #  include <features.h>
  41 #  ifdef __GLIBC__
  42 // only gnu libc has getopt.h... getopt(3) is defined to be in unistd.h
  43 // by POSIX.2
  44 #ifndef _GNU_SOURCE
  45 #    define _GNU_SOURCE
  46 #endif
  47 #    include <getopt.h>
  48 #  endif // __GLIBC__
  49 #  define GNU_GETOPT
  50 #endif // linux
  51
  52
  53 void printVersion()
  54 {
  55    const char * versionInfo=\
  56    "\r\nThis is the LAN Information Server LISa "MYVERSION"\r\n"\
  57    "It is free software according the GNU General Public License\r\n"\
  58    "Copyright (c) 2000-2003 by Alexander Neundorf\r\n"\
  59    "email: neundorf@kde.org\r\n";
  60    std::cout<<versionInfo<<std::endl;
  61 }
  62
  63 void usage()
  64 {
  65    printVersion();
  66    const char * usageInfo=\
  67       "-v, --version      prints out a short version info\n"\
  68       "-u, --unix         deprecated\n"\
  69       "-k, --kde1         deprecated\n"\
  70       "-K, --kde2         deprecated\n"\
  71       "                   lisa now looks always first for $(HOME)/.lisarc, then for /etc/lisarc\n"\
  72       "-c, --config=FILE  read this and no other configuration file\n"\
  73       "-q, --quiet        start quiet without the greeting message\n"\
  74       "-p, --port PORTNR  start the server on this portnumber\n"\
  75       "                   if you use this LISa won't be able to\n"\
  76       "                   cooperate with other LISa's in the network\n"\
  77       "-h, --help         you are currently reading it ;-)\n";
  78       std::cout<<usageInfo<<std::endl;
  79 //I thought this would be the way to check wether long options are supported...
  80 //#ifndef _GNU_SOURCE
  81 //      std::cout<<"Please note that the long options are not supported on
  82 //      this system"<<std::endl;
  83 //#endif
  84 }
  85
  86 NetManager *manager(0);
  87
  88
  89 void destruct(int sigNumber)
  90 {
  91    signal(sigNumber,SIG_IGN);
  92    dcerr<<"signal caught: "<<sigNumber<<", exiting"<<std::endl;
  93    //signal(sigNumber,&destruct);
  94    if (manager!=0)
  95       manager->~NetManager();
  96    exit(0);
  97 }
  98
  99 void readConfig(int sigNumber)
 100 {
 101    dcerr<<"readConfig(): signal caught: "<<sigNumber<<std::endl;
 102    signal(SIGHUP,SIG_IGN);
 103    if (manager!=0)
 104       manager->readConfig();
 105    signal(SIGHUP,&readConfig);
 106 }
 107
 108 void printState(int sigNumber)
 109 {
 110    dcerr<<"printState(): signal caught: "<<sigNumber<<std::endl;
 111    signal(SIGUSR1,SIG_IGN);
 112    if (manager!=0)
 113       manager->printState();
 114    signal(SIGUSR1,&printState);
 115 }
 116
 117 void setSignalHandler()
 118 {
 119    signal(SIGHUP,&readConfig);
 120         signal(SIGUSR1,&printState);
 121
 122    signal(SIGINT,&destruct);
 123         signal(SIGQUIT,&destruct);
 124         signal(SIGILL,&destruct);
 125         signal(SIGTRAP,&destruct);
 126         signal(SIGABRT,&destruct);
 127         signal(SIGBUS,&destruct);
 128         signal(SIGSEGV,&destruct);
 129         signal(SIGUSR2,&destruct);
 130         signal(SIGPIPE,&destruct);
 131         signal(SIGALRM,&destruct);
 132         signal(SIGTERM,&destruct);
 133         signal(SIGFPE,&destruct);
 134 #ifdef SIGPOLL
 135    signal(SIGPOLL, &destruct);
 136 #endif
 137 #ifdef SIGSYS
 138    signal(SIGSYS, &destruct);
 139 #endif
 140 #ifdef SIGVTALRM
 141    signal(SIGVTALRM, &destruct);
 142 #endif
 143 #ifdef SIGXCPU
 144    signal(SIGXCPU, &destruct);
 145 #endif
 146 #ifdef SIGXFSZ
 147    signal(SIGXFSZ, &destruct);
 148 #endif
 149 }
 150
 151 #ifdef GNU_GETOPT
 152 static struct option const long_opts[] =
 153 {
 154   {"version", no_argument, 0, 'v'},
 155   {"quiet", no_argument, 0, 'q'},
 156   {"unix", no_argument, 0, 'u'},
 157   {"kde1", no_argument, 0, 'k'},
 158   {"kde2", no_argument, 0, 'K'},
 159   {"config", required_argument, 0, 'c'},
 160   {"port", required_argument, 0, 'p'},
 161   {"help", no_argument, 0, 'h'},
 162   {0, 0, 0, 0}
 163 };
 164 #endif
 165
 166 int main(int argc, char** argv)
 167 {
 168    int quiet(0);
 169    int c(0);
 170    int configStyle(UNIXCONFIGSTYLE);
 171    MyString configFile;
 172    int portToUse(MYPORT);
 173
 174 //I thought this would be the way to check wether long options are supported...
 175 #ifdef GNU_GETOPT
 176    while ((c=getopt_long(argc, argv, "vqukKc:h", long_opts, 0))!=-1)
 177 #else
 178    while ((c=getopt(argc, argv, "vqukKc:h"))!=-1)
 179 #endif
 180
 181    {
 182       char *endp(0);
 183       switch (c)
 184       {
 185       case 0:
 186          break;
 187       case 'v':
 188          printVersion();
 189          exit(0);
 190          break;
 191       case 'q':
 192          quiet=1;
 193          break;
 194       case 'u':
 195       case 'k':
 196       case 'K':
 197          std::cout<<"\a\nThe command line switches -k, -K, -u and \ntheir long versions "\
 198             "--kde1, --kde2 and --unix are not supported anymore.\n"\
 199             "Lisa will always first look for $(HOME)/.lisarc , then for /etc/lisarc.\n"\
 200             "If your lisa configuration file was created using an older version of \n"\
 201             "the KDE control center, copy the /root/.kde/share/config/lisarc to /etc and \n"\
 202             "then start lisa without any command line options.\n"<<std::endl;
 203          return 0;
 204          break;
 205
 206       case 'c':
 207          configFile = optarg;
 208          configStyle = EXTRACONFIGSTYLE;
 209          break;
 210
 211       case 'p':
 212          portToUse=strtol(optarg,&endp,10);
 213          if (endp!=0)
 214          {
 215             usage();
 216             exit(0);
 217          }
 218          break;
 219
 220       case 'h':
 221       default:
 222          usage();
 223          exit(0);
 224          break;
 225       }
 226    }
 227
 228    //fork and let the parent exit
 229    pid_t pid=fork();
 230    if (pid>0)
 231    {
 232       //this is the parent
 233       exit(0);
 234    }
 235    else if (pid<0)
 236    {
 237       std::cout<<"could not fork()"<<std::endl;
 238       exit(0);
 239    }
 240    //we will only read/write to/from this socket in the child process
 241    int rawSocket=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP);
 242    if (rawSocket==-1)
 243    {
 244       std::cout<<"could not create raw socket, root privileges required"<<std::endl;
 245       std::cout<<"take a look at the README for more information"<<std::endl;
 246       exit(0);
 247    }
 248    int bufferSize(60*1024);
 249    int on(1);
 250    setsockopt(rawSocket, SOL_SOCKET, SO_RCVBUF, (char*)&bufferSize,
 251               sizeof(bufferSize));
 252    int result=setsockopt(rawSocket, SOL_SOCKET, SO_BROADCAST, (char*)&on,
 253                          sizeof(on));
 254    dcerr<<"setsockopt returns "<<result<<std::endl;
 255    //dropping root privileges
 256    //they will be regained once in the child process
 257    //for creating a raw socket
 258
 259    //now dropping root privileges once and ever
 260
 261
 262    setuid(getuid());
 263    if (geteuid() != getuid())
 264      _exit(255);
 265
 266    //according to R. Stevens the following three lines
 267    //make daemons feel good :)
 268    setsid();
 269    chdir("/");
 270    umask(0);
 271
 272    dcerr<<"starting, dropped root privileges"<<std::endl;
 273    dcerr<<"port: "<<portToUse<<" file: "<<configFile<<std::endl;
 274    NetManager netmanager(rawSocket,portToUse,configFile,configStyle,0);
 275    manager=&netmanager;
 276    dcerr<<"NetManager created"<<std::endl;
 277    setSignalHandler();
 278
 279    netmanager.readConfig();
 280    if (netmanager.prepare())
 281    {
 282       if (!quiet)
 283       {
 284          printVersion();
 285          std::cout<<"\n\rrunning on port "<<portToUse<<"\n\rHave fun ! :-)"<<std::endl;
 286       }
 287       netmanager.run();
 288    };
 289    dcerr<<"server finished"<<std::endl;
 290 }