lanbrowsing/lisa/strictmain.cpp

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