pdns/dynlistener.cc

   1 /*
   2     PowerDNS Versatile Database Driven Nameserver
   3     Copyright (C) 2002  PowerDNS.COM BV
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19 // $Id: dynlistener.cc,v 1.1 2002/11/27 15:18:33 ahu Exp $
  20 /* (C) Copyright 2002 PowerDNS.COM BV */
  21 #include <cstring>
  22 #include <string>
  23 #include <map>
  24 #include <sys/types.h>
  25 #include <sys/un.h>
  26 #include <dlfcn.h>
  27 #include <pthread.h>
  28 #include <unistd.h>
  29
  30 #include <sys/socket.h>
  31 #include <netinet/in.h>
  32 #include <errno.h>
  33 #include <iostream>
  34 #include <sstream>
  35 #include <sys/types.h>
  36 #include <signal.h>
  37
  38 #include <sys/stat.h>
  39 #include <fcntl.h>
  40 #include <unistd.h>
  41
  42 #include "misc.hh"
  43 #include "dns.hh"
  44 #include "arguments.hh"
  45 #include "dnsbackend.hh"
  46 #include "dynlistener.hh"
  47 #include "dnspacket.hh"
  48 #include "logger.hh"
  49 #include "statbag.hh"
  50
  51
  52
  53 extern StatBag S;
  54
  55 DynListener::DynListener(const string &pname)
  56 {
  57   d_restfunc=0;
  58   string programname=pname;
  59
  60   if(!programname.empty()) {
  61     struct sockaddr_un local;
  62     d_s=socket(AF_UNIX,SOCK_DGRAM,0);
  63
  64     if(d_s<0) {
  65       L<<Logger::Error<<"creating socket for dynlistener: "<<strerror(errno)<<endl;;
  66       exit(1);
  67     }
  68
  69     int tmp=1;
  70     if(setsockopt(d_s,SOL_SOCKET,SO_REUSEADDR,(char*)&tmp,sizeof tmp)<0)
  71       throw AhuException(string("Setsockopt failed: ")+strerror(errno));
  72
  73     string socketname=arg()["socket-dir"]+"/";
  74     cleanSlashes(socketname);
  75
  76     if(!mkdir(socketname.c_str(),0700)) // make /var directory, if needed
  77       L<<Logger::Warning<<"Created local state directory '"<<socketname<<"'"<<endl;
  78     else if(errno!=EEXIST) {
  79       L<<Logger::Critical<<"FATAL: Unable to create socket directory ("<<socketname<<") and it does not exist yet"<<endl;
  80       exit(1);
  81     }
  82
  83     socketname+=programname+".controlsocket";
  84     unlink(socketname.c_str());
  85     memset(&local,0,sizeof(local));
  86     local.sun_family=AF_UNIX;
  87     strcpy(local.sun_path,socketname.c_str());
  88
  89     if(bind(d_s, (sockaddr*)&local,sizeof(local))<0) {
  90       L<<Logger::Critical<<"binding to dynlistener '"<<socketname<<"': "<<strerror(errno)<<endl;
  91       exit(1);
  92     }
  93
  94     if(!arg()["setgid"].empty()) {
  95       if(chown(socketname.c_str(),static_cast<uid_t>(-1),Utility::makeGidNumeric(arg()["setgid"]))<0)
  96         L<<Logger::Error<<"Unable to change group ownership of controlsocket: "<<strerror(errno)<<endl;
  97       if(chmod(socketname.c_str(),0660)<0)
  98         L<<Logger::Error<<"Unable to change group access mode of controlsocket: "<<strerror(errno)<<endl;
  99     }
 100
 101
 102     L<<Logger::Warning<<"Listening on controlsocket in '"<<socketname<<"'"<<endl;
 103     d_udp=true;
 104   }
 105   else
 106     d_udp=false;
 107
 108
 109 }
 110
 111 void DynListener::go()
 112 {
 113   d_ppid=getpid();
 114   pthread_create(&d_tid,0,&DynListener::theListenerHelper,this);
 115 }
 116
 117 void *DynListener::theListenerHelper(void *p)
 118 {
 119   DynListener *us=static_cast<DynListener *>(p);
 120   us->theListener();
 121   return 0;
 122 }
 123
 124 string DynListener::getLine()
 125 {
 126   char mesg[512];
 127   memset(mesg,0,sizeof(mesg));
 128   int len;
 129
 130   if(d_udp) {
 131     d_addrlen=sizeof(d_remote);
 132
 133     if((len=recvfrom(d_s,mesg,512,0,(sockaddr*) &d_remote, &d_addrlen))<0) {
 134       L<<Logger::Error<<"Unable to receive packet from controlsocket ("<<d_s<<") - exiting: "<<strerror(errno)<<endl;
 135       exit(1);
 136     }
 137   }
 138   else {
 139     if(isatty(0))
 140       write(1, "% ", 2);
 141     if((len=read(0,mesg,512))<0)
 142       throw AhuException("Reading from the control pipe: "+stringerror());
 143     else if(len==0)
 144       throw AhuException("Guardian exited - going down as well");
 145   }
 146
 147   return mesg;
 148 }
 149
 150 void DynListener::sendLine(const string &l)
 151 {
 152   if(d_udp)
 153     sendto(d_s,l.c_str(),l.length()+1,0,(struct sockaddr *)&d_remote,d_addrlen);
 154   else {
 155     string line=l;
 156     line.append("\n");
 157     write(1,line.c_str(),line.length());
 158   }
 159 }
 160
 161 void DynListener::registerFunc(const string &name, g_funk_t *gf)
 162 {
 163   d_funcdb[name]=gf;
 164 }
 165
 166 void DynListener::registerRestFunc(g_funk_t *gf)
 167 {
 168   d_restfunc=gf;
 169 }
 170
 171 void DynListener::theListener()
 172 {
 173   try {
 174     map<string,string> parameters;
 175
 176     for(;;) {
 177       string line=getLine();
 178       chomp(line,"\n");
 179
 180       vector<string>parts;
 181       stringtok(parts,line," ");
 182       if(parts.empty()) {
 183         sendLine("Empty line");
 184         continue;
 185       }
 186       upperCase(parts[0]);
 187       if(!d_funcdb[parts[0]]) {
 188         if(d_restfunc)
 189           sendLine((*d_restfunc)(parts,d_ppid));
 190         else
 191           sendLine("Unknown command: '"+parts[0]+"'");
 192         continue;
 193       }
 194
 195       sendLine((*d_funcdb[parts[0]])(parts,d_ppid));
 196     }
 197   }
 198   catch(AhuException &AE)
 199     {
 200       L<<Logger::Error<<"Fatal: "<<AE.reason<<endl;
 201     }
 202   catch(string &E)
 203     {
 204       L<<Logger::Error<<"Fatal: "<<E<<endl;
 205     }
 206   catch(...)
 207     {
 208       L<<Logger::Error<<"Fatal: unknown exception occured"<<endl;
 209     }
 210 }
 211