pdns/receiver.cc

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25 #include "packetcache.hh"
  26
  27 #include <cstdio>
  28 #include <signal.h>
  29 #include <cstring>
  30 #include <cstdlib>
  31 #include <sys/types.h>
  32 #include <sys/socket.h>
  33 #include <netinet/in.h>
  34 #include <arpa/inet.h>
  35 #include <iostream>
  36 #include <string>
  37 #include <sys/stat.h>
  38 #include <unistd.h>
  39 #include <sys/time.h>
  40 #include <sys/types.h>
  41 #include <sys/wait.h>
  42 #include <errno.h>
  43 #include <pthread.h>
  44 #include <unistd.h>
  45 #include <sys/mman.h>
  46 #include <fcntl.h>
  47 #include <fstream>
  48 #include <boost/algorithm/string.hpp>
  49 #ifdef HAVE_LIBSODIUM
  50 #include <sodium.h>
  51 #endif
  52 #include "opensslsigners.hh"
  53
  54 #include "dns.hh"
  55 #include "dnsbackend.hh"
  56 #include "ueberbackend.hh"
  57 #include "dnspacket.hh"
  58 #include "nameserver.hh"
  59 #include "distributor.hh"
  60 #include "logger.hh"
  61 #include "arguments.hh"
  62 #include "packethandler.hh"
  63 #include "statbag.hh"
  64 #include "tcpreceiver.hh"
  65 #include "misc.hh"
  66 #include "dynlistener.hh"
  67 #include "dynhandler.hh"
  68 #include "communicator.hh"
  69 #include "dnsproxy.hh"
  70 #include "utility.hh"
  71 #include "common_startup.hh"
  72 #include "dnsrecords.hh"
  73 #include "version.hh"
  74
  75 time_t s_starttime;
  76
  77 string s_programname="pdns"; // used in packethandler.cc
  78
  79 const char *funnytext=
  80 "*****************************************************************************\n"\
  81 "Ok, you just ran pdns_server through 'strings' hoping to find funny messages.\n"\
  82 "Well, you found one. \n"\
  83 "Two ions are flying through their particle accelerator, says the one to the\n"
  84 "other 'I think I've lost an electron!' \n"\
  85 "So the other one says, 'Are you sure?'. 'YEAH! I'M POSITIVE!'\n"\
  86 "                                            the pdns crew - pdns@powerdns.com\n"
  87 "*****************************************************************************\n";
  88
  89
  90 // start (sys)logging
  91
  92
  93 /**
  94 \file receiver.cc
  95 \brief The main loop of powerdns
  96
  97 This file is where it all happens - main is here, as are the two pivotal threads qthread() and athread()
  98 */
  99
 100 void daemonize(void)
 101 {
 102   if(fork())
 103     exit(0); // bye bye
 104
 105   setsid();
 106
 107   int i=open("/dev/null",O_RDWR); /* open stdin */
 108   if(i < 0)
 109     g_log<<Logger::Critical<<"Unable to open /dev/null: "<<stringerror()<<endl;
 110   else {
 111     dup2(i,0); /* stdin */
 112     dup2(i,1); /* stderr */
 113     dup2(i,2); /* stderr */
 114     close(i);
 115   }
 116 }
 117
 118 static int cpid;
 119 static void takedown(int i)
 120 {
 121   if(cpid) {
 122     g_log<<Logger::Error<<"Guardian is killed, taking down children with us"<<endl;
 123     kill(cpid,SIGKILL);
 124     exit(0);
 125   }
 126 }
 127
 128 static void writePid(void)
 129 {
 130   if(!::arg().mustDo("write-pid"))
 131     return;
 132
 133   string fname=::arg()["socket-dir"];
 134   if (::arg()["socket-dir"].empty()) {
 135     if (::arg()["chroot"].empty())
 136       fname = LOCALSTATEDIR;
 137     else
 138       fname = ::arg()["chroot"] + "/";
 139   } else if (!::arg()["socket-dir"].empty() && !::arg()["chroot"].empty()) {
 140     fname = ::arg()["chroot"] + ::arg()["socket-dir"];
 141   }
 142
 143   fname += + "/" + s_programname + ".pid";
 144   ofstream of(fname.c_str());
 145   if(of)
 146     of<<getpid()<<endl;
 147   else
 148     g_log<<Logger::Error<<"Writing pid for "<<getpid()<<" to "<<fname<<" failed: "<<strerror(errno)<<endl;
 149 }
 150
 151 int g_fd1[2], g_fd2[2];
 152 FILE *g_fp;
 153 pthread_mutex_t g_guardian_lock = PTHREAD_MUTEX_INITIALIZER;
 154
 155 // The next two methods are not in dynhandler.cc because they use a few items declared in this file.
 156 static string DLCycleHandler(const vector<string>&parts, pid_t ppid)
 157 {
 158   kill(cpid, SIGKILL); // why?
 159   kill(cpid, SIGKILL); // why?
 160   sleep(1);
 161   return "ok";
 162 }
 163
 164 static string DLRestHandler(const vector<string>&parts, pid_t ppid)
 165 {
 166   string line;
 167
 168   for(vector<string>::const_iterator i=parts.begin();i!=parts.end();++i) {
 169     if(i!=parts.begin())
 170       line.append(1,' ');
 171     line.append(*i);
 172   }
 173   line.append(1,'\n');
 174
 175   Lock l(&g_guardian_lock);
 176
 177   try {
 178     writen2(g_fd1[1],line.c_str(),line.size()+1);
 179   }
 180   catch(PDNSException &ae) {
 181     return "Error communicating with instance: "+ae.reason;
 182   }
 183   char mesg[512];
 184   string response;
 185   while(fgets(mesg,sizeof(mesg),g_fp)) {
 186     if(*mesg=='\0')
 187       break;
 188     response+=mesg;
 189   }
 190   boost::trim_right(response);
 191   return response;
 192 }
 193
 194
 195
 196 static int guardian(int argc, char **argv)
 197 {
 198   if(isGuarded(argv))
 199     return 0;
 200
 201   int infd=0, outfd=1;
 202
 203   DynListener dlg(s_programname);
 204   dlg.registerFunc("QUIT",&DLQuitHandler, "quit daemon");
 205   dlg.registerFunc("CYCLE",&DLCycleHandler, "restart instance");
 206   dlg.registerFunc("PING",&DLPingHandler, "ping guardian");
 207   dlg.registerFunc("STATUS",&DLStatusHandler, "get instance status from guardian");
 208   dlg.registerRestFunc(&DLRestHandler);
 209   dlg.go();
 210   string progname=argv[0];
 211
 212   bool first=true;
 213   cpid=0;
 214
 215   pthread_mutex_lock(&g_guardian_lock);
 216
 217   for(;;) {
 218     int pid;
 219     setStatus("Launching child");
 220
 221     if(pipe(g_fd1)<0 || pipe(g_fd2)<0) {
 222       g_log<<Logger::Critical<<"Unable to open pipe for coprocess: "<<strerror(errno)<<endl;
 223       exit(1);
 224     }
 225
 226     if(!(g_fp=fdopen(g_fd2[0],"r"))) {
 227       g_log<<Logger::Critical<<"Unable to associate a file pointer with pipe: "<<stringerror()<<endl;
 228       exit(1);
 229     }
 230     setbuf(g_fp,0); // no buffering please, confuses select
 231
 232     if(!(pid=fork())) { // child
 233       signal(SIGTERM, SIG_DFL);
 234
 235       signal(SIGHUP, SIG_DFL);
 236       signal(SIGUSR1, SIG_DFL);
 237       signal(SIGUSR2, SIG_DFL);
 238
 239       char **const newargv=new char*[argc+2];
 240       int n;
 241
 242       if(::arg()["config-name"]!="") {
 243         progname+="-"+::arg()["config-name"];
 244         g_log<<Logger::Error<<"Virtual configuration name: "<<::arg()["config-name"]<<endl;
 245       }
 246
 247       newargv[0]=strdup(const_cast<char *>((progname+"-instance").c_str()));
 248       for(n=1;n<argc;n++) {
 249         newargv[n]=argv[n];
 250       }
 251       newargv[n]=0;
 252
 253       g_log<<Logger::Error<<"Guardian is launching an instance"<<endl;
 254       close(g_fd1[1]);
 255       fclose(g_fp); // this closes g_fd2[0] for us
 256
 257       if(g_fd1[0]!= infd) {
 258         dup2(g_fd1[0], infd);
 259         close(g_fd1[0]);
 260       }
 261
 262       if(g_fd2[1]!= outfd) {
 263         dup2(g_fd2[1], outfd);
 264         close(g_fd2[1]);
 265       }
 266       if(execvp(argv[0], newargv)<0) {
 267         g_log<<Logger::Error<<"Unable to execvp '"<<argv[0]<<"': "<<strerror(errno)<<endl;
 268         char **p=newargv;
 269         while(*p)
 270           g_log<<Logger::Error<<*p++<<endl;
 271
 272         exit(1);
 273       }
 274       g_log<<Logger::Error<<"execvp returned!!"<<endl;
 275       // never reached
 276     }
 277     else if(pid>0) { // parent
 278       close(g_fd1[0]);
 279       close(g_fd2[1]);
 280
 281       if(first) {
 282         first=false;
 283         signal(SIGTERM, takedown);
 284
 285         signal(SIGHUP, SIG_IGN);
 286         signal(SIGUSR1, SIG_IGN);
 287         signal(SIGUSR2, SIG_IGN);
 288
 289         writePid();
 290       }
 291       pthread_mutex_unlock(&g_guardian_lock);
 292       int status;
 293       cpid=pid;
 294       for(;;) {
 295         int ret=waitpid(pid,&status,WNOHANG);
 296
 297         if(ret<0) {
 298           g_log<<Logger::Error<<"In guardian loop, waitpid returned error: "<<strerror(errno)<<endl;
 299           g_log<<Logger::Error<<"Dying"<<endl;
 300           exit(1);
 301         }
 302         else if(ret) // something exited
 303           break;
 304         else { // child is alive
 305           // execute some kind of ping here
 306           if(DLQuitPlease())
 307             takedown(1); // needs a parameter..
 308           setStatus("Child running on pid "+itoa(pid));
 309           sleep(1);
 310         }
 311       }
 312
 313       pthread_mutex_lock(&g_guardian_lock);
 314       close(g_fd1[1]);
 315       fclose(g_fp);
 316       g_fp=0;
 317
 318       if(WIFEXITED(status)) {
 319         int ret=WEXITSTATUS(status);
 320
 321         if(ret==99) {
 322           g_log<<Logger::Error<<"Child requested a stop, exiting"<<endl;
 323           exit(1);
 324         }
 325         setStatus("Child died with code "+itoa(ret));
 326         g_log<<Logger::Error<<"Our pdns instance exited with code "<<ret<<", respawning"<<endl;
 327
 328         sleep(1);
 329         continue;
 330       }
 331       if(WIFSIGNALED(status)) {
 332         int sig=WTERMSIG(status);
 333         setStatus("Child died because of signal "+itoa(sig));
 334         g_log<<Logger::Error<<"Our pdns instance ("<<pid<<") exited after signal "<<sig<<endl;
 335 #ifdef WCOREDUMP
 336         if(WCOREDUMP(status))
 337           g_log<<Logger::Error<<"Dumped core"<<endl;
 338 #endif
 339
 340         g_log<<Logger::Error<<"Respawning"<<endl;
 341         sleep(1);
 342         continue;
 343       }
 344       g_log<<Logger::Error<<"No clue what happened! Respawning"<<endl;
 345     }
 346     else {
 347       g_log<<Logger::Error<<"Unable to fork: "<<strerror(errno)<<endl;
 348       exit(1);
 349     }
 350   }
 351 }
 352
 353 #ifdef __GLIBC__
 354 #include <execinfo.h>
 355 static void tbhandler(int num)
 356 {
 357   g_log<<Logger::Critical<<"Got a signal "<<num<<", attempting to print trace: "<<endl;
 358   void *array[20]; //only care about last 17 functions (3 taken with tracing support)
 359   size_t size;
 360   char **strings;
 361   size_t i;
 362
 363   size = backtrace (array, 20);
 364   strings = backtrace_symbols (array, size); //Need -rdynamic gcc (linker) flag for this to work
 365
 366   for (i = 0; i < size; i++) //skip useless functions
 367     g_log<<Logger::Error<<strings[i]<<endl;
 368
 369
 370   signal(SIGABRT, SIG_DFL);
 371   abort();//hopefully will give core
 372
 373 }
 374 #endif
 375
 376 //! The main function of pdns, the pdns process
 377 int main(int argc, char **argv)
 378 {
 379   versionSetProduct(ProductAuthoritative);
 380   reportAllTypes(); // init MOADNSParser
 381
 382   s_programname="pdns";
 383   s_starttime=time(0);
 384
 385 #ifdef __GLIBC__
 386   signal(SIGSEGV,tbhandler);
 387   signal(SIGFPE,tbhandler);
 388   signal(SIGABRT,tbhandler);
 389   signal(SIGILL,tbhandler);
 390 #endif
 391
 392   std::ios_base::sync_with_stdio(false);
 393
 394   g_log.toConsole(Logger::Warning);
 395   try {
 396     declareArguments();
 397
 398     ::arg().laxParse(argc,argv); // do a lax parse
 399
 400     if(::arg().mustDo("version")) {
 401       showProductVersion();
 402       showBuildConfiguration();
 403       exit(99);
 404     }
 405
 406     if(::arg()["config-name"]!="")
 407       s_programname+="-"+::arg()["config-name"];
 408
 409     g_log.setName(s_programname);
 410
 411     string configname=::arg()["config-dir"]+"/"+s_programname+".conf";
 412     cleanSlashes(configname);
 413
 414     if(!::arg().mustDo("config") && !::arg().mustDo("no-config")) // "config" == print a configuration file
 415       ::arg().laxFile(configname.c_str());
 416
 417     ::arg().laxParse(argc,argv); // reparse so the commandline still wins
 418     if(!::arg()["logging-facility"].empty()) {
 419       int val=logFacilityToLOG(::arg().asNum("logging-facility") );
 420       if(val >= 0)
 421         g_log.setFacility(val);
 422       else
 423         g_log<<Logger::Error<<"Unknown logging facility "<<::arg().asNum("logging-facility") <<endl;
 424     }
 425
 426     g_log.setLoglevel((Logger::Urgency)(::arg().asNum("loglevel")));
 427     g_log.disableSyslog(::arg().mustDo("disable-syslog"));
 428     g_log.setTimestamps(::arg().mustDo("log-timestamp"));
 429     g_log.toConsole((Logger::Urgency)(::arg().asNum("loglevel")));
 430
 431     if(::arg().mustDo("help") || ::arg().mustDo("config")) {
 432       ::arg().set("daemon")="no";
 433       ::arg().set("guardian")="no";
 434     }
 435
 436     if(::arg().mustDo("guardian") && !isGuarded(argv)) {
 437       if(::arg().mustDo("daemon")) {
 438         g_log.toConsole(Logger::Critical);
 439         daemonize();
 440       }
 441       guardian(argc, argv);
 442       // never get here, guardian will reinvoke process
 443       cerr<<"Um, we did get here!"<<endl;
 444     }
 445
 446
 447     // we really need to do work - either standalone or as an instance
 448
 449 #ifdef __GLIBC__
 450     if(!::arg().mustDo("traceback-handler")) {
 451       g_log<<Logger::Warning<<"Disabling traceback handler"<<endl;
 452       signal(SIGSEGV,SIG_DFL);
 453       signal(SIGFPE,SIG_DFL);
 454       signal(SIGABRT,SIG_DFL);
 455       signal(SIGILL,SIG_DFL);
 456     }
 457 #endif
 458
 459 #ifdef HAVE_LIBSODIUM
 460       if (sodium_init() == -1) {
 461         cerr<<"Unable to initialize sodium crypto library"<<endl;
 462         exit(99);
 463       }
 464 #endif
 465
 466     openssl_thread_setup();
 467     openssl_seed();
 468     /* setup rng */
 469     dns_random_init();
 470
 471     if(!::arg()["load-modules"].empty()) {
 472       vector<string> modules;
 473
 474       stringtok(modules,::arg()["load-modules"], ", ");
 475       if (!UeberBackend::loadModules(modules, ::arg()["module-dir"])) {
 476         exit(1);
 477       }
 478     }
 479
 480     BackendMakers().launch(::arg()["launch"]); // vrooooom!
 481
 482     if(!::arg().getCommands().empty()) {
 483       cerr<<"Fatal: non-option on the command line, perhaps a '--setting=123' statement missed the '='?"<<endl;
 484       exit(99);
 485     }
 486
 487     if(::arg().mustDo("help")) {
 488       cout<<"syntax:"<<endl<<endl;
 489       cout<<::arg().helpstring(::arg()["help"])<<endl;
 490       exit(0);
 491     }
 492
 493     if(::arg().mustDo("config")) {
 494       cout<<::arg().configstring()<<endl;
 495       exit(0);
 496     }
 497
 498     if(::arg().mustDo("list-modules")) {
 499       auto modules = BackendMakers().getModules();
 500       cout<<"Modules available:"<<endl;
 501       for(const auto& m : modules)
 502         cout<< m <<endl;
 503
 504       _exit(99);
 505     }
 506
 507     if(!::arg().asNum("local-port")) {
 508       g_log<<Logger::Error<<"Unable to launch, binding to no port or port 0 makes no sense"<<endl;
 509       exit(99); // this isn't going to fix itself either
 510     }
 511     if(!BackendMakers().numLauncheable()) {
 512       g_log<<Logger::Error<<"Unable to launch, no backends configured for querying"<<endl;
 513       exit(99); // this isn't going to fix itself either
 514     }
 515     if(::arg().mustDo("daemon")) {
 516       g_log.toConsole(Logger::None);
 517       if(!isGuarded(argv))
 518         daemonize();
 519     }
 520
 521     if(isGuarded(argv)) {
 522       g_log<<Logger::Warning<<"This is a guarded instance of pdns"<<endl;
 523       dl=new DynListener; // listens on stdin
 524     }
 525     else {
 526       g_log<<Logger::Warning<<"This is a standalone pdns"<<endl;
 527
 528       if(::arg().mustDo("control-console"))
 529         dl=new DynListener();
 530       else
 531         dl=new DynListener(s_programname);
 532
 533       writePid();
 534     }
 535     DynListener::registerFunc("SHOW",&DLShowHandler, "show a specific statistic or * to get a list", "<statistic>");
 536     DynListener::registerFunc("RPING",&DLPingHandler, "ping instance");
 537     DynListener::registerFunc("QUIT",&DLRQuitHandler, "quit daemon");
 538     DynListener::registerFunc("UPTIME",&DLUptimeHandler, "get instance uptime");
 539     DynListener::registerFunc("NOTIFY-HOST",&DLNotifyHostHandler, "notify host for specific domain", "<domain> <host>");
 540     DynListener::registerFunc("NOTIFY",&DLNotifyHandler, "queue a notification", "<domain>");
 541     DynListener::registerFunc("RELOAD",&DLReloadHandler, "reload all zones");
 542     DynListener::registerFunc("REDISCOVER",&DLRediscoverHandler, "discover any new zones");
 543     DynListener::registerFunc("VERSION",&DLVersionHandler, "get instance version");
 544     DynListener::registerFunc("PURGE",&DLPurgeHandler, "purge entries from packet cache", "[<record>]");
 545     DynListener::registerFunc("CCOUNTS",&DLCCHandler, "get cache statistics");
 546     DynListener::registerFunc("QTYPES", &DLQTypesHandler, "get QType statistics");
 547     DynListener::registerFunc("RESPSIZES", &DLRSizesHandler, "get histogram of response sizes");
 548     DynListener::registerFunc("REMOTES", &DLRemotesHandler, "get top remotes");
 549     DynListener::registerFunc("SET",&DLSettingsHandler, "set config variables", "<var> <value>");
 550     DynListener::registerFunc("RETRIEVE",&DLNotifyRetrieveHandler, "retrieve slave domain", "<domain>");
 551     DynListener::registerFunc("CURRENT-CONFIG",&DLCurrentConfigHandler, "retrieve the current configuration");
 552     DynListener::registerFunc("LIST-ZONES",&DLListZones, "show list of zones", "[master|slave|native]");
 553     DynListener::registerFunc("TOKEN-LOGIN", &DLTokenLogin, "Login to a PKCS#11 token", "<module> <slot> <pin>");
 554
 555     if(!::arg()["tcp-control-address"].empty()) {
 556       DynListener* dlTCP=new DynListener(ComboAddress(::arg()["tcp-control-address"], ::arg().asNum("tcp-control-port")));
 557       dlTCP->go();
 558     }
 559
 560     // reparse, with error checking
 561     if(!::arg().mustDo("no-config"))
 562       ::arg().file(configname.c_str());
 563     ::arg().parse(argc,argv);
 564
 565     if(::arg()["server-id"].empty()) {
 566       char tmp[128];
 567       if(gethostname(tmp, sizeof(tmp)-1) == 0) {
 568         ::arg().set("server-id")=tmp;
 569       } else {
 570         g_log<<Logger::Warning<<"Unable to get the hostname, NSID and id.server values will be empty: "<<strerror(errno)<<endl;
 571       }
 572     }
 573
 574     UeberBackend::go();
 575     N=std::make_shared<UDPNameserver>(); // this fails when we are not root, throws exception
 576     g_udpReceivers.push_back(N);
 577
 578     size_t rthreads = ::arg().asNum("receiver-threads", 1);
 579     if (rthreads > 1 && N->canReusePort()) {
 580       g_udpReceivers.resize(rthreads);
 581
 582       for (size_t idx = 1; idx < rthreads; idx++) {
 583         try {
 584           g_udpReceivers[idx] = std::make_shared<UDPNameserver>(true);
 585         }
 586         catch(const PDNSException& e) {
 587           g_log<<Logger::Error<<"Unable to reuse port, falling back to original bind"<<endl;
 588           break;
 589         }
 590       }
 591     }
 592
 593     if(!::arg().mustDo("disable-tcp"))
 594       TN=new TCPNameserver;
 595   }
 596   catch(const ArgException &A) {
 597     g_log<<Logger::Error<<"Fatal error: "<<A.reason<<endl;
 598     exit(1);
 599   }
 600
 601   declareStats();
 602   DLOG(g_log<<Logger::Warning<<"Verbose logging in effect"<<endl);
 603
 604   showProductVersion();
 605
 606   try {
 607     mainthread();
 608   }
 609   catch(PDNSException &AE) {
 610     if(!::arg().mustDo("daemon"))
 611       cerr<<"Exiting because: "<<AE.reason<<endl;
 612     g_log<<Logger::Error<<"Exiting because: "<<AE.reason<<endl;
 613   }
 614   catch(std::exception &e) {
 615     if(!::arg().mustDo("daemon"))
 616       cerr<<"Exiting because of STL error: "<<e.what()<<endl;
 617     g_log<<Logger::Error<<"Exiting because of STL error: "<<e.what()<<endl;
 618   }
 619   catch(...) {
 620     cerr<<"Uncaught exception of unknown type - sorry"<<endl;
 621   }
 622
 623   exit(1);
 624
 625 }
 626
 627