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 #ifdef HAVE_LUA_RECORDS
  76 #include "minicurl.hh"
  77 #endif /* HAVE_LUA_RECORDS */
  78
  79 time_t s_starttime;
  80
  81 string s_programname="pdns"; // used in packethandler.cc
  82
  83 const char *funnytext=
  84 "*****************************************************************************\n"\
  85 "Ok, you just ran pdns_server through 'strings' hoping to find funny messages.\n"\
  86 "Well, you found one. \n"\
  87 "Two ions are flying through their particle accelerator, says the one to the\n"
  88 "other 'I think I've lost an electron!' \n"\
  89 "So the other one says, 'Are you sure?'. 'YEAH! I'M POSITIVE!'\n"\
  90 "                                            the pdns crew - pdns@powerdns.com\n"
  91 "*****************************************************************************\n";
  92
  93
  94 // start (sys)logging
  95
  96
  97 /**
  98 \file receiver.cc
  99 \brief The main loop of powerdns
 100
 101 This file is where it all happens - main is here, as are the two pivotal threads qthread() and athread()
 102 */
 103
 104 void daemonize(void)
 105 {
 106   if(fork())
 107     exit(0); // bye bye
 108
 109   setsid();
 110
 111   int i=open("/dev/null",O_RDWR); /* open stdin */
 112   if(i < 0)
 113     g_log<<Logger::Critical<<"Unable to open /dev/null: "<<stringerror()<<endl;
 114   else {
 115     dup2(i,0); /* stdin */
 116     dup2(i,1); /* stderr */
 117     dup2(i,2); /* stderr */
 118     close(i);
 119   }
 120 }
 121
 122 static int cpid;
 123 static void takedown(int i)
 124 {
 125   if(cpid) {
 126     g_log<<Logger::Error<<"Guardian is killed, taking down children with us"<<endl;
 127     kill(cpid,SIGKILL);
 128     exit(0);
 129   }
 130 }
 131
 132 static void writePid(void)
 133 {
 134   if(!::arg().mustDo("write-pid"))
 135     return;
 136
 137   string fname=::arg()["socket-dir"];
 138   if (::arg()["socket-dir"].empty()) {
 139     if (::arg()["chroot"].empty())
 140       fname = LOCALSTATEDIR;
 141     else
 142       fname = ::arg()["chroot"] + "/";
 143   } else if (!::arg()["socket-dir"].empty() && !::arg()["chroot"].empty()) {
 144     fname = ::arg()["chroot"] + ::arg()["socket-dir"];
 145   }
 146
 147   fname += + "/" + s_programname + ".pid";
 148   ofstream of(fname.c_str());
 149   if(of)
 150     of<<getpid()<<endl;
 151   else
 152     g_log<<Logger::Error<<"Writing pid for "<<getpid()<<" to "<<fname<<" failed: "<<strerror(errno)<<endl;
 153 }
 154
 155 int g_fd1[2], g_fd2[2];
 156 FILE *g_fp;
 157 pthread_mutex_t g_guardian_lock = PTHREAD_MUTEX_INITIALIZER;
 158
 159 // The next two methods are not in dynhandler.cc because they use a few items declared in this file.
 160 static string DLCycleHandler(const vector<string>&parts, pid_t ppid)
 161 {
 162   kill(cpid, SIGKILL); // why?
 163   kill(cpid, SIGKILL); // why?
 164   sleep(1);
 165   return "ok";
 166 }
 167
 168 static string DLRestHandler(const vector<string>&parts, pid_t ppid)
 169 {
 170   string line;
 171
 172   for(vector<string>::const_iterator i=parts.begin();i!=parts.end();++i) {
 173     if(i!=parts.begin())
 174       line.append(1,' ');
 175     line.append(*i);
 176   }
 177   line.append(1,'\n');
 178
 179   Lock l(&g_guardian_lock);
 180
 181   try {
 182     writen2(g_fd1[1],line.c_str(),line.size()+1);
 183   }
 184   catch(PDNSException &ae) {
 185     return "Error communicating with instance: "+ae.reason;
 186   }
 187   char mesg[512];
 188   string response;
 189   while(fgets(mesg,sizeof(mesg),g_fp)) {
 190     if(*mesg=='\0')
 191       break;
 192     response+=mesg;
 193   }
 194   boost::trim_right(response);
 195   return response;
 196 }
 197
 198
 199
 200 static int guardian(int argc, char **argv)
 201 {
 202   if(isGuarded(argv))
 203     return 0;
 204
 205   int infd=0, outfd=1;
 206
 207   DynListener dlg(s_programname);
 208   dlg.registerFunc("QUIT",&DLQuitHandler, "quit daemon");
 209   dlg.registerFunc("CYCLE",&DLCycleHandler, "restart instance");
 210   dlg.registerFunc("PING",&DLPingHandler, "ping guardian");
 211   dlg.registerFunc("STATUS",&DLStatusHandler, "get instance status from guardian");
 212   dlg.registerRestFunc(&DLRestHandler);
 213   dlg.go();
 214   string progname=argv[0];
 215
 216   bool first=true;
 217   cpid=0;
 218
 219   pthread_mutex_lock(&g_guardian_lock);
 220
 221   for(;;) {
 222     int pid;
 223     setStatus("Launching child");
 224
 225     if(pipe(g_fd1)<0 || pipe(g_fd2)<0) {
 226       g_log<<Logger::Critical<<"Unable to open pipe for coprocess: "<<strerror(errno)<<endl;
 227       exit(1);
 228     }
 229
 230     if(!(g_fp=fdopen(g_fd2[0],"r"))) {
 231       g_log<<Logger::Critical<<"Unable to associate a file pointer with pipe: "<<stringerror()<<endl;
 232       exit(1);
 233     }
 234     setbuf(g_fp,0); // no buffering please, confuses select
 235
 236     if(!(pid=fork())) { // child
 237       signal(SIGTERM, SIG_DFL);
 238
 239       signal(SIGHUP, SIG_DFL);
 240       signal(SIGUSR1, SIG_DFL);
 241       signal(SIGUSR2, SIG_DFL);
 242
 243       char **const newargv=new char*[argc+2];
 244       int n;
 245
 246       if(::arg()["config-name"]!="") {
 247         progname+="-"+::arg()["config-name"];
 248         g_log<<Logger::Error<<"Virtual configuration name: "<<::arg()["config-name"]<<endl;
 249       }
 250
 251       newargv[0]=strdup(const_cast<char *>((progname+"-instance").c_str()));
 252       for(n=1;n<argc;n++) {
 253         newargv[n]=argv[n];
 254       }
 255       newargv[n]=0;
 256
 257       g_log<<Logger::Error<<"Guardian is launching an instance"<<endl;
 258       close(g_fd1[1]);
 259       fclose(g_fp); // this closes g_fd2[0] for us
 260
 261       if(g_fd1[0]!= infd) {
 262         dup2(g_fd1[0], infd);
 263         close(g_fd1[0]);
 264       }
 265
 266       if(g_fd2[1]!= outfd) {
 267         dup2(g_fd2[1], outfd);
 268         close(g_fd2[1]);
 269       }
 270       if(execvp(argv[0], newargv)<0) {
 271         g_log<<Logger::Error<<"Unable to execvp '"<<argv[0]<<"': "<<strerror(errno)<<endl;
 272         char **p=newargv;
 273         while(*p)
 274           g_log<<Logger::Error<<*p++<<endl;
 275
 276         exit(1);
 277       }
 278       g_log<<Logger::Error<<"execvp returned!!"<<endl;
 279       // never reached
 280     }
 281     else if(pid>0) { // parent
 282       close(g_fd1[0]);
 283       close(g_fd2[1]);
 284
 285       if(first) {
 286         first=false;
 287         signal(SIGTERM, takedown);
 288
 289         signal(SIGHUP, SIG_IGN);
 290         signal(SIGUSR1, SIG_IGN);
 291         signal(SIGUSR2, SIG_IGN);
 292
 293         writePid();
 294       }
 295       pthread_mutex_unlock(&g_guardian_lock);
 296       int status;
 297       cpid=pid;
 298       for(;;) {
 299         int ret=waitpid(pid,&status,WNOHANG);
 300
 301         if(ret<0) {
 302           g_log<<Logger::Error<<"In guardian loop, waitpid returned error: "<<strerror(errno)<<endl;
 303           g_log<<Logger::Error<<"Dying"<<endl;
 304           exit(1);
 305         }
 306         else if(ret) // something exited
 307           break;
 308         else { // child is alive
 309           // execute some kind of ping here
 310           if(DLQuitPlease())
 311             takedown(1); // needs a parameter..
 312           setStatus("Child running on pid "+itoa(pid));
 313           sleep(1);
 314         }
 315       }
 316
 317       pthread_mutex_lock(&g_guardian_lock);
 318       close(g_fd1[1]);
 319       fclose(g_fp);
 320       g_fp=0;
 321
 322       if(WIFEXITED(status)) {
 323         int ret=WEXITSTATUS(status);
 324
 325         if(ret==99) {
 326           g_log<<Logger::Error<<"Child requested a stop, exiting"<<endl;
 327           exit(1);
 328         }
 329         setStatus("Child died with code "+itoa(ret));
 330         g_log<<Logger::Error<<"Our pdns instance exited with code "<<ret<<", respawning"<<endl;
 331
 332         sleep(1);
 333         continue;
 334       }
 335       if(WIFSIGNALED(status)) {
 336         int sig=WTERMSIG(status);
 337         setStatus("Child died because of signal "+itoa(sig));
 338         g_log<<Logger::Error<<"Our pdns instance ("<<pid<<") exited after signal "<<sig<<endl;
 339 #ifdef WCOREDUMP
 340         if(WCOREDUMP(status))
 341           g_log<<Logger::Error<<"Dumped core"<<endl;
 342 #endif
 343
 344         g_log<<Logger::Error<<"Respawning"<<endl;
 345         sleep(1);
 346         continue;
 347       }
 348       g_log<<Logger::Error<<"No clue what happened! Respawning"<<endl;
 349     }
 350     else {
 351       g_log<<Logger::Error<<"Unable to fork: "<<strerror(errno)<<endl;
 352       exit(1);
 353     }
 354   }
 355 }
 356
 357 #ifdef __GLIBC__
 358 #include <execinfo.h>
 359 static void tbhandler(int num)
 360 {
 361   g_log<<Logger::Critical<<"Got a signal "<<num<<", attempting to print trace: "<<endl;
 362   void *array[20]; //only care about last 17 functions (3 taken with tracing support)
 363   size_t size;
 364   char **strings;
 365   size_t i;
 366
 367   size = backtrace (array, 20);
 368   strings = backtrace_symbols (array, size); //Need -rdynamic gcc (linker) flag for this to work
 369
 370   for (i = 0; i < size; i++) //skip useless functions
 371     g_log<<Logger::Error<<strings[i]<<endl;
 372
 373
 374   signal(SIGABRT, SIG_DFL);
 375   abort();//hopefully will give core
 376
 377 }
 378 #endif
 379
 380 //! The main function of pdns, the pdns process
 381 int main(int argc, char **argv)
 382 {
 383   versionSetProduct(ProductAuthoritative);
 384   reportAllTypes(); // init MOADNSParser
 385
 386   s_programname="pdns";
 387   s_starttime=time(0);
 388
 389 #ifdef __GLIBC__
 390   signal(SIGSEGV,tbhandler);
 391   signal(SIGFPE,tbhandler);
 392   signal(SIGABRT,tbhandler);
 393   signal(SIGILL,tbhandler);
 394 #endif
 395
 396   std::ios_base::sync_with_stdio(false);
 397
 398   g_log.toConsole(Logger::Warning);
 399   try {
 400     declareArguments();
 401
 402     ::arg().laxParse(argc,argv); // do a lax parse
 403
 404     if(::arg().mustDo("version")) {
 405       showProductVersion();
 406       showBuildConfiguration();
 407       exit(99);
 408     }
 409
 410     if(::arg()["config-name"]!="")
 411       s_programname+="-"+::arg()["config-name"];
 412
 413     g_log.setName(s_programname);
 414
 415     string configname=::arg()["config-dir"]+"/"+s_programname+".conf";
 416     cleanSlashes(configname);
 417
 418     if(!::arg().mustDo("config") && !::arg().mustDo("no-config")) // "config" == print a configuration file
 419       ::arg().laxFile(configname.c_str());
 420
 421     ::arg().laxParse(argc,argv); // reparse so the commandline still wins
 422     if(!::arg()["logging-facility"].empty()) {
 423       int val=logFacilityToLOG(::arg().asNum("logging-facility") );
 424       if(val >= 0)
 425         g_log.setFacility(val);
 426       else
 427         g_log<<Logger::Error<<"Unknown logging facility "<<::arg().asNum("logging-facility") <<endl;
 428     }
 429
 430     g_log.setLoglevel((Logger::Urgency)(::arg().asNum("loglevel")));
 431     g_log.disableSyslog(::arg().mustDo("disable-syslog"));
 432     g_log.setTimestamps(::arg().mustDo("log-timestamp"));
 433     g_log.toConsole((Logger::Urgency)(::arg().asNum("loglevel")));
 434
 435     if(::arg().mustDo("help") || ::arg().mustDo("config")) {
 436       ::arg().set("daemon")="no";
 437       ::arg().set("guardian")="no";
 438     }
 439
 440     if(::arg().mustDo("guardian") && !isGuarded(argv)) {
 441       if(::arg().mustDo("daemon")) {
 442         g_log.toConsole(Logger::Critical);
 443         daemonize();
 444       }
 445       guardian(argc, argv);
 446       // never get here, guardian will reinvoke process
 447       cerr<<"Um, we did get here!"<<endl;
 448     }
 449
 450
 451     // we really need to do work - either standalone or as an instance
 452
 453 #ifdef __GLIBC__
 454     if(!::arg().mustDo("traceback-handler")) {
 455       g_log<<Logger::Warning<<"Disabling traceback handler"<<endl;
 456       signal(SIGSEGV,SIG_DFL);
 457       signal(SIGFPE,SIG_DFL);
 458       signal(SIGABRT,SIG_DFL);
 459       signal(SIGILL,SIG_DFL);
 460     }
 461 #endif
 462
 463 #ifdef HAVE_LIBSODIUM
 464       if (sodium_init() == -1) {
 465         cerr<<"Unable to initialize sodium crypto library"<<endl;
 466         exit(99);
 467       }
 468 #endif
 469
 470     openssl_thread_setup();
 471     openssl_seed();
 472     /* setup rng */
 473     dns_random_init();
 474
 475 #ifdef HAVE_LUA_RECORDS
 476     MiniCurl::init();
 477 #endif /* HAVE_LUA_RECORDS */
 478
 479     if(!::arg()["load-modules"].empty()) {
 480       vector<string> modules;
 481
 482       stringtok(modules,::arg()["load-modules"], ", ");
 483       if (!UeberBackend::loadModules(modules, ::arg()["module-dir"])) {
 484         exit(1);
 485       }
 486     }
 487
 488     BackendMakers().launch(::arg()["launch"]); // vrooooom!
 489
 490     if(!::arg().getCommands().empty()) {
 491       cerr<<"Fatal: non-option on the command line, perhaps a '--setting=123' statement missed the '='?"<<endl;
 492       exit(99);
 493     }
 494
 495     if(::arg().mustDo("help")) {
 496       cout<<"syntax:"<<endl<<endl;
 497       cout<<::arg().helpstring(::arg()["help"])<<endl;
 498       exit(0);
 499     }
 500
 501     if(::arg().mustDo("config")) {
 502       cout<<::arg().configstring()<<endl;
 503       exit(0);
 504     }
 505
 506     if(::arg().mustDo("list-modules")) {
 507       auto modules = BackendMakers().getModules();
 508       cout<<"Modules available:"<<endl;
 509       for(const auto& m : modules)
 510         cout<< m <<endl;
 511
 512       _exit(99);
 513     }
 514
 515     if(!::arg().asNum("local-port")) {
 516       g_log<<Logger::Error<<"Unable to launch, binding to no port or port 0 makes no sense"<<endl;
 517       exit(99); // this isn't going to fix itself either
 518     }
 519     if(!BackendMakers().numLauncheable()) {
 520       g_log<<Logger::Error<<"Unable to launch, no backends configured for querying"<<endl;
 521       exit(99); // this isn't going to fix itself either
 522     }
 523     if(::arg().mustDo("daemon")) {
 524       g_log.toConsole(Logger::None);
 525       if(!isGuarded(argv))
 526         daemonize();
 527     }
 528
 529     if(isGuarded(argv)) {
 530       g_log<<Logger::Warning<<"This is a guarded instance of pdns"<<endl;
 531       dl=new DynListener; // listens on stdin
 532     }
 533     else {
 534       g_log<<Logger::Warning<<"This is a standalone pdns"<<endl;
 535
 536       if(::arg().mustDo("control-console"))
 537         dl=new DynListener();
 538       else
 539         dl=new DynListener(s_programname);
 540
 541       writePid();
 542     }
 543     DynListener::registerFunc("SHOW",&DLShowHandler, "show a specific statistic or * to get a list", "<statistic>");
 544     DynListener::registerFunc("RPING",&DLPingHandler, "ping instance");
 545     DynListener::registerFunc("QUIT",&DLRQuitHandler, "quit daemon");
 546     DynListener::registerFunc("UPTIME",&DLUptimeHandler, "get instance uptime");
 547     DynListener::registerFunc("NOTIFY-HOST",&DLNotifyHostHandler, "notify host for specific domain", "<domain> <host>");
 548     DynListener::registerFunc("NOTIFY",&DLNotifyHandler, "queue a notification", "<domain>");
 549     DynListener::registerFunc("RELOAD",&DLReloadHandler, "reload all zones");
 550     DynListener::registerFunc("REDISCOVER",&DLRediscoverHandler, "discover any new zones");
 551     DynListener::registerFunc("VERSION",&DLVersionHandler, "get instance version");
 552     DynListener::registerFunc("PURGE",&DLPurgeHandler, "purge entries from packet cache", "[<record>]");
 553     DynListener::registerFunc("CCOUNTS",&DLCCHandler, "get cache statistics");
 554     DynListener::registerFunc("QTYPES", &DLQTypesHandler, "get QType statistics");
 555     DynListener::registerFunc("RESPSIZES", &DLRSizesHandler, "get histogram of response sizes");
 556     DynListener::registerFunc("REMOTES", &DLRemotesHandler, "get top remotes");
 557     DynListener::registerFunc("SET",&DLSettingsHandler, "set config variables", "<var> <value>");
 558     DynListener::registerFunc("RETRIEVE",&DLNotifyRetrieveHandler, "retrieve slave domain", "<domain>");
 559     DynListener::registerFunc("CURRENT-CONFIG",&DLCurrentConfigHandler, "retrieve the current configuration");
 560     DynListener::registerFunc("LIST-ZONES",&DLListZones, "show list of zones", "[master|slave|native]");
 561     DynListener::registerFunc("TOKEN-LOGIN", &DLTokenLogin, "Login to a PKCS#11 token", "<module> <slot> <pin>");
 562
 563     if(!::arg()["tcp-control-address"].empty()) {
 564       DynListener* dlTCP=new DynListener(ComboAddress(::arg()["tcp-control-address"], ::arg().asNum("tcp-control-port")));
 565       dlTCP->go();
 566     }
 567
 568     // reparse, with error checking
 569     if(!::arg().mustDo("no-config"))
 570       ::arg().file(configname.c_str());
 571     ::arg().parse(argc,argv);
 572
 573     if(::arg()["server-id"].empty()) {
 574       char tmp[128];
 575       if(gethostname(tmp, sizeof(tmp)-1) == 0) {
 576         ::arg().set("server-id")=tmp;
 577       } else {
 578         g_log<<Logger::Warning<<"Unable to get the hostname, NSID and id.server values will be empty: "<<strerror(errno)<<endl;
 579       }
 580     }
 581
 582     UeberBackend::go();
 583     N=std::make_shared<UDPNameserver>(); // this fails when we are not root, throws exception
 584     g_udpReceivers.push_back(N);
 585
 586     size_t rthreads = ::arg().asNum("receiver-threads", 1);
 587     if (rthreads > 1 && N->canReusePort()) {
 588       g_udpReceivers.resize(rthreads);
 589
 590       for (size_t idx = 1; idx < rthreads; idx++) {
 591         try {
 592           g_udpReceivers[idx] = std::make_shared<UDPNameserver>(true);
 593         }
 594         catch(const PDNSException& e) {
 595           g_log<<Logger::Error<<"Unable to reuse port, falling back to original bind"<<endl;
 596           break;
 597         }
 598       }
 599     }
 600
 601     TN = make_unique<TCPNameserver>();
 602   }
 603   catch(const ArgException &A) {
 604     g_log<<Logger::Error<<"Fatal error: "<<A.reason<<endl;
 605     exit(1);
 606   }
 607
 608   declareStats();
 609   S.blacklist("special-memory-usage");
 610
 611   DLOG(g_log<<Logger::Warning<<"Verbose logging in effect"<<endl);
 612
 613   showProductVersion();
 614
 615   try {
 616     mainthread();
 617   }
 618   catch(PDNSException &AE) {
 619     if(!::arg().mustDo("daemon"))
 620       cerr<<"Exiting because: "<<AE.reason<<endl;
 621     g_log<<Logger::Error<<"Exiting because: "<<AE.reason<<endl;
 622   }
 623   catch(std::exception &e) {
 624     if(!::arg().mustDo("daemon"))
 625       cerr<<"Exiting because of STL error: "<<e.what()<<endl;
 626     g_log<<Logger::Error<<"Exiting because of STL error: "<<e.what()<<endl;
 627   }
 628   catch(...) {
 629     cerr<<"Uncaught exception of unknown type - sorry"<<endl;
 630   }
 631
 632   exit(1);
 633
 634 }
 635
 636