sys/src/cmd/ndb/dns.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <auth.h>
   4 #include <fcall.h>
   5 #include <bio.h>
   6 #include <ctype.h>
   7 #include <ip.h>
   8 #include <pool.h>
   9 #include "dns.h"
  10
  11 enum
  12 {
  13         Maxrequest=             1024,
  14         Maxreply=               8192,           /* was 512 */
  15         Maxrrr=                 32,             /* was 16 */
  16         Maxfdata=               8192,
  17
  18         Defmaxage=              60*60,  /* default domain name max. age */
  19
  20         Qdir=                   0,
  21         Qdns=                   1,
  22 };
  23
  24 typedef struct Mfile    Mfile;
  25 typedef struct Job      Job;
  26 typedef struct Network  Network;
  27
  28 int vers;               /* incremented each clone/attach */
  29
  30 static volatile int stop;
  31
  32 /* holds data to be returned via read of /net/dns, perhaps multiple reads */
  33 struct Mfile
  34 {
  35         Mfile           *next;          /* next free mfile */
  36
  37         char            *user;
  38         Qid             qid;
  39         int             fid;
  40
  41         int             type;           /* reply type */
  42         char            reply[Maxreply];
  43         ushort          rr[Maxrrr];     /* offset of rr's */
  44         ushort          nrr;            /* number of rr's */
  45 };
  46
  47 /*
  48  *  active local requests
  49  */
  50 struct Job
  51 {
  52         Job     *next;
  53         int     flushed;
  54         Fcall   request;
  55         Fcall   reply;
  56 };
  57 Lock    joblock;
  58 Job     *joblist;
  59
  60 struct {
  61         Lock;
  62         Mfile   *inuse;         /* active mfile's */
  63 } mfalloc;
  64
  65 Cfg     cfg;
  66 int     debug;
  67 int     maxage = Defmaxage;
  68 int     mfd[2];
  69 int     needrefresh;
  70 ulong   now;
  71 vlong   nowns;
  72 int     sendnotifies;
  73 int     testing;
  74 char    *trace;
  75 int     traceactivity;
  76 char    *zonerefreshprogram;
  77
  78 char    *logfile = "dns";       /* or "dns.test" */
  79 char    *dbfile;
  80 char    *dnsuser;
  81 char    mntpt[Maxpath];
  82
  83 int     addforwtarg(char *);
  84 int     fillreply(Mfile*, int);
  85 void    freejob(Job*);
  86 void    io(void);
  87 void    mountinit(char*, char*);
  88 Job*    newjob(void);
  89 void    rattach(Job*, Mfile*);
  90 void    rauth(Job*);
  91 void    rclunk(Job*, Mfile*);
  92 void    rcreate(Job*, Mfile*);
  93 void    rflush(Job*);
  94 void    ropen(Job*, Mfile*);
  95 void    rread(Job*, Mfile*);
  96 void    rremove(Job*, Mfile*);
  97 void    rstat(Job*, Mfile*);
  98 void    rversion(Job*);
  99 char*   rwalk(Job*, Mfile*);
 100 void    rwrite(Job*, Mfile*, Request*);
 101 void    rwstat(Job*, Mfile*);
 102 void    sendmsg(Job*, char*);
 103 void    setext(char*, int, char*);
 104
 105 static char *lookupquery(Job*, Mfile*, Request*, char*, char*, int, int);
 106 static char *respond(Job*, Mfile*, RR*, char*, int, int);
 107
 108 void
 109 usage(void)
 110 {
 111         fprint(2, "usage: %s [-FnorRst] [-a maxage] [-f ndb-file] [-N target] "
 112                 "[-T forwip] [-x netmtpt] [-z refreshprog]\n", argv0);
 113         exits("usage");
 114 }
 115
 116 void
 117 main(int argc, char *argv[])
 118 {
 119         int kid, pid;
 120         char servefile[Maxpath], ext[Maxpath];
 121         Dir *dir;
 122
 123         setnetmtpt(mntpt, sizeof mntpt, nil);
 124         ext[0] = 0;
 125         ARGBEGIN{
 126         case 'a':
 127                 maxage = atol(EARGF(usage()));
 128                 if (maxage <= 0)
 129                         maxage = Defmaxage;
 130                 break;
 131         case 'd':
 132                 debug = 1;
 133                 traceactivity = 1;
 134                 break;
 135         case 'f':
 136                 dbfile = EARGF(usage());
 137                 break;
 138         case 'F':
 139                 cfg.justforw = cfg.resolver = 1;
 140                 break;
 141         case 'n':
 142                 sendnotifies = 1;
 143                 break;
 144         case 'N':
 145                 target = atol(EARGF(usage()));
 146                 if (target < 1000)
 147                         target = 1000;
 148                 break;
 149         case 'o':
 150                 cfg.straddle = 1;       /* straddle inside & outside networks */
 151                 break;
 152         case 'r':
 153                 cfg.resolver = 1;
 154                 break;
 155         case 'R':
 156                 norecursion = 1;
 157                 break;
 158         case 's':
 159                 cfg.serve = 1;          /* serve network */
 160                 cfg.cachedb = 1;
 161                 break;
 162         case 't':
 163                 testing = 1;
 164                 break;
 165         case 'T':
 166                 addforwtarg(EARGF(usage()));
 167                 break;
 168         case 'x':
 169                 setnetmtpt(mntpt, sizeof mntpt, EARGF(usage()));
 170                 setext(ext, sizeof ext, mntpt);
 171                 break;
 172         case 'z':
 173                 zonerefreshprogram = EARGF(usage());
 174                 break;
 175         default:
 176                 usage();
 177                 break;
 178         }ARGEND
 179         if(argc != 0)
 180                 usage();
 181
 182         if(testing)
 183                 mainmem->flags |= POOL_NOREUSE | POOL_ANTAGONISM;
 184         mainmem->flags |= POOL_ANTAGONISM;
 185         rfork(RFREND|RFNOTEG);
 186
 187         cfg.inside = (*mntpt == '\0' || strcmp(mntpt, "/net") == 0);
 188
 189         /* start syslog before we fork */
 190         fmtinstall('F', fcallfmt);
 191         dninit();
 192         dnslog("starting %s%sdns %s%s%son %s",
 193                 (cfg.straddle? "straddling ": ""),
 194                 (cfg.cachedb? "caching ": ""),
 195                 (cfg.serve?   "udp server ": ""),
 196                 (cfg.justforw? "forwarding-only ": ""),
 197                 (cfg.resolver? "resolver ": ""), mntpt);
 198
 199         opendatabase();
 200         now = time(nil);                /* open time files before we fork */
 201         nowns = nsec();
 202         dnsuser = estrdup(getuser());
 203
 204         snprint(servefile, sizeof servefile, "#s/dns%s", ext);
 205         dir = dirstat(servefile);
 206         if (dir)
 207                 sysfatal("%s exists; another dns instance is running",
 208                         servefile);
 209         free(dir);
 210 //      unmount(servefile, mntpt);
 211 //      remove(servefile);
 212
 213         mountinit(servefile, mntpt);    /* forks, parent exits */
 214
 215         srand(now*getpid());
 216         db2cache(1);
 217
 218         if (cfg.straddle && !seerootns())
 219                 dnslog("straddle server misconfigured; can't see root name servers");
 220         /*
 221          * fork without sharing heap.
 222          * parent waits around for child to die, then forks & restarts.
 223          * child may spawn udp server, notify procs, etc.; when it gets too
 224          * big, it kills itself and any children.
 225          * /srv/dns and /net/dns remain open and valid.
 226          */
 227         for (;;) {
 228                 kid = rfork(RFPROC|RFFDG|RFNOTEG);
 229                 switch (kid) {
 230                 case -1:
 231                         sysfatal("fork failed: %r");
 232                 case 0:
 233                         if(cfg.serve)
 234                                 dnudpserver(mntpt);
 235                         if(sendnotifies)
 236                                 notifyproc();
 237                         io();
 238                         _exits("restart");
 239                 default:
 240                         while ((pid = waitpid()) != kid && pid != -1)
 241                                 continue;
 242                         break;
 243                 }
 244                 dnslog("dns restarting");
 245         }
 246 }
 247
 248 /*
 249  *  if a mount point is specified, set the cs extension to be the mount point
 250  *  with '_'s replacing '/'s
 251  */
 252 void
 253 setext(char *ext, int n, char *p)
 254 {
 255         int i, c;
 256
 257         n--;
 258         for(i = 0; i < n; i++){
 259                 c = p[i];
 260                 if(c == 0)
 261                         break;
 262                 if(c == '/')
 263                         c = '_';
 264                 ext[i] = c;
 265         }
 266         ext[i] = 0;
 267 }
 268
 269 void
 270 mountinit(char *service, char *mntpt)
 271 {
 272         int f;
 273         int p[2];
 274         char buf[32];
 275
 276         if(pipe(p) < 0)
 277                 sysfatal("pipe failed: %r");
 278
 279         /*
 280          *  make a /srv/dns
 281          */
 282         if((f = create(service, OWRITE|ORCLOSE, 0666)) < 0)
 283                 sysfatal("create %s failed: %r", service);
 284         snprint(buf, sizeof buf, "%d", p[1]);
 285         if(write(f, buf, strlen(buf)) != strlen(buf))
 286                 sysfatal("write %s failed: %r", service);
 287
 288         /* copy namespace to avoid a deadlock */
 289         switch(rfork(RFFDG|RFPROC|RFNAMEG)){
 290         case 0:                 /* child: hang around and (re)start main proc */
 291                 close(p[1]);
 292                 procsetname("%s restarter", mntpt);
 293                 break;
 294         case -1:
 295                 sysfatal("fork failed: %r");
 296         default:                /* parent: make /srv/dns, mount it, exit */
 297                 close(p[0]);
 298
 299                 /*
 300                  *  put ourselves into the file system
 301                  */
 302                 if(mount(p[1], -1, mntpt, MAFTER, "") < 0)
 303                         fprint(2, "dns mount failed: %r\n");
 304                 _exits(0);
 305         }
 306         mfd[0] = mfd[1] = p[0];
 307 }
 308
 309 Mfile*
 310 newfid(int fid, int needunused)
 311 {
 312         Mfile *mf;
 313
 314         lock(&mfalloc);
 315         for(mf = mfalloc.inuse; mf != nil; mf = mf->next)
 316                 if(mf->fid == fid){
 317                         unlock(&mfalloc);
 318                         if(needunused)
 319                                 return nil;
 320                         return mf;
 321                 }
 322         mf = emalloc(sizeof(*mf));
 323         mf->fid = fid;
 324         mf->user = estrdup("dummy");
 325         mf->next = mfalloc.inuse;
 326         mfalloc.inuse = mf;
 327         unlock(&mfalloc);
 328         return mf;
 329 }
 330
 331 void
 332 freefid(Mfile *mf)
 333 {
 334         Mfile **l;
 335
 336         lock(&mfalloc);
 337         for(l = &mfalloc.inuse; *l != nil; l = &(*l)->next)
 338                 if(*l == mf){
 339                         *l = mf->next;
 340                         free(mf->user);
 341                         memset(mf, 0, sizeof *mf);      /* cause trouble */
 342                         free(mf);
 343                         unlock(&mfalloc);
 344                         return;
 345                 }
 346         unlock(&mfalloc);
 347         sysfatal("freeing unused fid");
 348 }
 349
 350 Mfile*
 351 copyfid(Mfile *mf, int fid)
 352 {
 353         Mfile *nmf;
 354
 355         nmf = newfid(fid, 1);
 356         if(nmf == nil)
 357                 return nil;
 358         nmf->fid = fid;
 359         free(nmf->user);                        /* estrdup("dummy") */
 360         nmf->user = estrdup(mf->user);
 361         nmf->qid.type = mf->qid.type;
 362         nmf->qid.path = mf->qid.path;
 363         nmf->qid.vers = vers++;
 364         return nmf;
 365 }
 366
 367 Job*
 368 newjob(void)
 369 {
 370         Job *job;
 371
 372         job = emalloc(sizeof *job);
 373         lock(&joblock);
 374         job->next = joblist;
 375         joblist = job;
 376         job->request.tag = -1;
 377         unlock(&joblock);
 378         return job;
 379 }
 380
 381 void
 382 freejob(Job *job)
 383 {
 384         Job **l;
 385
 386         lock(&joblock);
 387         for(l = &joblist; *l; l = &(*l)->next)
 388                 if(*l == job){
 389                         *l = job->next;
 390                         memset(job, 0, sizeof *job);    /* cause trouble */
 391                         free(job);
 392                         break;
 393                 }
 394         unlock(&joblock);
 395 }
 396
 397 void
 398 flushjob(int tag)
 399 {
 400         Job *job;
 401
 402         lock(&joblock);
 403         for(job = joblist; job; job = job->next)
 404                 if(job->request.tag == tag && job->request.type != Tflush){
 405                         job->flushed = 1;
 406                         break;
 407                 }
 408         unlock(&joblock);
 409 }
 410
 411 void
 412 io(void)
 413 {
 414         volatile long n;
 415         volatile uchar mdata[IOHDRSZ + Maxfdata];
 416         Job *volatile job;
 417         Mfile *volatile mf;
 418         volatile Request req;
 419
 420         memset(&req, 0, sizeof req);
 421         /*
 422          *  a slave process is sometimes forked to wait for replies from other
 423          *  servers.  The master process returns immediately via a longjmp
 424          *  through 'mret'.
 425          */
 426         if(setjmp(req.mret))
 427                 putactivity(0);
 428         req.isslave = 0;
 429         stop = 0;
 430         while(!stop){
 431                 procsetname("%d %s/dns Twrites of %d 9p rpcs read; %d alarms",
 432                         stats.qrecvd9p, mntpt, stats.qrecvd9prpc, stats.alarms);
 433                 while((n = read9pmsg(mfd[0], mdata, sizeof mdata)) == 0)
 434                         ;
 435                 if(n < 0){
 436                         dnslog("error reading 9P from %s: %r", mntpt);
 437                         sleep(2000);    /* don't thrash after read error */
 438                         return;
 439                 }
 440
 441                 stats.qrecvd9prpc++;
 442                 job = newjob();
 443                 if(convM2S(mdata, n, &job->request) != n){
 444                         freejob(job);
 445                         continue;
 446                 }
 447                 mf = newfid(job->request.fid, 0);
 448                 if(debug)
 449                         dnslog("%F", &job->request);
 450
 451                 getactivity(&req, 0);
 452                 req.aborttime = timems() + Maxreqtm;
 453                 req.from = "9p";
 454
 455                 switch(job->request.type){
 456                 default:
 457                         warning("unknown request type %d", job->request.type);
 458                         break;
 459                 case Tversion:
 460                         rversion(job);
 461                         break;
 462                 case Tauth:
 463                         rauth(job);
 464                         break;
 465                 case Tflush:
 466                         rflush(job);
 467                         break;
 468                 case Tattach:
 469                         rattach(job, mf);
 470                         break;
 471                 case Twalk:
 472                         rwalk(job, mf);
 473                         break;
 474                 case Topen:
 475                         ropen(job, mf);
 476                         break;
 477                 case Tcreate:
 478                         rcreate(job, mf);
 479                         break;
 480                 case Tread:
 481                         rread(job, mf);
 482                         break;
 483                 case Twrite:
 484                         /* &req is handed to dnresolve() */
 485                         rwrite(job, mf, &req);
 486                         break;
 487                 case Tclunk:
 488                         rclunk(job, mf);
 489                         break;
 490                 case Tremove:
 491                         rremove(job, mf);
 492                         break;
 493                 case Tstat:
 494                         rstat(job, mf);
 495                         break;
 496                 case Twstat:
 497                         rwstat(job, mf);
 498                         break;
 499                 }
 500
 501                 freejob(job);
 502
 503                 /*
 504                  *  slave processes die after replying
 505                  */
 506                 if(req.isslave){
 507                         putactivity(0);
 508                         _exits(0);
 509                 }
 510
 511                 putactivity(0);
 512         }
 513         /* kill any udp server, notifier, etc. processes */
 514         postnote(PNGROUP, getpid(), "die");
 515         sleep(1000);
 516 }
 517
 518 void
 519 rversion(Job *job)
 520 {
 521         if(job->request.msize > IOHDRSZ + Maxfdata)
 522                 job->reply.msize = IOHDRSZ + Maxfdata;
 523         else
 524                 job->reply.msize = job->request.msize;
 525         if(strncmp(job->request.version, "9P2000", 6) != 0)
 526                 sendmsg(job, "unknown 9P version");
 527         else{
 528                 job->reply.version = "9P2000";
 529                 sendmsg(job, 0);
 530         }
 531 }
 532
 533 void
 534 rauth(Job *job)
 535 {
 536         sendmsg(job, "dns: authentication not required");
 537 }
 538
 539 /*
 540  *  don't flush till all the slaves are done
 541  */
 542 void
 543 rflush(Job *job)
 544 {
 545         flushjob(job->request.oldtag);
 546         sendmsg(job, 0);
 547 }
 548
 549 void
 550 rattach(Job *job, Mfile *mf)
 551 {
 552         if(mf->user != nil)
 553                 free(mf->user);
 554         mf->user = estrdup(job->request.uname);
 555         mf->qid.vers = vers++;
 556         mf->qid.type = QTDIR;
 557         mf->qid.path = 0LL;
 558         job->reply.qid = mf->qid;
 559         sendmsg(job, 0);
 560 }
 561
 562 char*
 563 rwalk(Job *job, Mfile *mf)
 564 {
 565         int i, nelems;
 566         char *err;
 567         char **elems;
 568         Mfile *nmf;
 569         Qid qid;
 570
 571         err = 0;
 572         nmf = nil;
 573         elems  = job->request.wname;
 574         nelems = job->request.nwname;
 575         job->reply.nwqid = 0;
 576
 577         if(job->request.newfid != job->request.fid){
 578                 /* clone fid */
 579                 nmf = copyfid(mf, job->request.newfid);
 580                 if(nmf == nil){
 581                         err = "clone bad newfid";
 582                         goto send;
 583                 }
 584                 mf = nmf;
 585         }
 586         /* else nmf will be nil */
 587
 588         qid = mf->qid;
 589         if(nelems > 0)
 590                 /* walk fid */
 591                 for(i=0; i<nelems && i<MAXWELEM; i++){
 592                         if((qid.type & QTDIR) == 0){
 593                                 err = "not a directory";
 594                                 break;
 595                         }
 596                         if (strcmp(elems[i], "..") == 0 ||
 597                             strcmp(elems[i], ".") == 0){
 598                                 qid.type = QTDIR;
 599                                 qid.path = Qdir;
 600 Found:
 601                                 job->reply.wqid[i] = qid;
 602                                 job->reply.nwqid++;
 603                                 continue;
 604                         }
 605                         if(strcmp(elems[i], "dns") == 0){
 606                                 qid.type = QTFILE;
 607                                 qid.path = Qdns;
 608                                 goto Found;
 609                         }
 610                         err = "file does not exist";
 611                         break;
 612                 }
 613
 614 send:
 615         if(nmf != nil && (err!=nil || job->reply.nwqid<nelems))
 616                 freefid(nmf);
 617         if(err == nil)
 618                 mf->qid = qid;
 619         sendmsg(job, err);
 620         return err;
 621 }
 622
 623 void
 624 ropen(Job *job, Mfile *mf)
 625 {
 626         int mode;
 627         char *err;
 628
 629         err = 0;
 630         mode = job->request.mode;
 631         if(mf->qid.type & QTDIR)
 632                 if(mode)
 633                         err = "permission denied";
 634         job->reply.qid = mf->qid;
 635         job->reply.iounit = 0;
 636         sendmsg(job, err);
 637 }
 638
 639 void
 640 rcreate(Job *job, Mfile *mf)
 641 {
 642         USED(mf);
 643         sendmsg(job, "creation permission denied");
 644 }
 645
 646 void
 647 rread(Job *job, Mfile *mf)
 648 {
 649         int i, n;
 650         long clock;
 651         ulong cnt;
 652         vlong off;
 653         char *err;
 654         uchar buf[Maxfdata];
 655         Dir dir;
 656
 657         n = 0;
 658         err = nil;
 659         off = job->request.offset;
 660         cnt = job->request.count;
 661         *buf = '\0';
 662         job->reply.data = (char*)buf;
 663         if(mf->qid.type & QTDIR){
 664                 clock = time(nil);
 665                 if(off == 0){
 666                         memset(&dir, 0, sizeof dir);
 667                         dir.name = "dns";
 668                         dir.qid.type = QTFILE;
 669                         dir.qid.vers = vers;
 670                         dir.qid.path = Qdns;
 671                         dir.mode = 0666;
 672                         dir.length = 0;
 673                         dir.uid = dir.gid = dir.muid = mf->user;
 674                         dir.atime = dir.mtime = clock;          /* wrong */
 675                         n = convD2M(&dir, buf, sizeof buf);
 676                 }
 677         } else if (off < 0)
 678                 err = "negative read offset";
 679         else {
 680                 /* first offset will always be zero */
 681                 for(i = 1; i <= mf->nrr; i++)
 682                         if(mf->rr[i] > off)
 683                                 break;
 684                 if(i <= mf->nrr) {
 685                         if(off + cnt > mf->rr[i])
 686                                 n = mf->rr[i] - off;
 687                         else
 688                                 n = cnt;
 689                         assert(n >= 0);
 690                         job->reply.data = mf->reply + off;
 691                 }
 692         }
 693         job->reply.count = n;
 694         sendmsg(job, err);
 695 }
 696
 697 void
 698 rwrite(Job *job, Mfile *mf, Request *req)
 699 {
 700         int rooted, wantsav, send;
 701         ulong cnt;
 702         char *err, *p, *atype;
 703         char errbuf[ERRMAX];
 704
 705         err = nil;
 706         cnt = job->request.count;
 707         send = 1;
 708         if(mf->qid.type & QTDIR)
 709                 err = "can't write directory";
 710         else if (job->request.offset != 0)
 711                 err = "writing at non-zero offset";
 712         else if(cnt >= Maxrequest)
 713                 err = "request too long";
 714         else
 715                 send = 0;
 716         if (send)
 717                 goto send;
 718
 719         job->request.data[cnt] = 0;
 720         if(cnt > 0 && job->request.data[cnt-1] == '\n')
 721                 job->request.data[cnt-1] = 0;
 722
 723         if(strcmp(mf->user, "none") == 0 || strcmp(mf->user, dnsuser) != 0)
 724                 goto query;     /* skip special commands if not owner */
 725
 726         /*
 727          *  special commands
 728          */
 729         if(debug)
 730                 dnslog("rwrite got: %s", job->request.data);
 731         send = 1;
 732         if(strcmp(job->request.data, "debug")==0)
 733                 debug ^= 1;
 734         else if(strcmp(job->request.data, "testing")==0)
 735                 testing ^= 1;
 736         else if(strcmp(job->request.data, "dump")==0)
 737                 dndump("/lib/ndb/dnsdump");
 738         else if(strcmp(job->request.data, "poolcheck")==0)
 739                 poolcheck(mainmem);
 740         else if(strcmp(job->request.data, "refresh")==0)
 741                 needrefresh = 1;
 742         else if(strcmp(job->request.data, "restart")==0)
 743                 stop = 1;
 744         else if(strcmp(job->request.data, "stats")==0)
 745                 dnstats("/lib/ndb/dnsstats");
 746         else if(strncmp(job->request.data, "target ", 7)==0){
 747                 target = atol(job->request.data + 7);
 748                 dnslog("target set to %ld", target);
 749         } else
 750                 send = 0;
 751         if (send)
 752                 goto send;
 753
 754 query:
 755         /*
 756          *  kill previous reply
 757          */
 758         mf->nrr = 0;
 759         mf->rr[0] = 0;
 760
 761         /*
 762          *  break up request (into a name and a type)
 763          */
 764         atype = strchr(job->request.data, ' ');
 765         if(atype == 0){
 766                 snprint(errbuf, sizeof errbuf, "illegal request %s",
 767                         job->request.data);
 768                 err = errbuf;
 769                 goto send;
 770         } else
 771                 *atype++ = 0;
 772
 773         /*
 774          *  tracing request
 775          */
 776         if(strcmp(atype, "trace") == 0){
 777                 if(trace)
 778                         free(trace);
 779                 if(*job->request.data)
 780                         trace = estrdup(job->request.data);
 781                 else
 782                         trace = 0;
 783                 goto send;
 784         }
 785
 786         /* normal request: domain [type] */
 787         stats.qrecvd9p++;
 788         mf->type = rrtype(atype);
 789         if(mf->type < 0){
 790                 snprint(errbuf, sizeof errbuf, "unknown type %s", atype);
 791                 err = errbuf;
 792                 goto send;
 793         }
 794
 795         p = atype - 2;
 796         if(p >= job->request.data && *p == '.'){
 797                 rooted = 1;
 798                 *p = 0;
 799         } else
 800                 rooted = 0;
 801
 802         p = job->request.data;
 803         if(*p == '!'){
 804                 wantsav = 1;
 805                 p++;
 806         } else
 807                 wantsav = 0;
 808
 809         err = lookupquery(job, mf, req, errbuf, p, wantsav, rooted);
 810 send:
 811         job->reply.count = cnt;
 812         sendmsg(job, err);
 813 }
 814
 815 /*
 816  * dnsdebug calls
 817  *      rr = dnresolve(buf, Cin, type, &req, 0, 0, Recurse, rooted, 0);
 818  * which generates a UDP query, which eventually calls
 819  *      dnserver(&reqmsg, &repmsg, &req, buf, rcode);
 820  * which calls
 821  *      rp = dnresolve(name, Cin, type, req, &mp->an, 0, recurse, 1, 0);
 822  *
 823  * but here we just call dnresolve directly.
 824  */
 825 static char *
 826 lookupquery(Job *job, Mfile *mf, Request *req, char *errbuf, char *p,
 827         int wantsav, int rooted)
 828 {
 829         int status;
 830         RR *rp, *neg;
 831
 832         status = Rok;
 833         rp = dnresolve(p, Cin, mf->type, req, 0, 0, Recurse, rooted, &status);
 834
 835         neg = rrremneg(&rp);
 836         if(neg){
 837                 status = neg->negrcode;
 838                 rrfreelist(neg);
 839         }
 840
 841         return respond(job, mf, rp, errbuf, status, wantsav);
 842 }
 843
 844 static char *
 845 respond(Job *job, Mfile *mf, RR *rp, char *errbuf, int status, int wantsav)
 846 {
 847         long n;
 848         RR *tp;
 849
 850         if(rp == nil)
 851                 switch(status){
 852                 case Rname:
 853                         return "name does not exist";
 854                 case Rserver:
 855                         return "dns failure";
 856                 case Rok:
 857                 default:
 858                         snprint(errbuf, ERRMAX,
 859                                 "resource does not exist; negrcode %d", status);
 860                         return errbuf;
 861                 }
 862
 863         lock(&joblock);
 864         if(!job->flushed){
 865                 /* format data to be read later */
 866                 n = 0;
 867                 mf->nrr = 0;
 868                 for(tp = rp; mf->nrr < Maxrrr-1 && n < Maxreply && tp &&
 869                     tsame(mf->type, tp->type); tp = tp->next){
 870                         mf->rr[mf->nrr++] = n;
 871                         if(wantsav)
 872                                 n += snprint(mf->reply+n, Maxreply-n, "%Q", tp);
 873                         else
 874                                 n += snprint(mf->reply+n, Maxreply-n, "%R", tp);
 875                 }
 876                 mf->rr[mf->nrr] = n;
 877         }
 878         unlock(&joblock);
 879
 880         rrfreelist(rp);
 881
 882         return nil;
 883 }
 884
 885 void
 886 rclunk(Job *job, Mfile *mf)
 887 {
 888         freefid(mf);
 889         sendmsg(job, 0);
 890 }
 891
 892 void
 893 rremove(Job *job, Mfile *mf)
 894 {
 895         USED(mf);
 896         sendmsg(job, "remove permission denied");
 897 }
 898
 899 void
 900 rstat(Job *job, Mfile *mf)
 901 {
 902         Dir dir;
 903         uchar buf[IOHDRSZ+Maxfdata];
 904
 905         memset(&dir, 0, sizeof dir);
 906         if(mf->qid.type & QTDIR){
 907                 dir.name = ".";
 908                 dir.mode = DMDIR|0555;
 909         } else {
 910                 dir.name = "dns";
 911                 dir.mode = 0666;
 912         }
 913         dir.qid = mf->qid;
 914         dir.length = 0;
 915         dir.uid = dir.gid = dir.muid = mf->user;
 916         dir.atime = dir.mtime = time(nil);
 917         job->reply.nstat = convD2M(&dir, buf, sizeof buf);
 918         job->reply.stat = buf;
 919         sendmsg(job, 0);
 920 }
 921
 922 void
 923 rwstat(Job *job, Mfile *mf)
 924 {
 925         USED(mf);
 926         sendmsg(job, "wstat permission denied");
 927 }
 928
 929 void
 930 sendmsg(Job *job, char *err)
 931 {
 932         int n;
 933         uchar mdata[IOHDRSZ + Maxfdata];
 934         char ename[ERRMAX];
 935
 936         if(err){
 937                 job->reply.type = Rerror;
 938                 snprint(ename, sizeof ename, "dns: %s", err);
 939                 job->reply.ename = ename;
 940         }else
 941                 job->reply.type = job->request.type+1;
 942         job->reply.tag = job->request.tag;
 943         n = convS2M(&job->reply, mdata, sizeof mdata);
 944         if(n == 0){
 945                 warning("sendmsg convS2M of %F returns 0", &job->reply);
 946                 abort();
 947         }
 948         lock(&joblock);
 949         if(job->flushed == 0)
 950                 if(write(mfd[1], mdata, n)!=n)
 951                         sysfatal("mount write");
 952         unlock(&joblock);
 953         if(debug)
 954                 dnslog("%F %d", &job->reply, n);
 955 }
 956
 957 /*
 958  *  the following varies between dnsdebug and dns
 959  */
 960 void
 961 logreply(int id, uchar *addr, DNSmsg *mp)
 962 {
 963         RR *rp;
 964
 965         dnslog("%d: rcvd %I flags:%s%s%s%s%s", id, addr,
 966                 mp->flags & Fauth? " auth": "",
 967                 mp->flags & Ftrunc? " trunc": "",
 968                 mp->flags & Frecurse? " rd": "",
 969                 mp->flags & Fcanrec? " ra": "",
 970                 (mp->flags & (Fauth|Rmask)) == (Fauth|Rname)? " nx": "");
 971         for(rp = mp->qd; rp != nil; rp = rp->next)
 972                 dnslog("%d: rcvd %I qd %s", id, addr, rp->owner->name);
 973         for(rp = mp->an; rp != nil; rp = rp->next)
 974                 dnslog("%d: rcvd %I an %R", id, addr, rp);
 975         for(rp = mp->ns; rp != nil; rp = rp->next)
 976                 dnslog("%d: rcvd %I ns %R", id, addr, rp);
 977         for(rp = mp->ar; rp != nil; rp = rp->next)
 978                 dnslog("%d: rcvd %I ar %R", id, addr, rp);
 979 }
 980
 981 void
 982 logsend(int id, int subid, uchar *addr, char *sname, char *rname, int type)
 983 {
 984         char buf[12];
 985
 986         dnslog("[%d] %d.%d: sending to %I/%s %s %s",
 987                 getpid(), id, subid, addr, sname, rname,
 988                 rrname(type, buf, sizeof buf));
 989 }
 990
 991 RR*
 992 getdnsservers(int class)
 993 {
 994         return dnsservers(class);
 995 }