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