sys/src/cmd/cpu.c

   1 /*
   2  * cpu.c - Make a connection to a cpu server
   3  *
   4  *         Invoked by listen as 'cpu -R | -N service net netdir'
   5  *                 by users  as 'cpu [-h system] [-c cmd args ...]'
   6  */
   7
   8 #include <u.h>
   9 #include <libc.h>
  10 #include <auth.h>
  11 #include <fcall.h>
  12 #include <libsec.h>
  13
  14 #define Maxfdata 8192
  15 #define MaxStr 128
  16
  17 void    remoteside(void);
  18 void    fatal(char*, ...);
  19 void    lclnoteproc(int);
  20 void    rmtnoteproc(void);
  21 void    catcher(void*, char*);
  22 void    usage(void);
  23 void    writestr(int, char*, char*, int);
  24 int     readstr(int, char*, int);
  25 char    *rexcall(int*, char*, char*);
  26 int     setamalg(char*);
  27 char    *keyspec = "";
  28
  29 int     notechan;
  30 int     exportpid;
  31 char    *system;
  32 int     cflag;
  33 int     nflag;
  34 int     dbg;
  35 char    *user;
  36 char    *patternfile;
  37 char    *origargs;
  38
  39 char    *srvname = "ncpu";
  40 char    *exportfs = "/bin/exportfs";
  41 char    *ealgs = "rc4_256 sha1";
  42
  43 /* message size for exportfs; may be larger so we can do big graphics in CPU window */
  44 int     msgsize = Maxfdata+IOHDRSZ;
  45
  46 /* encryption mechanisms */
  47 static int      clear(int);
  48
  49 int (*encryption)(int) = clear;
  50
  51 /* authentication mechanisms */
  52 static int      netkeyauth(int);
  53 static int      netkeysrvauth(int, char*);
  54 static int      p9auth(int);
  55 static int      srvp9auth(int, char*);
  56 static int      noauth(int);
  57 static int      srvnoauth(int, char*);
  58
  59 typedef struct AuthMethod AuthMethod;
  60 struct AuthMethod {
  61         char    *name;                  /* name of method */
  62         int     (*cf)(int);             /* client side authentication */
  63         int     (*sf)(int, char*);      /* server side authentication */
  64 } authmethod[] = {
  65         { "p9",         p9auth,         srvp9auth,},
  66         { "netkey",     netkeyauth,     netkeysrvauth,},
  67         { "none",       noauth,         srvnoauth,},
  68         { nil,  nil}
  69 };
  70 AuthMethod *am = authmethod;    /* default is p9 */
  71
  72 int setam(char*);
  73
  74 char    *aan = "/bin/aan";
  75 char    *anstring = "tcp!*!0";
  76 char    *filterp = nil;
  77
  78 int filter(int fd, char *host);
  79
  80 void
  81 usage(void)
  82 {
  83         fprint(2, "usage: cpu [-p] [-h system] [-u user] [-a authmethod] "
  84                 "[-e 'crypt hash'] [-k keypattern] [-P patternfile] "
  85                 "[-c cmd arg ...]\n");
  86         exits("usage");
  87 }
  88
  89 /*
  90  * reading /proc/pid/args yields either "name args" or "name [display args]",
  91  * so return only args or display args.
  92  */
  93 static char *
  94 procgetname(void)
  95 {
  96         int fd, n;
  97         char *lp, *rp;
  98         char buf[256];
  99
 100         snprint(buf, sizeof buf, "#p/%d/args", getpid());
 101         if((fd = open(buf, OREAD)) < 0)
 102                 return strdup("");
 103         *buf = '\0';
 104         n = read(fd, buf, sizeof buf-1);
 105         close(fd);
 106         if (n >= 0)
 107                 buf[n] = '\0';
 108         if ((lp = strchr(buf, '[')) == nil || (rp = strrchr(buf, ']')) == nil) {
 109                 lp = strchr(buf, ' ');
 110                 if (lp == nil)
 111                         return strdup("");
 112                 else
 113                         return strdup(lp+1);
 114         }
 115         *rp = '\0';
 116         return strdup(lp+1);
 117 }
 118
 119 void
 120 main(int argc, char **argv)
 121 {
 122         char dat[MaxStr], buf[MaxStr], cmd[MaxStr], *p, *s, *err;
 123         int ac, fd, ms, data;
 124         char *av[10];
 125
 126         quotefmtinstall();
 127         origargs = procgetname();
 128         /* see if we should use a larger message size */
 129         fd = open("/dev/draw", OREAD);
 130         if(fd >= 0){
 131                 ms = iounit(fd);
 132                 if(msgsize < ms+IOHDRSZ)
 133                         msgsize = ms+IOHDRSZ;
 134                 close(fd);
 135         }
 136
 137         user = getuser();
 138         if(user == nil)
 139                 fatal("can't read user name: %r");
 140         ARGBEGIN{
 141         case 'a':
 142                 p = EARGF(usage());
 143                 if(setam(p) < 0)
 144                         fatal("unknown auth method %s", p);
 145                 break;
 146         case 'e':
 147                 ealgs = EARGF(usage());
 148                 if(*ealgs == 0 || strcmp(ealgs, "clear") == 0)
 149                         ealgs = nil;
 150                 break;
 151         case 'd':
 152                 dbg++;
 153                 break;
 154         case 'f':
 155                 /* ignored but accepted for compatibility */
 156                 break;
 157         case 'n':
 158                 /* must be specified before -R/-O */
 159                 nflag++;
 160                 break;
 161         case 'A':
 162                 anstring = EARGF(usage());
 163                 break;
 164         case 'R':                               /* From listen */
 165                 remoteside();
 166                 break;
 167         case 'h':
 168                 system = EARGF(usage());
 169                 break;
 170         case 'c':
 171                 cflag++;
 172                 s = cmd;
 173                 *s++ = '!';
 174                 *s = 0;
 175                 while(p = ARGF())
 176                         s = seprint(s, cmd+sizeof(cmd), " %q", p);
 177                 break;
 178         case 'k':
 179                 keyspec = smprint("%s %s", keyspec, EARGF(usage()));
 180                 break;
 181         case 'P':
 182                 patternfile = EARGF(usage());
 183                 break;
 184         case 'u':
 185                 user = EARGF(usage());
 186                 keyspec = smprint("%s user=%s", keyspec, user);
 187                 break;
 188         case 'p':
 189                 filterp = aan;
 190                 break;
 191         default:
 192                 usage();
 193         }ARGEND;
 194
 195
 196         if(argc != 0)
 197                 usage();
 198
 199         if(system == nil) {
 200                 p = getenv("cpu");
 201                 if(p == 0)
 202                         fatal("set $cpu");
 203                 system = p;
 204         }
 205
 206         if(err = rexcall(&data, system, srvname))
 207                 fatal("%s: %s: %r", err, system);
 208
 209         procsetname("%s", origargs);
 210         /* Tell the remote side the command to execute and where our working directory is */
 211         if(cflag)
 212                 writestr(data, cmd, "command", 0);
 213         if(getwd(dat, sizeof(dat)) == 0)
 214                 writestr(data, "NO", "dir", 0);
 215         else
 216                 writestr(data, dat, "dir", 0);
 217
 218         /* start up a process to pass along notes */
 219         lclnoteproc(data);
 220
 221         /*
 222          *  Wait for the other end to execute and start our file service
 223          *  of /mnt/term
 224          */
 225         if(readstr(data, buf, sizeof(buf)) < 0)
 226                 fatal("waiting for FS: %r");
 227         if(strncmp("FS", buf, 2) != 0) {
 228                 print("remote cpu: %s", buf);
 229                 exits(buf);
 230         }
 231
 232         /* Begin serving the gnot namespace */
 233         close(0);
 234         dup(data, 0);
 235         close(data);
 236
 237         sprint(buf, "%d", msgsize);
 238         ac = 0;
 239         av[ac++] = exportfs;
 240         av[ac++] = "-m";
 241         av[ac++] = buf;
 242         if(dbg)
 243                 av[ac++] = "-d";
 244         if(patternfile != nil){
 245                 av[ac++] = "-P";
 246                 av[ac++] = patternfile;
 247         }
 248         av[ac] = nil;
 249         exec(exportfs, av);
 250         fatal("starting exportfs: %r");
 251 }
 252
 253 void
 254 fatal(char *fmt, ...)
 255 {
 256         char buf[1024];
 257         va_list arg;
 258
 259         va_start(arg, fmt);
 260         vsnprint(buf, sizeof(buf), fmt, arg);
 261         va_end(arg);
 262         fprint(2, "cpu: %s\n", buf);
 263         syslog(0, "cpu", "%s", buf);
 264         exits(buf);
 265 }
 266
 267 char *negstr = "negotiating authentication method";
 268
 269 /* Invoked with stdin and stdout connected to the network connection */
 270 void
 271 remoteside(void)
 272 {
 273         char user[MaxStr], buf[MaxStr], xdir[MaxStr], cmd[MaxStr];
 274         int i, n, fd, badchdir, gotcmd;
 275
 276         rfork(RFENVG);
 277         putenv("service", "cpu");
 278         fd = 0;
 279
 280         /* negotiate authentication mechanism */
 281         n = readstr(fd, cmd, sizeof(cmd));
 282         if(n < 0)
 283                 fatal("authenticating: %r");
 284         filterp = nil;
 285         if(strcmp(cmd, "aan") == 0){
 286                 filterp = aan;
 287                 writestr(fd, "", nil, 1);
 288                 n = readstr(fd, cmd, sizeof(cmd));
 289                 if(n < 0)
 290                         fatal("authenticating: %r");
 291         }
 292         if(setamalg(cmd) < 0 || (nflag == 0 && am->sf == srvnoauth)) {
 293                 writestr(fd, "unsupported auth method", nil, 0);
 294                 fatal("bad auth method %s", cmd);
 295         } else
 296                 writestr(fd, "", "", 1);
 297
 298         if((fd = (*am->sf)(fd, user)) < 0)
 299                 fatal("srvauth: %r");
 300         if((fd = filter(fd, nil)) < 0)
 301                 fatal("filter: %r");
 302         if((fd = encryption(fd)) < 0)
 303                 fatal("encrypt: %r");
 304
 305         /* Now collect invoking cpu's current directory or possibly a command */
 306         gotcmd = 0;
 307         if(readstr(fd, xdir, sizeof(xdir)) < 0)
 308                 fatal("dir/cmd: %r");
 309         if(xdir[0] == '!') {
 310                 strcpy(cmd, &xdir[1]);
 311                 gotcmd = 1;
 312                 if(readstr(fd, xdir, sizeof(xdir)) < 0)
 313                         fatal("dir: %r");
 314         }
 315
 316         /* Establish the new process at the current working directory of the gnot */
 317         badchdir = 0;
 318         if(strcmp(xdir, "NO") != 0)
 319                 if(chdir(xdir) < 0)
 320                         badchdir = 1;
 321
 322         /* Start the gnot serving its namespace */
 323         writestr(fd, "FS", "FS", 0);
 324         writestr(fd, "/", "exportfs dir", 0);
 325
 326         n = read(fd, buf, sizeof(buf));
 327         if(n != 2 || buf[0] != 'O' || buf[1] != 'K')
 328                 exits("remote tree");
 329
 330         /* make sure buffers are big by doing fversion explicitly; pick a huge number; other side will trim */
 331         strcpy(buf, VERSION9P);
 332         if(fversion(fd, 64*1024, buf, sizeof buf) < 0)
 333                 exits("fversion failed");
 334         if(mount(fd, -1, "/mnt/term", MCREATE|MREPL, "") < 0)
 335                 exits("mount failed");
 336
 337         close(fd);
 338
 339         /* the remote noteproc uses the mount so it must follow it */
 340         rmtnoteproc();
 341
 342         for(i = 0; i < 3; i++)
 343                 close(i);
 344
 345         if(open("/mnt/term/dev/cons", OREAD) != 0)
 346                 exits("open stdin");
 347         if(open("/mnt/term/dev/cons", OWRITE) != 1)
 348                 exits("open stdout");
 349         dup(1, 2);
 350
 351         if(badchdir)
 352                 print("cpu: failed to chdir to '%s'\n", xdir);
 353
 354         if(gotcmd)
 355                 execl("/bin/rc", "rc", "-lc", cmd, nil);
 356         else
 357                 execl("/bin/rc", "rc", "-li", nil);
 358         fatal("exec shell: %r");
 359 }
 360
 361 char*
 362 rexcall(int *fd, char *host, char *service)
 363 {
 364         char *na;
 365         char err[ERRMAX];
 366         char msg[MaxStr];
 367         int n;
 368
 369         na = netmkaddr(host, 0, service);
 370         procsetname("dialing %s", na);
 371         if((*fd = dial(na, 0, 0, 0)) < 0)
 372                 return "can't dial";
 373
 374         /* negotiate aan filter extension */
 375         if(filterp == aan){
 376                 writestr(*fd, "aan", "negotiating aan", 0);
 377                 n = readstr(*fd, err, sizeof err);
 378                 if(n < 0)
 379                         return "negotiating aan";
 380                 if(*err){
 381                         errstr(err, sizeof err);
 382                         return negstr;
 383                 }
 384         }
 385
 386         /* negotiate authentication mechanism */
 387         if(ealgs != nil)
 388                 snprint(msg, sizeof(msg), "%s %s", am->name, ealgs);
 389         else
 390                 snprint(msg, sizeof(msg), "%s", am->name);
 391         procsetname("writing %s", msg);
 392         writestr(*fd, msg, negstr, 0);
 393         procsetname("awaiting auth method");
 394         n = readstr(*fd, err, sizeof err);
 395         if(n < 0)
 396                 return negstr;
 397         if(*err){
 398                 errstr(err, sizeof err);
 399                 return negstr;
 400         }
 401
 402         /* authenticate */
 403         procsetname("%s: auth via %s", origargs, am->name);
 404         if((*fd = (*am->cf)(*fd)) < 0)
 405                 return "can't authenticate";
 406         if((*fd = filter(*fd, system)) < 0)
 407                 return "can't filter";
 408         if((*fd = encryption(*fd)) < 0)
 409                 return "can't encrypt";
 410         return nil;
 411 }
 412
 413 void
 414 writestr(int fd, char *str, char *thing, int ignore)
 415 {
 416         int l, n;
 417
 418         l = strlen(str);
 419         n = write(fd, str, l+1);
 420         if(!ignore && n < 0)
 421                 fatal("writing network: %s: %r", thing);
 422 }
 423
 424 int
 425 readstr(int fd, char *str, int len)
 426 {
 427         int n;
 428
 429         while(len) {
 430                 n = read(fd, str, 1);
 431                 if(n < 0)
 432                         return -1;
 433                 if(*str == '\0')
 434                         return 0;
 435                 str++;
 436                 len--;
 437         }
 438         return -1;
 439 }
 440
 441 static int
 442 readln(char *buf, int n)
 443 {
 444         int i;
 445         char *p;
 446
 447         n--;    /* room for \0 */
 448         p = buf;
 449         for(i=0; i<n; i++){
 450                 if(read(0, p, 1) != 1)
 451                         break;
 452                 if(*p == '\n' || *p == '\r')
 453                         break;
 454                 p++;
 455         }
 456         *p = '\0';
 457         return p-buf;
 458 }
 459
 460 /*
 461  *  user level challenge/response
 462  */
 463 static int
 464 netkeyauth(int fd)
 465 {
 466         char chall[32];
 467         char resp[32];
 468
 469         strecpy(chall, chall+sizeof chall, getuser());
 470         print("user[%s]: ", chall);
 471         if(readln(resp, sizeof(resp)) < 0)
 472                 return -1;
 473         if(*resp != 0)
 474                 strcpy(chall, resp);
 475         writestr(fd, chall, "challenge/response", 1);
 476
 477         for(;;){
 478                 if(readstr(fd, chall, sizeof chall) < 0)
 479                         break;
 480                 if(*chall == 0)
 481                         return fd;
 482                 print("challenge: %s\nresponse: ", chall);
 483                 if(readln(resp, sizeof(resp)) < 0)
 484                         break;
 485                 writestr(fd, resp, "challenge/response", 1);
 486         }
 487         return -1;
 488 }
 489
 490 static int
 491 netkeysrvauth(int fd, char *user)
 492 {
 493         char response[32];
 494         Chalstate *ch;
 495         int tries;
 496         AuthInfo *ai;
 497
 498         if(readstr(fd, user, MaxStr) < 0)
 499                 return -1;
 500
 501         ai = nil;
 502         ch = nil;
 503         for(tries = 0; tries < 10; tries++){
 504                 if((ch = auth_challenge("proto=p9cr role=server user=%q", user)) == nil)
 505                         return -1;
 506                 writestr(fd, ch->chal, "challenge", 1);
 507                 if(readstr(fd, response, sizeof response) < 0)
 508                         return -1;
 509                 ch->resp = response;
 510                 ch->nresp = strlen(response);
 511                 if((ai = auth_response(ch)) != nil)
 512                         break;
 513         }
 514         auth_freechal(ch);
 515         if(ai == nil)
 516                 return -1;
 517         writestr(fd, "", "challenge", 1);
 518         if(auth_chuid(ai, 0) < 0)
 519                 fatal("newns: %r");
 520         auth_freeAI(ai);
 521         return fd;
 522 }
 523
 524 static int
 525 clear(int fd)
 526 {
 527         return fd;
 528 }
 529
 530 static char sslsecret[2][21];
 531
 532 static int
 533 sslencrypt(int fd)
 534 {
 535         return pushssl(fd, ealgs, sslsecret[0], sslsecret[1], nil);
 536 }
 537
 538 static void
 539 mksecret(char *t, uchar *f)
 540 {
 541         sprint(t, "%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux",
 542                 f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
 543 }
 544
 545 static int
 546 sslsetup(int fd, uchar *secret, int nsecret, int isclient)
 547 {
 548         uchar key[16], digest[SHA1dlen];
 549         int i;
 550
 551         if(ealgs == nil)
 552                 return fd;
 553
 554         if(nsecret < 8){
 555                 werrstr("secret too small to ssl");
 556                 return -1;
 557         }
 558         memmove(key+4, secret, 8);
 559
 560         /* exchange random numbers */
 561         srand(truerand());
 562
 563         if(isclient){
 564                 for(i = 0; i < 4; i++)
 565                         key[i] = rand();
 566                 if(write(fd, key, 4) != 4)
 567                         return -1;
 568                 if(readn(fd, key+12, 4) != 4)
 569                         return -1;
 570         } else {
 571                 for(i = 0; i < 4; i++)
 572                         key[i+12] = rand();
 573                 if(readn(fd, key, 4) != 4)
 574                         return -1;
 575                 if(write(fd, key+12, 4) != 4)
 576                         return -1;
 577         }
 578
 579         /* scramble into two secrets */
 580         sha1(key, sizeof(key), digest, nil);
 581         mksecret(sslsecret[isclient == 0], digest);
 582         mksecret(sslsecret[isclient != 0], digest+10);
 583
 584         encryption = sslencrypt;
 585
 586         return fd;
 587 }
 588
 589 /*
 590  *  plan9 authentication followed by rc4 encryption
 591  */
 592 static int
 593 p9auth(int fd)
 594 {
 595         AuthInfo *ai;
 596
 597         ai = auth_proxy(fd, auth_getkey, "proto=p9any role=client %s", keyspec);
 598         if(ai == nil)
 599                 return -1;
 600         fd = sslsetup(fd, ai->secret, ai->nsecret, 1);
 601         auth_freeAI(ai);
 602         return fd;
 603 }
 604
 605 static int
 606 noauth(int fd)
 607 {
 608         ealgs = nil;
 609         return fd;
 610 }
 611
 612 static int
 613 srvnoauth(int fd, char *user)
 614 {
 615         strecpy(user, user+MaxStr, getuser());
 616         ealgs = nil;
 617         newns(user, nil);
 618         return fd;
 619 }
 620
 621 static int
 622 srvp9auth(int fd, char *user)
 623 {
 624         AuthInfo *ai;
 625
 626         ai = auth_proxy(fd, nil, "proto=p9any role=server %s", keyspec);
 627         if(ai == nil)
 628                 return -1;
 629         if(auth_chuid(ai, nil) < 0)
 630                 fatal("newns: %r");
 631         snprint(user, MaxStr, "%s", ai->cuid);
 632         fd = sslsetup(fd, ai->secret, ai->nsecret, 0);
 633         auth_freeAI(ai);
 634         return fd;
 635 }
 636
 637 /*
 638  *  set authentication mechanism
 639  */
 640 int
 641 setam(char *name)
 642 {
 643         for(am = authmethod; am->name != nil; am++)
 644                 if(strcmp(am->name, name) == 0)
 645                         return 0;
 646         am = authmethod;
 647         return -1;
 648 }
 649
 650 /*
 651  *  set authentication mechanism and encryption/hash algs
 652  */
 653 int
 654 setamalg(char *s)
 655 {
 656         ealgs = strchr(s, ' ');
 657         if(ealgs != nil)
 658                 *ealgs++ = 0;
 659         return setam(s);
 660 }
 661
 662 int
 663 filter(int fd, char *host)
 664 {
 665         char addr[128], buf[256], *s, *file, *argv[16];
 666         int p[2], lfd, flags, len, argc;
 667
 668         if(filterp == nil)
 669                 return fd;
 670         procsetname("filter %s", filterp);
 671         flags = RFNOWAIT|RFPROC|RFMEM|RFFDG|RFREND;
 672         if(host == nil){
 673                 /* remote side */
 674                 if(announce(anstring, addr) < 0)
 675                         fatal("filter: Cannot announce %s: %r", anstring);
 676                 snprint(buf, sizeof(buf), "%s/local", addr);
 677                 if((lfd = open(buf, OREAD)) < 0)
 678                         fatal("filter: Cannot open %s: %r", buf);
 679                 if((len = read(lfd, buf, sizeof buf - 1)) < 0)
 680                         fatal("filter: Cannot read %s: %r", buf);
 681                 close(lfd);
 682                 buf[len] = 0;
 683                 if(s = strchr(buf, '\n'))
 684                         len = s - buf;
 685                 if(write(fd, buf, len) != len)
 686                         fatal("filter: cannot write port; %r");
 687         } else {
 688                 /* client side */
 689                 flags |= RFNOTEG;
 690                 if((len = read(fd, buf, sizeof buf - 1)) < 0)
 691                         fatal("filter: cannot read port; %r");
 692                 buf[len] = '\0';
 693                 if((s = strrchr(buf, '!')) == nil)
 694                         fatal("filter: malformed remote port: %s", buf);
 695                 strecpy(addr, addr+sizeof(addr), netmkaddr(host, "tcp", s+1));
 696                 strecpy(strrchr(addr, '!'), addr+sizeof(addr), s);
 697         }
 698
 699         snprint(buf, sizeof(buf), "%s", filterp);
 700         if((argc = tokenize(buf, argv, nelem(argv)-3)) <= 0)
 701                 fatal("filter: empty command");
 702         if(host)
 703                 argv[argc++] = "-c";
 704         argv[argc++] = addr;
 705         argv[argc] = nil;
 706         file = argv[0];
 707         if(s = strrchr(argv[0], '/'))
 708                 argv[0] = s+1;
 709
 710         if(pipe(p) < 0)
 711                 fatal("filter: pipe; %r");
 712
 713         switch(rfork(flags)) {
 714         case -1:
 715                 fatal("filter: rfork; %r\n");
 716         case 0:
 717                 if (dup(p[0], 1) < 0)
 718                         fatal("filter: Cannot dup to 1; %r");
 719                 if (dup(p[0], 0) < 0)
 720                         fatal("filter: Cannot dup to 0; %r");
 721                 close(p[0]);
 722                 close(p[1]);
 723                 exec(file, argv);
 724                 fatal("filter: exec; %r");
 725         default:
 726                 close(fd);
 727                 close(p[0]);
 728         }
 729         return p[1];
 730 }
 731
 732 char *rmtnotefile = "/mnt/term/dev/cpunote";
 733
 734 /*
 735  *  loop reading /mnt/term/dev/note looking for notes.
 736  *  The child returns to start the shell.
 737  */
 738 void
 739 rmtnoteproc(void)
 740 {
 741         int n, fd, pid, notepid;
 742         char buf[256];
 743
 744         /* new proc returns to start shell */
 745         pid = rfork(RFPROC|RFFDG|RFNOTEG|RFNAMEG|RFMEM);
 746         switch(pid){
 747         case -1:
 748                 syslog(0, "cpu", "cpu -R: can't start noteproc: %r");
 749                 return;
 750         case 0:
 751                 return;
 752         }
 753
 754         /* new proc reads notes from other side and posts them to shell */
 755         switch(notepid = rfork(RFPROC|RFFDG|RFMEM)){
 756         case -1:
 757                 syslog(0, "cpu", "cpu -R: can't start wait proc: %r");
 758                 _exits(0);
 759         case 0:
 760                 fd = open(rmtnotefile, OREAD);
 761                 if(fd < 0)
 762                         _exits(0);
 763
 764                 for(;;){
 765                         n = read(fd, buf, sizeof(buf)-1);
 766                         if(n <= 0){
 767                                 postnote(PNGROUP, pid, "hangup");
 768                                 _exits(0);
 769                         }
 770                         buf[n] = 0;
 771                         postnote(PNGROUP, pid, buf);
 772                 }
 773         }
 774
 775         /* original proc waits for shell proc to die and kills note proc */
 776         for(;;){
 777                 n = waitpid();
 778                 if(n < 0 || n == pid)
 779                         break;
 780         }
 781         postnote(PNPROC, notepid, "kill");
 782         _exits(0);
 783 }
 784
 785 enum
 786 {
 787         Qdir,
 788         Qcpunote,
 789
 790         Nfid = 32,
 791 };
 792
 793 struct {
 794         char    *name;
 795         Qid     qid;
 796         ulong   perm;
 797 } fstab[] =
 798 {
 799         [Qdir]          { ".",          {Qdir, 0, QTDIR},       DMDIR|0555      },
 800         [Qcpunote]      { "cpunote",    {Qcpunote, 0},          0444            },
 801 };
 802
 803 typedef struct Note Note;
 804 struct Note
 805 {
 806         Note *next;
 807         char msg[ERRMAX];
 808 };
 809
 810 typedef struct Request Request;
 811 struct Request
 812 {
 813         Request *next;
 814         Fcall f;
 815 };
 816
 817 typedef struct Fid Fid;
 818 struct Fid
 819 {
 820         int     fid;
 821         int     file;
 822         int     omode;
 823 };
 824 Fid fids[Nfid];
 825
 826 struct {
 827         Lock;
 828         Note *nfirst, *nlast;
 829         Request *rfirst, *rlast;
 830 } nfs;
 831
 832 int
 833 fsreply(int fd, Fcall *f)
 834 {
 835         uchar buf[IOHDRSZ+Maxfdata];
 836         int n;
 837
 838         if(dbg)
 839                 fprint(2, "notefs: <-%F\n", f);
 840         n = convS2M(f, buf, sizeof buf);
 841         if(n > 0){
 842                 if(write(fd, buf, n) != n){
 843                         close(fd);
 844                         return -1;
 845                 }
 846         }
 847         return 0;
 848 }
 849
 850 /* match a note read request with a note, reply to the request */
 851 int
 852 kick(int fd)
 853 {
 854         Request *rp;
 855         Note *np;
 856         int rv;
 857
 858         for(;;){
 859                 lock(&nfs);
 860                 rp = nfs.rfirst;
 861                 np = nfs.nfirst;
 862                 if(rp == nil || np == nil){
 863                         unlock(&nfs);
 864                         break;
 865                 }
 866                 nfs.rfirst = rp->next;
 867                 nfs.nfirst = np->next;
 868                 unlock(&nfs);
 869
 870                 rp->f.type = Rread;
 871                 rp->f.count = strlen(np->msg);
 872                 rp->f.data = np->msg;
 873                 rv = fsreply(fd, &rp->f);
 874                 free(rp);
 875                 free(np);
 876                 if(rv < 0)
 877                         return -1;
 878         }
 879         return 0;
 880 }
 881
 882 void
 883 flushreq(int tag)
 884 {
 885         Request **l, *rp;
 886
 887         lock(&nfs);
 888         for(l = &nfs.rfirst; *l != nil; l = &(*l)->next){
 889                 rp = *l;
 890                 if(rp->f.tag == tag){
 891                         *l = rp->next;
 892                         unlock(&nfs);
 893                         free(rp);
 894                         return;
 895                 }
 896         }
 897         unlock(&nfs);
 898 }
 899
 900 Fid*
 901 getfid(int fid)
 902 {
 903         int i, freefid;
 904
 905         freefid = -1;
 906         for(i = 0; i < Nfid; i++){
 907                 if(freefid < 0 && fids[i].file < 0)
 908                         freefid = i;
 909                 if(fids[i].fid == fid)
 910                         return &fids[i];
 911         }
 912         if(freefid >= 0){
 913                 fids[freefid].fid = fid;
 914                 return &fids[freefid];
 915         }
 916         return nil;
 917 }
 918
 919 int
 920 fsstat(int fd, Fid *fid, Fcall *f)
 921 {
 922         Dir d;
 923         uchar statbuf[256];
 924
 925         memset(&d, 0, sizeof(d));
 926         d.name = fstab[fid->file].name;
 927         d.uid = user;
 928         d.gid = user;
 929         d.muid = user;
 930         d.qid = fstab[fid->file].qid;
 931         d.mode = fstab[fid->file].perm;
 932         d.atime = d.mtime = time(0);
 933         f->stat = statbuf;
 934         f->nstat = convD2M(&d, statbuf, sizeof statbuf);
 935         return fsreply(fd, f);
 936 }
 937
 938 int
 939 fsread(int fd, Fid *fid, Fcall *f)
 940 {
 941         Dir d;
 942         uchar buf[256];
 943         Request *rp;
 944
 945         switch(fid->file){
 946         default:
 947                 return -1;
 948         case Qdir:
 949                 if(f->offset == 0 && f->count >0){
 950                         memset(&d, 0, sizeof(d));
 951                         d.name = fstab[Qcpunote].name;
 952                         d.uid = user;
 953                         d.gid = user;
 954                         d.muid = user;
 955                         d.qid = fstab[Qcpunote].qid;
 956                         d.mode = fstab[Qcpunote].perm;
 957                         d.atime = d.mtime = time(0);
 958                         f->count = convD2M(&d, buf, sizeof buf);
 959                         f->data = (char*)buf;
 960                 } else
 961                         f->count = 0;
 962                 return fsreply(fd, f);
 963         case Qcpunote:
 964                 rp = mallocz(sizeof(*rp), 1);
 965                 if(rp == nil)
 966                         return -1;
 967                 rp->f = *f;
 968                 lock(&nfs);
 969                 if(nfs.rfirst == nil)
 970                         nfs.rfirst = rp;
 971                 else
 972                         nfs.rlast->next = rp;
 973                 nfs.rlast = rp;
 974                 unlock(&nfs);
 975                 return kick(fd);;
 976         }
 977 }
 978
 979 char Eperm[] = "permission denied";
 980 char Enofile[] = "out of files";
 981 char Enotdir[] = "not a directory";
 982
 983 void
 984 notefs(int fd)
 985 {
 986         uchar buf[IOHDRSZ+Maxfdata];
 987         int i, n, ncpunote;
 988         Fcall f;
 989         Qid wqid[MAXWELEM];
 990         Fid *fid, *nfid;
 991         int doreply;
 992
 993         rfork(RFNOTEG);
 994         fmtinstall('F', fcallfmt);
 995
 996         for(n = 0; n < Nfid; n++){
 997                 fids[n].file = -1;
 998                 fids[n].omode = -1;
 999         }
1000
1001         ncpunote = 0;
1002         for(;;){
1003                 n = read9pmsg(fd, buf, sizeof(buf));
1004                 if(n <= 0 || convM2S(buf, n, &f) != n)
1005                         break;
1006                 if(dbg)
1007                         fprint(2, "notefs: ->%F\n", &f);
1008                 doreply = 1;
1009                 fid = getfid(f.fid);
1010                 if(fid == nil){
1011 nofids:
1012                         f.type = Rerror;
1013                         f.ename = Enofile;
1014                         fsreply(fd, &f);
1015                         continue;
1016                 }
1017                 switch(f.type++){
1018                 default:
1019                         f.type = Rerror;
1020                         f.ename = "unknown type";
1021                         break;
1022                 case Tflush:
1023                         flushreq(f.oldtag);
1024                         break;
1025                 case Tversion:
1026                         if(f.msize > IOHDRSZ+Maxfdata)
1027                                 f.msize = IOHDRSZ+Maxfdata;
1028                         break;
1029                 case Tauth:
1030                         f.type = Rerror;
1031                         f.ename = "authentication not required";
1032                         break;
1033                 case Tattach:
1034                         f.qid = fstab[Qdir].qid;
1035                         fid->file = Qdir;
1036                         break;
1037                 case Twalk:
1038                         nfid = nil;
1039                         if(f.newfid != f.fid){
1040                                 nfid = getfid(f.newfid);
1041                                 if(nfid == nil)
1042                                         goto nofids;
1043                                 nfid->file = fid->file;
1044                                 fid = nfid;
1045                         }
1046                         for(i=0; i<f.nwname && i<MAXWELEM; i++){
1047                                 if(fid->file != Qdir){
1048                                         f.type = Rerror;
1049                                         f.ename = Enotdir;
1050                                         break;
1051                                 }
1052                                 if(strcmp(f.wname[i], "..") == 0){
1053                                         wqid[i] = fstab[Qdir].qid;
1054                                         continue;
1055                                 }
1056                                 if(strcmp(f.wname[i], "cpunote") != 0){
1057                                         if(i == 0){
1058                                                 f.type = Rerror;
1059                                                 f.ename = "file does not exist";
1060                                         }
1061                                         break;
1062                                 }
1063                                 fid->file = Qcpunote;
1064                                 wqid[i] = fstab[Qcpunote].qid;
1065                         }
1066                         if(nfid != nil && (f.type == Rerror || i < f.nwname))
1067                                 nfid ->file = -1;
1068                         if(f.type != Rerror){
1069                                 f.nwqid = i;
1070                                 for(i=0; i<f.nwqid; i++)
1071                                         f.wqid[i] = wqid[i];
1072                         }
1073                         break;
1074                 case Topen:
1075                         if(f.mode != OREAD){
1076                                 f.type = Rerror;
1077                                 f.ename = Eperm;
1078                                 break;
1079                         }
1080                         fid->omode = f.mode;
1081                         if(fid->file == Qcpunote)
1082                                 ncpunote++;
1083                         f.qid = fstab[fid->file].qid;
1084                         f.iounit = 0;
1085                         break;
1086                 case Tread:
1087                         if(fsread(fd, fid, &f) < 0)
1088                                 goto err;
1089                         doreply = 0;
1090                         break;
1091                 case Tclunk:
1092                         if(fid->omode != -1 && fid->file == Qcpunote){
1093                                 ncpunote--;
1094                                 if(ncpunote == 0)       /* remote side is done */
1095                                         goto err;
1096                         }
1097                         fid->file = -1;
1098                         fid->omode = -1;
1099                         break;
1100                 case Tstat:
1101                         if(fsstat(fd, fid, &f) < 0)
1102                                 goto err;
1103                         doreply = 0;
1104                         break;
1105                 case Tcreate:
1106                 case Twrite:
1107                 case Tremove:
1108                 case Twstat:
1109                         f.type = Rerror;
1110                         f.ename = Eperm;
1111                         break;
1112                 }
1113                 if(doreply)
1114                         if(fsreply(fd, &f) < 0)
1115                                 break;
1116         }
1117 err:
1118         if(dbg)
1119                 fprint(2, "notefs exiting: %r\n");
1120         werrstr("success");
1121         postnote(PNGROUP, exportpid, "kill");
1122         if(dbg)
1123                 fprint(2, "postnote PNGROUP %d: %r\n", exportpid);
1124         close(fd);
1125 }
1126
1127 char    notebuf[ERRMAX];
1128
1129 void
1130 catcher(void*, char *text)
1131 {
1132         int n;
1133
1134         n = strlen(text);
1135         if(n >= sizeof(notebuf))
1136                 n = sizeof(notebuf)-1;
1137         memmove(notebuf, text, n);
1138         notebuf[n] = '\0';
1139         noted(NCONT);
1140 }
1141
1142 /*
1143  *  mount in /dev a note file for the remote side to read.
1144  */
1145 void
1146 lclnoteproc(int netfd)
1147 {
1148         Waitmsg *w;
1149         Note *np;
1150         int pfd[2];
1151         int pid;
1152
1153         if(pipe(pfd) < 0){
1154                 fprint(2, "cpu: can't start note proc: pipe: %r\n");
1155                 return;
1156         }
1157
1158         /* new proc mounts and returns to start exportfs */
1159         switch(pid = rfork(RFPROC|RFNAMEG|RFFDG|RFMEM)){
1160         default:
1161                 exportpid = pid;
1162                 break;
1163         case -1:
1164                 fprint(2, "cpu: can't start note proc: rfork: %r\n");
1165                 return;
1166         case 0:
1167                 close(pfd[0]);
1168                 if(mount(pfd[1], -1, "/dev", MBEFORE, "") < 0)
1169                         fprint(2, "cpu: can't mount note proc: %r\n");
1170                 close(pfd[1]);
1171                 return;
1172         }
1173
1174         close(netfd);
1175         close(pfd[1]);
1176
1177         /* new proc listens for note file system rpc's */
1178         switch(rfork(RFPROC|RFNAMEG|RFMEM)){
1179         case -1:
1180                 fprint(2, "cpu: can't start note proc: rfork1: %r\n");
1181                 _exits(0);
1182         case 0:
1183                 notefs(pfd[0]);
1184                 _exits(0);
1185         }
1186
1187         /* original proc waits for notes */
1188         notify(catcher);
1189         w = nil;
1190         for(;;) {
1191                 *notebuf = 0;
1192                 free(w);
1193                 w = wait();
1194                 if(w == nil) {
1195                         if(*notebuf == 0)
1196                                 break;
1197                         np = mallocz(sizeof(Note), 1);
1198                         if(np != nil){
1199                                 strcpy(np->msg, notebuf);
1200                                 lock(&nfs);
1201                                 if(nfs.nfirst == nil)
1202                                         nfs.nfirst = np;
1203                                 else
1204                                         nfs.nlast->next = np;
1205                                 nfs.nlast = np;
1206                                 unlock(&nfs);
1207                                 kick(pfd[0]);
1208                         }
1209                         unlock(&nfs);
1210                 } else if(w->pid == exportpid)
1211                         break;
1212         }
1213
1214         if(w == nil)
1215                 exits(nil);
1216         exits(0);
1217 /*      exits(w->msg); */
1218 }