1 /*- 2 * Copyright (c) 1983, 1991, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/usr.sbin/inetd/builtins.c,v 1.19.2.7 2002/07/22 14:05:56 fanf Exp $ 27 * 28 */ 29 30 #include <sys/filio.h> 31 #include <sys/param.h> 32 #include <sys/stat.h> 33 #include <sys/socket.h> 34 #include <sys/sysctl.h> 35 #include <sys/ucred.h> 36 #include <sys/uio.h> 37 #include <sys/utsname.h> 38 39 #include <ctype.h> 40 #include <err.h> 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <limits.h> 44 #include <pwd.h> 45 #include <signal.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <sysexits.h> 49 #include <syslog.h> 50 #include <unistd.h> 51 52 #include "inetd.h" 53 54 void chargen_dg(int, struct servtab *); 55 void chargen_stream(int, struct servtab *); 56 void daytime_dg(int, struct servtab *); 57 void daytime_stream(int, struct servtab *); 58 void discard_dg(int, struct servtab *); 59 void discard_stream(int, struct servtab *); 60 void echo_dg(int, struct servtab *); 61 void echo_stream(int, struct servtab *); 62 static int getline(int, char *, int); 63 void iderror(int, int, int, const char *); 64 void ident_stream(int, struct servtab *); 65 void initring(void); 66 unsigned long machtime(void); 67 void machtime_dg(int, struct servtab *); 68 void machtime_stream(int, struct servtab *); 69 70 char ring[128]; 71 char *endring; 72 73 74 struct biltin biltins[] = { 75 /* Echo received data */ 76 { "echo", SOCK_STREAM, 1, -1, echo_stream }, 77 { "echo", SOCK_DGRAM, 0, 1, echo_dg }, 78 79 /* Internet /dev/null */ 80 { "discard", SOCK_STREAM, 1, -1, discard_stream }, 81 { "discard", SOCK_DGRAM, 0, 1, discard_dg }, 82 83 /* Return 32 bit time since 1900 */ 84 { "time", SOCK_STREAM, 0, -1, machtime_stream }, 85 { "time", SOCK_DGRAM, 0, 1, machtime_dg }, 86 87 /* Return human-readable time */ 88 { "daytime", SOCK_STREAM, 0, -1, daytime_stream }, 89 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg }, 90 91 /* Familiar character generator */ 92 { "chargen", SOCK_STREAM, 1, -1, chargen_stream }, 93 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg }, 94 95 { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux }, 96 97 { "auth", SOCK_STREAM, 1, -1, ident_stream }, 98 99 { NULL, 0, 0, 0, NULL } 100 }; 101 102 /* 103 * RFC864 Character Generator Protocol. Generates character data without 104 * any regard for input. 105 */ 106 107 void 108 initring(void) 109 { 110 int i; 111 112 endring = ring; 113 114 for (i = 0; i <= 128; ++i) 115 if (isprint(i)) 116 *endring++ = i; 117 } 118 119 /* ARGSUSED */ 120 void 121 chargen_dg(int s, struct servtab *sep) /* Character generator */ 122 { 123 struct sockaddr_storage ss; 124 static char *rs; 125 int len; 126 socklen_t size; 127 char text[LINESIZ+2]; 128 129 if (endring == NULL) { 130 initring(); 131 rs = ring; 132 } 133 134 size = sizeof(ss); 135 if (recvfrom(s, text, sizeof(text), 0, 136 (struct sockaddr *)&ss, &size) < 0) 137 return; 138 139 if (check_loop((struct sockaddr *)&ss, sep)) 140 return; 141 142 if ((len = endring - rs) >= LINESIZ) 143 memmove(text, rs, LINESIZ); 144 else { 145 memmove(text, rs, len); 146 memmove(text + len, ring, LINESIZ - len); 147 } 148 if (++rs == endring) 149 rs = ring; 150 text[LINESIZ] = '\r'; 151 text[LINESIZ + 1] = '\n'; 152 sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size); 153 } 154 155 /* ARGSUSED */ 156 void 157 chargen_stream(int s, struct servtab *sep) /* Character generator */ 158 { 159 int len; 160 char *rs, text[LINESIZ+2]; 161 162 inetd_setproctitle(sep->se_service, s); 163 164 if (!endring) { 165 initring(); 166 rs = ring; 167 } 168 169 text[LINESIZ] = '\r'; 170 text[LINESIZ + 1] = '\n'; 171 for (rs = ring;;) { 172 if ((len = endring - rs) >= LINESIZ) 173 memmove(text, rs, LINESIZ); 174 else { 175 memmove(text, rs, len); 176 memmove(text + len, ring, LINESIZ - len); 177 } 178 if (++rs == endring) 179 rs = ring; 180 if (write(s, text, sizeof(text)) != sizeof(text)) 181 break; 182 } 183 exit(0); 184 } 185 186 /* 187 * RFC867 Daytime Protocol. Sends the current date and time as an ascii 188 * character string without any regard for input. 189 */ 190 191 /* ARGSUSED */ 192 void 193 daytime_dg(int s, struct servtab *sep) /* Return human-readable time of day */ 194 { 195 char buffer[256]; 196 time_t now; 197 struct sockaddr_storage ss; 198 socklen_t size; 199 200 now = time(NULL); 201 202 size = sizeof(ss); 203 if (recvfrom(s, buffer, sizeof(buffer), 0, 204 (struct sockaddr *)&ss, &size) < 0) 205 return; 206 207 if (check_loop((struct sockaddr *)&ss, sep)) 208 return; 209 210 sprintf(buffer, "%.24s\r\n", ctime(&now)); 211 sendto(s, buffer, strlen(buffer), 0, (struct sockaddr *)&ss, size); 212 } 213 214 /* ARGSUSED */ 215 void 216 daytime_stream(int s, struct servtab *sep __unused) /* Return human-readable time of day */ 217 { 218 char buffer[256]; 219 time_t now; 220 221 now = time(NULL); 222 223 sprintf(buffer, "%.24s\r\n", ctime(&now)); 224 send(s, buffer, strlen(buffer), MSG_EOF); 225 } 226 227 /* 228 * RFC863 Discard Protocol. Any data received is thrown away and no response 229 * is sent. 230 */ 231 232 /* ARGSUSED */ 233 void 234 discard_dg(int s, struct servtab *sep __unused) /* Discard service -- ignore data */ 235 { 236 char buffer[BUFSIZE]; 237 238 read(s, buffer, sizeof(buffer)); 239 } 240 241 /* ARGSUSED */ 242 void 243 discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */ 244 { 245 int ret; 246 char buffer[BUFSIZE]; 247 248 inetd_setproctitle(sep->se_service, s); 249 while (1) { 250 while ((ret = read(s, buffer, sizeof(buffer))) > 0) 251 ; 252 if (ret == 0 || errno != EINTR) 253 break; 254 } 255 exit(0); 256 } 257 258 /* 259 * RFC862 Echo Protocol. Any data received is sent back to the sender as 260 * received. 261 */ 262 263 /* ARGSUSED */ 264 void 265 echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */ 266 { 267 char buffer[65536]; /* Should be sizeof(max datagram). */ 268 int i; 269 socklen_t size; 270 struct sockaddr_storage ss; 271 272 size = sizeof(ss); 273 if ((i = recvfrom(s, buffer, sizeof(buffer), 0, 274 (struct sockaddr *)&ss, &size)) < 0) 275 return; 276 277 if (check_loop((struct sockaddr *)&ss, sep)) 278 return; 279 280 sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size); 281 } 282 283 /* ARGSUSED */ 284 void 285 echo_stream(int s, struct servtab *sep) /* Echo service -- echo data back */ 286 { 287 char buffer[BUFSIZE]; 288 int i; 289 290 inetd_setproctitle(sep->se_service, s); 291 while ((i = read(s, buffer, sizeof(buffer))) > 0 && 292 write(s, buffer, i) > 0) 293 ; 294 exit(0); 295 } 296 297 /* 298 * RFC1413 Identification Protocol. Given a TCP port number pair, return a 299 * character string which identifies the owner of that connection on the 300 * server's system. Extended to allow for ~/.fakeid support and ~/.noident 301 * support. 302 */ 303 304 /* RFC 1413 says the following are the only errors you can return. */ 305 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */ 306 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */ 307 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */ 308 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */ 309 310 /* ARGSUSED */ 311 void 312 iderror(int lport, int fport, int s, const char *er) /* Generic ident_stream error-sending func */ 313 { 314 char *p; 315 316 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er); 317 if (p == NULL) { 318 syslog(LOG_ERR, "asprintf: %m"); 319 exit(EX_OSERR); 320 } 321 send(s, p, strlen(p), MSG_EOF); 322 free(p); 323 324 exit(0); 325 } 326 327 /* ARGSUSED */ 328 void 329 ident_stream(int s, struct servtab *sep) /* Ident service (AKA "auth") */ 330 { 331 struct utsname un; 332 struct stat sb; 333 struct sockaddr_in sin4[2]; 334 #ifdef INET6 335 struct sockaddr_in6 sin6[2]; 336 #endif 337 struct sockaddr_storage ss[2]; 338 struct ucred uc; 339 struct timeval tv = { 340 10, 341 0 342 }, to; 343 struct passwd *pw = NULL; 344 fd_set fdset; 345 char buf[BUFSIZE], *p, **av, *osname = NULL, e; 346 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */ 347 socklen_t socklen; 348 ssize_t ssize; 349 size_t size, bufsiz; 350 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0; 351 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen; 352 u_short lport, fport; 353 354 inetd_setproctitle(sep->se_service, s); 355 /* 356 * Reset getopt() since we are a fork() but not an exec() from 357 * a parent which used getopt() already. 358 */ 359 optind = 1; 360 optreset = 1; 361 /* 362 * Take the internal argument vector and count it out to make an 363 * argument count for getopt. This can be used for any internal 364 * service to read arguments and use getopt() easily. 365 */ 366 for (av = sep->se_argv; *av; av++) 367 argc++; 368 if (argc) { 369 int sec, usec; 370 size_t i; 371 u_int32_t rnd32; 372 373 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1) 374 switch (c) { 375 case 'd': 376 if (!gflag) 377 strlcpy(idbuf, optarg, sizeof(idbuf)); 378 break; 379 case 'f': 380 fflag = 1; 381 break; 382 case 'F': 383 fflag = 1; 384 Fflag=1; 385 break; 386 case 'g': 387 gflag = 1; 388 rnd32 = 0; /* Shush, compiler. */ 389 /* 390 * The number of bits in "rnd32" divided 391 * by the number of bits needed per iteration 392 * gives a more optimal way to reload the 393 * random number only when necessary. 394 * 395 * 32 bits from arc4random corresponds to 396 * about 6 base-36 digits, so we reseed evey 6. 397 */ 398 for (i = 0; i < sizeof(idbuf) - 1; i++) { 399 static const char *const base36 = 400 "0123456789" 401 "abcdefghijklmnopqrstuvwxyz"; 402 if (i % 6 == 0) 403 rnd32 = arc4random(); 404 idbuf[i] = base36[rnd32 % 36]; 405 rnd32 /= 36; 406 } 407 idbuf[i] = '\0'; 408 break; 409 case 'i': 410 iflag = 1; 411 break; 412 case 'n': 413 nflag = 1; 414 break; 415 case 'o': 416 osname = optarg; 417 break; 418 case 'r': 419 rflag = 1; 420 break; 421 case 't': 422 switch (sscanf(optarg, "%d.%d", &sec, &usec)) { 423 case 2: 424 tv.tv_usec = usec; 425 /* FALLTHROUGH */ 426 case 1: 427 tv.tv_sec = sec; 428 break; 429 default: 430 if (debug) 431 warnx("bad -t argument"); 432 break; 433 } 434 break; 435 default: 436 break; 437 } 438 } 439 if (osname == NULL) { 440 if (uname(&un) == -1) 441 iderror(0, 0, s, ID_UNKNOWN); 442 osname = un.sysname; 443 } 444 445 /* 446 * We're going to prepare for and execute reception of a 447 * packet of data from the user. The data is in the format 448 * "local_port , foreign_port\r\n" (with local being the 449 * server's port and foreign being the client's.) 450 */ 451 gettimeofday(&to, NULL); 452 to.tv_sec += tv.tv_sec; 453 to.tv_usec += tv.tv_usec; 454 if (to.tv_usec >= 1000000) { 455 to.tv_usec -= 1000000; 456 to.tv_sec++; 457 } 458 459 size = 0; 460 bufsiz = sizeof(buf) - 1; 461 FD_ZERO(&fdset); 462 while (bufsiz > 0) { 463 gettimeofday(&tv, NULL); 464 tv.tv_sec = to.tv_sec - tv.tv_sec; 465 tv.tv_usec = to.tv_usec - tv.tv_usec; 466 if (tv.tv_usec < 0) { 467 tv.tv_usec += 1000000; 468 tv.tv_sec--; 469 } 470 if (tv.tv_sec < 0) 471 break; 472 FD_SET(s, &fdset); 473 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1) 474 iderror(0, 0, s, ID_UNKNOWN); 475 if (ioctl(s, FIONREAD, &onreadlen) == -1) 476 iderror(0, 0, s, ID_UNKNOWN); 477 if ((size_t)onreadlen > bufsiz) 478 onreadlen = bufsiz; 479 ssize = read(s, &buf[size], (size_t)onreadlen); 480 if (ssize == -1) 481 iderror(0, 0, s, ID_UNKNOWN); 482 else if (ssize == 0) 483 break; 484 bufsiz -= ssize; 485 size += ssize; 486 if (memchr(&buf[size - ssize], '\n', ssize) != NULL) 487 break; 488 } 489 buf[size] = '\0'; 490 /* Read two characters, and check for a delimiting character */ 491 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e)) 492 iderror(0, 0, s, ID_INVALID); 493 494 /* Send garbage? */ 495 if (gflag) 496 goto printit; 497 498 /* 499 * If not "real" (-r), send a HIDDEN-USER error for everything. 500 * If -d is used to set a fallback username, this is used to 501 * override it, and the fallback is returned instead. 502 */ 503 if (!rflag) { 504 if (*idbuf == '\0') 505 iderror(lport, fport, s, ID_HIDDEN); 506 goto printit; 507 } 508 509 /* 510 * We take the input and construct an array of two sockaddr_ins 511 * which contain the local address information and foreign 512 * address information, respectively, used to look up the 513 * credentials for the socket (which are returned by the 514 * sysctl "net.inet.tcp.getcred" when we call it.) 515 */ 516 socklen = sizeof(ss[0]); 517 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1) 518 iderror(lport, fport, s, ID_UNKNOWN); 519 socklen = sizeof(ss[1]); 520 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1) 521 iderror(lport, fport, s, ID_UNKNOWN); 522 if (ss[0].ss_family != ss[1].ss_family) 523 iderror(lport, fport, s, ID_UNKNOWN); 524 size = sizeof(uc); 525 switch (ss[0].ss_family) { 526 case AF_INET: 527 sin4[0] = *(struct sockaddr_in *)&ss[0]; 528 sin4[0].sin_port = htons(lport); 529 sin4[1] = *(struct sockaddr_in *)&ss[1]; 530 sin4[1].sin_port = htons(fport); 531 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4, 532 sizeof(sin4)) == -1) 533 getcredfail = errno; 534 break; 535 #ifdef INET6 536 case AF_INET6: 537 sin6[0] = *(struct sockaddr_in6 *)&ss[0]; 538 sin6[0].sin6_port = htons(lport); 539 sin6[1] = *(struct sockaddr_in6 *)&ss[1]; 540 sin6[1].sin6_port = htons(fport); 541 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6, 542 sizeof(sin6)) == -1) 543 getcredfail = errno; 544 break; 545 #endif 546 default: /* should not reach here */ 547 getcredfail = EAFNOSUPPORT; 548 break; 549 } 550 if (getcredfail != 0) { 551 if (*idbuf == '\0') 552 iderror(lport, fport, s, 553 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN); 554 goto printit; 555 } 556 557 /* Look up the pw to get the username and home directory*/ 558 errno = 0; 559 pw = getpwuid(uc.cr_uid); 560 if (pw == NULL) 561 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN); 562 563 if (iflag) 564 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid); 565 else 566 strlcpy(idbuf, pw->pw_name, sizeof(idbuf)); 567 568 /* 569 * If enabled, we check for a file named ".noident" in the user's 570 * home directory. If found, we return HIDDEN-USER. 571 */ 572 if (nflag) { 573 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1) 574 iderror(lport, fport, s, ID_UNKNOWN); 575 if (lstat(p, &sb) == 0) { 576 free(p); 577 iderror(lport, fport, s, ID_HIDDEN); 578 } 579 free(p); 580 } 581 582 /* 583 * Here, if enabled, we read a user's ".fakeid" file in their 584 * home directory. It consists of a line containing the name 585 * they want. 586 */ 587 if (fflag) { 588 int fakeid_fd; 589 590 /* 591 * Here we set ourself to effectively be the user, so we don't 592 * open any files we have no permission to open, especially 593 * symbolic links to sensitive root-owned files or devices. 594 */ 595 if (initgroups(pw->pw_name, pw->pw_gid) == -1) 596 iderror(lport, fport, s, ID_UNKNOWN); 597 if (seteuid(pw->pw_uid) == -1) 598 iderror(lport, fport, s, ID_UNKNOWN); 599 /* 600 * We can't stat() here since that would be a race 601 * condition. 602 * Therefore, we open the file we have permissions to open 603 * and if it's not a regular file, we close it and end up 604 * returning the user's real username. 605 */ 606 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1) 607 iderror(lport, fport, s, ID_UNKNOWN); 608 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK); 609 free(p); 610 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 || 611 !S_ISREG(sb.st_mode)) 612 goto fakeid_fail; 613 614 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0) 615 goto fakeid_fail; 616 buf[ssize] = '\0'; 617 618 /* 619 * Usually, the file will have the desired identity 620 * in the form "identity\n". Allow for leading white 621 * space and trailing white space/end of line. 622 */ 623 p = buf; 624 p += strspn(p, " \t"); 625 p[strcspn(p, " \t\r\n")] = '\0'; 626 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */ 627 p[MAXLOGNAME - 1] = '\0'; 628 629 /* 630 * If the name is a zero-length string or matches it 631 * the id or name of another user (unless permitted by -F) 632 * then it is invalid. 633 */ 634 if (*p == '\0') 635 goto fakeid_fail; 636 if (!Fflag) { 637 if (iflag) { 638 if (p[strspn(p, "0123456789")] == '\0' && 639 getpwuid(atoi(p)) != NULL) 640 goto fakeid_fail; 641 } else { 642 if (getpwnam(p) != NULL) 643 goto fakeid_fail; 644 } 645 } 646 647 strlcpy(idbuf, p, sizeof(idbuf)); 648 649 fakeid_fail: 650 if (fakeid_fd != -1) 651 close(fakeid_fd); 652 } 653 654 printit: 655 /* Finally, we make and send the reply. */ 656 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname, 657 idbuf) == -1) { 658 syslog(LOG_ERR, "asprintf: %m"); 659 exit(EX_OSERR); 660 } 661 send(s, p, strlen(p), MSG_EOF); 662 free(p); 663 664 exit(0); 665 } 666 667 /* 668 * RFC738 Time Server. 669 * Return a machine readable date and time, in the form of the 670 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday 671 * returns the number of seconds since midnight, Jan 1, 1970, 672 * we must add 2208988800 seconds to this figure to make up for 673 * some seventy years Bell Labs was asleep. 674 */ 675 676 unsigned long 677 machtime(void) 678 { 679 struct timeval tv; 680 681 if (gettimeofday(&tv, NULL) < 0) { 682 if (debug) 683 warnx("unable to get time of day"); 684 return (0L); 685 } 686 #define OFFSET ((u_long)25567 * 24*60*60) 687 return (htonl((long)(tv.tv_sec + OFFSET))); 688 #undef OFFSET 689 } 690 691 /* ARGSUSED */ 692 void 693 machtime_dg(int s, struct servtab *sep) 694 { 695 unsigned long result; 696 struct sockaddr_storage ss; 697 socklen_t size; 698 699 size = sizeof(ss); 700 if (recvfrom(s, (char *)&result, sizeof(result), 0, 701 (struct sockaddr *)&ss, &size) < 0) 702 return; 703 704 if (check_loop((struct sockaddr *)&ss, sep)) 705 return; 706 707 result = machtime(); 708 sendto(s, (char *) &result, sizeof(result), 0, 709 (struct sockaddr *)&ss, size); 710 } 711 712 /* ARGSUSED */ 713 void 714 machtime_stream(int s, struct servtab *sep __unused) 715 { 716 unsigned long result; 717 718 result = machtime(); 719 send(s, (char *) &result, sizeof(result), MSG_EOF); 720 } 721 722 /* 723 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to 724 * services based on the service name sent. 725 * 726 * Based on TCPMUX.C by Mark K. Lottor November 1988 727 * sri-nic::ps:<mkl>tcpmux.c 728 */ 729 730 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */ 731 #define strwrite(fd, buf) write(fd, buf, sizeof(buf)-1) 732 733 static int /* # of characters upto \r,\n or \0 */ 734 getline(int fd, char *buf, int len) 735 { 736 int count = 0, n; 737 struct sigaction sa; 738 739 sa.sa_flags = 0; 740 sigemptyset(&sa.sa_mask); 741 sa.sa_handler = SIG_DFL; 742 sigaction(SIGALRM, &sa, NULL); 743 do { 744 alarm(10); 745 n = read(fd, buf, len-count); 746 alarm(0); 747 if (n == 0) 748 return (count); 749 if (n < 0) 750 return (-1); 751 while (--n >= 0) { 752 if (*buf == '\r' || *buf == '\n' || *buf == '\0') 753 return (count); 754 count++; 755 buf++; 756 } 757 } while (count < len); 758 return (count); 759 } 760 761 struct servtab * 762 tcpmux(int s) 763 { 764 struct servtab *sep; 765 char service[MAX_SERV_LEN+1]; 766 int len; 767 768 /* Get requested service name */ 769 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) { 770 strwrite(s, "-Error reading service name\r\n"); 771 return (NULL); 772 } 773 service[len] = '\0'; 774 775 if (debug) 776 warnx("tcpmux: someone wants %s", service); 777 778 /* 779 * Help is a required command, and lists available services, 780 * one per line. 781 */ 782 if (!strcasecmp(service, "help")) { 783 for (sep = servtab; sep; sep = sep->se_next) { 784 if (!ISMUX(sep)) 785 continue; 786 write(s,sep->se_service,strlen(sep->se_service)); 787 strwrite(s, "\r\n"); 788 } 789 return (NULL); 790 } 791 792 /* Try matching a service in inetd.conf with the request */ 793 for (sep = servtab; sep; sep = sep->se_next) { 794 if (!ISMUX(sep)) 795 continue; 796 if (!strcasecmp(service, sep->se_service)) { 797 if (ISMUXPLUS(sep)) { 798 strwrite(s, "+Go\r\n"); 799 } 800 return (sep); 801 } 802 } 803 strwrite(s, "-Service not available\r\n"); 804 return (NULL); 805 } 806