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