rshd.c revision 56939
1/*- 2 * Copyright (c) 1988, 1989, 1992, 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#ifndef lint 35static const char copyright[] = 36"@(#) Copyright (c) 1988, 1989, 1992, 1993, 1994\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38#endif /* not lint */ 39 40#ifndef lint 41#if 0 42static const char sccsid[] = "@(#)rshd.c 8.2 (Berkeley) 4/6/94"; 43#endif 44static const char rcsid[] = 45 "$FreeBSD: head/libexec/rshd/rshd.c 56939 2000-02-01 15:55:56Z shin $"; 46#endif /* not lint */ 47 48/* 49 * remote shell server: 50 * [port]\0 51 * remuser\0 52 * locuser\0 53 * command\0 54 * data 55 */ 56#include <sys/param.h> 57#include <sys/ioctl.h> 58#include <sys/time.h> 59#include <sys/socket.h> 60 61#include <netinet/in_systm.h> 62#include <netinet/in.h> 63#include <netinet/ip.h> 64#include <netinet/tcp.h> 65#include <arpa/inet.h> 66#include <netdb.h> 67 68#include <errno.h> 69#include <fcntl.h> 70#include <libutil.h> 71#include <paths.h> 72#include <pwd.h> 73#include <signal.h> 74#include <stdio.h> 75#include <stdlib.h> 76#include <string.h> 77#include <syslog.h> 78#include <unistd.h> 79#ifdef LOGIN_CAP 80#include <login_cap.h> 81#endif 82 83/* wrapper for KAME-special getnameinfo() */ 84#ifndef NI_WITHSCOPEID 85#define NI_WITHSCOPEID 0 86#endif 87 88int keepalive = 1; 89int log_success; /* If TRUE, log all successful accesses */ 90int sent_null; 91int no_delay; 92#ifdef CRYPT 93int doencrypt = 0; 94#endif 95 96union sockunion { 97 struct sockinet { 98 u_char si_len; 99 u_char si_family; 100 u_short si_port; 101 } su_si; 102 struct sockaddr_in su_sin; 103 struct sockaddr_in6 su_sin6; 104}; 105#define su_len su_si.si_len 106#define su_family su_si.si_family 107#define su_port su_si.si_port 108 109void doit __P((union sockunion *)); 110void error __P((const char *, ...)); 111void getstr __P((char *, int, char *)); 112int local_domain __P((char *)); 113char *topdomain __P((char *)); 114void usage __P((void)); 115 116#ifndef NO_PAM 117extern int auth_pam __P((char *)); 118#endif 119 120#define OPTIONS "alnDL" 121 122int 123main(argc, argv) 124 int argc; 125 char *argv[]; 126{ 127 extern int __check_rhosts_file; 128 struct linger linger; 129 int ch, on = 1, fromlen; 130 struct sockaddr_storage from; 131 132 openlog("rshd", LOG_PID | LOG_ODELAY, LOG_DAEMON); 133 134 opterr = 0; 135 while ((ch = getopt(argc, argv, OPTIONS)) != -1) 136 switch (ch) { 137 case 'a': 138 /* ignored for compatability */ 139 break; 140 case 'l': 141 __check_rhosts_file = 0; 142 break; 143 case 'n': 144 keepalive = 0; 145 break; 146#ifdef CRYPT 147 case 'x': 148 doencrypt = 1; 149 break; 150#endif 151 case 'D': 152 no_delay = 1; 153 break; 154 case 'L': 155 log_success = 1; 156 break; 157 case '?': 158 default: 159 usage(); 160 break; 161 } 162 163 argc -= optind; 164 argv += optind; 165 166#ifdef CRYPT 167 if (doencrypt) { 168 syslog(LOG_ERR, "-k is required for -x"); 169 exit(2); 170 } 171#endif 172 173 fromlen = sizeof (from); 174 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { 175 syslog(LOG_ERR, "getpeername: %m"); 176 exit(1); 177 } 178 if (keepalive && 179 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, 180 sizeof(on)) < 0) 181 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 182 linger.l_onoff = 1; 183 linger.l_linger = 60; /* XXX */ 184 if (setsockopt(0, SOL_SOCKET, SO_LINGER, (char *)&linger, 185 sizeof (linger)) < 0) 186 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m"); 187 if (no_delay && 188 setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0) 189 syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m"); 190 doit((union sockunion *)&from); 191 /* NOTREACHED */ 192 return(0); 193} 194 195char username[20] = "USER="; 196char homedir[64] = "HOME="; 197char shell[64] = "SHELL="; 198char path[100] = "PATH="; 199char *envinit[] = 200 {homedir, shell, path, username, 0}; 201char **environ; 202 203void 204doit(fromp) 205 union sockunion *fromp; 206{ 207 extern char *__rcmd_errstr; /* syslog hook from libc/net/rcmd.c. */ 208 struct passwd *pwd; 209 u_short port; 210 fd_set ready, readfrom; 211 int cc, nfd, pv[2], pid, s; 212 int one = 1; 213 char *errorstr; 214 char *cp, sig, buf[BUFSIZ]; 215 char cmdbuf[NCARGS+1], locuser[16], remuser[16]; 216 char fromhost[2 * MAXHOSTNAMELEN + 1]; 217 char numericname[INET6_ADDRSTRLEN]; 218 int af = fromp->su_family, err; 219 int retval; 220#ifdef CRYPT 221 int rc; 222 int pv1[2], pv2[2]; 223#endif 224#ifdef LOGIN_CAP 225 login_cap_t *lc; 226#endif 227 228 (void) signal(SIGINT, SIG_DFL); 229 (void) signal(SIGQUIT, SIG_DFL); 230 (void) signal(SIGTERM, SIG_DFL); 231#ifdef DEBUG 232 { int t = open(_PATH_TTY, 2); 233 if (t >= 0) { 234 ioctl(t, TIOCNOTTY, (char *)0); 235 (void) close(t); 236 } 237 } 238#endif 239 fromp->su_port = ntohs((u_short)fromp->su_port); 240 if (af != AF_INET 241#ifdef INET6 242 && af != AF_INET6 243#endif 244 ) { 245 syslog(LOG_ERR, "malformed \"from\" address (af %d)\n", af); 246 exit(1); 247 } 248 err = getnameinfo((struct sockaddr *)fromp, fromp->su_len, numericname, 249 sizeof(numericname), NULL, 0, 250 NI_NUMERICHOST|NI_WITHSCOPEID); 251 /* XXX: do 'err' check */ 252#ifdef IP_OPTIONS 253 if (af == AF_INET) { 254 u_char optbuf[BUFSIZ/3]; 255 int optsize = sizeof(optbuf), ipproto, i; 256 struct protoent *ip; 257 258 if ((ip = getprotobyname("ip")) != NULL) 259 ipproto = ip->p_proto; 260 else 261 ipproto = IPPROTO_IP; 262 if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) && 263 optsize != 0) { 264 for (i = 0; i < optsize; ) { 265 u_char c = optbuf[i]; 266 if (c == IPOPT_LSRR || c == IPOPT_SSRR) { 267 syslog(LOG_NOTICE, 268 "connection refused from %s with IP option %s", 269 numericname, 270 c == IPOPT_LSRR ? "LSRR" : "SSRR"); 271 exit(1); 272 } 273 if (c == IPOPT_EOL) 274 break; 275 i += (c == IPOPT_NOP) ? 1 : optbuf[i+1]; 276 } 277 } 278 } 279#endif 280 281 if (fromp->su_port >= IPPORT_RESERVED || 282 fromp->su_port < IPPORT_RESERVED/2) { 283 syslog(LOG_NOTICE|LOG_AUTH, 284 "connection from %s on illegal port %u", 285 numericname, 286 fromp->su_port); 287 exit(1); 288 } 289 290 (void) alarm(60); 291 port = 0; 292 s = 0; /* not set or used if port == 0 */ 293 for (;;) { 294 char c; 295 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) { 296 if (cc < 0) 297 syslog(LOG_NOTICE, "read: %m"); 298 shutdown(0, 1+1); 299 exit(1); 300 } 301 if (c == 0) 302 break; 303 port = port * 10 + c - '0'; 304 } 305 306 (void) alarm(0); 307 if (port != 0) { 308 int lport = IPPORT_RESERVED - 1; 309 s = rresvport_af(&lport, af); 310 if (s < 0) { 311 syslog(LOG_ERR, "can't get stderr port: %m"); 312 exit(1); 313 } 314 if (port >= IPPORT_RESERVED || 315 port < IPPORT_RESERVED/2) { 316 syslog(LOG_NOTICE|LOG_AUTH, 317 "2nd socket from %s on unreserved port %u", 318 numericname, 319 port); 320 exit(1); 321 } 322 fromp->su_port = htons(port); 323 if (connect(s, (struct sockaddr *)fromp, fromp->su_len) < 0) { 324 syslog(LOG_INFO, "connect second port %d: %m", port); 325 exit(1); 326 } 327 } 328 329 errorstr = NULL; 330 realhostname_sa(fromhost, sizeof(fromhost) - 1, 331 (struct sockaddr *)fromp, 332 fromp->su_len); 333 fromhost[sizeof(fromhost) - 1] = '\0'; 334 335#ifdef CRYPT 336 if (doencrypt && af == AF_INET) { 337 struct sockaddr_in local_addr; 338 rc = sizeof(local_addr); 339 if (getsockname(0, (struct sockaddr *)&local_addr, 340 &rc) < 0) { 341 syslog(LOG_ERR, "getsockname: %m"); 342 error("rlogind: getsockname: %m"); 343 exit(1); 344 } 345 authopts = KOPT_DO_MUTUAL; 346 rc = krb_recvauth(authopts, 0, ticket, 347 "rcmd", instance, &fromaddr, 348 &local_addr, kdata, "", schedule, 349 version); 350 des_set_key(&kdata->session, schedule); 351 } 352#endif 353 getstr(remuser, sizeof(remuser), "remuser"); 354 355 getstr(locuser, sizeof(locuser), "locuser"); 356 getstr(cmdbuf, sizeof(cmdbuf), "command"); 357 setpwent(); 358 pwd = getpwnam(locuser); 359 if (pwd == NULL) { 360 syslog(LOG_INFO|LOG_AUTH, 361 "%s@%s as %s: unknown login. cmd='%.80s'", 362 remuser, fromhost, locuser, cmdbuf); 363 if (errorstr == NULL) 364 errorstr = "Login incorrect.\n"; 365 goto fail; 366 } 367#ifdef LOGIN_CAP 368 lc = login_getpwclass(pwd); 369#endif 370 if (chdir(pwd->pw_dir) < 0) { 371#ifdef LOGIN_CAP 372 if (chdir("/") < 0 || 373 login_getcapbool(lc, "requirehome", !!pwd->pw_uid)) { 374 syslog(LOG_INFO|LOG_AUTH, 375 "%s@%s as %s: no home directory. cmd='%.80s'", 376 remuser, fromhost, locuser, cmdbuf); 377 error("No remote home directory.\n"); 378 exit(0); 379 } 380#else 381 (void) chdir("/"); 382#ifdef notdef 383 syslog(LOG_INFO|LOG_AUTH, 384 "%s@%s as %s: no home directory. cmd='%.80s'", 385 remuser, fromhost, locuser, cmdbuf); 386 error("No remote directory.\n"); 387 exit(1); 388#endif 389#endif 390 pwd->pw_dir = "/"; 391 } 392 393#ifndef NO_PAM 394 retval = auth_pam(locuser); 395 396 if (retval) { 397 if (retval == -1) { 398 syslog(LOG_ERR,"PAM authentication failed"); 399 } 400 else { 401 syslog(LOG_ERR, 402 "User %s failed PAM authentication", locuser); 403 exit(1); 404 } 405 } 406#endif 407 408 if (errorstr || 409 (pwd->pw_expire && time(NULL) >= pwd->pw_expire) || 410 (pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0' && 411 iruserok_sa(fromp, fromp->su_len, pwd->pw_uid == 0, 412 remuser, locuser) < 0)) { 413 if (__rcmd_errstr) 414 syslog(LOG_INFO|LOG_AUTH, 415 "%s@%s as %s: permission denied (%s). cmd='%.80s'", 416 remuser, fromhost, locuser, __rcmd_errstr, 417 cmdbuf); 418 else 419 syslog(LOG_INFO|LOG_AUTH, 420 "%s@%s as %s: permission denied. cmd='%.80s'", 421 remuser, fromhost, locuser, cmdbuf); 422fail: 423 if (errorstr == NULL) 424 errorstr = "Login incorrect.\n"; 425 error(errorstr, fromhost); 426 exit(1); 427 } 428 429 if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) { 430 error("Logins currently disabled.\n"); 431 exit(1); 432 } 433#ifdef LOGIN_CAP 434 if (lc != NULL && fromp->su_family == AF_INET) { /*XXX*/ 435 char remote_ip[MAXHOSTNAMELEN]; 436 437 strncpy(remote_ip, numericname, 438 sizeof(remote_ip) - 1); 439 remote_ip[sizeof(remote_ip) - 1] = 0; 440 if (!auth_hostok(lc, fromhost, remote_ip)) { 441 syslog(LOG_INFO|LOG_AUTH, 442 "%s@%s as %s: permission denied (%s). cmd='%.80s'", 443 remuser, fromhost, locuser, __rcmd_errstr, 444 cmdbuf); 445 error("Login incorrect.\n"); 446 exit(1); 447 } 448 if (!auth_timeok(lc, time(NULL))) { 449 error("Logins not available right now\n"); 450 exit(1); 451 } 452 } 453#endif /* !LOGIN_CAP */ 454#if BSD > 43 455 /* before fork, while we're session leader */ 456 if (setlogin(pwd->pw_name) < 0) 457 syslog(LOG_ERR, "setlogin() failed: %m"); 458#endif 459 460 (void) write(STDERR_FILENO, "\0", 1); 461 sent_null = 1; 462 463 if (port) { 464 if (pipe(pv) < 0) { 465 error("Can't make pipe.\n"); 466 exit(1); 467 } 468#ifdef CRYPT 469 if (doencrypt) { 470 if (pipe(pv1) < 0) { 471 error("Can't make 2nd pipe.\n"); 472 exit(1); 473 } 474 if (pipe(pv2) < 0) { 475 error("Can't make 3rd pipe.\n"); 476 exit(1); 477 } 478 } 479#endif 480 pid = fork(); 481 if (pid == -1) { 482 error("Can't fork; try again.\n"); 483 exit(1); 484 } 485 if (pid) { 486#ifdef CRYPT 487 if (doencrypt) { 488 static char msg[] = SECURE_MESSAGE; 489 (void) close(pv1[1]); 490 (void) close(pv2[1]); 491 des_enc_write(s, msg, sizeof(msg) - 1, 492 schedule, &kdata->session); 493 494 } else 495#endif 496 { 497 (void) close(0); 498 (void) close(1); 499 } 500 (void) close(2); 501 (void) close(pv[1]); 502 503 FD_ZERO(&readfrom); 504 FD_SET(s, &readfrom); 505 FD_SET(pv[0], &readfrom); 506 if (pv[0] > s) 507 nfd = pv[0]; 508 else 509 nfd = s; 510#ifdef CRYPT 511 if (doencrypt) { 512 FD_ZERO(&writeto); 513 FD_SET(pv2[0], &writeto); 514 FD_SET(pv1[0], &readfrom); 515 516 nfd = MAX(nfd, pv2[0]); 517 nfd = MAX(nfd, pv1[0]); 518 } else 519#endif 520 ioctl(pv[0], FIONBIO, (char *)&one); 521 522 /* should set s nbio! */ 523 nfd++; 524 do { 525 ready = readfrom; 526#ifdef CRYPT 527 if (doencrypt) { 528 wready = writeto; 529 if (select(nfd, &ready, 530 &wready, (fd_set *) 0, 531 (struct timeval *) 0) < 0) 532 break; 533 } else 534#endif 535 if (select(nfd, &ready, (fd_set *)0, 536 (fd_set *)0, (struct timeval *)0) < 0) 537 break; 538 if (FD_ISSET(s, &ready)) { 539 int ret; 540#ifdef CRYPT 541 if (doencrypt) 542 ret = des_enc_read(s, &sig, 1, 543 schedule, &kdata->session); 544 else 545#endif 546 ret = read(s, &sig, 1); 547 if (ret <= 0) 548 FD_CLR(s, &readfrom); 549 else 550 killpg(pid, sig); 551 } 552 if (FD_ISSET(pv[0], &ready)) { 553 errno = 0; 554 cc = read(pv[0], buf, sizeof(buf)); 555 if (cc <= 0) { 556 shutdown(s, 1+1); 557 FD_CLR(pv[0], &readfrom); 558 } else { 559#ifdef CRYPT 560 if (doencrypt) 561 (void) 562 des_enc_write(s, buf, cc, 563 schedule, &kdata->session); 564 else 565#endif 566 (void) 567 write(s, buf, cc); 568 } 569 } 570#ifdef CRYPT 571 if (doencrypt && FD_ISSET(pv1[0], &ready)) { 572 errno = 0; 573 cc = read(pv1[0], buf, sizeof(buf)); 574 if (cc <= 0) { 575 shutdown(pv1[0], 1+1); 576 FD_CLR(pv1[0], &readfrom); 577 } else 578 (void) des_enc_write(STDOUT_FILENO, 579 buf, cc, 580 schedule, &kdata->session); 581 } 582 583 if (doencrypt && FD_ISSET(pv2[0], &wready)) { 584 errno = 0; 585 cc = des_enc_read(STDIN_FILENO, 586 buf, sizeof(buf), 587 schedule, &kdata->session); 588 if (cc <= 0) { 589 shutdown(pv2[0], 1+1); 590 FD_CLR(pv2[0], &writeto); 591 } else 592 (void) write(pv2[0], buf, cc); 593 } 594#endif 595 596 } while (FD_ISSET(s, &readfrom) || 597#ifdef CRYPT 598 (doencrypt && FD_ISSET(pv1[0], &readfrom)) || 599#endif 600 FD_ISSET(pv[0], &readfrom)); 601 exit(0); 602 } 603 setpgrp(0, getpid()); 604 (void) close(s); 605 (void) close(pv[0]); 606#ifdef CRYPT 607 if (doencrypt) { 608 close(pv1[0]); close(pv2[0]); 609 dup2(pv1[1], 1); 610 dup2(pv2[1], 0); 611 close(pv1[1]); 612 close(pv2[1]); 613 } 614#endif 615 dup2(pv[1], 2); 616 close(pv[1]); 617 } 618 if (*pwd->pw_shell == '\0') 619 pwd->pw_shell = _PATH_BSHELL; 620 environ = envinit; 621 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6); 622 strcat(path, _PATH_DEFPATH); 623 strncat(shell, pwd->pw_shell, sizeof(shell)-7); 624 strncat(username, pwd->pw_name, sizeof(username)-6); 625 cp = strrchr(pwd->pw_shell, '/'); 626 if (cp) 627 cp++; 628 else 629 cp = pwd->pw_shell; 630#ifdef LOGIN_CAP 631 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETALL) != 0) { 632 syslog(LOG_ERR, "setusercontext: %m"); 633 exit(1); 634 } 635 login_close(lc); 636#else 637 (void) setgid((gid_t)pwd->pw_gid); 638 initgroups(pwd->pw_name, pwd->pw_gid); 639 (void) setuid((uid_t)pwd->pw_uid); 640#endif 641 endpwent(); 642 if (log_success || pwd->pw_uid == 0) { 643 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'", 644 remuser, fromhost, locuser, cmdbuf); 645 } 646 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 647 perror(pwd->pw_shell); 648 exit(1); 649} 650 651/* 652 * Report error to client. Note: can't be used until second socket has 653 * connected to client, or older clients will hang waiting for that 654 * connection first. 655 */ 656#if __STDC__ 657#include <stdarg.h> 658#else 659#include <varargs.h> 660#endif 661 662void 663#if __STDC__ 664error(const char *fmt, ...) 665#else 666error(fmt, va_alist) 667 char *fmt; 668 va_dcl 669#endif 670{ 671 va_list ap; 672 int len; 673 char *bp, buf[BUFSIZ]; 674#if __STDC__ 675 va_start(ap, fmt); 676#else 677 va_start(ap); 678#endif 679 bp = buf; 680 if (sent_null == 0) { 681 *bp++ = 1; 682 len = 1; 683 } else 684 len = 0; 685 (void)vsnprintf(bp, sizeof(buf) - 1, fmt, ap); 686 (void)write(STDERR_FILENO, buf, len + strlen(bp)); 687} 688 689void 690getstr(buf, cnt, err) 691 char *buf, *err; 692 int cnt; 693{ 694 char c; 695 696 do { 697 if (read(STDIN_FILENO, &c, 1) != 1) 698 exit(1); 699 *buf++ = c; 700 if (--cnt == 0) { 701 error("%s too long\n", err); 702 exit(1); 703 } 704 } while (c != 0); 705} 706 707/* 708 * Check whether host h is in our local domain, 709 * defined as sharing the last two components of the domain part, 710 * or the entire domain part if the local domain has only one component. 711 * If either name is unqualified (contains no '.'), 712 * assume that the host is local, as it will be 713 * interpreted as such. 714 */ 715int 716local_domain(h) 717 char *h; 718{ 719 char localhost[MAXHOSTNAMELEN]; 720 char *p1, *p2; 721 722 localhost[0] = 0; 723 (void) gethostname(localhost, sizeof(localhost) - 1); 724 localhost[sizeof(localhost) - 1] = '\0'; 725 p1 = topdomain(localhost); 726 p2 = topdomain(h); 727 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 728 return (1); 729 return (0); 730} 731 732char * 733topdomain(h) 734 char *h; 735{ 736 char *p, *maybe = NULL; 737 int dots = 0; 738 739 for (p = h + strlen(h); p >= h; p--) { 740 if (*p == '.') { 741 if (++dots == 2) 742 return (p); 743 maybe = p; 744 } 745 } 746 return (maybe); 747} 748 749void 750usage() 751{ 752 753 syslog(LOG_ERR, "usage: rshd [-%s]", OPTIONS); 754 exit(2); 755} 756