1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Donn Seeley at Berkeley Software Design, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 static char copyright[] = 39 "@(#) Copyright (c) 1991, 1993\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif /* not lint */ 42 43 #ifndef lint 44 /*static char sccsid[] = "from: @(#)init.c 8.1 (Berkeley) 7/15/93";*/ 45 static char *rcsid = "$Id: init.c,v 1.16 1994/06/11 07:54:04 mycroft Exp $"; 46 #endif /* not lint */ 47 48 #include <sys/param.h> 49 #include <sys/sysctl.h> 50 #include <sys/wait.h> 51 52 #include <db.h> 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <signal.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <syslog.h> 60 #include <time.h> 61 #include <ttyent.h> 62 #include <unistd.h> 63 64 #ifdef __STDC__ 65 #include <stdarg.h> 66 #else 67 #include <varargs.h> 68 #endif 69 70 #ifdef SECURE 71 #include <pwd.h> 72 #endif 73 74 #include "pathnames.h" 75 76 /* 77 * Until the mythical util.h arrives... 78 */ 79 extern int login_tty __P((int)); 80 extern int logout __P((const char *)); 81 extern void logwtmp __P((const char *, const char *, const char *)); 82 83 /* 84 * Sleep times; used to prevent thrashing. 85 */ 86 #define GETTY_SPACING 5 /* N secs minimum getty spacing */ 87 #define GETTY_SLEEP 30 /* sleep N secs after spacing problem */ 88 #define WINDOW_WAIT 3 /* wait N secs after starting window */ 89 #define STALL_TIMEOUT 30 /* wait N secs after warning */ 90 #define DEATH_WATCH 10 /* wait N secs for procs to die */ 91 92 void handle __P((sig_t, ...)); 93 void delset __P((sigset_t *, ...)); 94 95 void stall __P((char *, ...)); 96 void warning __P((char *, ...)); 97 void emergency __P((char *, ...)); 98 void disaster __P((int)); 99 void badsys __P((int)); 100 101 /* 102 * We really need a recursive typedef... 103 * The following at least guarantees that the return type of (*state_t)() 104 * is sufficiently wide to hold a function pointer. 105 */ 106 typedef long (*state_func_t) __P((void)); 107 typedef state_func_t (*state_t) __P((void)); 108 109 state_func_t single_user __P((void)); 110 state_func_t runcom __P((void)); 111 state_func_t read_ttys __P((void)); 112 state_func_t multi_user __P((void)); 113 state_func_t clean_ttys __P((void)); 114 state_func_t catatonia __P((void)); 115 state_func_t death __P((void)); 116 117 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT; 118 119 void transition __P((state_t)); 120 #ifndef LETS_GET_SMALL 121 state_t requested_transition = runcom; 122 #else /* LETS_GET_SMALL */ 123 state_t requested_transition = single_user; 124 #endif /* LETS_GET_SMALL */ 125 126 void setctty __P((char *)); 127 128 typedef struct init_session { 129 int se_index; /* index of entry in ttys file */ 130 pid_t se_process; /* controlling process */ 131 time_t se_started; /* used to avoid thrashing */ 132 int se_flags; /* status of session */ 133 #define SE_SHUTDOWN 0x1 /* session won't be restarted */ 134 char *se_device; /* filename of port */ 135 char *se_getty; /* what to run on that port */ 136 char **se_getty_argv; /* pre-parsed argument array */ 137 char *se_window; /* window system (started only once) */ 138 char **se_window_argv; /* pre-parsed argument array */ 139 struct init_session *se_prev; 140 struct init_session *se_next; 141 } session_t; 142 143 void free_session __P((session_t *)); 144 session_t *new_session __P((session_t *, int, struct ttyent *)); 145 session_t *sessions; 146 147 char **construct_argv __P((char *)); 148 void start_window_system __P((session_t *)); 149 void collect_child __P((pid_t)); 150 pid_t start_getty __P((session_t *)); 151 void transition_handler __P((int)); 152 void alrm_handler __P((int)); 153 void setsecuritylevel __P((int)); 154 int getsecuritylevel __P((void)); 155 int setupargv __P((session_t *, struct ttyent *)); 156 int clang; 157 158 void clear_session_logs __P((session_t *)); 159 160 int start_session_db __P((void)); 161 void add_session __P((session_t *)); 162 void del_session __P((session_t *)); 163 session_t *find_session __P((pid_t)); 164 DB *session_db; 165 166 /* 167 * The mother of all processes. 168 */ 169 int 170 main(argc, argv) 171 int argc; 172 char **argv; 173 { 174 int c; 175 struct sigaction sa; 176 sigset_t mask; 177 178 #ifndef LETS_GET_SMALL 179 /* Dispose of random users. */ 180 if (getuid() != 0) { 181 (void)fprintf(stderr, "init: %s\n", strerror(EPERM)); 182 exit (1); 183 } 184 185 /* System V users like to reexec init. */ 186 if (getpid() != 1) { 187 (void)fprintf(stderr, "init: already running\n"); 188 exit (1); 189 } 190 191 /* 192 * Note that this does NOT open a file... 193 * Does 'init' deserve its own facility number? 194 */ 195 openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH); 196 #endif /* LETS_GET_SMALL */ 197 198 /* 199 * Create an initial session. 200 */ 201 if (setsid() < 0) 202 warning("initial setsid() failed: %m"); 203 204 /* 205 * Establish an initial user so that programs running 206 * single user do not freak out and die (like passwd). 207 */ 208 if (setlogin("root") < 0) 209 warning("setlogin() failed: %m"); 210 211 #ifndef LETS_GET_SMALL 212 /* 213 * This code assumes that we always get arguments through flags, 214 * never through bits set in some random machine register. 215 */ 216 while ((c = getopt(argc, argv, "sf")) != -1) 217 switch (c) { 218 case 's': 219 requested_transition = single_user; 220 break; 221 case 'f': 222 runcom_mode = FASTBOOT; 223 break; 224 default: 225 warning("unrecognized flag '-%c'", c); 226 break; 227 } 228 229 if (optind != argc) 230 warning("ignoring excess arguments"); 231 #else /* LETS_GET_SMALL */ 232 requested_transition = single_user; 233 #endif /* LETS_GET_SMALL */ 234 235 /* 236 * We catch or block signals rather than ignore them, 237 * so that they get reset on exec. 238 */ 239 handle(badsys, SIGSYS, 0); 240 handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, 241 SIGBUS, SIGXCPU, SIGXFSZ, 0); 242 handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0); 243 handle(alrm_handler, SIGALRM, 0); 244 sigfillset(&mask); 245 delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS, 246 SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0); 247 sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); 248 sigemptyset(&sa.sa_mask); 249 sa.sa_flags = 0; 250 sa.sa_handler = SIG_IGN; 251 (void) sigaction(SIGTTIN, &sa, (struct sigaction *)0); 252 (void) sigaction(SIGTTOU, &sa, (struct sigaction *)0); 253 254 /* 255 * Paranoia. 256 */ 257 close(0); 258 close(1); 259 close(2); 260 261 /* 262 * Start the state machine. 263 */ 264 transition(requested_transition); 265 266 /* 267 * Should never reach here. 268 */ 269 return 1; 270 } 271 272 /* 273 * Associate a function with a signal handler. 274 */ 275 void 276 #ifdef __STDC__ 277 handle(sig_t handler, ...) 278 #else 279 handle(va_alist) 280 va_dcl 281 #endif 282 { 283 int sig; 284 struct sigaction sa; 285 int mask_everything; 286 va_list ap; 287 #ifndef __STDC__ 288 sig_t handler; 289 290 va_start(ap); 291 handler = va_arg(ap, sig_t); 292 #else 293 va_start(ap, handler); 294 #endif 295 296 sa.sa_handler = handler; 297 sigfillset(&mask_everything); 298 299 while (sig = va_arg(ap, int)) { 300 sa.sa_mask = mask_everything; 301 /* XXX SA_RESTART? */ 302 sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0; 303 sigaction(sig, &sa, (struct sigaction *) 0); 304 } 305 va_end(ap); 306 } 307 308 /* 309 * Delete a set of signals from a mask. 310 */ 311 void 312 #ifdef __STDC__ 313 delset(sigset_t *maskp, ...) 314 #else 315 delset(va_alist) 316 va_dcl 317 #endif 318 { 319 int sig; 320 va_list ap; 321 #ifndef __STDC__ 322 sigset_t *maskp; 323 324 va_start(ap); 325 maskp = va_arg(ap, sigset_t *); 326 #else 327 va_start(ap, maskp); 328 #endif 329 330 while (sig = va_arg(ap, int)) 331 sigdelset(maskp, sig); 332 va_end(ap); 333 } 334 335 /* 336 * Log a message and sleep for a while (to give someone an opportunity 337 * to read it and to save log or hardcopy output if the problem is chronic). 338 * NB: should send a message to the session logger to avoid blocking. 339 */ 340 void 341 #ifdef __STDC__ 342 stall(char *message, ...) 343 #else 344 stall(va_alist) 345 va_dcl 346 #endif 347 { 348 va_list ap; 349 #ifndef __STDC__ 350 char *message; 351 352 va_start(ap); 353 message = va_arg(ap, char *); 354 #else 355 va_start(ap, message); 356 #endif 357 358 vsyslog(LOG_ALERT, message, ap); 359 va_end(ap); 360 sleep(STALL_TIMEOUT); 361 } 362 363 /* 364 * Like stall(), but doesn't sleep. 365 * If cpp had variadic macros, the two functions could be #defines for another. 366 * NB: should send a message to the session logger to avoid blocking. 367 */ 368 void 369 #ifdef __STDC__ 370 warning(char *message, ...) 371 #else 372 warning(va_alist) 373 va_dcl 374 #endif 375 { 376 va_list ap; 377 #ifndef __STDC__ 378 char *message; 379 380 va_start(ap); 381 message = va_arg(ap, char *); 382 #else 383 va_start(ap, message); 384 #endif 385 386 vsyslog(LOG_ALERT, message, ap); 387 va_end(ap); 388 } 389 390 /* 391 * Log an emergency message. 392 * NB: should send a message to the session logger to avoid blocking. 393 */ 394 void 395 #ifdef __STDC__ 396 emergency(char *message, ...) 397 #else 398 emergency(va_alist) 399 va_dcl 400 #endif 401 { 402 va_list ap; 403 #ifndef __STDC__ 404 char *message; 405 406 va_start(ap); 407 message = va_arg(ap, char *); 408 #else 409 va_start(ap, message); 410 #endif 411 412 vsyslog(LOG_EMERG, message, ap); 413 va_end(ap); 414 } 415 416 /* 417 * Catch a SIGSYS signal. 418 * 419 * These may arise if a system does not support sysctl. 420 * We tolerate up to 25 of these, then throw in the towel. 421 */ 422 void 423 badsys(sig) 424 int sig; 425 { 426 static int badcount = 0; 427 428 if (badcount++ < 25) 429 return; 430 disaster(sig); 431 } 432 433 /* 434 * Catch an unexpected signal. 435 */ 436 void 437 disaster(sig) 438 int sig; 439 { 440 emergency("fatal signal: %s", 441 sig < (unsigned) NSIG ? sys_siglist[sig] : "unknown signal"); 442 443 sleep(STALL_TIMEOUT); 444 _exit(sig); /* reboot */ 445 } 446 447 /* 448 * Get the security level of the kernel. 449 */ 450 int 451 getsecuritylevel() 452 { 453 #ifdef KERN_SECURELVL 454 int name[2], curlevel; 455 size_t len; 456 extern int errno; 457 458 name[0] = CTL_KERN; 459 name[1] = KERN_SECURELVL; 460 len = sizeof curlevel; 461 if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) { 462 emergency("cannot get kernel security level: %s", 463 strerror(errno)); 464 return (-1); 465 } 466 return (curlevel); 467 #else 468 return (-1); 469 #endif 470 } 471 472 /* 473 * Set the security level of the kernel. 474 */ 475 void 476 setsecuritylevel(newlevel) 477 int newlevel; 478 { 479 #ifdef KERN_SECURELVL 480 int name[2], curlevel; 481 extern int errno; 482 483 curlevel = getsecuritylevel(); 484 if (newlevel == curlevel) 485 return; 486 name[0] = CTL_KERN; 487 name[1] = KERN_SECURELVL; 488 if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) { 489 emergency( 490 "cannot change kernel security level from %d to %d: %s", 491 curlevel, newlevel, strerror(errno)); 492 return; 493 } 494 #ifdef SECURE 495 warning("kernel security level changed from %d to %d", 496 curlevel, newlevel); 497 #endif 498 #endif 499 } 500 501 /* 502 * Change states in the finite state machine. 503 * The initial state is passed as an argument. 504 */ 505 void 506 transition(s) 507 state_t s; 508 { 509 for (;;) 510 s = (state_t) (*s)(); 511 } 512 513 /* 514 * Close out the accounting files for a login session. 515 * NB: should send a message to the session logger to avoid blocking. 516 */ 517 void 518 clear_session_logs(sp) 519 session_t *sp; 520 { 521 char *line = sp->se_device + sizeof(_PATH_DEV) - 1; 522 523 if (logout(line)) 524 logwtmp(line, "", ""); 525 } 526 527 /* 528 * Start a session and allocate a controlling terminal. 529 * Only called by children of init after forking. 530 */ 531 void 532 setctty(name) 533 char *name; 534 { 535 int fd; 536 537 (void) revoke(name); 538 sleep (2); /* leave DTR low */ 539 if ((fd = open(name, O_RDWR)) == -1) { 540 stall("can't open %s: %m", name); 541 _exit(1); 542 } 543 if (login_tty(fd) == -1) { 544 stall("can't get %s for controlling terminal: %m", name); 545 _exit(1); 546 } 547 } 548 549 /* 550 * Bring the system up single user. 551 */ 552 state_func_t 553 single_user() 554 { 555 pid_t pid, wpid; 556 int status; 557 sigset_t mask; 558 char *shell = _PATH_BSHELL; 559 char *argv[2]; 560 #ifdef SECURE 561 struct ttyent *typ; 562 struct passwd *pp; 563 static const char banner[] = 564 "Enter root password, or ^D to go multi-user\n"; 565 char *clear, *password; 566 #endif 567 568 /* 569 * If the kernel is in secure mode, downgrade it to insecure mode. 570 */ 571 if (getsecuritylevel() > 0) 572 setsecuritylevel(0); 573 574 if ((pid = fork()) == 0) { 575 /* 576 * Start the single user session. 577 */ 578 setctty(_PATH_CONSOLE); 579 580 #ifdef SECURE 581 /* 582 * Check the root password. 583 * We don't care if the console is 'on' by default; 584 * it's the only tty that can be 'off' and 'secure'. 585 */ 586 typ = getttynam("console"); 587 pp = getpwnam("root"); 588 if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp) { 589 write(2, banner, sizeof banner - 1); 590 for (;;) { 591 clear = getpass("Password:"); 592 if (clear == 0 || *clear == '\0') 593 _exit(0); 594 password = crypt(clear, pp->pw_passwd); 595 bzero(clear, _PASSWORD_LEN); 596 if (strcmp(password, pp->pw_passwd) == 0) 597 break; 598 warning("single-user login failed\n"); 599 } 600 } 601 endttyent(); 602 endpwent(); 603 #endif /* SECURE */ 604 605 #ifdef DEBUGSHELL 606 { 607 char altshell[128], *cp = altshell; 608 int num; 609 610 #define SHREQUEST \ 611 "Enter pathname of shell or RETURN for sh: " 612 (void)write(STDERR_FILENO, 613 SHREQUEST, sizeof(SHREQUEST) - 1); 614 while ((num = read(STDIN_FILENO, cp, 1)) != -1 && 615 num != 0 && *cp != '\n' && cp < &altshell[127]) 616 cp++; 617 *cp = '\0'; 618 if (altshell[0] != '\0') 619 shell = altshell; 620 } 621 #endif /* DEBUGSHELL */ 622 623 /* 624 * Unblock signals. 625 * We catch all the interesting ones, 626 * and those are reset to SIG_DFL on exec. 627 */ 628 sigemptyset(&mask); 629 sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); 630 631 /* 632 * Fire off a shell. 633 * If the default one doesn't work, try the Bourne shell. 634 */ 635 argv[0] = "-sh"; 636 argv[1] = 0; 637 execv(shell, argv); 638 emergency("can't exec %s for single user: %m", shell); 639 execv(_PATH_BSHELL, argv); 640 emergency("can't exec %s for single user: %m", _PATH_BSHELL); 641 sleep(STALL_TIMEOUT); 642 _exit(1); 643 } 644 645 if (pid == -1) { 646 /* 647 * We are seriously hosed. Do our best. 648 */ 649 emergency("can't fork single-user shell, trying again"); 650 while (waitpid(-1, (int *) 0, WNOHANG) > 0) 651 continue; 652 return (state_func_t) single_user; 653 } 654 655 requested_transition = 0; 656 do { 657 if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) 658 collect_child(wpid); 659 if (wpid == -1) { 660 if (errno == EINTR) 661 continue; 662 warning("wait for single-user shell failed: %m; restarting"); 663 return (state_func_t) single_user; 664 } 665 if (wpid == pid && WIFSTOPPED(status)) { 666 warning("init: shell stopped, restarting\n"); 667 kill(pid, SIGCONT); 668 wpid = -1; 669 } 670 } while (wpid != pid && !requested_transition); 671 672 if (requested_transition) 673 return (state_func_t) requested_transition; 674 675 if (!WIFEXITED(status)) { 676 if (WTERMSIG(status) == SIGKILL) { 677 /* 678 * reboot(8) killed shell? 679 */ 680 warning("single user shell terminated."); 681 sleep(STALL_TIMEOUT); 682 _exit(0); 683 } else { 684 warning("single user shell terminated, restarting"); 685 return (state_func_t) single_user; 686 } 687 } 688 689 runcom_mode = FASTBOOT; 690 #ifndef LETS_GET_SMALL 691 return (state_func_t) runcom; 692 #else /* LETS_GET_SMALL */ 693 return (state_func_t) single_user; 694 #endif /* LETS_GET_SMALL */ 695 } 696 697 #ifndef LETS_GET_SMALL 698 /* 699 * Run the system startup script. 700 */ 701 state_func_t 702 runcom() 703 { 704 pid_t pid, wpid; 705 int status; 706 char *argv[4]; 707 struct sigaction sa; 708 709 if ((pid = fork()) == 0) { 710 sigemptyset(&sa.sa_mask); 711 sa.sa_flags = 0; 712 sa.sa_handler = SIG_IGN; 713 (void) sigaction(SIGTSTP, &sa, (struct sigaction *)0); 714 (void) sigaction(SIGHUP, &sa, (struct sigaction *)0); 715 716 setctty(_PATH_CONSOLE); 717 718 argv[0] = "sh"; 719 argv[1] = _PATH_RUNCOM; 720 argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0; 721 argv[3] = 0; 722 723 sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0); 724 725 execv(_PATH_BSHELL, argv); 726 stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM); 727 _exit(1); /* force single user mode */ 728 } 729 730 if (pid == -1) { 731 emergency("can't fork for %s on %s: %m", 732 _PATH_BSHELL, _PATH_RUNCOM); 733 while (waitpid(-1, (int *) 0, WNOHANG) > 0) 734 continue; 735 sleep(STALL_TIMEOUT); 736 return (state_func_t) single_user; 737 } 738 739 /* 740 * Copied from single_user(). This is a bit paranoid. 741 */ 742 do { 743 if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) 744 collect_child(wpid); 745 if (wpid == -1) { 746 if (errno == EINTR) 747 continue; 748 warning("wait for %s on %s failed: %m; going to single user mode", 749 _PATH_BSHELL, _PATH_RUNCOM); 750 return (state_func_t) single_user; 751 } 752 if (wpid == pid && WIFSTOPPED(status)) { 753 warning("init: %s on %s stopped, restarting\n", 754 _PATH_BSHELL, _PATH_RUNCOM); 755 kill(pid, SIGCONT); 756 wpid = -1; 757 } 758 } while (wpid != pid); 759 760 if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM && 761 requested_transition == catatonia) { 762 /* /etc/rc executed /sbin/reboot; wait for the end quietly */ 763 sigset_t s; 764 765 sigfillset(&s); 766 for (;;) 767 sigsuspend(&s); 768 } 769 770 if (!WIFEXITED(status)) { 771 warning("%s on %s terminated abnormally, going to single user mode", 772 _PATH_BSHELL, _PATH_RUNCOM); 773 return (state_func_t) single_user; 774 } 775 776 if (WEXITSTATUS(status)) 777 return (state_func_t) single_user; 778 779 runcom_mode = AUTOBOOT; /* the default */ 780 /* NB: should send a message to the session logger to avoid blocking. */ 781 logwtmp("~", "reboot", ""); 782 return (state_func_t) read_ttys; 783 } 784 785 /* 786 * Open the session database. 787 * 788 * NB: We could pass in the size here; is it necessary? 789 */ 790 int 791 start_session_db() 792 { 793 if (session_db && (*session_db->close)(session_db)) 794 emergency("session database close: %s", strerror(errno)); 795 if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) { 796 emergency("session database open: %s", strerror(errno)); 797 return (1); 798 } 799 return (0); 800 801 } 802 803 /* 804 * Add a new login session. 805 */ 806 void 807 add_session(sp) 808 session_t *sp; 809 { 810 DBT key; 811 DBT data; 812 813 key.data = &sp->se_process; 814 key.size = sizeof sp->se_process; 815 data.data = &sp; 816 data.size = sizeof sp; 817 818 if ((*session_db->put)(session_db, &key, &data, 0)) 819 emergency("insert %d: %s", sp->se_process, strerror(errno)); 820 } 821 822 /* 823 * Delete an old login session. 824 */ 825 void 826 del_session(sp) 827 session_t *sp; 828 { 829 DBT key; 830 831 key.data = &sp->se_process; 832 key.size = sizeof sp->se_process; 833 834 if ((*session_db->del)(session_db, &key, 0)) 835 emergency("delete %d: %s", sp->se_process, strerror(errno)); 836 } 837 838 /* 839 * Look up a login session by pid. 840 */ 841 session_t * 842 #ifdef __STDC__ 843 find_session(pid_t pid) 844 #else 845 find_session(pid) 846 pid_t pid; 847 #endif 848 { 849 DBT key; 850 DBT data; 851 session_t *ret; 852 853 key.data = &pid; 854 key.size = sizeof pid; 855 if ((*session_db->get)(session_db, &key, &data, 0) != 0) 856 return 0; 857 bcopy(data.data, (char *)&ret, sizeof(ret)); 858 return ret; 859 } 860 861 /* 862 * Construct an argument vector from a command line. 863 */ 864 char ** 865 construct_argv(command) 866 char *command; 867 { 868 register int argc = 0; 869 register char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1) 870 * sizeof (char *)); 871 static const char separators[] = " \t"; 872 873 if ((argv[argc++] = strtok(command, separators)) == 0) 874 return 0; 875 while (argv[argc++] = strtok((char *) 0, separators)) 876 continue; 877 return argv; 878 } 879 880 /* 881 * Deallocate a session descriptor. 882 */ 883 void 884 free_session(sp) 885 register session_t *sp; 886 { 887 free(sp->se_device); 888 if (sp->se_getty) { 889 free(sp->se_getty); 890 free(sp->se_getty_argv); 891 } 892 if (sp->se_window) { 893 free(sp->se_window); 894 free(sp->se_window_argv); 895 } 896 free(sp); 897 } 898 899 /* 900 * Allocate a new session descriptor. 901 */ 902 session_t * 903 new_session(sprev, session_index, typ) 904 session_t *sprev; 905 int session_index; 906 register struct ttyent *typ; 907 { 908 register session_t *sp; 909 910 if ((typ->ty_status & TTY_ON) == 0 || 911 typ->ty_name == 0 || 912 typ->ty_getty == 0) 913 return 0; 914 915 sp = (session_t *) malloc(sizeof (session_t)); 916 bzero(sp, sizeof *sp); 917 918 sp->se_index = session_index; 919 920 sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name)); 921 (void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name); 922 923 if (setupargv(sp, typ) == 0) { 924 free_session(sp); 925 return (0); 926 } 927 928 sp->se_next = 0; 929 if (sprev == 0) { 930 sessions = sp; 931 sp->se_prev = 0; 932 } else { 933 sprev->se_next = sp; 934 sp->se_prev = sprev; 935 } 936 937 return sp; 938 } 939 940 /* 941 * Calculate getty and if useful window argv vectors. 942 */ 943 int 944 setupargv(sp, typ) 945 session_t *sp; 946 struct ttyent *typ; 947 { 948 949 if (sp->se_getty) { 950 free(sp->se_getty); 951 free(sp->se_getty_argv); 952 } 953 sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2); 954 (void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name); 955 sp->se_getty_argv = construct_argv(sp->se_getty); 956 if (sp->se_getty_argv == 0) { 957 warning("can't parse getty for port %s", sp->se_device); 958 free(sp->se_getty); 959 sp->se_getty = 0; 960 return (0); 961 } 962 if (typ->ty_window) { 963 if (sp->se_window) 964 free(sp->se_window); 965 sp->se_window = strdup(typ->ty_window); 966 sp->se_window_argv = construct_argv(sp->se_window); 967 if (sp->se_window_argv == 0) { 968 warning("can't parse window for port %s", 969 sp->se_device); 970 free(sp->se_window); 971 sp->se_window = 0; 972 return (0); 973 } 974 } 975 return (1); 976 } 977 978 /* 979 * Walk the list of ttys and create sessions for each active line. 980 */ 981 state_func_t 982 read_ttys() 983 { 984 int session_index = 0; 985 register session_t *sp, *snext; 986 register struct ttyent *typ; 987 988 /* 989 * Destroy any previous session state. 990 * There shouldn't be any, but just in case... 991 */ 992 for (sp = sessions; sp; sp = snext) { 993 if (sp->se_process) 994 clear_session_logs(sp); 995 snext = sp->se_next; 996 free_session(sp); 997 } 998 sessions = 0; 999 if (start_session_db()) 1000 return (state_func_t) single_user; 1001 1002 /* 1003 * Allocate a session entry for each active port. 1004 * Note that sp starts at 0. 1005 */ 1006 while (typ = getttyent()) 1007 if (snext = new_session(sp, ++session_index, typ)) 1008 sp = snext; 1009 1010 endttyent(); 1011 1012 return (state_func_t) multi_user; 1013 } 1014 1015 /* 1016 * Start a window system running. 1017 */ 1018 void 1019 start_window_system(sp) 1020 session_t *sp; 1021 { 1022 pid_t pid; 1023 sigset_t mask; 1024 1025 if ((pid = fork()) == -1) { 1026 emergency("can't fork for window system on port %s: %m", 1027 sp->se_device); 1028 /* hope that getty fails and we can try again */ 1029 return; 1030 } 1031 1032 if (pid) 1033 return; 1034 1035 sigemptyset(&mask); 1036 sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); 1037 1038 if (setsid() < 0) 1039 emergency("setsid failed (window) %m"); 1040 1041 execv(sp->se_window_argv[0], sp->se_window_argv); 1042 stall("can't exec window system '%s' for port %s: %m", 1043 sp->se_window_argv[0], sp->se_device); 1044 _exit(1); 1045 } 1046 1047 /* 1048 * Start a login session running. 1049 */ 1050 pid_t 1051 start_getty(sp) 1052 session_t *sp; 1053 { 1054 pid_t pid; 1055 sigset_t mask; 1056 time_t current_time = time((time_t *) 0); 1057 1058 /* 1059 * fork(), not vfork() -- we can't afford to block. 1060 */ 1061 if ((pid = fork()) == -1) { 1062 emergency("can't fork for getty on port %s: %m", sp->se_device); 1063 return -1; 1064 } 1065 1066 if (pid) 1067 return pid; 1068 1069 if (current_time > sp->se_started && 1070 current_time - sp->se_started < GETTY_SPACING) { 1071 warning("getty repeating too quickly on port %s, sleeping", 1072 sp->se_device); 1073 sleep((unsigned) GETTY_SLEEP); 1074 } 1075 1076 if (sp->se_window) { 1077 start_window_system(sp); 1078 sleep(WINDOW_WAIT); 1079 } 1080 1081 sigemptyset(&mask); 1082 sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); 1083 1084 execv(sp->se_getty_argv[0], sp->se_getty_argv); 1085 stall("can't exec getty '%s' for port %s: %m", 1086 sp->se_getty_argv[0], sp->se_device); 1087 _exit(1); 1088 } 1089 #endif /* LETS_GET_SMALL */ 1090 1091 /* 1092 * Collect exit status for a child. 1093 * If an exiting login, start a new login running. 1094 */ 1095 void 1096 #ifdef __STDC__ 1097 collect_child(pid_t pid) 1098 #else 1099 collect_child(pid) 1100 pid_t pid; 1101 #endif 1102 { 1103 #ifndef LETS_GET_SMALL 1104 register session_t *sp, *sprev, *snext; 1105 1106 if (! sessions) 1107 return; 1108 1109 if (! (sp = find_session(pid))) 1110 return; 1111 1112 clear_session_logs(sp); 1113 del_session(sp); 1114 sp->se_process = 0; 1115 1116 if (sp->se_flags & SE_SHUTDOWN) { 1117 if (sprev = sp->se_prev) 1118 sprev->se_next = sp->se_next; 1119 else 1120 sessions = sp->se_next; 1121 if (snext = sp->se_next) 1122 snext->se_prev = sp->se_prev; 1123 free_session(sp); 1124 return; 1125 } 1126 1127 if ((pid = start_getty(sp)) == -1) { 1128 /* serious trouble */ 1129 requested_transition = clean_ttys; 1130 return; 1131 } 1132 1133 sp->se_process = pid; 1134 sp->se_started = time((time_t *) 0); 1135 add_session(sp); 1136 #endif /* LETS_GET_SMALL */ 1137 } 1138 1139 /* 1140 * Catch a signal and request a state transition. 1141 */ 1142 void 1143 transition_handler(sig) 1144 int sig; 1145 { 1146 1147 switch (sig) { 1148 #ifndef LETS_GET_SMALL 1149 case SIGHUP: 1150 requested_transition = clean_ttys; 1151 break; 1152 case SIGTERM: 1153 requested_transition = death; 1154 break; 1155 case SIGTSTP: 1156 requested_transition = catatonia; 1157 break; 1158 #endif /* LETS_GET_SMALL */ 1159 default: 1160 requested_transition = 0; 1161 break; 1162 } 1163 } 1164 1165 #ifndef LETS_GET_SMALL 1166 /* 1167 * Take the system multiuser. 1168 */ 1169 state_func_t 1170 multi_user() 1171 { 1172 pid_t pid; 1173 register session_t *sp; 1174 1175 requested_transition = 0; 1176 1177 /* 1178 * If the administrator has not set the security level to -1 1179 * to indicate that the kernel should not run multiuser in secure 1180 * mode, and the run script has not set a higher level of security 1181 * than level 1, then put the kernel into secure mode. 1182 */ 1183 if (getsecuritylevel() == 0) 1184 setsecuritylevel(1); 1185 1186 for (sp = sessions; sp; sp = sp->se_next) { 1187 if (sp->se_process) 1188 continue; 1189 if ((pid = start_getty(sp)) == -1) { 1190 /* serious trouble */ 1191 requested_transition = clean_ttys; 1192 break; 1193 } 1194 sp->se_process = pid; 1195 sp->se_started = time((time_t *) 0); 1196 add_session(sp); 1197 } 1198 1199 while (!requested_transition) 1200 if ((pid = waitpid(-1, (int *) 0, 0)) != -1) 1201 collect_child(pid); 1202 1203 return (state_func_t) requested_transition; 1204 } 1205 1206 /* 1207 * This is an n-squared algorithm. We hope it isn't run often... 1208 */ 1209 state_func_t 1210 clean_ttys() 1211 { 1212 register session_t *sp, *sprev; 1213 register struct ttyent *typ; 1214 register int session_index = 0; 1215 register int devlen; 1216 1217 devlen = sizeof(_PATH_DEV) - 1; 1218 while (typ = getttyent()) { 1219 ++session_index; 1220 1221 for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next) 1222 if (strcmp(typ->ty_name, sp->se_device + devlen) == 0) 1223 break; 1224 1225 if (sp) { 1226 if (sp->se_index != session_index) { 1227 warning("port %s changed utmp index from %d to %d", 1228 sp->se_device, sp->se_index, 1229 session_index); 1230 sp->se_index = session_index; 1231 } 1232 if ((typ->ty_status & TTY_ON) == 0 || 1233 typ->ty_getty == 0) { 1234 sp->se_flags |= SE_SHUTDOWN; 1235 kill(sp->se_process, SIGHUP); 1236 continue; 1237 } 1238 sp->se_flags &= ~SE_SHUTDOWN; 1239 if (setupargv(sp, typ) == 0) { 1240 warning("can't parse getty for port %s", 1241 sp->se_device); 1242 sp->se_flags |= SE_SHUTDOWN; 1243 kill(sp->se_process, SIGHUP); 1244 } 1245 continue; 1246 } 1247 1248 new_session(sprev, session_index, typ); 1249 } 1250 1251 endttyent(); 1252 1253 return (state_func_t) multi_user; 1254 } 1255 1256 /* 1257 * Block further logins. 1258 */ 1259 state_func_t 1260 catatonia() 1261 { 1262 register session_t *sp; 1263 1264 for (sp = sessions; sp; sp = sp->se_next) 1265 sp->se_flags |= SE_SHUTDOWN; 1266 1267 return (state_func_t) multi_user; 1268 } 1269 #endif /* LETS_GET_SMALL */ 1270 1271 /* 1272 * Note SIGALRM. 1273 */ 1274 void 1275 alrm_handler(sig) 1276 int sig; 1277 { 1278 clang = 1; 1279 } 1280 1281 #ifndef LETS_GET_SMALL 1282 /* 1283 * Bring the system down to single user. 1284 */ 1285 state_func_t 1286 death() 1287 { 1288 register session_t *sp; 1289 register int i; 1290 pid_t pid; 1291 static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL }; 1292 1293 for (sp = sessions; sp; sp = sp->se_next) 1294 sp->se_flags |= SE_SHUTDOWN; 1295 1296 /* NB: should send a message to the session logger to avoid blocking. */ 1297 logwtmp("~", "shutdown", ""); 1298 1299 for (i = 0; i < 3; ++i) { 1300 if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH) 1301 return (state_func_t) single_user; 1302 1303 clang = 0; 1304 alarm(DEATH_WATCH); 1305 do 1306 if ((pid = waitpid(-1, (int *)0, 0)) != -1) 1307 collect_child(pid); 1308 while (clang == 0 && errno != ECHILD); 1309 1310 if (errno == ECHILD) 1311 return (state_func_t) single_user; 1312 } 1313 1314 warning("some processes would not die; ps axl advised"); 1315 1316 return (state_func_t) single_user; 1317 } 1318 #endif /* LETS_GET_SMALL */ 1319