init.c revision 1.57
1/* $OpenBSD: init.c,v 1.57 2015/12/23 02:41:12 mmcc Exp $ */ 2/* $NetBSD: init.c,v 1.22 1996/05/15 23:29:33 jtc Exp $ */ 3 4/*- 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Donn Seeley at Berkeley Software Design, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36#include <sys/types.h> 37#include <sys/sysctl.h> 38#include <sys/wait.h> 39#include <sys/reboot.h> 40#include <machine/cpu.h> 41 42#include <db.h> 43#include <err.h> 44#include <errno.h> 45#include <fcntl.h> 46#include <signal.h> 47#include <stdarg.h> 48#include <stdio.h> 49#include <stdlib.h> 50#include <string.h> 51#include <syslog.h> 52#include <time.h> 53#include <ttyent.h> 54#include <unistd.h> 55#include <util.h> 56 57#ifdef SECURE 58#include <pwd.h> 59#endif 60 61#ifdef LOGIN_CAP 62#include <login_cap.h> 63#endif 64 65#include "pathnames.h" 66 67/* 68 * Sleep times; used to prevent thrashing. 69 */ 70#define GETTY_SPACING 5 /* N secs minimum getty spacing */ 71#define GETTY_SLEEP 30 /* sleep N secs after spacing problem */ 72#define WINDOW_WAIT 3 /* wait N secs after starting window */ 73#define STALL_TIMEOUT 30 /* wait N secs after warning */ 74#define DEATH_WATCH 10 /* wait N secs for procs to die */ 75 76/* 77 * User-based resource limits. 78 */ 79#define RESOURCE_RC "daemon" 80#define RESOURCE_WINDOW "default" 81#define RESOURCE_GETTY "default" 82 83#ifndef DEFAULT_STATE 84#define DEFAULT_STATE runcom 85#endif 86 87void handle(sig_t, ...); 88void delset(sigset_t *, ...); 89 90void stall(char *, ...); 91void warning(char *, ...); 92void emergency(char *, ...); 93void disaster(int); 94void badsys(int); 95 96typedef enum { 97 invalid_state, 98 single_user, 99 runcom, 100 read_ttys, 101 multi_user, 102 clean_ttys, 103 catatonia, 104 death, 105 do_reboot, 106 hard_death, 107 nice_death 108} state_t; 109typedef state_t (*state_func_t)(void); 110 111state_t f_single_user(void); 112state_t f_runcom(void); 113state_t f_read_ttys(void); 114state_t f_multi_user(void); 115state_t f_clean_ttys(void); 116state_t f_catatonia(void); 117state_t f_death(void); 118state_t f_do_reboot(void); 119state_t f_hard_death(void); 120state_t f_nice_death(void); 121 122state_func_t state_funcs[] = { 123 NULL, 124 f_single_user, 125 f_runcom, 126 f_read_ttys, 127 f_multi_user, 128 f_clean_ttys, 129 f_catatonia, 130 f_death, 131 f_do_reboot, 132 f_hard_death, 133 f_nice_death 134}; 135 136enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT; 137 138void transition(state_t); 139volatile sig_atomic_t requested_transition = DEFAULT_STATE; 140 141void setctty(char *); 142 143typedef struct init_session { 144 int se_index; /* index of entry in ttys file */ 145 pid_t se_process; /* controlling process */ 146 time_t se_started; /* used to avoid thrashing */ 147 int se_flags; /* status of session */ 148#define SE_SHUTDOWN 0x1 /* session won't be restarted */ 149#define SE_PRESENT 0x2 /* session is in /etc/ttys */ 150#define SE_DEVEXISTS 0x4 /* open does not result in ENODEV */ 151 char *se_device; /* filename of port */ 152 char *se_getty; /* what to run on that port */ 153 char **se_getty_argv; /* pre-parsed argument array */ 154 char *se_window; /* window system (started only once) */ 155 char **se_window_argv; /* pre-parsed argument array */ 156 struct init_session *se_prev; 157 struct init_session *se_next; 158} session_t; 159 160void free_session(session_t *); 161session_t *new_session(session_t *, int, struct ttyent *); 162session_t *sessions; 163 164char **construct_argv(char *); 165void start_window_system(session_t *); 166void collect_child(pid_t); 167pid_t start_getty(session_t *); 168void transition_handler(int); 169void alrm_handler(int); 170void setsecuritylevel(int); 171int getsecuritylevel(void); 172int setupargv(session_t *, struct ttyent *); 173int clang; 174 175#ifdef LOGIN_CAP 176void setprocresources(char *); 177#else 178#define setprocresources(p) 179#endif 180 181void clear_session_logs(session_t *); 182 183int start_session_db(void); 184void add_session(session_t *); 185void del_session(session_t *); 186session_t *find_session(pid_t); 187DB *session_db; 188 189/* 190 * The mother of all processes. 191 */ 192int 193main(int argc, char *argv[]) 194{ 195 int c; 196 struct sigaction sa; 197 sigset_t mask; 198 199 /* Dispose of random users. */ 200 if (getuid() != 0) { 201 (void)fprintf(stderr, "init: %s\n", strerror(EPERM)); 202 exit (1); 203 } 204 205 /* System V users like to reexec init. */ 206 if (getpid() != 1) { 207 (void)fprintf(stderr, "init: already running\n"); 208 exit (1); 209 } 210 211 /* 212 * Note that this does NOT open a file... 213 * Does 'init' deserve its own facility number? 214 */ 215 openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH); 216 217 /* 218 * Create an initial session. 219 */ 220 if (setsid() < 0) 221 warning("initial setsid() failed: %m"); 222 223 /* 224 * Establish an initial user so that programs running 225 * single user do not freak out and die (like passwd). 226 */ 227 if (setlogin("root") < 0) 228 warning("setlogin() failed: %m"); 229 230 /* 231 * This code assumes that we always get arguments through flags, 232 * never through bits set in some random machine register. 233 */ 234 while ((c = getopt(argc, argv, "sf")) != -1) 235 switch (c) { 236 case 's': 237 requested_transition = single_user; 238 break; 239 case 'f': 240 runcom_mode = FASTBOOT; 241 break; 242 default: 243 warning("unrecognized flag '-%c'", c); 244 break; 245 } 246 247 if (optind != argc) 248 warning("ignoring excess arguments"); 249 250 /* 251 * We catch or block signals rather than ignore them, 252 * so that they get reset on exec. 253 */ 254 handle(badsys, SIGSYS, 0); 255 handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, 256 SIGBUS, SIGXCPU, SIGXFSZ, 0); 257 handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP, 258 SIGUSR1, SIGUSR2, 0); 259 handle(alrm_handler, SIGALRM, 0); 260 sigfillset(&mask); 261 delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS, 262 SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2, 263 SIGTSTP, SIGALRM, 0); 264 sigprocmask(SIG_SETMASK, &mask, NULL); 265 memset(&sa, 0, sizeof sa); 266 sigemptyset(&sa.sa_mask); 267 sa.sa_flags = 0; 268 sa.sa_handler = SIG_IGN; 269 (void) sigaction(SIGTTIN, &sa, NULL); 270 (void) sigaction(SIGTTOU, &sa, NULL); 271 272 /* 273 * Paranoia. 274 */ 275 close(STDIN_FILENO); 276 close(STDOUT_FILENO); 277 close(STDERR_FILENO); 278 279 /* 280 * Start the state machine. 281 */ 282 transition(requested_transition); 283 284 /* 285 * Should never reach here. 286 */ 287 exit(1); 288} 289 290/* 291 * Associate a function with a signal handler. 292 */ 293void 294handle(sig_t handler, ...) 295{ 296 int sig; 297 struct sigaction sa; 298 sigset_t mask_everything; 299 va_list ap; 300 301 va_start(ap, handler); 302 303 memset(&sa, 0, sizeof sa); 304 sa.sa_handler = handler; 305 sigfillset(&mask_everything); 306 307 while ((sig = va_arg(ap, int))) { 308 sa.sa_mask = mask_everything; 309 /* XXX SA_RESTART? */ 310 sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0; 311 sigaction(sig, &sa, NULL); 312 } 313 va_end(ap); 314} 315 316/* 317 * Delete a set of signals from a mask. 318 */ 319void 320delset(sigset_t *maskp, ...) 321{ 322 int sig; 323 va_list ap; 324 325 va_start(ap, maskp); 326 while ((sig = va_arg(ap, int))) 327 sigdelset(maskp, sig); 328 va_end(ap); 329} 330 331/* 332 * Log a message and sleep for a while (to give someone an opportunity 333 * to read it and to save log or hardcopy output if the problem is chronic). 334 * NB: should send a message to the session logger to avoid blocking. 335 */ 336void 337stall(char *message, ...) 338{ 339 va_list ap; 340 341 va_start(ap, message); 342 vsyslog(LOG_ALERT, message, ap); 343 va_end(ap); 344 closelog(); 345 sleep(STALL_TIMEOUT); 346} 347 348/* 349 * Like stall(), but doesn't sleep. 350 * If cpp had variadic macros, the two functions could be #defines for another. 351 * NB: should send a message to the session logger to avoid blocking. 352 */ 353void 354warning(char *message, ...) 355{ 356 va_list ap; 357 358 va_start(ap, message); 359 vsyslog(LOG_ALERT, message, ap); 360 va_end(ap); 361 closelog(); 362} 363 364/* 365 * Log an emergency message. 366 * NB: should send a message to the session logger to avoid blocking. 367 */ 368void 369emergency(char *message, ...) 370{ 371 struct syslog_data sdata = SYSLOG_DATA_INIT; 372 va_list ap; 373 374 va_start(ap, message); 375 vsyslog_r(LOG_EMERG, &sdata, message, ap); 376 va_end(ap); 377} 378 379/* 380 * Catch a SIGSYS signal. 381 * 382 * These may arise if a system does not support sysctl. 383 * We tolerate up to 25 of these, then throw in the towel. 384 */ 385void 386badsys(int sig) 387{ 388 static int badcount = 0; 389 390 if (badcount++ < 25) 391 return; 392 disaster(sig); 393} 394 395/* 396 * Catch an unexpected signal. 397 */ 398void 399disaster(int sig) 400{ 401 emergency("fatal signal: %s", strsignal(sig)); 402 403 sleep(STALL_TIMEOUT); 404 _exit(sig); /* reboot */ 405} 406 407/* 408 * Get the security level of the kernel. 409 */ 410int 411getsecuritylevel(void) 412{ 413#ifdef KERN_SECURELVL 414 int name[2], curlevel; 415 size_t len; 416 417 name[0] = CTL_KERN; 418 name[1] = KERN_SECURELVL; 419 len = sizeof curlevel; 420 if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) { 421 emergency("cannot get kernel security level: %s", 422 strerror(errno)); 423 return (-1); 424 } 425 return (curlevel); 426#else 427 return (-1); 428#endif 429} 430 431/* 432 * Set the security level of the kernel. 433 */ 434void 435setsecuritylevel(int newlevel) 436{ 437#ifdef KERN_SECURELVL 438 int name[2], curlevel; 439 440 curlevel = getsecuritylevel(); 441 if (newlevel == curlevel) 442 return; 443 name[0] = CTL_KERN; 444 name[1] = KERN_SECURELVL; 445 if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) { 446 emergency( 447 "cannot change kernel security level from %d to %d: %s", 448 curlevel, newlevel, strerror(errno)); 449 return; 450 } 451#ifdef SECURE 452 warning("kernel security level changed from %d to %d", 453 curlevel, newlevel); 454#endif 455#endif 456} 457 458/* 459 * Change states in the finite state machine. 460 * The initial state is passed as an argument. 461 */ 462void 463transition(state_t s) 464{ 465 for (;;) 466 s = (*state_funcs[s])(); 467} 468 469/* 470 * Close out the accounting files for a login session. 471 * NB: should send a message to the session logger to avoid blocking. 472 */ 473void 474clear_session_logs(session_t *sp) 475{ 476 char *line = sp->se_device + sizeof(_PATH_DEV) - 1; 477 478 if (logout(line)) 479 logwtmp(line, "", ""); 480} 481 482/* 483 * Start a session and allocate a controlling terminal. 484 * Only called by children of init after forking. 485 */ 486void 487setctty(char *name) 488{ 489 int fd; 490 491 (void) revoke(name); 492 sleep(2); /* leave DTR low */ 493 if ((fd = open(name, O_RDWR)) == -1) { 494 stall("can't open %s: %m", name); 495 _exit(1); 496 } 497 if (login_tty(fd) == -1) { 498 stall("can't get %s for controlling terminal: %m", name); 499 _exit(1); 500 } 501} 502 503/* 504 * Bring the system up single user. 505 */ 506state_t 507f_single_user(void) 508{ 509 pid_t pid, wpid; 510 int status; 511 sigset_t mask; 512 char shell[PATH_MAX]; /* Allocate space here */ 513 char name[PATH_MAX]; /* Name (argv[0]) of shell */ 514 char *argv[2]; 515#ifdef SECURE 516 struct ttyent *typ; 517 struct passwd *pp; 518 static const char banner[] = 519 "Enter root password, or ^D to go multi-user\n"; 520 char *clear, *password; 521#endif 522 523 /* Init shell and name */ 524 strlcpy(shell, _PATH_BSHELL, sizeof shell); 525 strlcpy(name, "-sh", sizeof name); 526 527 /* 528 * If the kernel is in secure mode, downgrade it to insecure mode. 529 */ 530 if (getsecuritylevel() > 0) 531 setsecuritylevel(0); 532 533 if ((pid = fork()) == 0) { 534 /* 535 * Start the single user session. 536 */ 537 setctty(_PATH_CONSOLE); 538 539#ifdef SECURE 540 /* 541 * Check the root password. 542 * We don't care if the console is 'on' by default; 543 * it's the only tty that can be 'off' and 'secure'. 544 */ 545 typ = getttynam("console"); 546 pp = getpwnam_shadow("root"); 547 if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp && 548 *pp->pw_passwd) { 549 write(STDERR_FILENO, banner, sizeof banner - 1); 550 for (;;) { 551 int ok = 0; 552 clear = getpass("Password:"); 553 if (clear == NULL || *clear == '\0') 554 _exit(0); 555 if (crypt_checkpass(clear, pp->pw_passwd) == 0) 556 ok = 1; 557 memset(clear, 0, strlen(clear)); 558 if (ok) 559 break; 560 warning("single-user login failed\n"); 561 } 562 } 563 endttyent(); 564 endpwent(); 565#endif /* SECURE */ 566 567#ifdef DEBUGSHELL 568 { 569 char altshell[128], *cp = altshell; 570 int num; 571 572#define SHREQUEST \ 573 "Enter pathname of shell or RETURN for sh: " 574 575 (void)write(STDERR_FILENO, 576 SHREQUEST, sizeof(SHREQUEST) - 1); 577 while ((num = read(STDIN_FILENO, cp, 1)) != -1 && 578 num != 0 && *cp != '\n' && cp < &altshell[127]) 579 cp++; 580 *cp = '\0'; 581 582 /* Copy in alternate shell */ 583 if (altshell[0] != '\0'){ 584 char *p; 585 586 /* Binary to exec */ 587 strlcpy(shell, altshell, sizeof shell); 588 589 /* argv[0] */ 590 p = strrchr(altshell, '/'); 591 if(p == NULL) p = altshell; 592 else p++; 593 594 name[0] = '-'; 595 strlcpy(&name[1], p, sizeof name -1); 596 } 597 } 598#endif /* DEBUGSHELL */ 599 600 /* 601 * Unblock signals. 602 * We catch all the interesting ones, 603 * and those are reset to SIG_DFL on exec. 604 */ 605 sigemptyset(&mask); 606 sigprocmask(SIG_SETMASK, &mask, NULL); 607 608 /* 609 * Fire off a shell. 610 * If the default one doesn't work, try the Bourne shell. 611 */ 612 argv[0] = name; 613 argv[1] = NULL; 614 setenv("PATH", _PATH_STDPATH, 1); 615 execv(shell, argv); 616 emergency("can't exec %s for single user: %m", shell); 617 618 argv[0] = "-sh"; 619 argv[1] = NULL; 620 execv(_PATH_BSHELL, argv); 621 emergency("can't exec %s for single user: %m", _PATH_BSHELL); 622 sleep(STALL_TIMEOUT); 623 _exit(1); 624 } 625 626 if (pid == -1) { 627 /* 628 * We are seriously hosed. Do our best. 629 */ 630 emergency("can't fork single-user shell, trying again"); 631 while (waitpid(-1, NULL, WNOHANG) > 0) 632 continue; 633 return single_user; 634 } 635 636 requested_transition = 0; 637 do { 638 if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) 639 collect_child(wpid); 640 if (wpid == -1) { 641 if (errno == EINTR) 642 continue; 643 warning("wait for single-user shell failed: %m; restarting"); 644 return single_user; 645 } 646 if (wpid == pid && WIFSTOPPED(status)) { 647 warning("init: shell stopped, restarting\n"); 648 kill(pid, SIGCONT); 649 wpid = -1; 650 } 651 } while (wpid != pid && !requested_transition); 652 653 if (requested_transition) 654 return requested_transition; 655 656 if (!WIFEXITED(status)) { 657 if (WTERMSIG(status) == SIGKILL) { 658 /* 659 * reboot(8) killed shell? 660 */ 661 warning("single user shell terminated."); 662 sleep(STALL_TIMEOUT); 663 _exit(0); 664 } else { 665 warning("single user shell terminated, restarting"); 666 return single_user; 667 } 668 } 669 670 runcom_mode = FASTBOOT; 671 return runcom; 672} 673 674/* 675 * Run the system startup script. 676 */ 677state_t 678f_runcom(void) 679{ 680 pid_t pid, wpid; 681 int status; 682 char *argv[4]; 683 struct sigaction sa; 684 685 if ((pid = fork()) == 0) { 686 memset(&sa, 0, sizeof sa); 687 sigemptyset(&sa.sa_mask); 688 sa.sa_flags = 0; 689 sa.sa_handler = SIG_IGN; 690 (void) sigaction(SIGTSTP, &sa, NULL); 691 (void) sigaction(SIGHUP, &sa, NULL); 692 693 setctty(_PATH_CONSOLE); 694 695 argv[0] = "sh"; 696 argv[1] = _PATH_RUNCOM; 697 argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : NULL; 698 argv[3] = NULL; 699 700 sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL); 701 702 setprocresources(RESOURCE_RC); 703 704 execv(_PATH_BSHELL, argv); 705 stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM); 706 _exit(1); /* force single user mode */ 707 } 708 709 if (pid == -1) { 710 emergency("can't fork for %s on %s: %m", 711 _PATH_BSHELL, _PATH_RUNCOM); 712 while (waitpid(-1, NULL, WNOHANG) > 0) 713 continue; 714 sleep(STALL_TIMEOUT); 715 return single_user; 716 } 717 718 /* 719 * Copied from single_user(). This is a bit paranoid. 720 */ 721 do { 722 if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) 723 collect_child(wpid); 724 if (wpid == -1) { 725 if (errno == EINTR) 726 continue; 727 warning("wait for %s on %s failed: %m; going to single user mode", 728 _PATH_BSHELL, _PATH_RUNCOM); 729 return single_user; 730 } 731 if (wpid == pid && WIFSTOPPED(status)) { 732 warning("init: %s on %s stopped, restarting\n", 733 _PATH_BSHELL, _PATH_RUNCOM); 734 kill(pid, SIGCONT); 735 wpid = -1; 736 } 737 } while (wpid != pid); 738 739 if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM && 740 requested_transition == catatonia) { 741 /* /etc/rc executed /sbin/reboot; wait for the end quietly */ 742 sigset_t s; 743 744 sigfillset(&s); 745 for (;;) 746 sigsuspend(&s); 747 } 748 749 if (!WIFEXITED(status)) { 750 warning("%s on %s terminated abnormally, going to single user mode", 751 _PATH_BSHELL, _PATH_RUNCOM); 752 return single_user; 753 } 754 755 if (WEXITSTATUS(status)) 756 return single_user; 757 758 runcom_mode = AUTOBOOT; /* the default */ 759 /* NB: should send a message to the session logger to avoid blocking. */ 760 logwtmp("~", "reboot", ""); 761 return read_ttys; 762} 763 764/* 765 * Open the session database. 766 * 767 * NB: We could pass in the size here; is it necessary? 768 */ 769int 770start_session_db(void) 771{ 772 if (session_db && (*session_db->close)(session_db)) 773 emergency("session database close: %s", strerror(errno)); 774 if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) { 775 emergency("session database open: %s", strerror(errno)); 776 return (1); 777 } 778 return (0); 779} 780 781/* 782 * Add a new login session. 783 */ 784void 785add_session(session_t *sp) 786{ 787 DBT key; 788 DBT data; 789 790 key.data = &sp->se_process; 791 key.size = sizeof sp->se_process; 792 data.data = &sp; 793 data.size = sizeof sp; 794 795 if ((*session_db->put)(session_db, &key, &data, 0)) 796 emergency("insert %d: %s", sp->se_process, strerror(errno)); 797} 798 799/* 800 * Delete an old login session. 801 */ 802void 803del_session(session_t *sp) 804{ 805 DBT key; 806 807 key.data = &sp->se_process; 808 key.size = sizeof sp->se_process; 809 810 if ((*session_db->del)(session_db, &key, 0)) 811 emergency("delete %d: %s", sp->se_process, strerror(errno)); 812} 813 814/* 815 * Look up a login session by pid. 816 */ 817session_t * 818find_session(pid_t pid) 819{ 820 DBT key; 821 DBT data; 822 session_t *ret; 823 824 key.data = &pid; 825 key.size = sizeof pid; 826 if ((*session_db->get)(session_db, &key, &data, 0) != 0) 827 return (0); 828 memcpy(&ret, data.data, sizeof(ret)); 829 return (ret); 830} 831 832/* 833 * Construct an argument vector from a command line. 834 */ 835char ** 836construct_argv(char *command) 837{ 838 int argc = 0; 839 char **argv = calloc((strlen(command) + 1) / 2 + 1, sizeof (char *)); 840 static const char separators[] = " \t"; 841 842 if (argv == NULL) 843 return (0); 844 845 if ((argv[argc++] = strtok(command, separators)) == 0) { 846 free(argv); 847 return (0); 848 } 849 while ((argv[argc++] = strtok(NULL, separators))) 850 continue; 851 return (argv); 852} 853 854/* 855 * Deallocate a session descriptor. 856 */ 857void 858free_session(session_t *sp) 859{ 860 free(sp->se_device); 861 if (sp->se_getty) { 862 free(sp->se_getty); 863 free(sp->se_getty_argv); 864 } 865 if (sp->se_window) { 866 free(sp->se_window); 867 free(sp->se_window_argv); 868 } 869 free(sp); 870} 871 872/* 873 * Allocate a new session descriptor. 874 */ 875session_t * 876new_session(session_t *sprev, int session_index, struct ttyent *typ) 877{ 878 session_t *sp; 879 880 if ((typ->ty_status & TTY_ON) == 0 || 881 typ->ty_name == 0 || 882 typ->ty_getty == 0) 883 return (0); 884 885 sp = calloc(1, sizeof (session_t)); 886 if (sp == NULL) 887 err(1, "calloc"); 888 889 sp->se_flags = SE_PRESENT; 890 sp->se_index = session_index; 891 892 if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1) 893 err(1, "asprintf"); 894 895 if (setupargv(sp, typ) == 0) { 896 free_session(sp); 897 return (0); 898 } 899 900 sp->se_next = NULL; 901 if (sprev == NULL) { 902 sessions = sp; 903 sp->se_prev = NULL; 904 } else { 905 sprev->se_next = sp; 906 sp->se_prev = sprev; 907 } 908 909 return (sp); 910} 911 912/* 913 * Calculate getty and if useful window argv vectors. 914 */ 915int 916setupargv(session_t *sp, struct ttyent *typ) 917{ 918 if (sp->se_getty) { 919 free(sp->se_getty); 920 free(sp->se_getty_argv); 921 } 922 if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1) 923 err(1, "asprintf"); 924 sp->se_getty_argv = construct_argv(sp->se_getty); 925 if (sp->se_getty_argv == 0) { 926 warning("can't parse getty for port %s", sp->se_device); 927 free(sp->se_getty); 928 sp->se_getty = NULL; 929 return (0); 930 } 931 if (typ->ty_window) { 932 free(sp->se_window); 933 sp->se_window = strdup(typ->ty_window); 934 if (sp->se_window == NULL) { 935 warning("can't allocate window"); 936 return (0); 937 } 938 sp->se_window_argv = construct_argv(sp->se_window); 939 if (sp->se_window_argv == NULL) { 940 warning("can't parse window for port %s", 941 sp->se_device); 942 free(sp->se_window); 943 sp->se_window = NULL; 944 return (0); 945 } 946 } 947 return (1); 948} 949 950/* 951 * Walk the list of ttys and create sessions for each active line. 952 */ 953state_t 954f_read_ttys(void) 955{ 956 int session_index = 0; 957 session_t *sp, *snext; 958 struct ttyent *typ; 959 960 /* 961 * Destroy any previous session state. 962 * There shouldn't be any, but just in case... 963 */ 964 for (sp = sessions; sp; sp = snext) { 965 if (sp->se_process) 966 clear_session_logs(sp); 967 snext = sp->se_next; 968 free_session(sp); 969 } 970 sessions = NULL; 971 if (start_session_db()) 972 return single_user; 973 974 /* 975 * Allocate a session entry for each active port. 976 * Note that sp starts at 0. 977 */ 978 while ((typ = getttyent())) 979 if ((snext = new_session(sp, ++session_index, typ))) 980 sp = snext; 981 982 endttyent(); 983 984 return multi_user; 985} 986 987/* 988 * Start a window system running. 989 */ 990void 991start_window_system(session_t *sp) 992{ 993 pid_t pid; 994 sigset_t mask; 995 996 if ((pid = fork()) == -1) { 997 emergency("can't fork for window system on port %s: %m", 998 sp->se_device); 999 /* hope that getty fails and we can try again */ 1000 return; 1001 } 1002 1003 if (pid) 1004 return; 1005 1006 sigemptyset(&mask); 1007 sigprocmask(SIG_SETMASK, &mask, NULL); 1008 1009 if (setsid() < 0) 1010 emergency("setsid failed (window) %m"); 1011 1012 setprocresources(RESOURCE_WINDOW); 1013 1014 execv(sp->se_window_argv[0], sp->se_window_argv); 1015 stall("can't exec window system '%s' for port %s: %m", 1016 sp->se_window_argv[0], sp->se_device); 1017 _exit(1); 1018} 1019 1020/* 1021 * Start a login session running. 1022 * For first open, man-handle tty directly to determine if it 1023 * really exists. It is not efficient to spawn gettys on devices 1024 * that do not exist. 1025 */ 1026pid_t 1027start_getty(session_t *sp) 1028{ 1029 pid_t pid; 1030 sigset_t mask; 1031 time_t current_time = time(NULL); 1032 int p[2], new = 1; 1033 1034 if (sp->se_flags & SE_DEVEXISTS) 1035 new = 0; 1036 1037 if (new) { 1038 if (pipe(p) == -1) 1039 return (-1); 1040 } 1041 1042 /* 1043 * fork(), not vfork() -- we can't afford to block. 1044 */ 1045 if ((pid = fork()) == -1) { 1046 emergency("can't fork for getty on port %s: %m", sp->se_device); 1047 return (-1); 1048 } 1049 1050 if (pid) { 1051 if (new) { 1052 char c; 1053 1054 close(p[1]); 1055 if (read(p[0], &c, 1) != 1) { 1056 close(p[0]); 1057 return (-1); 1058 } 1059 close(p[0]); 1060 if (c == '1') 1061 sp->se_flags |= SE_DEVEXISTS; 1062 else 1063 sp->se_flags |= SE_SHUTDOWN; 1064 } 1065 return (pid); 1066 } 1067 if (new) { 1068 int fd; 1069 1070 close(p[0]); 1071 fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666); 1072 if (fd == -1 && (errno == ENXIO || errno == ENOENT || 1073 errno == EISDIR)) { 1074 (void)write(p[1], "0", 1); 1075 close(p[1]); 1076 _exit(1); 1077 } 1078 (void)write(p[1], "1", 1); 1079 close(p[1]); 1080 close(fd); 1081 sleep(1); 1082 } 1083 1084 if (current_time > sp->se_started && 1085 current_time - sp->se_started < GETTY_SPACING) { 1086 warning("getty repeating too quickly on port %s, sleeping", 1087 sp->se_device); 1088 sleep(GETTY_SLEEP); 1089 } 1090 1091 if (sp->se_window) { 1092 start_window_system(sp); 1093 sleep(WINDOW_WAIT); 1094 } 1095 1096 sigemptyset(&mask); 1097 sigprocmask(SIG_SETMASK, &mask, NULL); 1098 1099 setprocresources(RESOURCE_GETTY); 1100 1101 execv(sp->se_getty_argv[0], sp->se_getty_argv); 1102 stall("can't exec getty '%s' for port %s: %m", 1103 sp->se_getty_argv[0], sp->se_device); 1104 _exit(1); 1105} 1106 1107/* 1108 * Collect exit status for a child. 1109 * If an exiting login, start a new login running. 1110 */ 1111void 1112collect_child(pid_t pid) 1113{ 1114 session_t *sp, *sprev, *snext; 1115 1116 if (sessions == NULL) 1117 return; 1118 1119 if ((sp = find_session(pid)) == NULL) 1120 return; 1121 1122 clear_session_logs(sp); 1123 login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0); 1124 del_session(sp); 1125 sp->se_process = 0; 1126 1127 if (sp->se_flags & SE_SHUTDOWN) { 1128 if ((sprev = sp->se_prev)) 1129 sprev->se_next = sp->se_next; 1130 else 1131 sessions = sp->se_next; 1132 if ((snext = sp->se_next)) 1133 snext->se_prev = sp->se_prev; 1134 free_session(sp); 1135 return; 1136 } 1137 1138 if ((pid = start_getty(sp)) == -1) { 1139 /* serious trouble */ 1140 requested_transition = clean_ttys; 1141 return; 1142 } 1143 1144 sp->se_process = pid; 1145 sp->se_started = time(NULL); 1146 add_session(sp); 1147} 1148 1149/* 1150 * Catch a signal and request a state transition. 1151 */ 1152void 1153transition_handler(int sig) 1154{ 1155 1156 switch (sig) { 1157 case SIGHUP: 1158 requested_transition = clean_ttys; 1159 break; 1160 case SIGINT: 1161 requested_transition = do_reboot; 1162 break; 1163 case SIGTERM: 1164 requested_transition = death; 1165 break; 1166 case SIGUSR1: 1167 requested_transition = nice_death; 1168 break; 1169 case SIGUSR2: 1170 requested_transition = hard_death; 1171 break; 1172 case SIGTSTP: 1173 requested_transition = catatonia; 1174 break; 1175 default: 1176 requested_transition = 0; 1177 break; 1178 } 1179} 1180 1181/* 1182 * Take the system multiuser. 1183 */ 1184state_t 1185f_multi_user(void) 1186{ 1187 pid_t pid; 1188 session_t *sp; 1189 1190 /* 1191 * If the administrator has not set the security level to -1 1192 * to indicate that the kernel should not run multiuser in secure 1193 * mode, and the run script has not set a higher level of security 1194 * than level 1, then put the kernel into secure mode. 1195 */ 1196 if (requested_transition != catatonia) { 1197 if (getsecuritylevel() == 0) 1198 setsecuritylevel(1); 1199 } 1200 1201 requested_transition = 0; 1202 1203 for (sp = sessions; sp; sp = sp->se_next) { 1204 if (sp->se_process) 1205 continue; 1206 if ((pid = start_getty(sp)) == -1) { 1207 /* serious trouble */ 1208 requested_transition = clean_ttys; 1209 break; 1210 } 1211 sp->se_process = pid; 1212 sp->se_started = time(NULL); 1213 add_session(sp); 1214 } 1215 1216 while (!requested_transition) 1217 if ((pid = waitpid(-1, NULL, 0)) != -1) 1218 collect_child(pid); 1219 1220 return requested_transition; 1221} 1222 1223/* 1224 * This is an n-squared algorithm. We hope it isn't run often... 1225 */ 1226state_t 1227f_clean_ttys(void) 1228{ 1229 session_t *sp, *sprev; 1230 struct ttyent *typ; 1231 int session_index = 0; 1232 int devlen; 1233 1234 for (sp = sessions; sp; sp = sp->se_next) 1235 sp->se_flags &= ~SE_PRESENT; 1236 1237 devlen = sizeof(_PATH_DEV) - 1; 1238 while ((typ = getttyent())) { 1239 ++session_index; 1240 1241 for (sprev = NULL, sp = sessions; sp; sprev = sp, sp = sp->se_next) 1242 if (strcmp(typ->ty_name, sp->se_device + devlen) == 0) 1243 break; 1244 1245 if (sp) { 1246 sp->se_flags |= SE_PRESENT; 1247 if (sp->se_index != session_index) { 1248 warning("port %s changed utmp index from %d to %d", 1249 sp->se_device, sp->se_index, 1250 session_index); 1251 sp->se_index = session_index; 1252 } 1253 if ((typ->ty_status & TTY_ON) == 0 || 1254 typ->ty_getty == 0) { 1255 sp->se_flags |= SE_SHUTDOWN; 1256 kill(sp->se_process, SIGHUP); 1257 continue; 1258 } 1259 sp->se_flags &= ~SE_SHUTDOWN; 1260 if (setupargv(sp, typ) == 0) { 1261 warning("can't parse getty for port %s", 1262 sp->se_device); 1263 sp->se_flags |= SE_SHUTDOWN; 1264 kill(sp->se_process, SIGHUP); 1265 } 1266 continue; 1267 } 1268 1269 new_session(sprev, session_index, typ); 1270 } 1271 1272 endttyent(); 1273 1274 for (sp = sessions; sp; sp = sp->se_next) 1275 if ((sp->se_flags & SE_PRESENT) == 0) { 1276 sp->se_flags |= SE_SHUTDOWN; 1277 kill(sp->se_process, SIGHUP); 1278 } 1279 1280 return multi_user; 1281} 1282 1283/* 1284 * Block further logins. 1285 */ 1286state_t 1287f_catatonia(void) 1288{ 1289 session_t *sp; 1290 1291 for (sp = sessions; sp; sp = sp->se_next) 1292 sp->se_flags |= SE_SHUTDOWN; 1293 1294 return multi_user; 1295} 1296 1297/* 1298 * Note SIGALRM. 1299 */ 1300void 1301alrm_handler(int sig) 1302{ 1303 clang = 1; 1304} 1305 1306int death_howto = RB_HALT; 1307 1308/* 1309 * Reboot the system. 1310 */ 1311state_t 1312f_do_reboot(void) 1313{ 1314 death_howto = RB_AUTOBOOT; 1315 return nice_death; 1316} 1317 1318/* 1319 * Bring the system down nicely, then we must powerdown because something 1320 * is very wrong. 1321 */ 1322state_t 1323f_hard_death(void) 1324{ 1325 death_howto |= RB_POWERDOWN; 1326 return nice_death; 1327} 1328 1329/* 1330 * Bring the system down to single user nicely, after run the shutdown script. 1331 */ 1332state_t 1333f_nice_death(void) 1334{ 1335 session_t *sp; 1336 int i; 1337 pid_t pid; 1338 static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL }; 1339 int status; 1340 1341#ifdef CPU_LIDSUSPEND 1342 int lidsuspend_mib[] = {CTL_MACHDEP, CPU_LIDSUSPEND}; 1343 int dontsuspend = 0; 1344 1345 if ((death_howto & RB_POWERDOWN) && 1346 (sysctl(lidsuspend_mib, 2, NULL, NULL, &dontsuspend, 1347 sizeof(dontsuspend)) == -1) && (errno != EOPNOTSUPP)) 1348 warning("cannot disable lid suspend"); 1349#endif 1350 1351 for (sp = sessions; sp; sp = sp->se_next) { 1352 sp->se_flags &= ~SE_PRESENT; 1353 sp->se_flags |= SE_SHUTDOWN; 1354 kill(sp->se_process, SIGHUP); 1355 } 1356 1357 /* terminate the accounting process */ 1358 acct(NULL); 1359 1360 /* NB: should send a message to the session logger to avoid blocking. */ 1361 logwtmp("~", "shutdown", ""); 1362 1363 if (access(_PATH_RUNCOM, R_OK) != -1) { 1364 struct sigaction sa; 1365 1366 switch ((pid = fork())) { 1367 case -1: 1368 break; 1369 case 0: 1370 1371 memset(&sa, 0, sizeof sa); 1372 sigemptyset(&sa.sa_mask); 1373 sa.sa_flags = 0; 1374 sa.sa_handler = SIG_IGN; 1375 (void) sigaction(SIGTSTP, &sa, NULL); 1376 (void) sigaction(SIGHUP, &sa, NULL); 1377 1378 setctty(_PATH_CONSOLE); 1379 1380 sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL); 1381 1382 execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown", 1383 (char *)NULL); 1384 stall("can't exec %s for %s %s: %m", _PATH_BSHELL, 1385 _PATH_RUNCOM, "shutdown"); 1386 _exit(1); 1387 default: 1388 waitpid(pid, &status, 0); 1389 if (WIFEXITED(status) && WEXITSTATUS(status) == 2) 1390 death_howto |= RB_POWERDOWN; 1391 } 1392 } 1393 1394 for (i = 0; i < 3; ++i) { 1395 if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH) 1396 goto die; 1397 1398 clang = 0; 1399 alarm(DEATH_WATCH); 1400 do { 1401 if ((pid = waitpid(-1, NULL, 0)) != -1) 1402 collect_child(pid); 1403 } while (clang == 0 && errno != ECHILD); 1404 1405 if (errno == ECHILD) 1406 goto die; 1407 } 1408 1409 warning("some processes would not die; ps axl advised"); 1410 1411die: 1412 reboot(death_howto); 1413 1414 /* ... and if that fails.. oh well */ 1415 return single_user; 1416} 1417 1418/* 1419 * Bring the system down to single user. 1420 */ 1421state_t 1422f_death(void) 1423{ 1424 session_t *sp; 1425 int i; 1426 pid_t pid; 1427 static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL }; 1428 1429 /* terminate the accounting process */ 1430 acct(NULL); 1431 1432 for (sp = sessions; sp; sp = sp->se_next) 1433 sp->se_flags |= SE_SHUTDOWN; 1434 1435 /* NB: should send a message to the session logger to avoid blocking. */ 1436 logwtmp("~", "shutdown", ""); 1437 1438 for (i = 0; i < 3; ++i) { 1439 if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH) 1440 return single_user; 1441 1442 clang = 0; 1443 alarm(DEATH_WATCH); 1444 do { 1445 if ((pid = waitpid(-1, NULL, 0)) != -1) 1446 collect_child(pid); 1447 } while (clang == 0 && errno != ECHILD); 1448 1449 if (errno == ECHILD) 1450 return single_user; 1451 } 1452 1453 warning("some processes would not die; ps axl advised"); 1454 1455 return single_user; 1456} 1457 1458#ifdef LOGIN_CAP 1459void 1460setprocresources(char *class) 1461{ 1462 login_cap_t *lc; 1463 1464 if ((lc = login_getclass(class)) != NULL) { 1465 setusercontext(lc, NULL, 0, 1466 LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK); 1467 login_close(lc); 1468 } 1469} 1470#endif 1471