sbin/init/init.c

   1 /*      $NetBSD: init.c,v 1.106 2015/06/16 23:18:55 christos Exp $      */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Donn Seeley at Berkeley Software Design, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 __COPYRIGHT("@(#) Copyright (c) 1991, 1993\
  38  The Regents of the University of California.  All rights reserved.");
  39 #endif /* not lint */
  40
  41 #ifndef lint
  42 #if 0
  43 static char sccsid[] = "@(#)init.c      8.2 (Berkeley) 4/28/95";
  44 #else
  45 __RCSID("$NetBSD: init.c,v 1.106 2015/06/16 23:18:55 christos Exp $");
  46 #endif
  47 #endif /* not lint */
  48
  49 #include <sys/param.h>
  50 #include <sys/sysctl.h>
  51 #include <sys/wait.h>
  52 #include <sys/mman.h>
  53 #include <sys/stat.h>
  54 #include <sys/mount.h>
  55 #include <machine/cpu.h>
  56
  57 #include <db.h>
  58 #include <errno.h>
  59 #include <fcntl.h>
  60 #include <signal.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64 #include <syslog.h>
  65 #include <time.h>
  66 #include <ttyent.h>
  67 #include <unistd.h>
  68 #include <util.h>
  69 #include <paths.h>
  70 #include <err.h>
  71 #ifdef SUPPORT_UTMP
  72 #include <utmp.h>
  73 #endif
  74 #ifdef SUPPORT_UTMPX
  75 #include <utmpx.h>
  76 #endif
  77
  78 #include <stdarg.h>
  79
  80 #ifdef SECURE
  81 #include <pwd.h>
  82 #endif
  83
  84 #include "pathnames.h"
  85
  86 #define XSTR(x) #x
  87 #define STR(x) XSTR(x)
  88
  89 /*
  90  * Sleep times; used to prevent thrashing.
  91  */
  92 #define GETTY_SPACING            5      /* N secs minimum getty spacing */
  93 #define GETTY_SLEEP             30      /* sleep N secs after spacing problem */
  94 #define WINDOW_WAIT              3      /* wait N secs after starting window */
  95 #define STALL_TIMEOUT           30      /* wait N secs after warning */
  96 #define DEATH_WATCH             10      /* wait N secs for procs to die */
  97
  98 static const struct timespec dtrtime = {.tv_sec = 0, .tv_nsec = 250000};
  99
 100 #if defined(RESCUEDIR)
 101 #define INIT_BSHELL     RESCUEDIR "/sh"
 102 #define INIT_MOUNT_MFS  RESCUEDIR "/mount_mfs"
 103 #define INIT_PATH       RESCUEDIR ":" _PATH_STDPATH
 104 #else
 105 #define INIT_BSHELL     _PATH_BSHELL
 106 #define INIT_MOUNT_MFS  "/sbin/mount_mfs"
 107 #define INIT_PATH       _PATH_STDPATH
 108 #endif
 109
 110 static void handle(sig_t, ...);
 111 static void delset(sigset_t *, ...);
 112
 113 static void stall(const char *, ...) __printflike(1, 2);
 114 static void warning(const char *, ...) __printflike(1, 2);
 115 static void emergency(const char *, ...) __printflike(1, 2);
 116 __dead static void disaster(int);
 117
 118 #if defined(__minix)
 119 static void minixreboot(int);
 120 static void minixpowerdown(int);
 121 #else
 122 static void badsys(int);
 123 #endif /* defined(__minix) */
 124
 125 /*
 126  * We really need a recursive typedef...
 127  * The following at least guarantees that the return type of (*state_t)()
 128  * is sufficiently wide to hold a function pointer.
 129  */
 130 typedef long (*state_func_t)(void);
 131 typedef state_func_t (*state_t)(void);
 132
 133 #define DEATH           'd'
 134 #define SINGLE_USER     's'
 135 #define RUNCOM          'r'
 136 #define READ_TTYS       't'
 137 #define MULTI_USER      'm'
 138 #define CLEAN_TTYS      'T'
 139 #define CATATONIA       'c'
 140
 141 static state_func_t single_user(void);
 142 #ifndef LETS_GET_SMALL
 143 static state_func_t runcom(void);
 144 static state_func_t read_ttys(void);
 145 static state_func_t multi_user(void);
 146 static state_func_t clean_ttys(void);
 147 static state_func_t catatonia(void);
 148 static state_func_t death(void);
 149 #endif
 150
 151 static enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
 152
 153 static void transition(state_t);
 154 static void setctty(const char *);
 155
 156 typedef struct init_session {
 157         int     se_index;               /* index of entry in ttys file */
 158         pid_t   se_process;             /* controlling process */
 159         struct timeval  se_started;     /* used to avoid thrashing */
 160         int     se_flags;               /* status of session */
 161 #define SE_SHUTDOWN     0x1             /* session won't be restarted */
 162 #define SE_PRESENT      0x2             /* session is in /etc/ttys */
 163         char    *se_device;             /* filename of port */
 164         char    *se_getty;              /* what to run on that port */
 165         char    **se_getty_argv;        /* pre-parsed argument array */
 166         char    *se_window;             /* window system (started only once) */
 167         char    **se_window_argv;       /* pre-parsed argument array */
 168         struct  init_session *se_prev;
 169         struct  init_session *se_next;
 170 } session_t;
 171
 172 static void collect_child(pid_t, int);
 173 static int clang;
 174 static void transition_handler(int);
 175 static void alrm_handler(int);
 176 static int has_securelevel(void);
 177 static int securelevel_present;
 178
 179 #ifndef LETS_GET_SMALL
 180 static int do_setttyent(void);
 181 static void start_window_system(session_t *);
 182 static char **construct_argv(char *);
 183 static int setupargv(session_t *, struct ttyent *);
 184 static pid_t start_getty(session_t *);
 185 static void free_session(session_t *);
 186 static session_t *new_session(session_t *, int, struct ttyent *);
 187 static session_t *sessions;
 188 static void setsecuritylevel(int);
 189 static int getsecuritylevel(void);
 190 static int start_session_db(void);
 191 static void add_session(session_t *);
 192 static void del_session(session_t *);
 193 static session_t *find_session(pid_t);
 194 static DB *session_db;
 195 static state_t requested_transition = runcom;
 196
 197 static void clear_session_logs(session_t *, int);
 198 static state_func_t runetcrc(int);
 199 #ifdef SUPPORT_UTMPX
 200 static struct timeval boot_time;
 201 static state_t current_state = death;
 202 static void session_utmpx(const session_t *, int);
 203 static void make_utmpx(const char *, const char *, int, pid_t,
 204     const struct timeval *, int);
 205 static char get_runlevel(const state_t);
 206 static void utmpx_set_runlevel(char, char);
 207 #endif
 208
 209 #ifdef CHROOT
 210 static int did_multiuser_chroot = 0;
 211 static char rootdir[PATH_MAX];
 212 static int shouldchroot(void);
 213 static int createsysctlnode(void);
 214 #endif /* CHROOT */
 215
 216 #else /* LETS_GET_SMALL */
 217 static state_t requested_transition = single_user;
 218 #endif /* !LETS_GET_SMALL */
 219
 220 #ifdef MFS_DEV_IF_NO_CONSOLE
 221
 222 static int mfs_dev(void);
 223
 224 #endif
 225
 226 /*
 227  * The mother of all processes.
 228  */
 229 int
 230 main(int argc, char **argv)
 231 {
 232         struct sigaction sa;
 233         sigset_t mask;
 234 #ifndef LETS_GET_SMALL
 235         int c;
 236
 237 #ifdef SUPPORT_UTMPX
 238         (void)gettimeofday(&boot_time, NULL);
 239 #endif /* SUPPORT_UTMPX */
 240
 241         /* Dispose of random users. */
 242         if (getuid() != 0) {
 243                 errno = EPERM;
 244                 err(1, NULL);
 245         }
 246
 247         /* System V users like to reexec init. */
 248         if (getpid() != 1)
 249                 errx(1, "already running");
 250 #endif
 251
 252         /*
 253          * Create an initial session.
 254          */
 255         if (setsid() < 0)
 256                 warn("initial setsid() failed");
 257
 258         /*
 259          * Establish an initial user so that programs running
 260          * single user do not freak out and die (like passwd).
 261          */
 262 #if !defined(__minix)
 263         if (setlogin("root") < 0)
 264                 warn("setlogin() failed");
 265 #endif /* !defined(__minix) */
 266
 267
 268 #ifdef MFS_DEV_IF_NO_CONSOLE
 269         if (mfs_dev() == -1)
 270                 requested_transition = single_user;
 271 #endif
 272
 273 #ifndef LETS_GET_SMALL
 274         /*
 275          * Note that this does NOT open a file...
 276          * Does 'init' deserve its own facility number?
 277          */
 278         openlog("init", LOG_CONS, LOG_AUTH);
 279 #endif /* LETS_GET_SMALL */
 280
 281
 282 #ifndef LETS_GET_SMALL
 283         /*
 284          * This code assumes that we always get arguments through flags,
 285          * never through bits set in some random machine register.
 286          */
 287         while ((c = getopt(argc, argv, "sf")) != -1)
 288                 switch (c) {
 289                 case 's':
 290                         requested_transition = single_user;
 291                         break;
 292                 case 'f':
 293                         runcom_mode = FASTBOOT;
 294                         break;
 295                 default:
 296                         warning("unrecognized flag `%c'", c);
 297                         break;
 298                 }
 299
 300         if (optind != argc)
 301                 warning("ignoring excess arguments");
 302 #else /* LETS_GET_SMALL */
 303         requested_transition = single_user;
 304 #endif /* LETS_GET_SMALL */
 305
 306         /*
 307          * We catch or block signals rather than ignore them,
 308          * so that they get reset on exec.
 309          */
 310 #if !defined(__minix)
 311         handle(badsys, SIGSYS, 0);
 312         handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
 313                SIGBUS, SIGXCPU, SIGXFSZ, 0);
 314 #else
 315         handle(minixreboot, SIGABRT, 0);
 316         handle(minixpowerdown, SIGUSR1, 0);
 317         handle(disaster, SIGFPE, SIGILL, SIGSEGV, SIGBUS, 0);
 318 #endif /* !defined(__minix) */
 319         handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0);
 320         handle(alrm_handler, SIGALRM, 0);
 321         (void)sigfillset(&mask);
 322 #if !defined(__minix)
 323         delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
 324             SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
 325 #else
 326         delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS,
 327             SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
 328 #endif /* !defined(__minix) */
 329         (void)sigprocmask(SIG_SETMASK, &mask, NULL);
 330         (void)sigemptyset(&sa.sa_mask);
 331         sa.sa_flags = 0;
 332         sa.sa_handler = SIG_IGN;
 333         (void)sigaction(SIGTTIN, &sa, NULL);
 334         (void)sigaction(SIGTTOU, &sa, NULL);
 335
 336         /*
 337          * Paranoia.
 338          */
 339         (void)close(0);
 340         (void)close(1);
 341         (void)close(2);
 342
 343 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
 344         /* Create "init.root" sysctl node. */
 345         (void)createsysctlnode();
 346 #endif /* !LETS_GET_SMALL && CHROOT*/
 347
 348         /*
 349          * Securelevel might not be supported by the kernel. Query for it, and
 350          * set a variable indicating whether we should attempt anything with it
 351          * or not.
 352          */
 353         securelevel_present = has_securelevel();
 354
 355         /*
 356          * Start the state machine.
 357          */
 358         transition(requested_transition);
 359
 360         /*
 361          * Should never reach here.
 362          */
 363         return 1;
 364 }
 365
 366 /*
 367  * Associate a function with a signal handler.
 368  */
 369 static void
 370 handle(sig_t handler, ...)
 371 {
 372         int sig;
 373         struct sigaction sa;
 374         sigset_t mask_everything;
 375         va_list ap;
 376
 377         va_start(ap, handler);
 378
 379         sa.sa_handler = handler;
 380         (void)sigfillset(&mask_everything);
 381
 382         while ((sig = va_arg(ap, int)) != 0) {
 383                 sa.sa_mask = mask_everything;
 384                 /* XXX SA_RESTART? */
 385                 sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
 386                 (void)sigaction(sig, &sa, NULL);
 387         }
 388         va_end(ap);
 389 }
 390
 391 /*
 392  * Delete a set of signals from a mask.
 393  */
 394 static void
 395 delset(sigset_t *maskp, ...)
 396 {
 397         int sig;
 398         va_list ap;
 399
 400         va_start(ap, maskp);
 401
 402         while ((sig = va_arg(ap, int)) != 0)
 403                 (void)sigdelset(maskp, sig);
 404         va_end(ap);
 405 }
 406
 407 #if 0   /* Enable to get error messages from init ! */
 408 #define vsyslog(level, fmt, ap) print_console(level, fmt, ap)
 409 #define closelog()
 410
 411 static void
 412 print_console(int level, const char *message, va_list ap)
 413 {
 414         /*
 415          * XXX: syslog seems to just plain not work in console-only
 416          * XXX: situation... that should be fixed.  Let's leave this
 417          * XXX: note + code here in case someone gets in trouble and
 418          * XXX: wants to debug. -- Jachym Holecek <freza@liberouter.org>
 419          */
 420         char errbuf[1024];
 421         int fd, len;
 422
 423         /* We can't do anything on errors, anyway... */
 424         fd = open(_PATH_CONSOLE, O_WRONLY);
 425         if (fd == -1)
 426                 return ;
 427
 428         /* %m will get lost... */
 429         len = vsnprintf(errbuf, sizeof(errbuf), message, ap);
 430         (void)write(fd, (void *)errbuf, len);
 431         (void)close(fd);
 432 }
 433 #endif
 434
 435 /*
 436  * Log a message and sleep for a while (to give someone an opportunity
 437  * to read it and to save log or hardcopy output if the problem is chronic).
 438  * NB: should send a message to the session logger to avoid blocking.
 439  */
 440 static void
 441 stall(const char *message, ...)
 442 {
 443         va_list ap;
 444
 445         va_start(ap, message);
 446         vsyslog(LOG_ALERT, message, ap);
 447         va_end(ap);
 448         closelog();
 449         (void)sleep(STALL_TIMEOUT);
 450 }
 451
 452 /*
 453  * Like stall(), but doesn't sleep.
 454  * If cpp had variadic macros, the two functions could be #defines for another.
 455  * NB: should send a message to the session logger to avoid blocking.
 456  */
 457 static void
 458 warning(const char *message, ...)
 459 {
 460         va_list ap;
 461
 462         va_start(ap, message);
 463         vsyslog(LOG_ALERT, message, ap);
 464         va_end(ap);
 465         closelog();
 466 }
 467
 468 /*
 469  * Log an emergency message.
 470  * NB: should send a message to the session logger to avoid blocking.
 471  */
 472 static void
 473 emergency(const char *message, ...)
 474 {
 475         va_list ap;
 476
 477         va_start(ap, message);
 478         vsyslog(LOG_EMERG, message, ap);
 479         va_end(ap);
 480         closelog();
 481 }
 482
 483 #if !defined(__minix)
 484 /*
 485  * Catch a SIGSYS signal.
 486  *
 487  * These may arise if a system does not support sysctl.
 488  * We tolerate up to 25 of these, then throw in the towel.
 489  */
 490 static void
 491 badsys(int sig)
 492 {
 493         static int badcount = 0;
 494
 495         if (badcount++ < 25)
 496                 return;
 497         disaster(sig);
 498 }
 499 #endif /* !defined(__minix) */
 500
 501 /*
 502  * Catch an unexpected signal.
 503  */
 504 static void
 505 disaster(int sig)
 506 {
 507
 508         emergency("fatal signal: %s", strsignal(sig));
 509         (void)sleep(STALL_TIMEOUT);
 510         _exit(sig);             /* reboot */
 511 }
 512
 513 #if defined(__minix)
 514 /*
 515  * controlled reboot - minix tradition, SIGABRT by tty
 516  */
 517 static void
 518 minixreboot(int sig)
 519 {
 520         if(fork() == 0) {
 521                 (void)execl("/sbin/shutdown",
 522                         "shutdown", "-r", "now", "CTRL-ALT_DEL", NULL);
 523                 _exit(1);
 524         }
 525 }
 526
 527 /*
 528  * controlled powerdown
 529  */
 530 static void
 531 minixpowerdown(int sig)
 532 {
 533         if(fork() == 0) {
 534                 (void)execl("/sbin/shutdown",
 535                         "shutdown", "-p", "now", "CTRL-ALT_DEL", NULL);
 536                 _exit(1);
 537         }
 538 }
 539 #endif /* defined(__minix) */
 540
 541 /*
 542  * Check if securelevel is present.
 543  */
 544 static int
 545 has_securelevel(void)
 546 {
 547 #ifdef KERN_SECURELVL
 548         int name[2], curlevel;
 549         size_t len;
 550
 551         name[0] = CTL_KERN;
 552         name[1] = KERN_SECURELVL;
 553         len = sizeof curlevel;
 554         if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
 555                 /* If it doesn't exist, it's okay. */
 556                 if (errno == ENOENT)
 557                         return 0;
 558         }
 559         return 1;
 560 #else
 561         return 0;
 562 #endif
 563 }
 564
 565 /*
 566  * Get the security level of the kernel.
 567  */
 568 static int
 569 getsecuritylevel(void)
 570 {
 571 #ifdef KERN_SECURELVL
 572         int name[2], curlevel;
 573         size_t len;
 574
 575         if (!securelevel_present)
 576                 return -1;
 577
 578         name[0] = CTL_KERN;
 579         name[1] = KERN_SECURELVL;
 580         len = sizeof curlevel;
 581         if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
 582                 emergency("cannot get kernel security level: %m");
 583                 return -1;
 584         }
 585         return curlevel;
 586 #else
 587         return -1;
 588 #endif
 589 }
 590
 591 /*
 592  * Set the security level of the kernel.
 593  */
 594 static void
 595 setsecuritylevel(int newlevel)
 596 {
 597 #ifdef KERN_SECURELVL
 598         int name[2], curlevel;
 599
 600         if (!securelevel_present)
 601                 return;
 602
 603         curlevel = getsecuritylevel();
 604         if (newlevel == curlevel)
 605                 return;
 606         name[0] = CTL_KERN;
 607         name[1] = KERN_SECURELVL;
 608         if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
 609                 emergency("cannot change kernel security level from"
 610                     " %d to %d: %m", curlevel, newlevel);
 611                 return;
 612         }
 613 #ifdef SECURE
 614         warning("kernel security level changed from %d to %d",
 615             curlevel, newlevel);
 616 #endif
 617 #endif
 618 }
 619
 620 /*
 621  * Change states in the finite state machine.
 622  * The initial state is passed as an argument.
 623  */
 624 static void
 625 transition(state_t s)
 626 {
 627
 628         if (s == NULL)
 629                 return;
 630         for (;;) {
 631 #ifdef SUPPORT_UTMPX
 632 #ifndef LETS_GET_SMALL
 633                 utmpx_set_runlevel(get_runlevel(current_state),
 634                     get_runlevel(s));
 635                 current_state = s;
 636 #endif
 637 #endif
 638                 s = (state_t)(*s)();
 639         }
 640 }
 641
 642 #ifndef LETS_GET_SMALL
 643 /*
 644  * Close out the accounting files for a login session.
 645  * NB: should send a message to the session logger to avoid blocking.
 646  */
 647 static void
 648 clear_session_logs(session_t *sp, int status)
 649 {
 650 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
 651         char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
 652 #endif
 653
 654 #ifdef SUPPORT_UTMPX
 655         if (logoutx(line, status, DEAD_PROCESS))
 656                 logwtmpx(line, "", "", status, DEAD_PROCESS);
 657 #endif
 658 #ifdef SUPPORT_UTMP
 659         if (logout(line))
 660                 logwtmp(line, "", "");
 661 #endif
 662 }
 663 #endif
 664
 665 /*
 666  * Start a session and allocate a controlling terminal.
 667  * Only called by children of init after forking.
 668  */
 669 static void
 670 setctty(const char *name)
 671 {
 672         int fd;
 673
 674 #if !defined(__minix)
 675         (void)revoke(name);
 676 #else
 677         if (setsid() < 0)
 678                 warn("child setsid() failed");
 679 #endif /* !defined(__minix) */
 680         (void)nanosleep(&dtrtime, NULL);        /* leave DTR low for a bit */
 681         if ((fd = open(name, O_RDWR)) == -1) {
 682                 stall("can't open %s: %m", name);
 683                 _exit(1);
 684         }
 685         if (login_tty(fd) == -1) {
 686                 stall("can't get %s for controlling terminal: %m", name);
 687                 _exit(2);
 688         }
 689 }
 690
 691 /*
 692  * Bring the system up single user.
 693  */
 694 static state_func_t
 695 single_user(void)
 696 {
 697         pid_t pid, wpid;
 698         int status;
 699         int from_securitylevel;
 700         sigset_t mask;
 701         struct sigaction sa, satstp, sahup;
 702 #ifdef ALTSHELL
 703         const char *shell = INIT_BSHELL;
 704 #endif
 705         const char *argv[2];
 706 #ifdef SECURE
 707         struct ttyent *typ;
 708         struct passwd *pp;
 709         char *clear, *password;
 710 #endif
 711 #ifdef ALTSHELL
 712         char altshell[128];
 713 #endif /* ALTSHELL */
 714
 715 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
 716         /* Clear previous idea, just in case. */
 717         did_multiuser_chroot = 0;
 718 #endif /* !LETS_GET_SMALL && CHROOT */
 719
 720         /*
 721          * If the kernel is in secure mode, downgrade it to insecure mode.
 722          */
 723         from_securitylevel = getsecuritylevel();
 724         if (from_securitylevel > 0)
 725                 setsecuritylevel(0);
 726
 727         (void)sigemptyset(&sa.sa_mask);
 728         sa.sa_flags = 0;
 729         sa.sa_handler = SIG_IGN;
 730         (void)sigaction(SIGTSTP, &sa, &satstp);
 731         (void)sigaction(SIGHUP, &sa, &sahup);
 732         if ((pid = fork()) == 0) {
 733                 /*
 734                  * Start the single user session.
 735                  */
 736                 if (access(_PATH_CONSTTY, F_OK) == 0)
 737                         setctty(_PATH_CONSTTY);
 738                 else
 739                         setctty(_PATH_CONSOLE);
 740
 741 #ifdef SECURE
 742                 /*
 743                  * Check the root password.
 744                  * We don't care if the console is 'on' by default;
 745                  * it's the only tty that can be 'off' and 'secure'.
 746                  */
 747                 typ = getttynam("console");
 748                 pp = getpwnam("root");
 749                 if (typ && (from_securitylevel >=2 || (typ->ty_status
 750                     & TTY_SECURE) == 0) && pp && *pp->pw_passwd != '\0') {
 751                         (void)fprintf(stderr,
 752                             "Enter root password, or ^D to go multi-user\n");
 753                         for (;;) {
 754                                 clear = getpass("Password:");
 755                                 if (clear == 0 || *clear == '\0')
 756                                         _exit(0);
 757                                 password = crypt(clear, pp->pw_passwd);
 758                                 (void)memset(clear, 0, _PASSWORD_LEN);
 759                                 if (strcmp(password, pp->pw_passwd) == 0)
 760                                         break;
 761                                 warning("single-user login failed");
 762                         }
 763                 }
 764                 (void)endttyent();
 765                 endpwent();
 766 #endif /* SECURE */
 767
 768 #ifdef ALTSHELL
 769                 (void)fprintf(stderr,
 770                     "Enter pathname of shell or RETURN for %s: ", shell);
 771                 if (fgets(altshell, sizeof(altshell), stdin) == NULL) {
 772                         altshell[0] = '\0';
 773                 } else {
 774                         /* nuke \n */
 775                         char *p;
 776
 777                         if ((p = strchr(altshell, '\n')) != NULL)
 778                                 *p = '\0';
 779                 }
 780
 781                 if (altshell[0])
 782                         shell = altshell;
 783 #endif /* ALTSHELL */
 784
 785                 /*
 786                  * Unblock signals.
 787                  * We catch all the interesting ones,
 788                  * and those are reset to SIG_DFL on exec.
 789                  */
 790                 (void)sigemptyset(&mask);
 791                 (void)sigprocmask(SIG_SETMASK, &mask, NULL);
 792
 793                 /*
 794                  * Fire off a shell.
 795                  * If the default one doesn't work, try the Bourne shell.
 796                  */
 797                 argv[0] = "-sh";
 798                 argv[1] = 0;
 799                 (void)setenv("PATH", INIT_PATH, 1);
 800 #ifdef ALTSHELL
 801                 if (altshell[0])
 802                         argv[0] = altshell;
 803                 (void)execv(shell, __UNCONST(argv));
 804                 emergency("can't exec `%s' for single user: %m", shell);
 805                 argv[0] = "-sh";
 806 #endif /* ALTSHELL */
 807                 (void)execv(INIT_BSHELL, __UNCONST(argv));
 808                 emergency("can't exec `%s' for single user: %m", INIT_BSHELL);
 809                 (void)sleep(STALL_TIMEOUT);
 810                 _exit(3);
 811         }
 812
 813         if (pid == -1) {
 814                 /*
 815                  * We are seriously hosed.  Do our best.
 816                  */
 817                 emergency("can't fork single-user shell: %m, trying again");
 818                 while (waitpid(-1, NULL, WNOHANG) > 0)
 819                         continue;
 820                 (void)sigaction(SIGTSTP, &satstp, NULL);
 821                 (void)sigaction(SIGHUP, &sahup, NULL);
 822                 return (state_func_t)single_user;
 823         }
 824
 825         requested_transition = 0;
 826         do {
 827                 if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
 828                         collect_child(wpid, status);
 829                 if (wpid == -1) {
 830                         if (errno == EINTR)
 831                                 continue;
 832                         warning("wait for single-user shell failed: %m; "
 833                             "restarting");
 834                         return (state_func_t)single_user;
 835                 }
 836                 if (wpid == pid && WIFSTOPPED(status)) {
 837                         warning("shell stopped, restarting");
 838                         (void)kill(pid, SIGCONT);
 839                         wpid = -1;
 840                 }
 841         } while (wpid != pid && !requested_transition);
 842
 843         if (requested_transition) {
 844                 (void)sigaction(SIGTSTP, &satstp, NULL);
 845                 (void)sigaction(SIGHUP, &sahup, NULL);
 846                 return (state_func_t)requested_transition;
 847         }
 848
 849         if (WIFSIGNALED(status)) {
 850                 if (WTERMSIG(status) == SIGKILL) {
 851                         /* executed /sbin/reboot; wait for the end quietly */
 852                         sigset_t s;
 853
 854                         (void)sigfillset(&s);
 855                         for (;;)
 856                                 (void)sigsuspend(&s);
 857                 } else {
 858                         warning("single user shell terminated (%x), restarting",
 859                                 status);
 860                         (void)sigaction(SIGTSTP, &satstp, NULL);
 861                         (void)sigaction(SIGHUP, &sahup, NULL);
 862                         return (state_func_t)single_user;
 863                 }
 864         }
 865
 866         runcom_mode = FASTBOOT;
 867         (void)sigaction(SIGTSTP, &satstp, NULL);
 868         (void)sigaction(SIGHUP, &sahup, NULL);
 869 #ifndef LETS_GET_SMALL
 870         return (state_func_t)runcom;
 871 #else /* LETS_GET_SMALL */
 872         return (state_func_t)single_user;
 873 #endif /* LETS_GET_SMALL */
 874 }
 875
 876 #ifndef LETS_GET_SMALL
 877
 878 /* ARGSUSED */
 879 static state_func_t
 880 runetcrc(int trychroot)
 881 {
 882         pid_t pid, wpid;
 883         int status;
 884         const char *argv[4];
 885         struct sigaction sa;
 886
 887         switch ((pid = fork())) {
 888         case 0:
 889                 (void)sigemptyset(&sa.sa_mask);
 890                 sa.sa_flags = 0;
 891                 sa.sa_handler = SIG_IGN;
 892                 (void)sigaction(SIGTSTP, &sa, NULL);
 893                 (void)sigaction(SIGHUP, &sa, NULL);
 894
 895                 setctty(_PATH_CONSOLE);
 896
 897                 argv[0] = "sh";
 898                 argv[1] = _PATH_RUNCOM;
 899                 argv[2] = (runcom_mode == AUTOBOOT ? "autoboot" : 0);
 900                 argv[3] = 0;
 901
 902                 (void)sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
 903
 904 #ifdef CHROOT
 905                 if (trychroot)
 906                         if (chroot(rootdir) != 0) {
 907                                 warning("failed to chroot to `%s': %m",
 908                                     rootdir);
 909                                 _exit(4);       /* force single user mode */
 910                         }
 911 #endif /* CHROOT */
 912
 913                 (void)execv(INIT_BSHELL, __UNCONST(argv));
 914                 stall("can't exec `%s' for `%s': %m", INIT_BSHELL, _PATH_RUNCOM);
 915                 _exit(5);       /* force single user mode */
 916                 /*NOTREACHED*/
 917         case -1:
 918                 emergency("can't fork for `%s' on `%s': %m", INIT_BSHELL,
 919                     _PATH_RUNCOM);
 920                 while (waitpid(-1, NULL, WNOHANG) > 0)
 921                         continue;
 922                 (void)sleep(STALL_TIMEOUT);
 923                 return (state_func_t)single_user;
 924         default:
 925                 break;
 926         }
 927
 928         /*
 929          * Copied from single_user().  This is a bit paranoid.
 930          */
 931         do {
 932                 if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
 933                         collect_child(wpid, status);
 934                 if (wpid == -1) {
 935                         if (errno == EINTR)
 936                                 continue;
 937                         warning("wait for `%s' on `%s' failed: %m; going to "
 938                             "single user mode", INIT_BSHELL, _PATH_RUNCOM);
 939                         return (state_func_t)single_user;
 940                 }
 941                 if (wpid == pid && WIFSTOPPED(status)) {
 942                         warning("`%s' on `%s' stopped, restarting",
 943                             INIT_BSHELL, _PATH_RUNCOM);
 944                         (void)kill(pid, SIGCONT);
 945                         wpid = -1;
 946                 }
 947         } while (wpid != pid);
 948
 949         if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
 950             requested_transition == catatonia) {
 951                 /* /etc/rc executed /sbin/reboot; wait for the end quietly */
 952                 sigset_t s;
 953
 954                 (void)sigfillset(&s);
 955                 for (;;)
 956                         (void)sigsuspend(&s);
 957         }
 958
 959         if (!WIFEXITED(status)) {
 960                 warning("`%s' on `%s' terminated abnormally, going to "
 961                     "single user mode", INIT_BSHELL, _PATH_RUNCOM);
 962                 return (state_func_t)single_user;
 963         }
 964
 965         if (WEXITSTATUS(status))
 966                 return (state_func_t)single_user;
 967
 968         return (state_func_t)read_ttys;
 969 }
 970
 971 /*
 972  * Run the system startup script.
 973  */
 974 static state_func_t
 975 runcom(void)
 976 {
 977         state_func_t next_step;
 978
 979         /* Run /etc/rc and choose next state depending on the result. */
 980         next_step = runetcrc(0);
 981         if (next_step != (state_func_t)read_ttys)
 982                 return (state_func_t)next_step;
 983
 984 #ifdef CHROOT
 985         /*
 986          * If init.root sysctl does not point to "/", we'll chroot and run
 987          * The Real(tm) /etc/rc now.  Global variable rootdir will tell us
 988          * where to go.
 989          */
 990         if (shouldchroot()) {
 991                 next_step = runetcrc(1);
 992                 if (next_step != (state_func_t)read_ttys)
 993                         return (state_func_t)next_step;
 994
 995                 did_multiuser_chroot = 1;
 996         } else {
 997                 did_multiuser_chroot = 0;
 998         }
 999 #endif /* CHROOT */
1000
1001         /*
1002          * Regardless of whether in chroot or not, we booted successfuly.
1003          * It's time to spawn gettys (ie. next_step's value at this point).
1004          */
1005         runcom_mode = AUTOBOOT;         /* the default */
1006         /* NB: should send a message to the session logger to avoid blocking. */
1007 #ifdef SUPPORT_UTMPX
1008         logwtmpx("~", "reboot", "", 0, INIT_PROCESS);
1009 #endif
1010 #ifdef SUPPORT_UTMP
1011         logwtmp("~", "reboot", "");
1012 #endif
1013         return (state_func_t)read_ttys;
1014 }
1015
1016 /*
1017  * Open the session database.
1018  *
1019  * NB: We could pass in the size here; is it necessary?
1020  */
1021 static int
1022 start_session_db(void)
1023 {
1024
1025         if (session_db && (*session_db->close)(session_db))
1026                 emergency("session database close: %m");
1027         if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
1028                 emergency("session database open: %m");
1029                 return 1;
1030         }
1031         return 0;
1032
1033 }
1034
1035 /*
1036  * Add a new login session.
1037  */
1038 static void
1039 add_session(session_t *sp)
1040 {
1041         DBT key;
1042         DBT data;
1043
1044         if (session_db == NULL)
1045                 return;
1046
1047         key.data = &sp->se_process;
1048         key.size = sizeof sp->se_process;
1049         data.data = &sp;
1050         data.size = sizeof sp;
1051
1052         if ((*session_db->put)(session_db, &key, &data, 0))
1053                 emergency("insert %d: %m", sp->se_process);
1054 #ifdef SUPPORT_UTMPX
1055         session_utmpx(sp, 1);
1056 #endif
1057 }
1058
1059 /*
1060  * Delete an old login session.
1061  */
1062 static void
1063 del_session(session_t *sp)
1064 {
1065         DBT key;
1066
1067         key.data = &sp->se_process;
1068         key.size = sizeof sp->se_process;
1069
1070         if ((*session_db->del)(session_db, &key, 0))
1071                 emergency("delete %d: %m", sp->se_process);
1072 #ifdef SUPPORT_UTMPX
1073         session_utmpx(sp, 0);
1074 #endif
1075 }
1076
1077 /*
1078  * Look up a login session by pid.
1079  */
1080 static session_t *
1081 find_session(pid_t pid)
1082 {
1083         DBT key;
1084         DBT data;
1085         session_t *ret;
1086
1087         if (session_db == NULL)
1088                 return NULL;
1089
1090         key.data = &pid;
1091         key.size = sizeof pid;
1092         if ((*session_db->get)(session_db, &key, &data, 0) != 0)
1093                 return 0;
1094         (void)memmove(&ret, data.data, sizeof(ret));
1095         return ret;
1096 }
1097
1098 /*
1099  * Construct an argument vector from a command line.
1100  */
1101 static char **
1102 construct_argv(char *command)
1103 {
1104         int argc = 0;
1105         char **argv = malloc(((strlen(command) + 1) / 2 + 1) * sizeof (char *));
1106         static const char separators[] = " \t";
1107
1108         if (argv == NULL)
1109                 return NULL;
1110
1111         if ((argv[argc++] = strtok(command, separators)) == 0) {
1112                 free(argv);
1113                 return NULL;
1114         }
1115         while ((argv[argc++] = strtok(NULL, separators)) != NULL)
1116                 continue;
1117         return argv;
1118 }
1119
1120 /*
1121  * Deallocate a session descriptor.
1122  */
1123 static void
1124 free_session(session_t *sp)
1125 {
1126
1127         free(sp->se_device);
1128         if (sp->se_getty) {
1129                 free(sp->se_getty);
1130                 free(sp->se_getty_argv);
1131         }
1132         if (sp->se_window) {
1133                 free(sp->se_window);
1134                 free(sp->se_window_argv);
1135         }
1136         free(sp);
1137 }
1138
1139 /*
1140  * Allocate a new session descriptor.
1141  */
1142 static session_t *
1143 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1144 {
1145         session_t *sp;
1146
1147         if ((typ->ty_status & TTY_ON) == 0 || typ->ty_name == NULL ||
1148             typ->ty_getty == NULL)
1149                 return NULL;
1150
1151         sp = malloc(sizeof (session_t));
1152         if (sp == NULL)
1153                 return NULL;
1154         (void)memset(sp, 0, sizeof *sp);
1155
1156         sp->se_flags = SE_PRESENT;
1157         sp->se_index = session_index;
1158
1159         (void)asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1160         if (!sp->se_device) {
1161                 free(sp);
1162                 return NULL;
1163         }
1164
1165         if (setupargv(sp, typ) == 0) {
1166                 free_session(sp);
1167                 return NULL;
1168         }
1169
1170         sp->se_next = NULL;
1171         if (sprev == NULL) {
1172                 sessions = sp;
1173                 sp->se_prev = NULL;
1174         } else {
1175                 sprev->se_next = sp;
1176                 sp->se_prev = sprev;
1177         }
1178
1179         return sp;
1180 }
1181
1182 /*
1183  * Calculate getty and if useful window argv vectors.
1184  */
1185 static int
1186 setupargv(session_t *sp, struct ttyent *typ)
1187 {
1188
1189         if (sp->se_getty) {
1190                 free(sp->se_getty);
1191                 free(sp->se_getty_argv);
1192         }
1193         (void)asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1194         if (!sp->se_getty)
1195                 return 0;
1196         sp->se_getty_argv = construct_argv(sp->se_getty);
1197         if (sp->se_getty_argv == NULL) {
1198                 warning("can't parse getty for port `%s'", sp->se_device);
1199                 free(sp->se_getty);
1200                 sp->se_getty = NULL;
1201                 return 0;
1202         }
1203         if (typ->ty_window) {
1204                 if (sp->se_window)
1205                         free(sp->se_window);
1206                 sp->se_window = strdup(typ->ty_window);
1207                 sp->se_window_argv = construct_argv(sp->se_window);
1208                 if (sp->se_window_argv == NULL) {
1209                         warning("can't parse window for port `%s'",
1210                             sp->se_device);
1211                         free(sp->se_window);
1212                         sp->se_window = NULL;
1213                         return 0;
1214                 }
1215         }
1216         return 1;
1217 }
1218
1219 /*
1220  * Walk the list of ttys and create sessions for each active line.
1221  */
1222 static state_func_t
1223 read_ttys(void)
1224 {
1225         int session_index = 0;
1226         session_t *sp, *snext;
1227         struct ttyent *typ;
1228
1229 #ifdef SUPPORT_UTMPX
1230         if (sessions == NULL) {
1231                 struct stat st;
1232
1233                 make_utmpx("", BOOT_MSG, BOOT_TIME, 0, &boot_time, 0);
1234
1235                 /*
1236                  * If wtmpx is not empty, pick the down time from there
1237                  */
1238                 if (stat(_PATH_WTMPX, &st) != -1 && st.st_size != 0) {
1239                         struct timeval down_time;
1240
1241                         TIMESPEC_TO_TIMEVAL(&down_time,
1242                             st.st_atime > st.st_mtime ?
1243                             &st.st_atimespec : &st.st_mtimespec);
1244                         make_utmpx("", DOWN_MSG, DOWN_TIME, 0, &down_time, 0);
1245                 }
1246         }
1247 #endif
1248         /*
1249          * Destroy any previous session state.
1250          * There shouldn't be any, but just in case...
1251          */
1252         for (sp = sessions; sp; sp = snext) {
1253 #ifndef LETS_GET_SMALL
1254                 if (sp->se_process)
1255                         clear_session_logs(sp, 0);
1256 #endif
1257                 snext = sp->se_next;
1258                 free_session(sp);
1259         }
1260         sessions = NULL;
1261
1262         if (start_session_db()) {
1263                 warning("start_session_db failed, death");
1264 #ifdef CHROOT
1265                 /* If /etc/rc ran in chroot, we want to kill any survivors. */
1266                 if (did_multiuser_chroot)
1267                         return (state_func_t)death;
1268                 else
1269 #endif /* CHROOT */
1270                         return (state_func_t)single_user;
1271         }
1272
1273         (void)do_setttyent();
1274
1275         /*
1276          * Allocate a session entry for each active port.
1277          * Note that sp starts at 0.
1278          */
1279         while ((typ = getttyent()) != NULL)
1280                 if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1281                         sp = snext;
1282         (void)endttyent();
1283
1284         return (state_func_t)multi_user;
1285 }
1286
1287 /*
1288  * Start a window system running.
1289  */
1290 static void
1291 start_window_system(session_t *sp)
1292 {
1293         pid_t pid;
1294         sigset_t mask;
1295
1296         if ((pid = fork()) == -1) {
1297                 emergency("can't fork for window system on port `%s': %m",
1298                     sp->se_device);
1299                 /* hope that getty fails and we can try again */
1300                 return;
1301         }
1302
1303         if (pid)
1304                 return;
1305
1306         (void)sigemptyset(&mask);
1307         (void)sigprocmask(SIG_SETMASK, &mask, NULL);
1308
1309         if (setsid() < 0)
1310                 emergency("setsid failed (window): %m");
1311
1312         (void)execv(sp->se_window_argv[0], sp->se_window_argv);
1313         stall("can't exec window system `%s' for port `%s': %m",
1314             sp->se_window_argv[0], sp->se_device);
1315         _exit(6);
1316 }
1317
1318 /*
1319  * Start a login session running.
1320  */
1321 static pid_t
1322 start_getty(session_t *sp)
1323 {
1324         pid_t pid;
1325         sigset_t mask;
1326         time_t current_time = time(NULL);
1327
1328         /*
1329          * fork(), not vfork() -- we can't afford to block.
1330          */
1331         if ((pid = fork()) == -1) {
1332                 emergency("can't fork for getty on port `%s': %m",
1333                     sp->se_device);
1334                 return -1;
1335         }
1336
1337         if (pid)
1338                 return pid;
1339
1340 #ifdef CHROOT
1341         /* If /etc/rc did proceed inside chroot, we have to try as well. */
1342         if (did_multiuser_chroot)
1343                 if (chroot(rootdir) != 0) {
1344                         stall("can't chroot getty `%s' inside `%s': %m",
1345                             sp->se_getty_argv[0], rootdir);
1346                         _exit(7);
1347                 }
1348 #endif /* CHROOT */
1349
1350         if (current_time > sp->se_started.tv_sec &&
1351             current_time - sp->se_started.tv_sec < GETTY_SPACING) {
1352                 warning("getty repeating too quickly on port `%s', sleeping",
1353                     sp->se_device);
1354                 (void)sleep(GETTY_SLEEP);
1355         }
1356
1357         if (sp->se_window) {
1358                 start_window_system(sp);
1359                 (void)sleep(WINDOW_WAIT);
1360         }
1361
1362         (void)sigemptyset(&mask);
1363         (void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1364
1365         (void)execv(sp->se_getty_argv[0], sp->se_getty_argv);
1366         stall("can't exec getty `%s' for port `%s': %m",
1367             sp->se_getty_argv[0], sp->se_device);
1368         _exit(8);
1369         /*NOTREACHED*/
1370 }
1371 #ifdef SUPPORT_UTMPX
1372 static void
1373 session_utmpx(const session_t *sp, int add)
1374 {
1375         const char *name = sp->se_getty ? sp->se_getty :
1376             (sp->se_window ? sp->se_window : "");
1377         const char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
1378
1379         make_utmpx(name, line, add ? LOGIN_PROCESS : DEAD_PROCESS,
1380             sp->se_process, &sp->se_started, sp->se_index);
1381 }
1382
1383 static void
1384 make_utmpx(const char *name, const char *line, int type, pid_t pid,
1385     const struct timeval *tv, int session)
1386 {
1387         struct utmpx ut;
1388         const char *eline;
1389
1390         (void)memset(&ut, 0, sizeof(ut));
1391         (void)strlcpy(ut.ut_name, name, sizeof(ut.ut_name));
1392         ut.ut_type = type;
1393         (void)strlcpy(ut.ut_line, line, sizeof(ut.ut_line));
1394         ut.ut_pid = pid;
1395         if (tv)
1396                 ut.ut_tv = *tv;
1397         else
1398                 (void)gettimeofday(&ut.ut_tv, NULL);
1399         ut.ut_session = session;
1400
1401         eline = line + strlen(line);
1402         if ((size_t)(eline - line) >= sizeof(ut.ut_id))
1403                 line = eline - sizeof(ut.ut_id);
1404         (void)strncpy(ut.ut_id, line, sizeof(ut.ut_id));
1405
1406         if (pututxline(&ut) == NULL)
1407                 warning("can't add utmpx record for `%s': %m", ut.ut_line);
1408         endutxent();
1409 }
1410
1411 static char
1412 get_runlevel(const state_t s)
1413 {
1414         if (s == (state_t)single_user)
1415                 return SINGLE_USER;
1416         if (s == (state_t)runcom)
1417                 return RUNCOM;
1418         if (s == (state_t)read_ttys)
1419                 return READ_TTYS;
1420         if (s == (state_t)multi_user)
1421                 return MULTI_USER;
1422         if (s == (state_t)clean_ttys)
1423                 return CLEAN_TTYS;
1424         if (s == (state_t)catatonia)
1425                 return CATATONIA;
1426         return DEATH;
1427 }
1428
1429 static void
1430 utmpx_set_runlevel(char old, char new)
1431 {
1432         struct utmpx ut;
1433
1434         /*
1435          * Don't record any transitions until we did the first transition
1436          * to read ttys, which is when we are guaranteed to have a read-write
1437          * /var. Perhaps use a different variable for this?
1438          */
1439         if (sessions == NULL)
1440                 return;
1441
1442         (void)memset(&ut, 0, sizeof(ut));
1443         (void)snprintf(ut.ut_line, sizeof(ut.ut_line), RUNLVL_MSG, new);
1444         ut.ut_type = RUN_LVL;
1445         (void)gettimeofday(&ut.ut_tv, NULL);
1446         ut.ut_exit.e_exit = old;
1447         ut.ut_exit.e_termination = new;
1448         if (pututxline(&ut) == NULL)
1449                 warning("can't add utmpx record for `runlevel': %m");
1450         endutxent();
1451 }
1452 #endif /* SUPPORT_UTMPX */
1453
1454 #endif /* LETS_GET_SMALL */
1455
1456 /*
1457  * Collect exit status for a child.
1458  * If an exiting login, start a new login running.
1459  */
1460 static void
1461 collect_child(pid_t pid, int status)
1462 {
1463 #ifndef LETS_GET_SMALL
1464         session_t *sp, *sprev, *snext;
1465
1466         if (! sessions)
1467                 return;
1468
1469         if ((sp = find_session(pid)) == NULL)
1470                 return;
1471
1472         clear_session_logs(sp, status);
1473         del_session(sp);
1474         sp->se_process = 0;
1475
1476         if (sp->se_flags & SE_SHUTDOWN) {
1477                 if ((sprev = sp->se_prev) != NULL)
1478                         sprev->se_next = sp->se_next;
1479                 else
1480                         sessions = sp->se_next;
1481                 if ((snext = sp->se_next) != NULL)
1482                         snext->se_prev = sp->se_prev;
1483                 free_session(sp);
1484                 return;
1485         }
1486
1487         if ((pid = start_getty(sp)) == -1) {
1488                 /* serious trouble */
1489                 requested_transition = clean_ttys;
1490                 return;
1491         }
1492
1493         sp->se_process = pid;
1494         (void)gettimeofday(&sp->se_started, NULL);
1495         add_session(sp);
1496 #endif /* LETS_GET_SMALL */
1497 }
1498
1499 /*
1500  * Catch a signal and request a state transition.
1501  */
1502 static void
1503 transition_handler(int sig)
1504 {
1505
1506         switch (sig) {
1507 #ifndef LETS_GET_SMALL
1508         case SIGHUP:
1509                 requested_transition = clean_ttys;
1510                 break;
1511         case SIGTERM:
1512                 requested_transition = death;
1513                 break;
1514         case SIGTSTP:
1515                 requested_transition = catatonia;
1516                 break;
1517 #endif /* LETS_GET_SMALL */
1518         default:
1519                 requested_transition = 0;
1520                 break;
1521         }
1522 }
1523
1524 #ifndef LETS_GET_SMALL
1525 /*
1526  * Take the system multiuser.
1527  */
1528 static state_func_t
1529 multi_user(void)
1530 {
1531         pid_t pid;
1532         int status;
1533         session_t *sp;
1534
1535         requested_transition = 0;
1536
1537         /*
1538          * If the administrator has not set the security level to -1
1539          * to indicate that the kernel should not run multiuser in secure
1540          * mode, and the run script has not set a higher level of security
1541          * than level 1, then put the kernel into secure mode.
1542          */
1543         if (getsecuritylevel() == 0)
1544                 setsecuritylevel(1);
1545
1546         for (sp = sessions; sp; sp = sp->se_next) {
1547                 if (sp->se_process)
1548                         continue;
1549                 if ((pid = start_getty(sp)) == -1) {
1550                         /* serious trouble */
1551                         requested_transition = clean_ttys;
1552                         break;
1553                 }
1554                 sp->se_process = pid;
1555                 (void)gettimeofday(&sp->se_started, NULL);
1556                 add_session(sp);
1557         }
1558
1559         while (!requested_transition)
1560                 if ((pid = waitpid(-1, &status, 0)) != -1)
1561                         collect_child(pid, status);
1562
1563         return (state_func_t)requested_transition;
1564 }
1565
1566 /*
1567  * This is an n-squared algorithm.  We hope it isn't run often...
1568  */
1569 static state_func_t
1570 clean_ttys(void)
1571 {
1572         session_t *sp, *sprev;
1573         struct ttyent *typ;
1574         int session_index = 0;
1575         int devlen;
1576
1577         for (sp = sessions; sp; sp = sp->se_next)
1578                 sp->se_flags &= ~SE_PRESENT;
1579
1580         (void)do_setttyent();
1581
1582         devlen = sizeof(_PATH_DEV) - 1;
1583         while ((typ = getttyent()) != NULL) {
1584                 ++session_index;
1585
1586                 for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1587                         if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1588                                 break;
1589
1590                 if (sp) {
1591                         sp->se_flags |= SE_PRESENT;
1592                         if (sp->se_index != session_index) {
1593                                 warning("port `%s' changed utmp index from "
1594                                     "%d to %d", sp->se_device, sp->se_index,
1595                                     session_index);
1596                                 sp->se_index = session_index;
1597                         }
1598                         if ((typ->ty_status & TTY_ON) == 0 ||
1599                             typ->ty_getty == 0) {
1600                                 sp->se_flags |= SE_SHUTDOWN;
1601                                 if (sp->se_process != 0)
1602                                         (void)kill(sp->se_process, SIGHUP);
1603                                 continue;
1604                         }
1605                         sp->se_flags &= ~SE_SHUTDOWN;
1606                         if (setupargv(sp, typ) == 0) {
1607                                 warning("can't parse getty for port `%s'",
1608                                     sp->se_device);
1609                                 sp->se_flags |= SE_SHUTDOWN;
1610                                 if (sp->se_process != 0)
1611                                         (void)kill(sp->se_process, SIGHUP);
1612                         }
1613                         continue;
1614                 }
1615
1616                 (void)new_session(sprev, session_index, typ);
1617         }
1618
1619         (void)endttyent();
1620
1621         for (sp = sessions; sp; sp = sp->se_next)
1622                 if ((sp->se_flags & SE_PRESENT) == 0) {
1623                         sp->se_flags |= SE_SHUTDOWN;
1624                         if (sp->se_process != 0)
1625                                 (void)kill(sp->se_process, SIGHUP);
1626                 }
1627
1628         return (state_func_t)multi_user;
1629 }
1630
1631 /*
1632  * Block further logins.
1633  */
1634 static state_func_t
1635 catatonia(void)
1636 {
1637         session_t *sp;
1638
1639         for (sp = sessions; sp; sp = sp->se_next)
1640                 sp->se_flags |= SE_SHUTDOWN;
1641
1642         return (state_func_t)multi_user;
1643 }
1644 #endif /* LETS_GET_SMALL */
1645
1646 /*
1647  * Note SIGALRM.
1648  */
1649 static void
1650 /*ARGSUSED*/
1651 alrm_handler(int sig)
1652 {
1653
1654         clang = 1;
1655 }
1656
1657 #ifndef LETS_GET_SMALL
1658 /*
1659  * Bring the system down to single user.
1660  */
1661 static state_func_t
1662 death(void)
1663 {
1664         session_t *sp;
1665         int i, status;
1666         pid_t pid;
1667         static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1668
1669         for (sp = sessions; sp; sp = sp->se_next)
1670                 sp->se_flags |= SE_SHUTDOWN;
1671
1672         /* NB: should send a message to the session logger to avoid blocking. */
1673 #ifdef SUPPORT_UTMPX
1674         logwtmpx("~", "shutdown", "", 0, INIT_PROCESS);
1675 #endif
1676 #ifdef SUPPORT_UTMP
1677         logwtmp("~", "shutdown", "");
1678 #endif
1679
1680         for (i = 0; i < 3; ++i) {
1681                 if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1682                         return (state_func_t)single_user;
1683
1684                 clang = 0;
1685                 (void)alarm(DEATH_WATCH);
1686                 do
1687                         if ((pid = waitpid(-1, &status, 0)) != -1)
1688                                 collect_child(pid, status);
1689                 while (clang == 0 && errno != ECHILD);
1690
1691                 if (errno == ECHILD)
1692                         return (state_func_t)single_user;
1693         }
1694
1695         warning("some processes would not die; ps axl advised");
1696
1697         return (state_func_t)single_user;
1698 }
1699 #endif /* LETS_GET_SMALL */
1700
1701 #ifdef MFS_DEV_IF_NO_CONSOLE
1702
1703 static int
1704 mfs_dev(void)
1705 {
1706         /*
1707          * We cannot print errors so we bail out silently...
1708          */
1709         pid_t pid;
1710         int status;
1711
1712         /* If we have /dev/console, assume all is OK  */
1713         if (access(_PATH_CONSOLE, F_OK) == 0)
1714                 return 0;
1715
1716 #if 0   /* Useful for testing MAKEDEV */
1717         /* Mount an mfs over /mnt so we can create a console entry */
1718         switch ((pid = fork())) {
1719         case 0:
1720                 (void)execl(INIT_MOUNT_MFS, "mount_mfs",
1721                     "-b", "4096", "-f", "512",
1722                     "-s", 64, "-n", 10,
1723                     "-p", "0755",
1724                     "swap", "/mnt", NULL);
1725                 _exit(9);
1726                 /*NOTREACHED*/
1727
1728         case -1:
1729                 return(-1);
1730
1731         default:
1732                 if (waitpid(pid, &status, 0) == -1)
1733                         return(-1);
1734                 if (status != 0)
1735                         return(-1);
1736                 break;
1737         }
1738
1739         {
1740                 dev_t dev;
1741 #ifdef CPU_CONSDEV
1742                 static int name[2] = { CTL_MACHDEP, CPU_CONSDEV };
1743                 size_t olen;
1744                 olen = sizeof(dev);
1745                 if (sysctl(name, sizeof(name) / sizeof(name[0]), &dev, &olen,
1746                     NULL, 0) == -1)
1747 #endif
1748                         dev = makedev(0, 0);
1749
1750                 /* Make a console for us, so we can see things happening */
1751                 if (mknod("/mnt/console", 0666 | S_IFCHR, dev) == -1)
1752                         return(-1);
1753                 (void)freopen("/mnt/console", "a", stderr);
1754         }
1755
1756 #endif
1757
1758         /* Run the makedev script to create devices */
1759         switch ((pid = fork())) {
1760         case 0:
1761                 (void)dup2(2, 1);       /* Give the script stdout */
1762                 if (chdir("/dev") == 0)
1763                         (void)execl(INIT_BSHELL, "sh",
1764                             access("./MAKEDEV", X_OK) == 0
1765                                 ? "./MAKEDEV" : "/etc/MAKEDEV",
1766                             "-MM", "init", NULL);
1767                 _exit(10);
1768                 /* NOTREACHED */
1769
1770         case -1:
1771                 break;
1772
1773         default:
1774                 if (waitpid(pid, &status, 0) == -1)
1775                         break;
1776                 if (status != 0)
1777                         warn("MAKEDEV exit status %d", status);
1778                 /*
1779                  * If /dev/console got created, then return 0
1780                  * regardless of MAKEDEV exit status.
1781                  */
1782                 if (access(_PATH_CONSOLE, F_OK) == 0)
1783                         return 0;
1784                 _exit(11);
1785         }
1786         warn("Unable to run MAKEDEV");
1787         _exit(12);
1788 }
1789 #endif
1790
1791 #ifndef LETS_GET_SMALL
1792 static int
1793 do_setttyent(void)
1794 {
1795         (void)endttyent();
1796 #ifdef CHROOT
1797         if (did_multiuser_chroot) {
1798                 char path[PATH_MAX];
1799
1800                 (void)snprintf(path, sizeof(path), "%s/%s", rootdir, _PATH_TTYS);
1801
1802                 return setttyentpath(path);
1803         } else
1804 #endif /* CHROOT */
1805                 return setttyent();
1806 }
1807 #endif
1808
1809 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
1810
1811 static int
1812 createsysctlnode(void)
1813 {
1814         struct sysctlnode node;
1815         int mib[2];
1816         size_t len;
1817
1818         /*
1819          * Create top-level dynamic sysctl node.  Its child nodes will only
1820          * be readable by the superuser, since regular mortals should not
1821          * care ("Sssh, it's a secret!").
1822          */
1823         len = sizeof(struct sysctlnode);
1824         mib[0] = CTL_CREATE;
1825
1826         (void)memset(&node, 0, len);
1827         node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1828             CTLFLAG_PRIVATE | CTLTYPE_NODE;
1829         node.sysctl_num = CTL_CREATE;
1830         (void)snprintf(node.sysctl_name, SYSCTL_NAMELEN, "init");
1831         if (sysctl(&mib[0], 1, &node, &len, &node, len) == -1) {
1832                 warning("could not create init node: %m");
1833                 return -1;
1834         }
1835
1836         /*
1837          * Create second level dynamic node capable of holding pathname.
1838          * Provide "/" as the default value.
1839          */
1840         len = sizeof(struct sysctlnode);
1841         mib[0] = node.sysctl_num;
1842         mib[1] = CTL_CREATE;
1843
1844         (void)memset(&node, 0, len);
1845         node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1846             CTLTYPE_STRING | CTLFLAG_OWNDATA;
1847         node.sysctl_size = _POSIX_PATH_MAX;
1848         node.sysctl_data = __UNCONST("/");
1849         node.sysctl_num = CTL_CREATE;
1850         (void)snprintf(node.sysctl_name, SYSCTL_NAMELEN, "root");
1851         if (sysctl(&mib[0], 2, NULL, NULL, &node, len) == -1) {
1852                 warning("could not create init.root node: %m");
1853                 return -1;
1854         }
1855
1856         return 0;
1857 }
1858
1859 static int
1860 shouldchroot(void)
1861 {
1862         struct sysctlnode node;
1863         size_t len, cnt;
1864         int mib;
1865
1866         len = sizeof(struct sysctlnode);
1867
1868         if (sysctlbyname("init.root", rootdir, &len, NULL, 0) == -1) {
1869                 warning("could not read init.root: %m");
1870
1871                 /* Child killed our node. Recreate it. */
1872                 if (errno == ENOENT) {
1873                         /* Destroy whatever is left, recreate from scratch. */
1874                         if (sysctlnametomib("init", &mib, &cnt) != -1) {
1875                                 (void)memset(&node, 0, sizeof(node));
1876                                 node.sysctl_flags = SYSCTL_VERSION;
1877                                 node.sysctl_num = mib;
1878                                 mib = CTL_DESTROY;
1879
1880                                 (void)sysctl(&mib, 1, NULL, NULL, &node,
1881                                     sizeof(node));
1882                         }
1883
1884                         (void)createsysctlnode();
1885                 }
1886
1887                 /* We certainly won't chroot. */
1888                 return 0;
1889         }
1890
1891         if (rootdir[len] != '\0' || strlen(rootdir) != len - 1) {
1892                 warning("init.root is not a string");
1893                 return 0;
1894         }
1895
1896         if (strcmp(rootdir, "/") == 0)
1897                 return 0;
1898
1899         return 1;
1900 }
1901
1902 #endif /* !LETS_GET_SMALL && CHROOT */