/* $OpenBSD: init.c,v 1.7 1996/07/31 18:29:38 deraadt Exp $ */ /* $NetBSD: init.c,v 1.22 1996/05/15 23:29:33 jtc Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Donn Seeley at Berkeley Software Design, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint static char copyright[] = "@(#) Copyright (c) 1991, 1993\n\ The Regents of the University of California. All rights reserved.\n"; #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)init.c 8.1 (Berkeley) 7/15/93"; #else static char rcsid[] = "$OpenBSD: init.c,v 1.7 1996/07/31 18:29:38 deraadt Exp $"; #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef __STDC__ #include #else #include #endif #ifdef SECURE #include #endif #include "pathnames.h" /* * Sleep times; used to prevent thrashing. */ #define GETTY_SPACING 5 /* N secs minimum getty spacing */ #define GETTY_SLEEP 30 /* sleep N secs after spacing problem */ #define WINDOW_WAIT 3 /* wait N secs after starting window */ #define STALL_TIMEOUT 30 /* wait N secs after warning */ #define DEATH_WATCH 10 /* wait N secs for procs to die */ void handle __P((sig_t, ...)); void delset __P((sigset_t *, ...)); void stall __P((char *, ...)); void warning __P((char *, ...)); void emergency __P((char *, ...)); void disaster __P((int)); void badsys __P((int)); /* * We really need a recursive typedef... * The following at least guarantees that the return type of (*state_t)() * is sufficiently wide to hold a function pointer. */ typedef long (*state_func_t) __P((void)); typedef state_func_t (*state_t) __P((void)); state_func_t single_user __P((void)); state_func_t runcom __P((void)); state_func_t read_ttys __P((void)); state_func_t multi_user __P((void)); state_func_t clean_ttys __P((void)); state_func_t catatonia __P((void)); state_func_t death __P((void)); enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT; void transition __P((state_t)); #ifndef LETS_GET_SMALL state_t requested_transition = runcom; #else /* LETS_GET_SMALL */ state_t requested_transition = single_user; #endif /* LETS_GET_SMALL */ void setctty __P((char *)); typedef struct init_session { int se_index; /* index of entry in ttys file */ pid_t se_process; /* controlling process */ time_t se_started; /* used to avoid thrashing */ int se_flags; /* status of session */ #define SE_SHUTDOWN 0x1 /* session won't be restarted */ #define SE_PRESENT 0x2 /* session is in /etc/ttys */ #define SE_DEVEXISTS 0x4 /* open does not result in ENODEV */ char *se_device; /* filename of port */ char *se_getty; /* what to run on that port */ char **se_getty_argv; /* pre-parsed argument array */ char *se_window; /* window system (started only once) */ char **se_window_argv; /* pre-parsed argument array */ struct init_session *se_prev; struct init_session *se_next; } session_t; void free_session __P((session_t *)); session_t *new_session __P((session_t *, int, struct ttyent *)); session_t *sessions; char **construct_argv __P((char *)); void start_window_system __P((session_t *)); void collect_child __P((pid_t)); pid_t start_getty __P((session_t *)); void transition_handler __P((int)); void alrm_handler __P((int)); void setsecuritylevel __P((int)); int getsecuritylevel __P((void)); int setupargv __P((session_t *, struct ttyent *)); int clang; void clear_session_logs __P((session_t *)); int start_session_db __P((void)); void add_session __P((session_t *)); void del_session __P((session_t *)); session_t *find_session __P((pid_t)); DB *session_db; /* * The mother of all processes. */ int main(argc, argv) int argc; char **argv; { int c; struct sigaction sa; sigset_t mask; #ifndef LETS_GET_SMALL /* Dispose of random users. */ if (getuid() != 0) { (void)fprintf(stderr, "init: %s\n", strerror(EPERM)); exit (1); } /* System V users like to reexec init. */ if (getpid() != 1) { (void)fprintf(stderr, "init: already running\n"); exit (1); } /* * Note that this does NOT open a file... * Does 'init' deserve its own facility number? */ openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH); #endif /* LETS_GET_SMALL */ /* * Create an initial session. */ if (setsid() < 0) warning("initial setsid() failed: %m"); /* * Establish an initial user so that programs running * single user do not freak out and die (like passwd). */ if (setlogin("root") < 0) warning("setlogin() failed: %m"); #ifndef LETS_GET_SMALL /* * This code assumes that we always get arguments through flags, * never through bits set in some random machine register. */ while ((c = getopt(argc, argv, "sf")) != -1) switch (c) { case 's': requested_transition = single_user; break; case 'f': runcom_mode = FASTBOOT; break; default: warning("unrecognized flag '-%c'", c); break; } if (optind != argc) warning("ignoring excess arguments"); #else /* LETS_GET_SMALL */ requested_transition = single_user; #endif /* LETS_GET_SMALL */ /* * We catch or block signals rather than ignore them, * so that they get reset on exec. */ handle(badsys, SIGSYS, 0); handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGXCPU, SIGXFSZ, 0); handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0); handle(alrm_handler, SIGALRM, 0); sigfillset(&mask); delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS, SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0); sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = SIG_IGN; (void) sigaction(SIGTTIN, &sa, (struct sigaction *)0); (void) sigaction(SIGTTOU, &sa, (struct sigaction *)0); /* * Paranoia. */ close(0); close(1); close(2); /* * Start the state machine. */ transition(requested_transition); /* * Should never reach here. */ return 1; } /* * Associate a function with a signal handler. */ void #ifdef __STDC__ handle(sig_t handler, ...) #else handle(va_alist) va_dcl #endif { int sig; struct sigaction sa; int mask_everything; va_list ap; #ifndef __STDC__ sig_t handler; va_start(ap); handler = va_arg(ap, sig_t); #else va_start(ap, handler); #endif sa.sa_handler = handler; sigfillset(&mask_everything); while (sig = va_arg(ap, int)) { sa.sa_mask = mask_everything; /* XXX SA_RESTART? */ sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0; sigaction(sig, &sa, (struct sigaction *) 0); } va_end(ap); } /* * Delete a set of signals from a mask. */ void #ifdef __STDC__ delset(sigset_t *maskp, ...) #else delset(va_alist) va_dcl #endif { int sig; va_list ap; #ifndef __STDC__ sigset_t *maskp; va_start(ap); maskp = va_arg(ap, sigset_t *); #else va_start(ap, maskp); #endif while (sig = va_arg(ap, int)) sigdelset(maskp, sig); va_end(ap); } /* * Log a message and sleep for a while (to give someone an opportunity * to read it and to save log or hardcopy output if the problem is chronic). * NB: should send a message to the session logger to avoid blocking. */ void #ifdef __STDC__ stall(char *message, ...) #else stall(va_alist) va_dcl #endif { va_list ap; #ifndef __STDC__ char *message; va_start(ap); message = va_arg(ap, char *); #else va_start(ap, message); #endif vsyslog(LOG_ALERT, message, ap); va_end(ap); sleep(STALL_TIMEOUT); } /* * Like stall(), but doesn't sleep. * If cpp had variadic macros, the two functions could be #defines for another. * NB: should send a message to the session logger to avoid blocking. */ void #ifdef __STDC__ warning(char *message, ...) #else warning(va_alist) va_dcl #endif { va_list ap; #ifndef __STDC__ char *message; va_start(ap); message = va_arg(ap, char *); #else va_start(ap, message); #endif vsyslog(LOG_ALERT, message, ap); va_end(ap); } /* * Log an emergency message. * NB: should send a message to the session logger to avoid blocking. */ void #ifdef __STDC__ emergency(char *message, ...) #else emergency(va_alist) va_dcl #endif { va_list ap; #ifndef __STDC__ char *message; va_start(ap); message = va_arg(ap, char *); #else va_start(ap, message); #endif vsyslog(LOG_EMERG, message, ap); va_end(ap); } /* * Catch a SIGSYS signal. * * These may arise if a system does not support sysctl. * We tolerate up to 25 of these, then throw in the towel. */ void badsys(sig) int sig; { static int badcount = 0; if (badcount++ < 25) return; disaster(sig); } /* * Catch an unexpected signal. */ void disaster(sig) int sig; { emergency("fatal signal: %s", strsignal(sig)); sleep(STALL_TIMEOUT); _exit(sig); /* reboot */ } /* * Get the security level of the kernel. */ int getsecuritylevel() { #ifdef KERN_SECURELVL int name[2], curlevel; size_t len; extern int errno; name[0] = CTL_KERN; name[1] = KERN_SECURELVL; len = sizeof curlevel; if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) { emergency("cannot get kernel security level: %s", strerror(errno)); return (-1); } return (curlevel); #else return (-1); #endif } /* * Set the security level of the kernel. */ void setsecuritylevel(newlevel) int newlevel; { #ifdef KERN_SECURELVL int name[2], curlevel; extern int errno; curlevel = getsecuritylevel(); if (newlevel == curlevel) return; name[0] = CTL_KERN; name[1] = KERN_SECURELVL; if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) { emergency( "cannot change kernel security level from %d to %d: %s", curlevel, newlevel, strerror(errno)); return; } #ifdef SECURE warning("kernel security level changed from %d to %d", curlevel, newlevel); #endif #endif } /* * Change states in the finite state machine. * The initial state is passed as an argument. */ void transition(s) state_t s; { for (;;) s = (state_t) (*s)(); } /* * Close out the accounting files for a login session. * NB: should send a message to the session logger to avoid blocking. */ void clear_session_logs(sp) session_t *sp; { char *line = sp->se_device + sizeof(_PATH_DEV) - 1; if (logout(line)) logwtmp(line, "", ""); } /* * Start a session and allocate a controlling terminal. * Only called by children of init after forking. */ void setctty(name) char *name; { int fd; (void) revoke(name); sleep (2); /* leave DTR low */ if ((fd = open(name, O_RDWR)) == -1) { stall("can't open %s: %m", name); _exit(1); } if (login_tty(fd) == -1) { stall("can't get %s for controlling terminal: %m", name); _exit(1); } } /* * Bring the system up single user. */ state_func_t single_user() { pid_t pid, wpid; int status; sigset_t mask; char shell[MAXPATHLEN]; /* Allocate space here */ char name[MAXPATHLEN]; /* Name (argv[0]) of shell */ char *argv[2]; #ifdef SECURE struct ttyent *typ; struct passwd *pp; static const char banner[] = "Enter root password, or ^D to go multi-user\n"; char *clear, *password; #endif /* Init shell and name */ strcpy(shell, _PATH_BSHELL); strcpy(name, "-sh"); /* * If the kernel is in secure mode, downgrade it to insecure mode. */ if (getsecuritylevel() > 0) setsecuritylevel(0); if ((pid = fork()) == 0) { /* * Start the single user session. */ setctty(_PATH_CONSOLE); #ifdef SECURE /* * Check the root password. * We don't care if the console is 'on' by default; * it's the only tty that can be 'off' and 'secure'. */ typ = getttynam("console"); pp = getpwnam("root"); if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp && *pp->pw_passwd) { write(2, banner, sizeof banner - 1); for (;;) { clear = getpass("Password:"); if (clear == 0 || *clear == '\0') _exit(0); password = crypt(clear, pp->pw_passwd); memset(clear, 0, _PASSWORD_LEN); if (strcmp(password, pp->pw_passwd) == 0) break; warning("single-user login failed\n"); } } endttyent(); endpwent(); #endif /* SECURE */ #ifdef DEBUGSHELL { char altshell[128], *cp = altshell; int num; #define SHREQUEST \ "Enter pathname of shell or RETURN for sh: " (void)write(STDERR_FILENO, SHREQUEST, sizeof(SHREQUEST) - 1); while ((num = read(STDIN_FILENO, cp, 1)) != -1 && num != 0 && *cp != '\n' && cp < &altshell[127]) cp++; *cp = '\0'; /* Copy in alternate shell */ if (altshell[0] != '\0'){ char *p; /* Binary to exec */ strcpy(shell, altshell); /* argv[0] */ p = strrchr(altshell, '/'); if(p == NULL) p = altshell; else p++; name[0] = '-'; strcpy(&name[1], p); } } #endif /* DEBUGSHELL */ /* * Unblock signals. * We catch all the interesting ones, * and those are reset to SIG_DFL on exec. */ sigemptyset(&mask); sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); /* * Fire off a shell. * If the default one doesn't work, try the Bourne shell. */ argv[0] = name; argv[1] = NULL; setenv("PATH", _PATH_STDPATH, 1); execv(shell, argv); emergency("can't exec %s for single user: %m", shell); argv[0] = "-sh"; argv[1] = NULL; execv(_PATH_BSHELL, argv); emergency("can't exec %s for single user: %m", _PATH_BSHELL); sleep(STALL_TIMEOUT); _exit(1); } if (pid == -1) { /* * We are seriously hosed. Do our best. */ emergency("can't fork single-user shell, trying again"); while (waitpid(-1, (int *) 0, WNOHANG) > 0) continue; return (state_func_t) single_user; } requested_transition = 0; do { if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) collect_child(wpid); if (wpid == -1) { if (errno == EINTR) continue; warning("wait for single-user shell failed: %m; restarting"); return (state_func_t) single_user; } if (wpid == pid && WIFSTOPPED(status)) { warning("init: shell stopped, restarting\n"); kill(pid, SIGCONT); wpid = -1; } } while (wpid != pid && !requested_transition); if (requested_transition) return (state_func_t) requested_transition; if (!WIFEXITED(status)) { if (WTERMSIG(status) == SIGKILL) { /* * reboot(8) killed shell? */ warning("single user shell terminated."); sleep(STALL_TIMEOUT); _exit(0); } else { warning("single user shell terminated, restarting"); return (state_func_t) single_user; } } runcom_mode = FASTBOOT; #ifndef LETS_GET_SMALL return (state_func_t) runcom; #else /* LETS_GET_SMALL */ return (state_func_t) single_user; #endif /* LETS_GET_SMALL */ } #ifndef LETS_GET_SMALL /* * Run the system startup script. */ state_func_t runcom() { pid_t pid, wpid; int status; char *argv[4]; struct sigaction sa; if ((pid = fork()) == 0) { sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = SIG_IGN; (void) sigaction(SIGTSTP, &sa, (struct sigaction *)0); (void) sigaction(SIGHUP, &sa, (struct sigaction *)0); setctty(_PATH_CONSOLE); argv[0] = "sh"; argv[1] = _PATH_RUNCOM; argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0; argv[3] = 0; sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0); execv(_PATH_BSHELL, argv); stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM); _exit(1); /* force single user mode */ } if (pid == -1) { emergency("can't fork for %s on %s: %m", _PATH_BSHELL, _PATH_RUNCOM); while (waitpid(-1, (int *) 0, WNOHANG) > 0) continue; sleep(STALL_TIMEOUT); return (state_func_t) single_user; } /* * Copied from single_user(). This is a bit paranoid. */ do { if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1) collect_child(wpid); if (wpid == -1) { if (errno == EINTR) continue; warning("wait for %s on %s failed: %m; going to single user mode", _PATH_BSHELL, _PATH_RUNCOM); return (state_func_t) single_user; } if (wpid == pid && WIFSTOPPED(status)) { warning("init: %s on %s stopped, restarting\n", _PATH_BSHELL, _PATH_RUNCOM); kill(pid, SIGCONT); wpid = -1; } } while (wpid != pid); if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM && requested_transition == catatonia) { /* /etc/rc executed /sbin/reboot; wait for the end quietly */ sigset_t s; sigfillset(&s); for (;;) sigsuspend(&s); } if (!WIFEXITED(status)) { warning("%s on %s terminated abnormally, going to single user mode", _PATH_BSHELL, _PATH_RUNCOM); return (state_func_t) single_user; } if (WEXITSTATUS(status)) return (state_func_t) single_user; runcom_mode = AUTOBOOT; /* the default */ /* NB: should send a message to the session logger to avoid blocking. */ logwtmp("~", "reboot", ""); return (state_func_t) read_ttys; } /* * Open the session database. * * NB: We could pass in the size here; is it necessary? */ int start_session_db() { if (session_db && (*session_db->close)(session_db)) emergency("session database close: %s", strerror(errno)); if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) { emergency("session database open: %s", strerror(errno)); return (1); } return (0); } /* * Add a new login session. */ void add_session(sp) session_t *sp; { DBT key; DBT data; key.data = &sp->se_process; key.size = sizeof sp->se_process; data.data = &sp; data.size = sizeof sp; if ((*session_db->put)(session_db, &key, &data, 0)) emergency("insert %d: %s", sp->se_process, strerror(errno)); } /* * Delete an old login session. */ void del_session(sp) session_t *sp; { DBT key; key.data = &sp->se_process; key.size = sizeof sp->se_process; if ((*session_db->del)(session_db, &key, 0)) emergency("delete %d: %s", sp->se_process, strerror(errno)); } /* * Look up a login session by pid. */ session_t * #ifdef __STDC__ find_session(pid_t pid) #else find_session(pid) pid_t pid; #endif { DBT key; DBT data; session_t *ret; key.data = &pid; key.size = sizeof pid; if ((*session_db->get)(session_db, &key, &data, 0) != 0) return 0; memcpy(&ret, data.data, sizeof(ret)); return ret; } /* * Construct an argument vector from a command line. */ char ** construct_argv(command) char *command; { register int argc = 0; register char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1) * sizeof (char *)); static const char separators[] = " \t"; if ((argv[argc++] = strtok(command, separators)) == 0) return 0; while (argv[argc++] = strtok((char *) 0, separators)) continue; return argv; } /* * Deallocate a session descriptor. */ void free_session(sp) register session_t *sp; { free(sp->se_device); if (sp->se_getty) { free(sp->se_getty); free(sp->se_getty_argv); } if (sp->se_window) { free(sp->se_window); free(sp->se_window_argv); } free(sp); } /* * Allocate a new session descriptor. */ session_t * new_session(sprev, session_index, typ) session_t *sprev; int session_index; register struct ttyent *typ; { register session_t *sp; if ((typ->ty_status & TTY_ON) == 0 || typ->ty_name == 0 || typ->ty_getty == 0) return 0; sp = (session_t *) malloc(sizeof (session_t)); memset(sp, 0, sizeof *sp); sp->se_flags = SE_PRESENT; sp->se_index = session_index; sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name)); (void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name); if (setupargv(sp, typ) == 0) { free_session(sp); return (0); } sp->se_next = 0; if (sprev == 0) { sessions = sp; sp->se_prev = 0; } else { sprev->se_next = sp; sp->se_prev = sprev; } return sp; } /* * Calculate getty and if useful window argv vectors. */ int setupargv(sp, typ) session_t *sp; struct ttyent *typ; { if (sp->se_getty) { free(sp->se_getty); free(sp->se_getty_argv); } sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2); (void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name); sp->se_getty_argv = construct_argv(sp->se_getty); if (sp->se_getty_argv == 0) { warning("can't parse getty for port %s", sp->se_device); free(sp->se_getty); sp->se_getty = 0; return (0); } if (typ->ty_window) { if (sp->se_window) free(sp->se_window); sp->se_window = strdup(typ->ty_window); sp->se_window_argv = construct_argv(sp->se_window); if (sp->se_window_argv == 0) { warning("can't parse window for port %s", sp->se_device); free(sp->se_window); sp->se_window = 0; return (0); } } return (1); } /* * Walk the list of ttys and create sessions for each active line. */ state_func_t read_ttys() { int session_index = 0; register session_t *sp, *snext; register struct ttyent *typ; /* * Destroy any previous session state. * There shouldn't be any, but just in case... */ for (sp = sessions; sp; sp = snext) { if (sp->se_process) clear_session_logs(sp); snext = sp->se_next; free_session(sp); } sessions = 0; if (start_session_db()) return (state_func_t) single_user; /* * Allocate a session entry for each active port. * Note that sp starts at 0. */ while (typ = getttyent()) if (snext = new_session(sp, ++session_index, typ)) sp = snext; endttyent(); return (state_func_t) multi_user; } /* * Start a window system running. */ void start_window_system(sp) session_t *sp; { pid_t pid; sigset_t mask; if ((pid = fork()) == -1) { emergency("can't fork for window system on port %s: %m", sp->se_device); /* hope that getty fails and we can try again */ return; } if (pid) return; sigemptyset(&mask); sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); if (setsid() < 0) emergency("setsid failed (window) %m"); execv(sp->se_window_argv[0], sp->se_window_argv); stall("can't exec window system '%s' for port %s: %m", sp->se_window_argv[0], sp->se_device); _exit(1); } /* * Start a login session running. * For first open, man-handle tty directly to determine if it * really exists. It is not efficient to spawn gettys on devices * that do not exist. */ pid_t start_getty(sp) session_t *sp; { pid_t pid; sigset_t mask; time_t current_time = time((time_t *) 0); int p[2], new = 1; if (sp->se_flags & SE_DEVEXISTS) new = 0; if (new) { if (pipe(p) == -1) return -1; } /* * fork(), not vfork() -- we can't afford to block. */ if ((pid = fork()) == -1) { emergency("can't fork for getty on port %s: %m", sp->se_device); return -1; } if (pid) { if (new) { char c; close(p[1]); if (read(p[0], &c, 1) != 1) { close(p[0]); return -1; } close(p[0]); if (c == '1') sp->se_flags |= SE_DEVEXISTS; else sp->se_flags |= SE_SHUTDOWN; } return pid; } if (new) { int fd; close(p[0]); fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666); if (fd == -1 && (errno == ENXIO || errno == ENOENT || errno == EISDIR)) { (void)write(p[1], "0", 1); close(p[1]); _exit(1); } (void)write(p[1], "1", 1); close(p[1]); close(fd); sleep(1); } if (current_time > sp->se_started && current_time - sp->se_started < GETTY_SPACING) { warning("getty repeating too quickly on port %s, sleeping", sp->se_device); sleep((unsigned) GETTY_SLEEP); } if (sp->se_window) { start_window_system(sp); sleep(WINDOW_WAIT); } sigemptyset(&mask); sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0); execv(sp->se_getty_argv[0], sp->se_getty_argv); stall("can't exec getty '%s' for port %s: %m", sp->se_getty_argv[0], sp->se_device); _exit(1); } #endif /* LETS_GET_SMALL */ /* * Collect exit status for a child. * If an exiting login, start a new login running. */ void #ifdef __STDC__ collect_child(pid_t pid) #else collect_child(pid) pid_t pid; #endif { #ifndef LETS_GET_SMALL register session_t *sp, *sprev, *snext; if (! sessions) return; if (! (sp = find_session(pid))) return; clear_session_logs(sp); login_fbtab(sp->se_device, 0, 0); del_session(sp); sp->se_process = 0; if (sp->se_flags & SE_SHUTDOWN) { if (sprev = sp->se_prev) sprev->se_next = sp->se_next; else sessions = sp->se_next; if (snext = sp->se_next) snext->se_prev = sp->se_prev; free_session(sp); return; } if ((pid = start_getty(sp)) == -1) { /* serious trouble */ requested_transition = clean_ttys; return; } sp->se_process = pid; sp->se_started = time((time_t *) 0); add_session(sp); #endif /* LETS_GET_SMALL */ } /* * Catch a signal and request a state transition. */ void transition_handler(sig) int sig; { switch (sig) { #ifndef LETS_GET_SMALL case SIGHUP: requested_transition = clean_ttys; break; case SIGTERM: requested_transition = death; break; case SIGTSTP: requested_transition = catatonia; break; #endif /* LETS_GET_SMALL */ default: requested_transition = 0; break; } } #ifndef LETS_GET_SMALL /* * Take the system multiuser. */ state_func_t multi_user() { pid_t pid; register session_t *sp; requested_transition = 0; /* * If the administrator has not set the security level to -1 * to indicate that the kernel should not run multiuser in secure * mode, and the run script has not set a higher level of security * than level 1, then put the kernel into secure mode. */ if (getsecuritylevel() == 0) setsecuritylevel(1); for (sp = sessions; sp; sp = sp->se_next) { if (sp->se_process) continue; if ((pid = start_getty(sp)) == -1) { /* serious trouble */ requested_transition = clean_ttys; break; } sp->se_process = pid; sp->se_started = time((time_t *) 0); add_session(sp); } while (!requested_transition) if ((pid = waitpid(-1, (int *) 0, 0)) != -1) collect_child(pid); return (state_func_t) requested_transition; } /* * This is an n-squared algorithm. We hope it isn't run often... */ state_func_t clean_ttys() { register session_t *sp, *sprev; register struct ttyent *typ; register int session_index = 0; register int devlen; for (sp = sessions; sp; sp = sp->se_next) sp->se_flags &= ~SE_PRESENT; devlen = sizeof(_PATH_DEV) - 1; while (typ = getttyent()) { ++session_index; for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next) if (strcmp(typ->ty_name, sp->se_device + devlen) == 0) break; if (sp) { sp->se_flags |= SE_PRESENT; if (sp->se_index != session_index) { warning("port %s changed utmp index from %d to %d", sp->se_device, sp->se_index, session_index); sp->se_index = session_index; } if ((typ->ty_status & TTY_ON) == 0 || typ->ty_getty == 0) { sp->se_flags |= SE_SHUTDOWN; kill(sp->se_process, SIGHUP); continue; } sp->se_flags &= ~SE_SHUTDOWN; if (setupargv(sp, typ) == 0) { warning("can't parse getty for port %s", sp->se_device); sp->se_flags |= SE_SHUTDOWN; kill(sp->se_process, SIGHUP); } continue; } new_session(sprev, session_index, typ); } endttyent(); for (sp = sessions; sp; sp = sp->se_next) if ((sp->se_flags & SE_PRESENT) == 0) { sp->se_flags |= SE_SHUTDOWN; kill(sp->se_process, SIGHUP); } return (state_func_t) multi_user; } /* * Block further logins. */ state_func_t catatonia() { register session_t *sp; for (sp = sessions; sp; sp = sp->se_next) sp->se_flags |= SE_SHUTDOWN; return (state_func_t) multi_user; } #endif /* LETS_GET_SMALL */ /* * Note SIGALRM. */ void alrm_handler(sig) int sig; { clang = 1; } #ifndef LETS_GET_SMALL /* * Bring the system down to single user. */ state_func_t death() { register session_t *sp; register int i; pid_t pid; static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL }; for (sp = sessions; sp; sp = sp->se_next) sp->se_flags |= SE_SHUTDOWN; /* NB: should send a message to the session logger to avoid blocking. */ logwtmp("~", "shutdown", ""); for (i = 0; i < 3; ++i) { if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH) return (state_func_t) single_user; clang = 0; alarm(DEATH_WATCH); do if ((pid = waitpid(-1, (int *)0, 0)) != -1) collect_child(pid); while (clang == 0 && errno != ECHILD); if (errno == ECHILD) return (state_func_t) single_user; } warning("some processes would not die; ps axl advised"); return (state_func_t) single_user; } #endif /* LETS_GET_SMALL */