/* $OpenBSD: init.c,v 1.41 2009/10/27 23:59:33 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. 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef SECURE #include #endif #ifdef LOGIN_CAP #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 */ /* * User-based resource limits. */ #define RESOURCE_RC "daemon" #define RESOURCE_WINDOW "default" #define RESOURCE_GETTY "default" #ifndef DEFAULT_STATE #define DEFAULT_STATE runcom #endif void handle(sig_t, ...); void delset(sigset_t *, ...); void stall(char *, ...); void warning(char *, ...); void emergency(char *, ...); void disaster(int); void badsys(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)(void); typedef state_func_t (*state_t)(void); state_func_t single_user(void); state_func_t runcom(void); state_func_t read_ttys(void); state_func_t multi_user(void); state_func_t clean_ttys(void); state_func_t catatonia(void); state_func_t death(void); state_func_t hard_death(void); state_func_t nice_death(void); enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT; void transition(state_t); state_t requested_transition = DEFAULT_STATE; void setctty(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(session_t *); session_t *new_session(session_t *, int, struct ttyent *); session_t *sessions; char **construct_argv(char *); void start_window_system(session_t *); void collect_child(pid_t); pid_t start_getty(session_t *); void transition_handler(int); void alrm_handler(int); void setsecuritylevel(int); int getsecuritylevel(void); int setupargv(session_t *, struct ttyent *); int clang; #ifdef LOGIN_CAP void setprocresources(char *); #else #define setprocresources(p) #endif void clear_session_logs(session_t *); int start_session_db(void); void add_session(session_t *); void del_session(session_t *); session_t *find_session(pid_t); DB *session_db; /* * The mother of all processes. */ int main(int argc, char *argv[]) { int c; struct sigaction sa; sigset_t mask; /* 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); /* * 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"); /* * 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"); /* * 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, SIGUSR1, SIGUSR2, 0); handle(alrm_handler, SIGALRM, 0); sigfillset(&mask); delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS, SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGUSR1, SIGUSR2, SIGTSTP, SIGALRM, 0); sigprocmask(SIG_SETMASK, &mask, NULL); memset(&sa, 0, sizeof sa); sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = SIG_IGN; (void) sigaction(SIGTTIN, &sa, NULL); (void) sigaction(SIGTTOU, &sa, NULL); /* * Paranoia. */ close(STDIN_FILENO); close(STDOUT_FILENO); close(STDERR_FILENO); /* * Start the state machine. */ transition(requested_transition); /* * Should never reach here. */ exit(1); } /* * Associate a function with a signal handler. */ void handle(sig_t handler, ...) { int sig; struct sigaction sa; sigset_t mask_everything; va_list ap; va_start(ap, handler); memset(&sa, 0, sizeof sa); 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, NULL); } va_end(ap); } /* * Delete a set of signals from a mask. */ void delset(sigset_t *maskp, ...) { int sig; va_list ap; va_start(ap, maskp); 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 stall(char *message, ...) { va_list ap; va_start(ap, message); vsyslog(LOG_ALERT, message, ap); va_end(ap); closelog(); 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 warning(char *message, ...) { va_list ap; va_start(ap, message); vsyslog(LOG_ALERT, message, ap); va_end(ap); closelog(); } /* * Log an emergency message. * NB: should send a message to the session logger to avoid blocking. */ void emergency(char *message, ...) { struct syslog_data sdata = SYSLOG_DATA_INIT; va_list ap; va_start(ap, message); vsyslog_r(LOG_EMERG, &sdata, 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(int sig) { static int badcount = 0; if (badcount++ < 25) return; disaster(sig); } /* * Catch an unexpected signal. */ void disaster(int sig) { emergency("fatal signal: %s", strsignal(sig)); sleep(STALL_TIMEOUT); _exit(sig); /* reboot */ } /* * Get the security level of the kernel. */ int getsecuritylevel(void) { #ifdef KERN_SECURELVL int name[2], curlevel; size_t len; 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(int newlevel) { #ifdef KERN_SECURELVL int name[2], curlevel; 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(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(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(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(void) { 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 */ strlcpy(shell, _PATH_BSHELL, sizeof shell); strlcpy(name, "-sh", sizeof name); /* * 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(STDERR_FILENO, 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 */ strlcpy(shell, altshell, sizeof shell); /* argv[0] */ p = strrchr(altshell, '/'); if(p == NULL) p = altshell; else p++; name[0] = '-'; strlcpy(&name[1], p, sizeof name -1); } } #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, NULL); /* * 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, NULL, 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; return (state_func_t) runcom; } /* * Run the system startup script. */ state_func_t runcom(void) { pid_t pid, wpid; int status; char *argv[4]; struct sigaction sa; if ((pid = fork()) == 0) { memset(&sa, 0, sizeof sa); sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = SIG_IGN; (void) sigaction(SIGTSTP, &sa, NULL); (void) sigaction(SIGHUP, &sa, NULL); 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, NULL); setprocresources(RESOURCE_RC); 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, NULL, 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(void) { 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(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(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 * find_session(pid_t pid) { 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(char *command) { int argc = 0; char **argv = (char **) calloc((strlen(command) + 1) / 2 + 1, sizeof (char *)); static const char separators[] = " \t"; if (argv == NULL) return (0); if ((argv[argc++] = strtok(command, separators)) == 0) { free(argv); return (0); } while ((argv[argc++] = strtok(NULL, separators))) continue; return (argv); } /* * Deallocate a session descriptor. */ void free_session(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(session_t *sprev, int session_index, struct ttyent *typ) { 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; if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1) err(1, "asprintf"); 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(session_t *sp, struct ttyent *typ) { if (sp->se_getty) { free(sp->se_getty); free(sp->se_getty_argv); } if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1) err(1, "asprintf"); 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); if (sp->se_window == NULL) { warning("can't allocate window"); return (0); } sp->se_window_argv = construct_argv(sp->se_window); if (sp->se_window_argv == NULL) { warning("can't parse window for port %s", sp->se_device); free(sp->se_window); sp->se_window = NULL; return (0); } } return (1); } /* * Walk the list of ttys and create sessions for each active line. */ state_func_t read_ttys(void) { int session_index = 0; session_t *sp, *snext; 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(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, NULL); if (setsid() < 0) emergency("setsid failed (window) %m"); setprocresources(RESOURCE_WINDOW); 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(session_t *sp) { pid_t pid; sigset_t mask; time_t current_time = time(NULL); 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, NULL); setprocresources(RESOURCE_GETTY); 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); } /* * Collect exit status for a child. * If an exiting login, start a new login running. */ void collect_child(pid_t pid) { session_t *sp, *sprev, *snext; if (sessions == NULL) return; if ((sp = find_session(pid)) == NULL) return; clear_session_logs(sp); login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 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(NULL); add_session(sp); } /* * Catch a signal and request a state transition. */ void transition_handler(int sig) { switch (sig) { case SIGHUP: requested_transition = clean_ttys; break; case SIGTERM: requested_transition = death; break; case SIGUSR1: requested_transition = nice_death; break; case SIGUSR2: requested_transition = hard_death; break; case SIGTSTP: requested_transition = catatonia; break; default: requested_transition = 0; break; } } /* * Take the system multiuser. */ state_func_t multi_user(void) { pid_t pid; 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(NULL); add_session(sp); } while (!requested_transition) if ((pid = waitpid(-1, NULL, 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(void) { session_t *sp, *sprev; struct ttyent *typ; int session_index = 0; 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(void) { session_t *sp; for (sp = sessions; sp; sp = sp->se_next) sp->se_flags |= SE_SHUTDOWN; return (state_func_t) multi_user; } /* * Note SIGALRM. */ void alrm_handler(int sig) { clang = 1; } int death_howto = RB_HALT; /* * Bring the system down nicely, then we must powerdown because something * is very wrong. */ state_func_t hard_death(void) { death_howto |= RB_POWERDOWN; return nice_death(); } /* * Bring the system down to single user nicely, after run the shutdown script. */ state_func_t nice_death(void) { session_t *sp; int i; pid_t pid; static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL }; int status; for (sp = sessions; sp; sp = sp->se_next) { sp->se_flags &= ~SE_PRESENT; sp->se_flags |= SE_SHUTDOWN; kill(sp->se_process, SIGHUP); } /* terminate the accounting process */ acct(NULL); /* NB: should send a message to the session logger to avoid blocking. */ logwtmp("~", "shutdown", ""); if (access(_PATH_RUNCOM, R_OK) != -1) { pid_t pid; struct sigaction sa; switch ((pid = fork())) { case -1: break; case 0: memset(&sa, 0, sizeof sa); sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = SIG_IGN; (void) sigaction(SIGTSTP, &sa, NULL); (void) sigaction(SIGHUP, &sa, NULL); setctty(_PATH_CONSOLE); sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL); execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown", (char *)NULL); stall("can't exec %s for %s %s: %m", _PATH_BSHELL, _PATH_RUNCOM, "shutdown"); _exit(1); default: waitpid(pid, &status, 0); if (WIFEXITED(status) && WEXITSTATUS(status) == 2) death_howto |= RB_POWERDOWN; } } for (i = 0; i < 3; ++i) { if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH) goto die; clang = 0; alarm(DEATH_WATCH); do { if ((pid = waitpid(-1, NULL, 0)) != -1) collect_child(pid); } while (clang == 0 && errno != ECHILD); if (errno == ECHILD) goto die; } warning("some processes would not die; ps axl advised"); die: reboot(death_howto); /* ... and if that fails.. oh well */ return (state_func_t) single_user; } /* * Bring the system down to single user. */ state_func_t death(void) { session_t *sp; int i; pid_t pid; static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL }; /* terminate the accounting process */ acct(NULL); 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, NULL, 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; } #ifdef LOGIN_CAP void setprocresources(char *class) { login_cap_t *lc; if ((lc = login_getclass(class)) != NULL) { setusercontext(lc, NULL, 0, LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK); login_close(lc); } } #endif