File: [cvs.NetBSD.org] / src / sbin / init / init.c (download)
Revision 1.13, Mon Apr 18 07:59:40 1994 UTC (30 years ago) by cgd
Branch: MAIN
Changes since 1.12: +25 -2
lines
if we want a LETS_GET_SMALL init, allow only single-user
|
/*-
* Copyright (c) 1991 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
char copyright[] =
"@(#) Copyright (c) 1991 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */
#ifndef lint
/*static char sccsid[] = "from: @(#)init.c 6.22 (Berkeley) 6/2/93";*/
static char rcsid[] = "$Id: init.c,v 1.13 1994/04/18 07:59:40 cgd Exp $";
#endif /* not lint */
#include <sys/param.h>
#ifndef NOSYSCTL
#include <sys/sysctl.h>
#endif
#include <sys/wait.h>
#include <db.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <ttyent.h>
#include <unistd.h>
#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#ifdef SECURE
#include <pwd.h>
#endif
#include "pathnames.h"
/*
* Until the mythical util.h arrives...
*/
extern int login_tty __P((int));
extern int logout __P((const char *));
extern void logwtmp __P((const char *, const char *, const char *));
/*
* 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 */
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",
sig < (unsigned) NSIG ? sys_siglist[sig] : "unknown signal");
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 = _PATH_BSHELL;
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
/*
* 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) {
write(2, banner, sizeof banner - 1);
for (;;) {
clear = getpass("Password:");
if (clear == 0 || *clear == '\0')
_exit(0);
password = crypt(clear, pp->pw_passwd);
bzero(clear, _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';
if (altshell[0] != '\0')
shell = altshell;
}
#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] = "-sh";
argv[1] = 0;
execv(shell, argv);
emergency("can't exec %s for single user: %m", shell);
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;
bcopy(data.data, (char *)&ret, 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));
bzero(sp, sizeof *sp);
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.
*/
pid_t
start_getty(sp)
session_t *sp;
{
pid_t pid;
sigset_t mask;
time_t current_time = time((time_t *) 0);
/*
* 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)
return pid;
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);
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;
if (! sessions)
return (state_func_t) multi_user;
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) {
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();
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 */
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