2005-04-21 16:53:53 +02:00
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/* This process is the father (mother) of all Minix user processes. When
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* Minix comes up, this is process number 2, and has a pid of 1. It
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* executes the /etc/rc shell file, and then reads the /etc/ttytab file to
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* determine which terminals need a login process.
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*
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* If the files /usr/adm/wtmp and /etc/utmp exist and are writable, init
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* (with help from login) will maintain login accounting. Sending a
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* signal 1 (SIGHUP) to init will cause it to rescan /etc/ttytab and start
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* up new shell processes if necessary. It will not, however, kill off
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* login processes for lines that have been turned off; do this manually.
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* Signal 15 (SIGTERM) makes init stop spawning new processes, this is
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* used by shutdown and friends when they are about to close the system
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* down.
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*/
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2005-06-03 15:55:06 +02:00
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#include <minix/type.h>
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2005-04-21 16:53:53 +02:00
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <sys/svrctl.h>
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#include <ttyent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <signal.h>
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#include <string.h>
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#include <time.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <utmp.h>
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/* Command to execute as a response to the three finger salute. */
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char *REBOOT_CMD[] = { "shutdown", "now", "CTRL-ALT-DEL", NULL };
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/* Associated fake ttytab entry. */
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struct ttyent TT_REBOOT = { "console", "-", REBOOT_CMD, NULL };
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char PATH_UTMP[] = "/etc/utmp"; /* current logins */
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char PATH_WTMP[] = "/usr/adm/wtmp"; /* login/logout history */
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#define PIDSLOTS 32 /* first this many ttys can be on */
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struct slotent {
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int errct; /* error count */
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pid_t pid; /* pid of login process for this tty line */
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};
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#define ERRCT_DISABLE 10 /* disable after this many errors */
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#define NO_PID 0 /* pid value indicating no process */
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struct slotent slots[PIDSLOTS]; /* init table of ttys and pids */
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int gothup = 0; /* flag, showing signal 1 was received */
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int gotabrt = 0; /* flag, showing signal 6 was received */
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int spawn = 1; /* flag, spawn processes only when set */
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void tell(int fd, char *s);
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void report(int fd, char *label);
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void wtmp(int type, int linenr, char *line, pid_t pid);
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void startup(int linenr, struct ttyent *ttyp);
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int execute(char **cmd);
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void onhup(int sig);
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void onterm(int sig);
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void onabrt(int sig);
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int main(void)
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{
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pid_t pid; /* pid of child process */
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int fd; /* generally useful */
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int linenr; /* loop variable */
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int check; /* check if a new process must be spawned */
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2009-12-11 01:08:19 +01:00
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int sn; /* signal number */
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2005-04-21 16:53:53 +02:00
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struct slotent *slotp; /* slots[] pointer */
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struct ttyent *ttyp; /* ttytab entry */
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struct sigaction sa;
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struct stat stb;
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2008-12-11 15:43:25 +01:00
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#define OPENFDS \
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if (fstat(0, &stb) < 0) { \
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/* Open standard input, output & error. */ \
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(void) open("/dev/null", O_RDONLY); \
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(void) open("/dev/log", O_WRONLY); \
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dup(1); \
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2005-04-21 16:53:53 +02:00
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}
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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2009-12-11 01:08:19 +01:00
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/* Default: Ignore every signal (except those that follow). */
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sa.sa_handler = SIG_IGN;
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for (sn = 1; sn < _NSIG; sn++) {
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sigaction(sn, &sa, NULL);
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}
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2005-04-21 16:53:53 +02:00
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/* Hangup: Reexamine /etc/ttytab for newly enabled terminal lines. */
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sa.sa_handler = onhup;
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sigaction(SIGHUP, &sa, NULL);
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/* Terminate: Stop spawning login processes, shutdown is near. */
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sa.sa_handler = onterm;
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sigaction(SIGTERM, &sa, NULL);
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/* Abort: Sent by the kernel on CTRL-ALT-DEL; shut the system down. */
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sa.sa_handler = onabrt;
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sigaction(SIGABRT, &sa, NULL);
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/* Execute the /etc/rc file. */
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if ((pid = fork()) != 0) {
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/* Parent just waits. */
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while (wait(NULL) != pid) {
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if (gotabrt) reboot(RBT_HALT);
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}
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} else {
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#if ! SYS_GETKENV
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struct sysgetenv sysgetenv;
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#endif
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char bootopts[16];
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static char *rc_command[] = { "sh", "/etc/rc", NULL, NULL, NULL };
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char **rcp = rc_command + 2;
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/* Get the boot options from the boot environment. */
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sysgetenv.key = "bootopts";
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sysgetenv.keylen = 8+1;
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sysgetenv.val = bootopts;
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sysgetenv.vallen = sizeof(bootopts);
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if (svrctl(MMGETPARAM, &sysgetenv) == 0) *rcp++ = bootopts;
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*rcp = "start";
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execute(rc_command);
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report(2, "sh /etc/rc");
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_exit(1); /* impossible, we hope */
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}
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2008-12-11 15:43:25 +01:00
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OPENFDS;
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2005-04-21 16:53:53 +02:00
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/* Clear /etc/utmp if it exists. */
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if ((fd = open(PATH_UTMP, O_WRONLY | O_TRUNC)) >= 0) close(fd);
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/* Log system reboot. */
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wtmp(BOOT_TIME, 0, NULL, 0);
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/* Main loop. If login processes have already been started up, wait for one
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* to terminate, or for a HUP signal to arrive. Start up new login processes
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* for all ttys which don't have them. Note that wait() also returns when
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* somebody's orphan dies, in which case ignore it. If the TERM signal is
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* sent then stop spawning processes, shutdown time is near.
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*/
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check = 1;
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while (1) {
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while ((pid = waitpid(-1, NULL, check ? WNOHANG : 0)) > 0) {
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/* Search to see which line terminated. */
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for (linenr = 0; linenr < PIDSLOTS; linenr++) {
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slotp = &slots[linenr];
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if (slotp->pid == pid) {
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/* Record process exiting. */
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wtmp(DEAD_PROCESS, linenr, NULL, pid);
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slotp->pid = NO_PID;
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check = 1;
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}
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}
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}
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/* If a signal 1 (SIGHUP) is received, simply reset error counts. */
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if (gothup) {
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gothup = 0;
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for (linenr = 0; linenr < PIDSLOTS; linenr++) {
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slots[linenr].errct = 0;
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}
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check = 1;
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}
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/* Shut down on signal 6 (SIGABRT). */
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if (gotabrt) {
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gotabrt = 0;
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startup(0, &TT_REBOOT);
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}
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if (spawn && check) {
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/* See which lines need a login process started up. */
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for (linenr = 0; linenr < PIDSLOTS; linenr++) {
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slotp = &slots[linenr];
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if ((ttyp = getttyent()) == NULL) break;
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if (ttyp->ty_getty != NULL
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&& ttyp->ty_getty[0] != NULL
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&& slotp->pid == NO_PID
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&& slotp->errct < ERRCT_DISABLE)
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{
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startup(linenr, ttyp);
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}
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}
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endttyent();
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}
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check = 0;
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}
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}
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void onhup(int sig)
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{
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gothup = 1;
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spawn = 1;
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}
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void onterm(int sig)
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{
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spawn = 0;
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}
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void onabrt(int sig)
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{
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static int count;
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if (++count == 2) reboot(RBT_HALT);
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gotabrt = 1;
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}
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void startup(int linenr, struct ttyent *ttyp)
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{
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/* Fork off a process for the indicated line. */
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struct slotent *slotp; /* pointer to ttyslot */
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pid_t pid; /* new pid */
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int err[2]; /* error reporting pipe */
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char line[32]; /* tty device name */
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int status;
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slotp = &slots[linenr];
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/* Error channel for between fork and exec. */
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if (pipe(err) < 0) err[0] = err[1] = -1;
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if ((pid = fork()) == -1 ) {
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report(2, "fork()");
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sleep(10);
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return;
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}
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if (pid == 0) {
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/* Child */
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close(err[0]);
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fcntl(err[1], F_SETFD, fcntl(err[1], F_GETFD) | FD_CLOEXEC);
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/* A new session. */
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setsid();
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/* Construct device name. */
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strcpy(line, "/dev/");
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strncat(line, ttyp->ty_name, sizeof(line) - 6);
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/* Open the line for standard input and output. */
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close(0);
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close(1);
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if (open(line, O_RDWR) < 0 || dup(0) < 0) {
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write(err[1], &errno, sizeof(errno));
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_exit(1);
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}
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if (ttyp->ty_init != NULL && ttyp->ty_init[0] != NULL) {
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/* Execute a command to initialize the terminal line. */
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if ((pid = fork()) == -1) {
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report(2, "fork()");
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errno= 0;
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write(err[1], &errno, sizeof(errno));
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_exit(1);
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}
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if (pid == 0) {
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alarm(10);
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execute(ttyp->ty_init);
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report(2, ttyp->ty_init[0]);
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_exit(1);
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}
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while (waitpid(pid, &status, 0) != pid) {}
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if (status != 0) {
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tell(2, "init: ");
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tell(2, ttyp->ty_name);
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tell(2, ": ");
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tell(2, ttyp->ty_init[0]);
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tell(2, ": bad exit status\n");
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errno = 0;
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write(err[1], &errno, sizeof(errno));
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_exit(1);
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}
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}
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/* Redirect standard error too. */
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dup2(0, 2);
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/* Execute the getty process. */
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execute(ttyp->ty_getty);
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/* Oops, disaster strikes. */
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fcntl(2, F_SETFL, fcntl(2, F_GETFL) | O_NONBLOCK);
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if (linenr != 0) report(2, ttyp->ty_getty[0]);
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write(err[1], &errno, sizeof(errno));
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_exit(1);
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}
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/* Parent */
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if (ttyp != &TT_REBOOT) slotp->pid = pid;
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close(err[1]);
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if (read(err[0], &errno, sizeof(errno)) != 0) {
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/* If an errno value goes down the error pipe: Problems. */
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switch (errno) {
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case ENOENT:
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case ENODEV:
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case ENXIO:
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/* Device nonexistent, no driver, or no minor device. */
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slotp->errct = ERRCT_DISABLE;
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close(err[0]);
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return;
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case 0:
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/* Error already reported. */
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break;
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default:
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/* Any other error on the line. */
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report(2, ttyp->ty_name);
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}
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close(err[0]);
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if (++slotp->errct >= ERRCT_DISABLE) {
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tell(2, "init: ");
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tell(2, ttyp->ty_name);
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tell(2, ": excessive errors, shutting down\n");
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} else {
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sleep(5);
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}
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return;
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}
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close(err[0]);
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if (ttyp != &TT_REBOOT) wtmp(LOGIN_PROCESS, linenr, ttyp->ty_name, pid);
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slotp->errct = 0;
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}
|
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|
int execute(char **cmd)
|
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|
|
{
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|
|
/* Execute a command with a path search along /sbin:/bin:/usr/sbin:/usr/bin.
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*/
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|
static char *nullenv[] = { NULL };
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|
|
char command[128];
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|
char *path[] = { "/sbin", "/bin", "/usr/sbin", "/usr/bin" };
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|
|
int i;
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if (cmd[0][0] == '/') {
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|
|
/* A full path. */
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return execve(cmd[0], cmd, nullenv);
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|
}
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|
|
/* Path search. */
|
|
|
|
for (i = 0; i < 4; i++) {
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|
|
if (strlen(path[i]) + 1 + strlen(cmd[0]) + 1 > sizeof(command)) {
|
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|
|
errno= ENAMETOOLONG;
|
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|
|
return -1;
|
|
|
|
}
|
|
|
|
strcpy(command, path[i]);
|
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|
|
strcat(command, "/");
|
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|
|
strcat(command, cmd[0]);
|
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|
|
execve(command, cmd, nullenv);
|
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|
|
if (errno != ENOENT) break;
|
|
|
|
}
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
void wtmp(type, linenr, line, pid)
|
|
|
|
int type; /* type of entry */
|
|
|
|
int linenr; /* line number in ttytab */
|
|
|
|
char *line; /* tty name (only good on login) */
|
|
|
|
pid_t pid; /* pid of process */
|
|
|
|
{
|
|
|
|
/* Log an event into the UTMP and WTMP files. */
|
|
|
|
|
|
|
|
struct utmp utmp; /* UTMP/WTMP User Accounting */
|
|
|
|
int fd;
|
|
|
|
|
|
|
|
/* Clear the utmp record. */
|
|
|
|
memset((void *) &utmp, 0, sizeof(utmp));
|
|
|
|
|
|
|
|
/* Fill in utmp. */
|
|
|
|
switch (type) {
|
|
|
|
case BOOT_TIME:
|
|
|
|
/* Make a special reboot record. */
|
|
|
|
strcpy(utmp.ut_name, "reboot");
|
|
|
|
strcpy(utmp.ut_line, "~");
|
|
|
|
break;
|
|
|
|
|
|
|
|
case LOGIN_PROCESS:
|
|
|
|
/* A new login, fill in line name. */
|
|
|
|
strncpy(utmp.ut_line, line, sizeof(utmp.ut_line));
|
|
|
|
break;
|
|
|
|
|
|
|
|
case DEAD_PROCESS:
|
|
|
|
/* A logout. Use the current utmp entry, but make sure it is a
|
|
|
|
* user process exiting, and not getty or login giving up.
|
|
|
|
*/
|
|
|
|
if ((fd = open(PATH_UTMP, O_RDONLY)) < 0) {
|
|
|
|
if (errno != ENOENT) report(2, PATH_UTMP);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (lseek(fd, (off_t) (linenr+1) * sizeof(utmp), SEEK_SET) == -1
|
|
|
|
|| read(fd, &utmp, sizeof(utmp)) == -1
|
|
|
|
) {
|
|
|
|
report(2, PATH_UTMP);
|
|
|
|
close(fd);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
close(fd);
|
|
|
|
if (utmp.ut_type != USER_PROCESS) return;
|
|
|
|
strncpy(utmp.ut_name, "", sizeof(utmp.ut_name));
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Finish new utmp entry. */
|
|
|
|
utmp.ut_pid = pid;
|
|
|
|
utmp.ut_type = type;
|
|
|
|
utmp.ut_time = time((time_t *) 0);
|
|
|
|
|
|
|
|
switch (type) {
|
|
|
|
case LOGIN_PROCESS:
|
|
|
|
case DEAD_PROCESS:
|
|
|
|
/* Write new entry to utmp. */
|
|
|
|
if ((fd = open(PATH_UTMP, O_WRONLY)) < 0
|
|
|
|
|| lseek(fd, (off_t) (linenr+1) * sizeof(utmp), SEEK_SET) == -1
|
|
|
|
|| write(fd, &utmp, sizeof(utmp)) == -1
|
|
|
|
) {
|
|
|
|
if (errno != ENOENT) report(2, PATH_UTMP);
|
|
|
|
}
|
|
|
|
if (fd != -1) close(fd);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
switch (type) {
|
|
|
|
case BOOT_TIME:
|
|
|
|
case DEAD_PROCESS:
|
|
|
|
/* Add new wtmp entry. */
|
|
|
|
if ((fd = open(PATH_WTMP, O_WRONLY | O_APPEND)) < 0
|
|
|
|
|| write(fd, &utmp, sizeof(utmp)) == -1
|
|
|
|
) {
|
|
|
|
if (errno != ENOENT) report(2, PATH_WTMP);
|
|
|
|
}
|
|
|
|
if (fd != -1) close(fd);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void tell(fd, s)
|
|
|
|
int fd;
|
|
|
|
char *s;
|
|
|
|
{
|
|
|
|
write(fd, s, strlen(s));
|
|
|
|
}
|
|
|
|
|
|
|
|
void report(fd, label)
|
|
|
|
int fd;
|
|
|
|
char *label;
|
|
|
|
{
|
|
|
|
int err = errno;
|
|
|
|
|
|
|
|
tell(fd, "init: ");
|
|
|
|
tell(fd, label);
|
|
|
|
tell(fd, ": ");
|
|
|
|
tell(fd, strerror(err));
|
|
|
|
tell(fd, "\n");
|
|
|
|
errno= err;
|
|
|
|
}
|