Bell 32V development

[unix-history] / usr / src / cmd / init.c

#include <signal.h>
#include <sys/types.h>
#include <utmp.h>
#include <setjmp.h>

#define TABSIZ  100
#define ALL     p = &itab[0]; p < &itab[TABSIZ]; p++
#define EVER    ;;

char    shell[] = "/bin/sh";
char    getty[]  = "/etc/getty";
char    minus[] = "-";
char    runc[]  = "/etc/rc";
char    ifile[] = "/etc/ttys";
char    utmp[]  = "/etc/utmp";
char    wtmpf[] = "/usr/adm/wtmp";
char    ctty[]  = "/dev/console";
char    dev[]   = "/dev/";

struct utmp wtmp;
struct
{
       char    line[8];
       char    comn;
       char    flag;
} line;
struct  tab
{
       char    line[8];
       char    comn;
       int     pid;
} itab[TABSIZ];

int     fi;
char    tty[20];
jmp_buf sjbuf;

main()
{
       int reset();

       setjmp(sjbuf);
       signal(SIGHUP, reset);
       for(EVER) {
               shutdown();
               single();
               runcom();
               merge();
               multiple();
       }
}

shutdown()
{
       register i;
       register struct tab *p;

       signal(SIGINT, SIG_IGN);
       for(ALL)
               term(p);
       signal(SIGALRM, reset);
       alarm(60);
       for(i=0; i<5; i++)
               kill(-1, SIGKILL);
       while(wait((int *)0) != -1)
               ;
       alarm(0);
       signal(SIGALRM, SIG_DFL);
       for(i=0; i<10; i++)
               close(i);
}

single()
{
       register pid;

       pid = fork();
       if(pid == 0) {
/*
               alarm(300);
*/
               signal(SIGHUP, SIG_DFL);
               signal(SIGINT, SIG_DFL);
               signal(SIGALRM, SIG_DFL);
               open(ctty, 2);
               dup(0);
               dup(0);
               execl(shell, minus, (char *)0);
               exit(0);
       }
       while(wait((int *)0) != pid)
               ;
}

runcom()
{
       register pid;

       pid = fork();
       if(pid == 0) {
               open("/", 0);
               dup(0);
               dup(0);
               execl(shell, shell, runc, (char *)0);
               exit(0);
       }
       while(wait((int *)0) != pid)
               ;
}

multiple()
{
       register struct tab *p;
       register pid;

       for(EVER) {
               pid = wait((int *)0);
               if(pid == -1)
                       return;
               for(ALL)
                       if(p->pid == pid || p->pid == -1) {
                               rmut(p);
                               dfork(p);
                       }
       }
}

term(p)
register struct tab *p;
{

       if(p->pid != 0) {
               rmut(p);
               kill(p->pid, SIGKILL);
       }
       p->pid = 0;
       p->line[0] = 0;
}

rline()
{
       register c, i;

       c = get();
       if(c < 0)
               return(0);
       if(c == 0)
               goto bad;
       line.flag = c;
       c = get();
       if(c <= 0)
               goto bad;
       line.comn = c;
       for(i=0; i<8; i++)
               line.line[i] = 0;
       for(i=0; i<7; i++) {
               c = get();
               if(c <= 0)
                       break;
               line.line[i] = c;
       }
       while(c > 0)
               c = get();
       maktty(line.line);
       if(access(tty, 06) < 0)
               goto bad;
       return(1);

bad:
       line.flag = '0';
       return(1);
}

maktty(lin)
char *lin;
{
       register i, j;

       for(i=0; dev[i]; i++)
               tty[i] = dev[i];
       for(j=0; lin[j]; j++) {
               tty[i] = lin[j];
               i++;
       }
       tty[i] = 0;
}

get()
{
       char b;

       if(read(fi, &b, 1) != 1)
               return(-1);
       if(b == '\n')
               return(0);
       return(b);
}

merge()
{
       register struct tab *p, *q;
       register i;

       close(creat(utmp, 0644));
       signal(SIGINT, merge);
       fi = open(ifile, 0);
       if(fi < 0)
               return;
       q = &itab[0];
       while(rline()) {
               if(line.flag == '0')
                       continue;
               for(ALL) {
                       if(p->line[0] != 0)
                       for(i=0; i<8; i++)
                               if(p->line[i] != line.line[i])
                                       goto contin;
                       if(p >= q) {
                               i = p->pid;
                               p->pid = q->pid;
                               q->pid = i;
                               for(i=0; i<8; i++)
                                       p->line[i] = q->line[i];
                               p->comn = q->comn;
                               for(i=0; i<8; i++)
                                       q->line[i] = line.line[i];
                               q->comn = line.comn;
                               q++;
                       }
                       break;
               contin:
                       ;
               }
       }
       close(fi);
       for(; q < &itab[TABSIZ]; q++)
               term(q);
       for(ALL)
               if(p->line[0] != 0 && p->pid == 0)
                       dfork(p);
}

dfork(p)
struct tab *p;
{
       register pid;

       pid = fork();
       if(pid == 0) {
               signal(SIGHUP, SIG_DFL);
               signal(SIGINT, SIG_DFL);
               maktty(p->line);
               chown(tty, 0, 0);
               chmod(tty, 0622);
               open(tty, 2);
               dup(0);
               dup(0);
               tty[0] = p->comn;
               tty[1] = 0;
               execl(getty, minus, tty, (char *)0);
               exit(0);
       }
       p->pid = pid;
}

rmut(p)
register struct tab *p;
{
       register i, f;

       f = open(utmp, 2);
       if(f >= 0) {
               while(read(f, (char *)&wtmp, sizeof(wtmp)) == sizeof(wtmp)) {
                       for(i=0; i<8; i++)
                               if(wtmp.ut_line[i] != p->line[i])
                                       goto contin;
                       lseek(f, (long)-sizeof(wtmp), 1);
                       for(i=0; i<8; i++)
                               wtmp.ut_name[i] = 0;
                       time(&wtmp.ut_time);
                       write(f, (char *)&wtmp, sizeof(wtmp));
               contin:;
               }
               close(f);
       }
       f = open(wtmpf, 1);
       if (f >= 0) {
               for(i=0; i<8; i++) {
                       wtmp.ut_name[i] = 0;
                       wtmp.ut_line[i] = p->line[i];
               }
               time(&wtmp.ut_time);
               lseek(f, (long)0, 2);
               write(f, (char *)&wtmp, sizeof(wtmp));
               close(f);
       }
}

reset()
{
       longjmp(sjbuf, 1);
}