BSD 4_1c_2 release

[unix-history] / usr / src / etc / cron.c

static char *sccsid = "@(#)cron.c       4.6 (Berkeley) 6/28/82";
#include <sys/types.h>
#include <stdio.h>
#include <ctype.h>
#include <signal.h>
#include <time.h>
#include <sys/stat.h>

#define LISTS   (2*BUFSIZ)
#define MAXLIN  BUFSIZ

#define EXACT   100
#define ANY     101
#define LIST    102
#define RANGE   103
#define EOS     104
char    crontab[]       = "/usr/lib/crontab";
time_t  itime;
struct  tm *loct;
struct  tm *localtime();
char    *malloc();
char    *realloc();
int     flag;
char    *list;
unsigned listsize;

main()
{
       register char *cp;
       char *cmp();
       time_t filetime = 0;

    /* setuid(1); */
       if (fork())
               exit(0);
       chdir("/");
       freopen(crontab, "r", stdin);
       freopen("/", "r", stdout);
       freopen("/", "r", stderr);
       signal(SIGHUP, SIG_IGN);
       signal(SIGINT, SIG_IGN);
       signal(SIGQUIT, SIG_IGN);
       time(&itime);
       itime -= localtime(&itime)->tm_sec;
       fclose(stdin);

       for (;; itime+=60, slp()) {
               struct stat cstat;

               if (stat(crontab, &cstat) == -1)
                       continue;
               if (cstat.st_mtime > filetime) {
                       filetime = cstat.st_mtime;
                       init();
               }
               loct = localtime(&itime);
               loct->tm_mon++;          /* 1-12 for month */
               if (loct->tm_wday == 0)
                       loct->tm_wday == 7;     /* sunday is 7, not 0 */
               for(cp = list; *cp != EOS;) {
                       flag = 0;
                       cp = cmp(cp, loct->tm_min);
                       cp = cmp(cp, loct->tm_hour);
                       cp = cmp(cp, loct->tm_mday);
                       cp = cmp(cp, loct->tm_mon);
                       cp = cmp(cp, loct->tm_wday);
                       if(flag == 0)
                               ex(cp);
                       while(*cp++ != 0)
                               ;
               }
       }
}

char *
cmp(p, v)
char *p;
{
       register char *cp;

       cp = p;
       switch(*cp++) {

       case EXACT:
               if (*cp++ != v)
                       flag++;
               return(cp);

       case ANY:
               return(cp);

       case LIST:
               while(*cp != LIST)
                       if(*cp++ == v) {
                               while(*cp++ != LIST)
                                       ;
                               return(cp);
                       }
               flag++;
               return(cp+1);

       case RANGE:
               if(*cp > v || cp[1] < v)
                       flag++;
               return(cp+2);
       }
       if(cp[-1] != v)
               flag++;
       return(cp);
}

slp()
{
       register i;
       time_t t;

       time(&t);
       i = itime - t;
       if(i < -60 * 60 || i > 60 * 60) {
               itime = t;
               i = 60 - localtime(&itime)->tm_sec;
               itime += i;
       }
       if(i > 0)
               sleep(i);
}

ex(s)
char *s;
{
       int st;

       if(fork()) {
               wait(&st);
               return;
       }
       if(fork())
               exit(0);
       freopen("/", "r", stdin);
       execl("/bin/sh", "sh", "-c", s, 0);
       exit(0);
}

init()
{
       register i, c;
       register char *cp;
       register char *ocp;
       register int n;

       freopen(crontab, "r", stdin);
       if (list) {
               free(list);
               list = realloc(list, LISTS);
       } else
               list = malloc(LISTS);
       listsize = LISTS;
       cp = list;

loop:
       if(cp > list+listsize-MAXLIN) {
               char *olist;
               listsize += LISTS;
               olist = list;
               free(list);
               list = realloc(list, listsize);
               cp = list + (cp - olist);
       }
       ocp = cp;
       for(i=0;; i++) {
               do
                       c = getchar();
               while(c == ' ' || c == '\t')
                       ;
               if(c == EOF || c == '\n')
                       goto ignore;
               if(i == 5)
                       break;
               if(c == '*') {
                       *cp++ = ANY;
                       continue;
               }
               if ((n = number(c)) < 0)
                       goto ignore;
               c = getchar();
               if(c == ',')
                       goto mlist;
               if(c == '-')
                       goto mrange;
               if(c != '\t' && c != ' ')
                       goto ignore;
               *cp++ = EXACT;
               *cp++ = n;
               continue;

       mlist:
               *cp++ = LIST;
               *cp++ = n;
               do {
                       if ((n = number(getchar())) < 0)
                               goto ignore;
                       *cp++ = n;
                       c = getchar();
               } while (c==',');
               if(c != '\t' && c != ' ')
                       goto ignore;
               *cp++ = LIST;
               continue;

       mrange:
               *cp++ = RANGE;
               *cp++ = n;
               if ((n = number(getchar())) < 0)
                       goto ignore;
               c = getchar();
               if(c != '\t' && c != ' ')
                       goto ignore;
               *cp++ = n;
       }
       while(c != '\n') {
               if(c == EOF)
                       goto ignore;
               if(c == '%')
                       c = '\n';
               *cp++ = c;
               c = getchar();
       }
       *cp++ = '\n';
       *cp++ = 0;
       goto loop;

ignore:
       cp = ocp;
       while(c != '\n') {
               if(c == EOF) {
                       *cp++ = EOS;
                       *cp++ = EOS;
                       fclose(stdin);
                       return;
               }
               c = getchar();
       }
       goto loop;
}

number(c)
register c;
{
       register n = 0;

       while (isdigit(c)) {
               n = n*10 + c - '0';
               c = getchar();
       }
       ungetc(c, stdin);
       if (n>100)
               return(-1);
       return(n);
}