1 static char *sccsid = "@(#)cron.c 4.3 (Berkeley) 07/05/81"; 2 #include <sys/types.h> 3 #include <stdio.h> 4 #include <ctype.h> 5 #include <signal.h> 6 #include <time.h> 7 #include <sys/stat.h> 8 9 #define LISTS 512 10 11 #define EXACT 100 12 #define ANY 101 13 #define LIST 102 14 #define RANGE 103 15 #define EOS 104 16 char crontab[] = "/usr/lib/crontab"; 17 time_t itime; 18 struct tm *loct; 19 struct tm *localtime(); 20 char *malloc(); 21 char *realloc(); 22 int flag; 23 char *list; 24 unsigned listsize; 25 26 main() 27 { 28 register char *cp; 29 char *cmp(); 30 time_t filetime = 0; 31 32 /* setuid(1); */ 33 if (fork()) 34 exit(0); 35 chdir("/"); 36 freopen(crontab, "r", stdin); 37 freopen("/", "r", stdout); 38 freopen("/", "r", stderr); 39 signal(SIGHUP, SIG_IGN); 40 signal(SIGINT, SIG_IGN); 41 signal(SIGQUIT, SIG_IGN); 42 time(&itime); 43 itime -= localtime(&itime)->tm_sec; 44 fclose(stdin); 45 46 for (;; itime+=60, slp()) { 47 struct stat cstat; 48 49 if (stat(crontab, &cstat) == -1) 50 continue; 51 if (cstat.st_mtime > filetime) { 52 filetime = cstat.st_mtime; 53 init(); 54 } 55 loct = localtime(&itime); 56 loct->tm_mon++; /* 1-12 for month */ 57 for(cp = list; *cp != EOS;) { 58 flag = 0; 59 cp = cmp(cp, loct->tm_min); 60 cp = cmp(cp, loct->tm_hour); 61 cp = cmp(cp, loct->tm_mday); 62 cp = cmp(cp, loct->tm_mon); 63 cp = cmp(cp, loct->tm_wday); 64 if(flag == 0) 65 ex(cp); 66 while(*cp++ != 0) 67 ; 68 } 69 } 70 } 71 72 char * 73 cmp(p, v) 74 char *p; 75 { 76 register char *cp; 77 78 cp = p; 79 switch(*cp++) { 80 81 case EXACT: 82 if (*cp++ != v) 83 flag++; 84 return(cp); 85 86 case ANY: 87 return(cp); 88 89 case LIST: 90 while(*cp != LIST) 91 if(*cp++ == v) { 92 while(*cp++ != LIST) 93 ; 94 return(cp); 95 } 96 flag++; 97 return(cp+1); 98 99 case RANGE: 100 if(*cp > v || cp[1] < v) 101 flag++; 102 return(cp+2); 103 } 104 if(cp[-1] != v) 105 flag++; 106 return(cp); 107 } 108 109 slp() 110 { 111 register i; 112 time_t t; 113 114 time(&t); 115 i = itime - t; 116 if(i < -60 * 60 || i > 60 * 60) { 117 itime = t; 118 i = 60 - localtime(&itime)->tm_sec; 119 itime += i; 120 } 121 if(i > 0) 122 sleep(i); 123 } 124 125 ex(s) 126 char *s; 127 { 128 int st; 129 130 if(fork()) { 131 wait(&st); 132 return; 133 } 134 if(fork()) 135 exit(0); 136 freopen("/", "r", stdin); 137 execl("/bin/sh", "sh", "-c", s, 0); 138 exit(0); 139 } 140 141 init() 142 { 143 register i, c; 144 register char *cp; 145 register char *ocp; 146 register int n; 147 148 freopen(crontab, "r", stdin); 149 if (list) { 150 free(list); 151 list = realloc(list, LISTS); 152 } else 153 list = malloc(LISTS); 154 listsize = LISTS; 155 cp = list; 156 157 loop: 158 if(cp > list+listsize-100) { 159 char *olist; 160 listsize += LISTS; 161 olist = list; 162 free(list); 163 list = realloc(list, listsize); 164 cp = list + (cp - olist); 165 } 166 ocp = cp; 167 for(i=0;; i++) { 168 do 169 c = getchar(); 170 while(c == ' ' || c == '\t') 171 ; 172 if(c == EOF || c == '\n') 173 goto ignore; 174 if(i == 5) 175 break; 176 if(c == '*') { 177 *cp++ = ANY; 178 continue; 179 } 180 if ((n = number(c)) < 0) 181 goto ignore; 182 c = getchar(); 183 if(c == ',') 184 goto mlist; 185 if(c == '-') 186 goto mrange; 187 if(c != '\t' && c != ' ') 188 goto ignore; 189 *cp++ = EXACT; 190 *cp++ = n; 191 continue; 192 193 mlist: 194 *cp++ = LIST; 195 *cp++ = n; 196 do { 197 if ((n = number(getchar())) < 0) 198 goto ignore; 199 *cp++ = n; 200 c = getchar(); 201 } while (c==','); 202 if(c != '\t' && c != ' ') 203 goto ignore; 204 *cp++ = LIST; 205 continue; 206 207 mrange: 208 *cp++ = RANGE; 209 *cp++ = n; 210 if ((n = number(getchar())) < 0) 211 goto ignore; 212 c = getchar(); 213 if(c != '\t' && c != ' ') 214 goto ignore; 215 *cp++ = n; 216 } 217 while(c != '\n') { 218 if(c == EOF) 219 goto ignore; 220 if(c == '%') 221 c = '\n'; 222 *cp++ = c; 223 c = getchar(); 224 } 225 *cp++ = '\n'; 226 *cp++ = 0; 227 goto loop; 228 229 ignore: 230 cp = ocp; 231 while(c != '\n') { 232 if(c == EOF) { 233 *cp++ = EOS; 234 *cp++ = EOS; 235 fclose(stdin); 236 return; 237 } 238 c = getchar(); 239 } 240 goto loop; 241 } 242 243 number(c) 244 register c; 245 { 246 register n = 0; 247 248 while (isdigit(c)) { 249 n = n*10 + c - '0'; 250 c = getchar(); 251 } 252 ungetc(c, stdin); 253 if (n>100) 254 return(-1); 255 return(n); 256 } 257