# 2.11BSD#431 - /usr/src/usr.sbin/cron/cron.c

##### Functions

    main              X

##### Macros

    MAIN_PROGRAM      X

       1: /* Copyright 1988,1990,1993,1994 by Paul Vixie
       2:  * All rights reserved
       3:  *
       4:  * Distribute freely, except: don't remove my name from the source or
       5:  * documentation (don't take credit for my work), mark your changes (don't
       6:  * get me blamed for your possible bugs), don't alter or remove this
       7:  * notice.  May be sold if buildable source is provided to buyer.  No
       8:  * warrantee of any kind, express or implied, is included with this
       9:  * software; use at your own risk, responsibility for damages (if any) to
      10:  * anyone resulting from the use of this software rests entirely with the
      11:  * user.
      12:  *
      13:  * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
      14:  * I'll try to keep a version up to date.  I can be reached as follows:
      15:  * Paul Vixie          <paul@vix.com>          uunet!decwrl!vixie!paul
      16:  */
      17:
      18: #if !defined(lint) && defined(DOSCCS)
      19: static char sccsid[] = "@(#)cron.c 2.11.1 (2.11BSD) 1999/08/05";
      20: #endif
      21:
      22: #define MAIN_PROGRAM
      23:
      24: #include "cron.h"
      25: #include <sys/signal.h>
      26: #include <sys/time.h>
      27:
      28: static  void    usage __P((void)),
      29:         run_reboot_jobs __P((cron_db *)),
      30:         cron_tick __P((cron_db *)),
      31:         cron_sync __P((void)),
      32:         cron_sleep __P((void)),
      33:         sigchld_handler __P((int)),
      34:         sighup_handler __P((int)),
      35:         parse_args __P((int c, char *v[]));
      36:
      37:
      38: static void
      39: usage() {
      40:     fprintf(stderr, "usage:  %s [-x debugflag[,...]]\n", ProgramName);
      41:     exit(ERROR_EXIT);
      42: }
      43:
      44:
      45: int
      46: main(argc, argv)
      47:     int argc;
      48:     char    *argv[];
      49: {
      50:     cron_db database;
      51:
      52:     ProgramName = argv[0];
      53:
      54:     setlinebuf(stdout);
      55:     setlinebuf(stderr);
      56:
      57:     parse_args(argc, argv);
      58:
      59:     (void) signal(SIGCHLD, sigchld_handler);
      60:     (void) signal(SIGHUP, sighup_handler);
      61:
      62:     acquire_daemonlock(0);
      63:     set_cron_uid();
      64:     set_cron_cwd();
      65:
      66:     setenv("PATH", _PATH_DEFPATH, 1);
      67:
      68:     /* if there are no debug flags turned on, fork as a daemon should.
      69: 	 */
      70: # if DEBUGGING
      71:     if (DebugFlags) {
      72: # else
      73:     if (0) {
      74: # endif
      75:         (void) fprintf(stderr, "[%d] cron started\n", getpid());
      76:     } else {
      77:         switch (fork()) {
      78:         case -1:
      79:             log_it("CRON",getpid(),"DEATH","can't fork");
      80:             exit(0);
      81:             break;
      82:         case 0:
      83:             /* child process */
      84:             log_it("CRON",getpid(),"STARTUP","fork ok");
      85:             (void) setsid();
      86:             break;
      87:         default:
      88:             /* parent process should just die */
      89:             _exit(0);
      90:         }
      91:     }
      92:
      93:     acquire_daemonlock(0);
      94:     database.head = NULL;
      95:     database.tail = NULL;
      96:     database.mtime = (time_t) 0;
      97:     load_database(&database);
      98:     run_reboot_jobs(&database);
      99:     cron_sync();
     100:     while (TRUE) {
     101: # if DEBUGGING
     102:         if (!(DebugFlags & DTEST))
     103: # endif /*DEBUGGING*/
     104:             cron_sleep();
     105:
     106:         load_database(&database);
     107:
     108:         /* do this iteration
     109: 		 */
     110:         cron_tick(&database);
     111:
     112:         /* sleep 1 minute
     113: 		 */
     114:         TargetTime += 60;
     115:     }
     116: }
     117:
     118:
     119: static void
     120: run_reboot_jobs(db)
     121:     cron_db *db;
     122: {
     123:     register user       *u;
     124:     register entry      *e;
     125:
     126:     for (u = db->head;  u != NULL;  u = u->next) {
     127:         for (e = u->crontab;  e != NULL;  e = e->next) {
     128:             if (e->flags & WHEN_REBOOT) {
     129:                 job_add(e, u);
     130:             }
     131:         }
     132:     }
     133:     (void) job_runqueue();
     134: }
     135:
     136:
     137: static void
     138: cron_tick(db)
     139:     cron_db *db;
     140: {
     141:     register struct tm  *tm = localtime(&TargetTime);
     142:     register int        minute, hour, dom, month, dow;
     143:     register user       *u;
     144:     register entry      *e;
     145:
     146:     /* make 0-based values out of these so we can use them as indicies
     147: 	 */
     148:     minute = tm->tm_min -FIRST_MINUTE;
     149:     hour = tm->tm_hour -FIRST_HOUR;
     150:     dom = tm->tm_mday -FIRST_DOM;
     151:     month = tm->tm_mon +1 /* 0..11 -> 1..12 */ -FIRST_MONTH;
     152:     dow = tm->tm_wday -FIRST_DOW;
     153:
     154:     Debug(DSCH, ("[%d] tick(%d,%d,%d,%d,%d)\n",
     155:         getpid(), minute, hour, dom, month, dow))
     156:
     157:     /* the dom/dow situation is odd.  '* * 1,15 * Sun' will run on the
     158: 	 * first and fifteenth AND every Sunday;  '* * * * Sun' will run *only*
     159: 	 * on Sundays;  '* * 1,15 * *' will run *only* the 1st and 15th.  this
     160: 	 * is why we keep 'e->dow_star' and 'e->dom_star'.  yes, it's bizarre.
     161: 	 * like many bizarre things, it's the standard.
     162: 	 */
     163:     for (u = db->head;  u != NULL;  u = u->next) {
     164:         for (e = u->crontab;  e != NULL;  e = e->next) {
     165:             Debug(DSCH|DEXT, ("user [%s:%d:%d:...] cmd=\"%s\"\n",
     166:                       env_get("LOGNAME", e->envp),
     167:                       e->uid, e->gid, e->cmd))
     168:             if (bit_test(e->minute, minute)
     169:              && bit_test(e->hour, hour)
     170:              && bit_test(e->month, month)
     171:              && ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
     172:                   ? (bit_test(e->dow,dow) && bit_test(e->dom,dom))
     173:                   : (bit_test(e->dow,dow) || bit_test(e->dom,dom))
     174:                 )
     175:                ) {
     176:                 job_add(e, u);
     177:             }
     178:         }
     179:     }
     180: }
     181:
     182:
     183: /* the task here is to figure out how long it's going to be until :00 of the
     184:  * following minute and initialize TargetTime to this value.  TargetTime
     185:  * will subsequently slide 60 seconds at a time, with correction applied
     186:  * implicitly in cron_sleep().  it would be nice to let cron execute in
     187:  * the "current minute" before going to sleep, but by restarting cron you
     188:  * could then get it to execute a given minute's jobs more than once.
     189:  * instead we have the chance of missing a minute's jobs completely, but
     190:  * that's something sysadmin's know to expect what with crashing computers..
     191:  */
     192: static void
     193: cron_sync() {
     194:     register struct tm  *tm;
     195:
     196:     TargetTime = time((time_t*)0);
     197:     tm = localtime(&TargetTime);
     198:     TargetTime += (60 - tm->tm_sec);
     199: }
     200:
     201:
     202: static void
     203: cron_sleep() {
     204:     register int    seconds_to_wait;
     205:
     206:     do {
     207:         seconds_to_wait = (int) (TargetTime - time((time_t*)0));
     208:         Debug(DSCH, ("[%d] TargetTime=%ld, sec-to-wait=%d\n",
     209:             getpid(), TargetTime, seconds_to_wait))
     210:
     211:         /* if we intend to sleep, this means that it's finally
     212: 		 * time to empty the job queue (execute it).
     213: 		 *
     214: 		 * if we run any jobs, we'll probably screw up our timing,
     215: 		 * so go recompute.
     216: 		 *
     217: 		 * note that we depend here on the left-to-right nature
     218: 		 * of &&, and the short-circuiting.
     219: 		 */
     220:     } while (seconds_to_wait > 0 && job_runqueue());
     221:
     222:     while (seconds_to_wait > 0) {
     223:         Debug(DSCH, ("[%d] sleeping for %d seconds\n",
     224:             getpid(), seconds_to_wait))
     225:         seconds_to_wait = (int) sleep((unsigned int) seconds_to_wait);
     226:     }
     227: }
     228:
     229:
     230: static void
     231: sigchld_handler(x) {
     232:     WAIT_T      waiter;
     233:     PID_T       pid;
     234:
     235:     for (;;) {
     236:         pid = waitpid(-1, &waiter, WNOHANG);
     237:         switch (pid) {
     238:         case -1:
     239:             Debug(DPROC,
     240:                 ("[%d] sigchld...no children\n", getpid()))
     241:             return;
     242:         case 0:
     243:             Debug(DPROC,
     244:                 ("[%d] sigchld...no dead kids\n", getpid()))
     245:             return;
     246:         default:
     247:             Debug(DPROC,
     248:                 ("[%d] sigchld...pid #%d died, stat=%d\n",
     249:                 getpid(), pid, WEXITSTATUS(waiter)))
     250:         }
     251:     }
     252: }
     253:
     254: static void
     255: sighup_handler(x) {
     256:     log_close();
     257: }
     258:
     259:
     260: static void
     261: parse_args(argc, argv)
     262:     int argc;
     263:     char    *argv[];
     264: {
     265:     int argch;
     266:
     267:     while (EOF != (argch = getopt(argc, argv, "x:"))) {
     268:         switch (argch) {
     269:         default:
     270:             usage();
     271:         case 'x':
     272:             if (!set_debug_flags(optarg))
     273:                 usage();
     274:             break;
     275:         }
     276:     }
     277: }

#### Defined functions

cron_sleep defined in line 202; used 1 times

- in line 104

cron_sync defined in line 192; used 1 times

- in line 99

cron_tick defined in line 137; used 1 times

- in line 110

main defined in line 45; never used
parse_args defined in line 260; used 1 times

- in line 57

run_reboot_jobs defined in line 119; used 1 times

- in line 98

sigchld_handler defined in line 230; used 1 times

- in line 59

sighup_handler defined in line 254; used 1 times

- in line 60

usage defined in line 38; used 2 times

- in line 270-273(2)

#### Defined variables

sccsid defined in line 19; never used

#### Defined macros

MAIN_PROGRAM defined in line 22; never used

Last modified: 1999-08-06 Generated: 2016-12-26 | Generated by src2html V0.67 page hit count: 1452 |