1/* Copyright 1988,1990,1993,1994 by Paul Vixie
2 * All rights reserved
3 */
4
5/*
6 * Copyright (c) 1997 by Internet Software Consortium
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
13 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
14 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
15 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
16 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
17 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
18 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
19 * SOFTWARE.
20 */
21
22#if !defined(lint) && !defined(LINT)
23static const char rcsid[] =
24    "$Id: cron.c,v 1.3 1998/08/14 00:32:36 vixie Exp $";
25#endif
26
27#define	MAIN_PROGRAM
28
29#include "cron.h"
30#include <sys/mman.h>
31
32static	void	usage(void),
33		run_reboot_jobs(cron_db *),
34		cron_tick(cron_db *, int),
35		cron_sync(int),
36		cron_sleep(cron_db *, int),
37		cron_clean(cron_db *),
38		sigchld_handler(int),
39		sighup_handler(int),
40		parse_args(int c, char *v[]);
41
42static int	run_at_secres(cron_db *);
43static void	find_interval_entry(pid_t);
44
45static cron_db	database;
46static time_t	last_time = 0;
47static int	dst_enabled = 0;
48static int	dont_daemonize = 0;
49struct pidfh *pfh;
50
51static void
52usage(void)
53{
54#if DEBUGGING
55	const char **dflags;
56#endif
57
58	fprintf(stderr, "usage: cron [-j jitter] [-J rootjitter] "
59			"[-m mailto] [-n] [-s] [-o] [-x debugflag[,...]]\n");
60#if DEBUGGING
61	fprintf(stderr, "\ndebugflags: ");
62
63        for (dflags = DebugFlagNames; *dflags; dflags++) {
64		fprintf(stderr, "%s ", *dflags);
65	}
66        fprintf(stderr, "\n");
67#endif
68
69	exit(ERROR_EXIT);
70}
71
72static void
73open_pidfile(void)
74{
75	const char *pidfile = PIDDIR PIDFILE;
76	char	buf[MAX_TEMPSTR];
77	int	otherpid;
78
79	pfh = pidfile_open(pidfile, 0600, &otherpid);
80	if (pfh == NULL) {
81		if (errno == EEXIST) {
82			snprintf(buf, sizeof(buf),
83			    "cron already running, pid: %d", otherpid);
84		} else {
85			snprintf(buf, sizeof(buf),
86			    "can't open or create %s: %s", pidfile,
87			    strerror(errno));
88		}
89		log_it("CRON", getpid(), "DEATH", buf);
90		errx(ERROR_EXIT, "%s", buf);
91	}
92}
93
94int
95main(int argc, char *argv[])
96{
97	int runnum;
98	int secres1, secres2;
99	struct tm *tm;
100
101	ProgramName = argv[0];
102
103#if defined(BSD)
104	setlinebuf(stdout);
105	setlinebuf(stderr);
106#endif
107
108	parse_args(argc, argv);
109
110	(void) signal(SIGCHLD, sigchld_handler);
111	(void) signal(SIGHUP, sighup_handler);
112
113	open_pidfile();
114	set_cron_uid();
115	set_cron_cwd();
116
117	putenv("PATH="_PATH_DEFPATH);
118
119	/* if there are no debug flags turned on, fork as a daemon should.
120	 */
121# if DEBUGGING
122	if (DebugFlags) {
123# else
124	if (0) {
125# endif
126		(void) fprintf(stderr, "[%d] cron started\n", getpid());
127	} else if (dont_daemonize == 0) {
128		if (daemon(1, 0) == -1) {
129			pidfile_remove(pfh);
130			log_it("CRON",getpid(),"DEATH","can't become daemon");
131			exit(0);
132		}
133	}
134
135	if (madvise(NULL, 0, MADV_PROTECT) != 0)
136		log_it("CRON", getpid(), "WARNING", "madvise() failed");
137
138	pidfile_write(pfh);
139	database.head = NULL;
140	database.tail = NULL;
141	database.mtime = (time_t) 0;
142	load_database(&database);
143	secres1 = secres2 = run_at_secres(&database);
144	cron_sync(secres1);
145	run_reboot_jobs(&database);
146	runnum = 0;
147	while (TRUE) {
148# if DEBUGGING
149	    /* if (!(DebugFlags & DTEST)) */
150# endif /*DEBUGGING*/
151			cron_sleep(&database, secres1);
152
153		if (secres1 == 0 || runnum % 60 == 0) {
154			load_database(&database);
155			secres2 = run_at_secres(&database);
156			if (secres2 != secres1) {
157				secres1 = secres2;
158				if (secres1 != 0) {
159					runnum = 0;
160				} else {
161					/*
162					 * Going from 1 sec to 60 sec res. If we
163					 * are already at minute's boundary, so
164					 * let it run, otherwise schedule for the
165					 * next minute.
166					 */
167					tm = localtime(&TargetTime);
168					if (tm->tm_sec > 0)  {
169						cron_sync(secres2);
170						continue;
171					}
172				}
173			}
174		}
175
176		/* do this iteration
177		 */
178		cron_tick(&database, secres1);
179
180		/* sleep 1 or 60 seconds
181		 */
182		TargetTime += (secres1 != 0) ? 1 : 60;
183		runnum += 1;
184	}
185}
186
187static void
188run_reboot_jobs(cron_db *db)
189{
190	user *u;
191	entry *e;
192
193	for (u = db->head; u != NULL; u = u->next) {
194		for (e = u->crontab; e != NULL; e = e->next) {
195			if (e->flags & WHEN_REBOOT) {
196				job_add(e, u);
197			}
198			if (e->flags & INTERVAL) {
199				e->lastexit = TargetTime;
200			}
201		}
202	}
203	(void) job_runqueue();
204}
205
206static void
207cron_tick(cron_db *db, int secres)
208{
209	static struct tm lasttm;
210	/* time difference in seconds from the last offset change */
211	static time_t diff = 0;
212	/* end point for the time zone correction */
213	static time_t difflimit = 0;
214	/* time in the old time zone */
215	struct tm otztm;
216	int otzsecond, otzminute, otzhour, otzdom, otzmonth, otzdow;
217	struct tm *tm = localtime(&TargetTime);
218	int second, minute, hour, dom, month, dow;
219	user *u;
220	entry *e;
221
222	/* make 0-based values out of these so we can use them as indices
223	 */
224	second = (secres == 0) ? 0 : tm->tm_sec -FIRST_SECOND;
225	minute = tm->tm_min -FIRST_MINUTE;
226	hour = tm->tm_hour -FIRST_HOUR;
227	dom = tm->tm_mday -FIRST_DOM;
228	month = tm->tm_mon +1 /* 0..11 -> 1..12 */ -FIRST_MONTH;
229	dow = tm->tm_wday -FIRST_DOW;
230
231	Debug(DSCH, ("[%d] tick(%d,%d,%d,%d,%d,%d)\n",
232		getpid(), second, minute, hour, dom, month, dow))
233
234	if (dst_enabled && last_time != 0
235	&& TargetTime > last_time /* exclude stepping back */
236	&& tm->tm_gmtoff != lasttm.tm_gmtoff ) {
237
238		diff = tm->tm_gmtoff - lasttm.tm_gmtoff;
239
240		if ( diff > 0 ) { /* ST->DST */
241			/* mark jobs for an earlier run */
242			difflimit = TargetTime + diff;
243			for (u = db->head; u != NULL; u = u->next) {
244				for (e = u->crontab; e != NULL; e = e->next) {
245					e->flags &= ~NOT_UNTIL;
246					if ( e->lastrun >= TargetTime )
247						e->lastrun = 0;
248					/* not include the ends of hourly ranges */
249					if ( e->lastrun < TargetTime - 3600 )
250						e->flags |= RUN_AT;
251					else
252						e->flags &= ~RUN_AT;
253				}
254			}
255		} else { /* diff < 0 : DST->ST */
256			/* mark jobs for skipping */
257			difflimit = TargetTime - diff;
258			for (u = db->head; u != NULL; u = u->next) {
259				for (e = u->crontab; e != NULL; e = e->next) {
260					e->flags |= NOT_UNTIL;
261					e->flags &= ~RUN_AT;
262				}
263			}
264		}
265	}
266
267	if (diff != 0) {
268		/* if the time was reset of the end of special zone is reached */
269		if (last_time == 0 || TargetTime >= difflimit) {
270			/* disable the TZ switch checks */
271			diff = 0;
272			difflimit = 0;
273			for (u = db->head; u != NULL; u = u->next) {
274				for (e = u->crontab; e != NULL; e = e->next) {
275					e->flags &= ~(RUN_AT|NOT_UNTIL);
276				}
277			}
278		} else {
279			/* get the time in the old time zone */
280			time_t difftime = TargetTime + tm->tm_gmtoff - diff;
281			gmtime_r(&difftime, &otztm);
282
283			/* make 0-based values out of these so we can use them as indices
284			 */
285			otzsecond = (secres == 0) ? 0 : otztm.tm_sec -FIRST_SECOND;
286			otzminute = otztm.tm_min -FIRST_MINUTE;
287			otzhour = otztm.tm_hour -FIRST_HOUR;
288			otzdom = otztm.tm_mday -FIRST_DOM;
289			otzmonth = otztm.tm_mon +1 /* 0..11 -> 1..12 */ -FIRST_MONTH;
290			otzdow = otztm.tm_wday -FIRST_DOW;
291		}
292	}
293
294	/* the dom/dow situation is odd.  '* * 1,15 * Sun' will run on the
295	 * first and fifteenth AND every Sunday;  '* * * * Sun' will run *only*
296	 * on Sundays;  '* * 1,15 * *' will run *only* the 1st and 15th.  this
297	 * is why we keep 'e->dow_star' and 'e->dom_star'.  yes, it's bizarre.
298	 * like many bizarre things, it's the standard.
299	 */
300	for (u = db->head; u != NULL; u = u->next) {
301		for (e = u->crontab; e != NULL; e = e->next) {
302			Debug(DSCH|DEXT, ("user [%s:%d:%d:...] cmd=\"%s\"\n",
303					  env_get("LOGNAME", e->envp),
304					  e->uid, e->gid, e->cmd))
305
306			if (e->flags & INTERVAL) {
307				if (e->lastexit > 0 &&
308				    TargetTime >= e->lastexit + e->interval)
309					job_add(e, u);
310				continue;
311			}
312
313			if ( diff != 0 && (e->flags & (RUN_AT|NOT_UNTIL)) ) {
314				if (bit_test(e->second, otzsecond) &&
315				    bit_test(e->minute, otzminute) &&
316				    bit_test(e->hour, otzhour) &&
317				    bit_test(e->month, otzmonth) &&
318				    ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
319					  ? (bit_test(e->dow,otzdow) && bit_test(e->dom,otzdom))
320					  : (bit_test(e->dow,otzdow) || bit_test(e->dom,otzdom))
321					)
322				   ) {
323					if ( e->flags & RUN_AT ) {
324						e->flags &= ~RUN_AT;
325						e->lastrun = TargetTime;
326						job_add(e, u);
327						continue;
328					} else
329						e->flags &= ~NOT_UNTIL;
330				} else if ( e->flags & NOT_UNTIL )
331					continue;
332			}
333
334			if (bit_test(e->second, second) &&
335			    bit_test(e->minute, minute) &&
336			    bit_test(e->hour, hour) &&
337			    bit_test(e->month, month) &&
338			    ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
339			      ? (bit_test(e->dow,dow) && bit_test(e->dom,dom))
340			      : (bit_test(e->dow,dow) || bit_test(e->dom,dom))
341			    )
342			   ) {
343				e->flags &= ~RUN_AT;
344				e->lastrun = TargetTime;
345				job_add(e, u);
346			}
347		}
348	}
349
350	last_time = TargetTime;
351	lasttm = *tm;
352}
353
354/* the task here is to figure out how long it's going to be until :00 of the
355 * following minute and initialize TargetTime to this value.  TargetTime
356 * will subsequently slide 60 seconds at a time, with correction applied
357 * implicitly in cron_sleep().  it would be nice to let cron execute in
358 * the "current minute" before going to sleep, but by restarting cron you
359 * could then get it to execute a given minute's jobs more than once.
360 * instead we have the chance of missing a minute's jobs completely, but
361 * that's something sysadmin's know to expect what with crashing computers..
362 */
363static void
364cron_sync(int secres) {
365	struct tm *tm;
366
367	TargetTime = time((time_t*)0);
368	if (secres != 0) {
369		TargetTime += 1;
370	} else {
371		tm = localtime(&TargetTime);
372		TargetTime += (60 - tm->tm_sec);
373	}
374}
375
376static void
377timespec_subtract(struct timespec *result, struct timespec *x,
378    struct timespec *y)
379{
380	*result = *x;
381	result->tv_sec -= y->tv_sec;
382	result->tv_nsec -= y->tv_nsec;
383	if (result->tv_nsec < 0) {
384		result->tv_sec--;
385		result->tv_nsec += 1000000000;
386	}
387}
388
389static void
390cron_sleep(cron_db *db, int secres)
391{
392	int seconds_to_wait;
393	int rval;
394	struct timespec ctime, ttime, stime, remtime;
395
396	/*
397	 * Loop until we reach the top of the next minute, sleep when possible.
398	 */
399
400	for (;;) {
401		clock_gettime(CLOCK_REALTIME, &ctime);
402		ttime.tv_sec = TargetTime;
403		ttime.tv_nsec = 0;
404		timespec_subtract(&stime, &ttime, &ctime);
405
406		/*
407		 * If the seconds_to_wait value is insane, jump the cron
408		 */
409
410		if (stime.tv_sec < -600 || stime.tv_sec > 600) {
411			cron_clean(db);
412			cron_sync(secres);
413			continue;
414		}
415
416		seconds_to_wait = (stime.tv_nsec > 0) ? stime.tv_sec + 1 :
417		    stime.tv_sec;
418
419		Debug(DSCH, ("[%d] TargetTime=%ld, sec-to-wait=%d\n",
420			getpid(), (long)TargetTime, seconds_to_wait))
421
422		/*
423		 * If we've run out of wait time or there are no jobs left
424		 * to run, break
425		 */
426
427		if (stime.tv_sec < 0)
428			break;
429		if (job_runqueue() == 0) {
430			Debug(DSCH, ("[%d] sleeping for %d seconds\n",
431				getpid(), seconds_to_wait))
432
433			for (;;) {
434				rval = nanosleep(&stime, &remtime);
435				if (rval == 0 || errno != EINTR)
436					break;
437				stime.tv_sec = remtime.tv_sec;
438				stime.tv_nsec = remtime.tv_nsec;
439			}
440		}
441	}
442}
443
444
445/* if the time was changed abruptly, clear the flags related
446 * to the daylight time switch handling to avoid strange effects
447 */
448
449static void
450cron_clean(cron_db *db)
451{
452	user		*u;
453	entry		*e;
454
455	last_time = 0;
456
457	for (u = db->head;  u != NULL;  u = u->next) {
458		for (e = u->crontab;  e != NULL;  e = e->next) {
459			e->flags &= ~(RUN_AT|NOT_UNTIL);
460		}
461	}
462}
463
464static void
465sigchld_handler(int x)
466{
467	WAIT_T waiter;
468	PID_T pid;
469
470	for (;;) {
471		pid = waitpid(-1, &waiter, WNOHANG);
472		switch (pid) {
473		case -1:
474			Debug(DPROC,
475				("[%d] sigchld...no children\n", getpid()))
476			return;
477		case 0:
478			Debug(DPROC,
479				("[%d] sigchld...no dead kids\n", getpid()))
480			return;
481		default:
482			find_interval_entry(pid);
483			Debug(DPROC,
484				("[%d] sigchld...pid #%d died, stat=%d\n",
485				getpid(), pid, WEXITSTATUS(waiter)))
486		}
487	}
488}
489
490static void
491sighup_handler(int x)
492{
493	log_close();
494}
495
496static void
497parse_args(int argc, char *argv[])
498{
499	int argch;
500	char *endp;
501
502	while ((argch = getopt(argc, argv, "j:J:m:nosx:")) != -1) {
503		switch (argch) {
504		case 'j':
505			Jitter = strtoul(optarg, &endp, 10);
506			if (*optarg == '\0' || *endp != '\0' || Jitter > 60)
507				errx(ERROR_EXIT,
508				     "bad value for jitter: %s", optarg);
509			break;
510		case 'J':
511			RootJitter = strtoul(optarg, &endp, 10);
512			if (*optarg == '\0' || *endp != '\0' || RootJitter > 60)
513				errx(ERROR_EXIT,
514				     "bad value for root jitter: %s", optarg);
515			break;
516		case 'm':
517			defmailto = optarg;
518			break;
519		case 'n':
520			dont_daemonize = 1;
521			break;
522		case 'o':
523			dst_enabled = 0;
524			break;
525		case 's':
526			dst_enabled = 1;
527			break;
528		case 'x':
529			if (!set_debug_flags(optarg))
530				usage();
531			break;
532		default:
533			usage();
534		}
535	}
536}
537
538static int
539run_at_secres(cron_db *db)
540{
541	user *u;
542	entry *e;
543
544	for (u = db->head;  u != NULL;  u = u->next) {
545		for (e = u->crontab;  e != NULL;  e = e->next) {
546			if ((e->flags & (SEC_RES | INTERVAL)) != 0)
547				return 1;
548		}
549	}
550	return 0;
551}
552
553static void
554find_interval_entry(pid_t pid)
555{
556	user *u;
557	entry *e;
558
559	for (u = database.head;  u != NULL;  u = u->next) {
560		for (e = u->crontab;  e != NULL;  e = e->next) {
561			if ((e->flags & INTERVAL) && e->child == pid) {
562				e->lastexit = time(NULL);
563				e->child = 0;
564				break;
565			}
566		}
567	}
568}
569