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(LINT)
19static const char rcsid[] =
20  "$FreeBSD$";
21#endif
22
23#define	MAIN_PROGRAM
24
25
26#include "cron.h"
27#include <sys/mman.h>
28#include <sys/signal.h>
29#if SYS_TIME_H
30# include <sys/time.h>
31#else
32# include <time.h>
33#endif
34
35
36static	void	usage(void),
37		run_reboot_jobs(cron_db *),
38		cron_tick(cron_db *),
39		cron_sync(void),
40		cron_sleep(cron_db *),
41		cron_clean(cron_db *),
42#ifdef USE_SIGCHLD
43		sigchld_handler(int),
44#endif
45		sighup_handler(int),
46		parse_args(int c, char *v[]);
47
48static time_t	last_time = 0;
49static int	dst_enabled = 0;
50struct pidfh *pfh;
51
52static void
53usage() {
54    char **dflags;
55
56	fprintf(stderr, "usage: cron [-j jitter] [-J rootjitter] "
57			"[-m mailto] [-s] [-o] [-x debugflag[,...]]\n");
58	fprintf(stderr, "\ndebugflags: ");
59
60        for(dflags = DebugFlagNames; *dflags; dflags++) {
61		fprintf(stderr, "%s ", *dflags);
62	}
63        fprintf(stderr, "\n");
64
65	exit(ERROR_EXIT);
66}
67
68static void
69open_pidfile(void)
70{
71	char	pidfile[MAX_FNAME];
72	char	buf[MAX_TEMPSTR];
73	int	otherpid;
74
75	(void) snprintf(pidfile, sizeof(pidfile), PIDFILE, PIDDIR);
76	pfh = pidfile_open(pidfile, 0600, &otherpid);
77	if (pfh == NULL) {
78		if (errno == EEXIST) {
79			snprintf(buf, sizeof(buf),
80			    "cron already running, pid: %d", otherpid);
81		} else {
82			snprintf(buf, sizeof(buf),
83			    "can't open or create %s: %s", pidfile,
84			    strerror(errno));
85		}
86		log_it("CRON", getpid(), "DEATH", buf);
87		errx(ERROR_EXIT, "%s", buf);
88	}
89}
90
91int
92main(argc, argv)
93	int	argc;
94	char	*argv[];
95{
96	cron_db	database;
97
98	ProgramName = argv[0];
99
100#if defined(BSD)
101	setlinebuf(stdout);
102	setlinebuf(stderr);
103#endif
104
105	parse_args(argc, argv);
106
107#ifdef USE_SIGCHLD
108	(void) signal(SIGCHLD, sigchld_handler);
109#else
110	(void) signal(SIGCLD, SIG_IGN);
111#endif
112	(void) signal(SIGHUP, sighup_handler);
113
114	open_pidfile();
115	set_cron_uid();
116	set_cron_cwd();
117
118#if defined(POSIX)
119	setenv("PATH", _PATH_DEFPATH, 1);
120#endif
121
122	/* if there are no debug flags turned on, fork as a daemon should.
123	 */
124# if DEBUGGING
125	if (DebugFlags) {
126# else
127	if (0) {
128# endif
129		(void) fprintf(stderr, "[%d] cron started\n", getpid());
130	} else {
131		if (daemon(1, 0) == -1) {
132			pidfile_remove(pfh);
133			log_it("CRON",getpid(),"DEATH","can't become daemon");
134			exit(0);
135		}
136	}
137
138	if (madvise(NULL, 0, MADV_PROTECT) != 0)
139		log_it("CRON", getpid(), "WARNING", "madvise() failed");
140
141	pidfile_write(pfh);
142	database.head = NULL;
143	database.tail = NULL;
144	database.mtime = (time_t) 0;
145	load_database(&database);
146	run_reboot_jobs(&database);
147	cron_sync();
148	while (TRUE) {
149# if DEBUGGING
150	    /* if (!(DebugFlags & DTEST)) */
151# endif /*DEBUGGING*/
152			cron_sleep(&database);
153
154		load_database(&database);
155
156		/* do this iteration
157		 */
158		cron_tick(&database);
159
160		/* sleep 1 minute
161		 */
162		TargetTime += 60;
163	}
164}
165
166
167static void
168run_reboot_jobs(db)
169	cron_db *db;
170{
171	register user		*u;
172	register entry		*e;
173
174	for (u = db->head;  u != NULL;  u = u->next) {
175		for (e = u->crontab;  e != NULL;  e = e->next) {
176			if (e->flags & WHEN_REBOOT) {
177				job_add(e, u);
178			}
179		}
180	}
181	(void) job_runqueue();
182}
183
184
185static void
186cron_tick(db)
187	cron_db	*db;
188{
189	static struct tm	lasttm;
190	static time_t	diff = 0, /* time difference in seconds from the last offset change */
191		difflimit = 0; /* end point for the time zone correction */
192	struct tm	otztm; /* time in the old time zone */
193	int		otzminute, otzhour, otzdom, otzmonth, otzdow;
194 	register struct tm	*tm = localtime(&TargetTime);
195	register int		minute, hour, dom, month, dow;
196	register user		*u;
197	register entry		*e;
198
199	/* make 0-based values out of these so we can use them as indicies
200	 */
201	minute = tm->tm_min -FIRST_MINUTE;
202	hour = tm->tm_hour -FIRST_HOUR;
203	dom = tm->tm_mday -FIRST_DOM;
204	month = tm->tm_mon +1 /* 0..11 -> 1..12 */ -FIRST_MONTH;
205	dow = tm->tm_wday -FIRST_DOW;
206
207	Debug(DSCH, ("[%d] tick(%d,%d,%d,%d,%d)\n",
208		getpid(), minute, hour, dom, month, dow))
209
210	if (dst_enabled && last_time != 0
211	&& TargetTime > last_time /* exclude stepping back */
212	&& tm->tm_gmtoff != lasttm.tm_gmtoff ) {
213
214		diff = tm->tm_gmtoff - lasttm.tm_gmtoff;
215
216		if ( diff > 0 ) { /* ST->DST */
217			/* mark jobs for an earlier run */
218			difflimit = TargetTime + diff;
219			for (u = db->head;  u != NULL;  u = u->next) {
220				for (e = u->crontab;  e != NULL;  e = e->next) {
221					e->flags &= ~NOT_UNTIL;
222					if ( e->lastrun >= TargetTime )
223						e->lastrun = 0;
224					/* not include the ends of hourly ranges */
225					if ( e->lastrun < TargetTime - 3600 )
226						e->flags |= RUN_AT;
227					else
228						e->flags &= ~RUN_AT;
229				}
230			}
231		} else { /* diff < 0 : DST->ST */
232			/* mark jobs for skipping */
233			difflimit = TargetTime - diff;
234			for (u = db->head;  u != NULL;  u = u->next) {
235				for (e = u->crontab;  e != NULL;  e = e->next) {
236					e->flags |= NOT_UNTIL;
237					e->flags &= ~RUN_AT;
238				}
239			}
240		}
241	}
242
243	if (diff != 0) {
244		/* if the time was reset of the end of special zone is reached */
245		if (last_time == 0 || TargetTime >= difflimit) {
246			/* disable the TZ switch checks */
247			diff = 0;
248			difflimit = 0;
249			for (u = db->head;  u != NULL;  u = u->next) {
250				for (e = u->crontab;  e != NULL;  e = e->next) {
251					e->flags &= ~(RUN_AT|NOT_UNTIL);
252				}
253			}
254		} else {
255			/* get the time in the old time zone */
256			time_t difftime = TargetTime + tm->tm_gmtoff - diff;
257			gmtime_r(&difftime, &otztm);
258
259			/* make 0-based values out of these so we can use them as indicies
260			 */
261			otzminute = otztm.tm_min -FIRST_MINUTE;
262			otzhour = otztm.tm_hour -FIRST_HOUR;
263			otzdom = otztm.tm_mday -FIRST_DOM;
264			otzmonth = otztm.tm_mon +1 /* 0..11 -> 1..12 */ -FIRST_MONTH;
265			otzdow = otztm.tm_wday -FIRST_DOW;
266		}
267	}
268
269	/* the dom/dow situation is odd.  '* * 1,15 * Sun' will run on the
270	 * first and fifteenth AND every Sunday;  '* * * * Sun' will run *only*
271	 * on Sundays;  '* * 1,15 * *' will run *only* the 1st and 15th.  this
272	 * is why we keep 'e->dow_star' and 'e->dom_star'.  yes, it's bizarre.
273	 * like many bizarre things, it's the standard.
274	 */
275	for (u = db->head;  u != NULL;  u = u->next) {
276		for (e = u->crontab;  e != NULL;  e = e->next) {
277			Debug(DSCH|DEXT, ("user [%s:%d:%d:...] cmd=\"%s\"\n",
278					  env_get("LOGNAME", e->envp),
279					  e->uid, e->gid, e->cmd))
280
281			if ( diff != 0 && (e->flags & (RUN_AT|NOT_UNTIL)) ) {
282				if (bit_test(e->minute, otzminute)
283				 && bit_test(e->hour, otzhour)
284				 && bit_test(e->month, otzmonth)
285				 && ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
286					  ? (bit_test(e->dow,otzdow) && bit_test(e->dom,otzdom))
287					  : (bit_test(e->dow,otzdow) || bit_test(e->dom,otzdom))
288					)
289				   ) {
290					if ( e->flags & RUN_AT ) {
291						e->flags &= ~RUN_AT;
292						e->lastrun = TargetTime;
293						job_add(e, u);
294						continue;
295					} else
296						e->flags &= ~NOT_UNTIL;
297				} else if ( e->flags & NOT_UNTIL )
298					continue;
299			}
300
301			if (bit_test(e->minute, minute)
302			 && bit_test(e->hour, hour)
303			 && bit_test(e->month, month)
304			 && ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
305			      ? (bit_test(e->dow,dow) && bit_test(e->dom,dom))
306			      : (bit_test(e->dow,dow) || bit_test(e->dom,dom))
307			    )
308			   ) {
309				e->flags &= ~RUN_AT;
310				e->lastrun = TargetTime;
311				job_add(e, u);
312			}
313		}
314	}
315
316	last_time = TargetTime;
317	lasttm = *tm;
318}
319
320
321/* the task here is to figure out how long it's going to be until :00 of the
322 * following minute and initialize TargetTime to this value.  TargetTime
323 * will subsequently slide 60 seconds at a time, with correction applied
324 * implicitly in cron_sleep().  it would be nice to let cron execute in
325 * the "current minute" before going to sleep, but by restarting cron you
326 * could then get it to execute a given minute's jobs more than once.
327 * instead we have the chance of missing a minute's jobs completely, but
328 * that's something sysadmin's know to expect what with crashing computers..
329 */
330static void
331cron_sync() {
332 	register struct tm	*tm;
333
334	TargetTime = time((time_t*)0);
335	tm = localtime(&TargetTime);
336	TargetTime += (60 - tm->tm_sec);
337}
338
339
340static void
341cron_sleep(db)
342	cron_db	*db;
343{
344	int	seconds_to_wait = 0;
345
346	/*
347	 * Loop until we reach the top of the next minute, sleep when possible.
348	 */
349
350	for (;;) {
351		seconds_to_wait = (int) (TargetTime - time((time_t*)0));
352
353		/*
354		 * If the seconds_to_wait value is insane, jump the cron
355		 */
356
357		if (seconds_to_wait < -600 || seconds_to_wait > 600) {
358			cron_clean(db);
359			cron_sync();
360			continue;
361		}
362
363		Debug(DSCH, ("[%d] TargetTime=%ld, sec-to-wait=%d\n",
364			getpid(), (long)TargetTime, seconds_to_wait))
365
366		/*
367		 * If we've run out of wait time or there are no jobs left
368		 * to run, break
369		 */
370
371		if (seconds_to_wait <= 0)
372			break;
373		if (job_runqueue() == 0) {
374			Debug(DSCH, ("[%d] sleeping for %d seconds\n",
375				getpid(), seconds_to_wait))
376
377			sleep(seconds_to_wait);
378		}
379	}
380}
381
382
383/* if the time was changed abruptly, clear the flags related
384 * to the daylight time switch handling to avoid strange effects
385 */
386
387static void
388cron_clean(db)
389	cron_db	*db;
390{
391	user		*u;
392	entry		*e;
393
394	last_time = 0;
395
396	for (u = db->head;  u != NULL;  u = u->next) {
397		for (e = u->crontab;  e != NULL;  e = e->next) {
398			e->flags &= ~(RUN_AT|NOT_UNTIL);
399		}
400	}
401}
402
403#ifdef USE_SIGCHLD
404static void
405sigchld_handler(int x)
406{
407	WAIT_T		waiter;
408	PID_T		pid;
409
410	for (;;) {
411#ifdef POSIX
412		pid = waitpid(-1, &waiter, WNOHANG);
413#else
414		pid = wait3(&waiter, WNOHANG, (struct rusage *)0);
415#endif
416		switch (pid) {
417		case -1:
418			Debug(DPROC,
419				("[%d] sigchld...no children\n", getpid()))
420			return;
421		case 0:
422			Debug(DPROC,
423				("[%d] sigchld...no dead kids\n", getpid()))
424			return;
425		default:
426			Debug(DPROC,
427				("[%d] sigchld...pid #%d died, stat=%d\n",
428				getpid(), pid, WEXITSTATUS(waiter)))
429		}
430	}
431}
432#endif /*USE_SIGCHLD*/
433
434
435static void
436sighup_handler(int x)
437{
438	log_close();
439}
440
441
442static void
443parse_args(argc, argv)
444	int	argc;
445	char	*argv[];
446{
447	int	argch;
448	char	*endp;
449
450	while ((argch = getopt(argc, argv, "j:J:m:osx:")) != -1) {
451		switch (argch) {
452		case 'j':
453			Jitter = strtoul(optarg, &endp, 10);
454			if (*optarg == '\0' || *endp != '\0' || Jitter > 60)
455				errx(ERROR_EXIT,
456				     "bad value for jitter: %s", optarg);
457			break;
458		case 'J':
459			RootJitter = strtoul(optarg, &endp, 10);
460			if (*optarg == '\0' || *endp != '\0' || RootJitter > 60)
461				errx(ERROR_EXIT,
462				     "bad value for root jitter: %s", optarg);
463			break;
464		case 'm':
465			defmailto = optarg;
466			break;
467		case 'o':
468			dst_enabled = 0;
469			break;
470		case 's':
471			dst_enabled = 1;
472			break;
473		case 'x':
474			if (!set_debug_flags(optarg))
475				usage();
476			break;
477		default:
478			usage();
479		}
480	}
481}
482
483