Second attempt to add @every_second keyword support. Due to multiple
requests, default to the previous 60-seconds scheduling method unless there is any @every_second entries to conserve CPU cycles and power. This change also improves scheduling in the default mode by running as close to the beginning of the minnute as possible by replacing sleep(3) with nanosleep(2). Previously, the tasks would run anywhere within the first second of the minute and that offset drifted back and forth each time cron(8) was engaged. MFC after: 1 month
This commit is contained in:
sobomax
parent
1206789da9
commit
83b5dc03eb
@ -35,9 +35,9 @@ static const char rcsid[] =
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static void usage(void),
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run_reboot_jobs(cron_db *),
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cron_tick(cron_db *),
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cron_sync(void),
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cron_sleep(cron_db *),
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cron_tick(cron_db *, int),
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cron_sync(int),
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cron_sleep(cron_db *, int),
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cron_clean(cron_db *),
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#ifdef USE_SIGCHLD
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sigchld_handler(int),
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@ -45,6 +45,8 @@ static void usage(void),
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sighup_handler(int),
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parse_args(int c, char *v[]);
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static int run_at_secres(cron_db *);
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static time_t last_time = 0;
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static int dst_enabled = 0;
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struct pidfh *pfh;
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@ -98,6 +100,9 @@ main(argc, argv)
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char *argv[];
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{
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cron_db database;
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int runnum;
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int secres1, secres2;
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struct tm *tm;
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ProgramName = argv[0];
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@ -147,23 +152,47 @@ main(argc, argv)
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database.tail = NULL;
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database.mtime = (time_t) 0;
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load_database(&database);
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secres1 = secres2 = run_at_secres(&database);
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run_reboot_jobs(&database);
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cron_sync();
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cron_sync(secres1);
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runnum = 0;
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while (TRUE) {
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# if DEBUGGING
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/* if (!(DebugFlags & DTEST)) */
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# endif /*DEBUGGING*/
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cron_sleep(&database);
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cron_sleep(&database, secres1);
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load_database(&database);
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if (secres1 == 0 || runnum % 60 == 0) {
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load_database(&database);
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secres2 = run_at_secres(&database);
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if (secres2 != secres1) {
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secres1 = secres2;
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if (secres1 != 0) {
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runnum = 0;
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} else {
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/*
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* Going from 1 sec to 60 sec res. If we
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* are already at minute's boundary, so
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* let it run, otherwise schedule for the
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* next minute.
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*/
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tm = localtime(&TargetTime);
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if (tm->tm_sec > 0) {
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cron_sync(secres2);
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continue;
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}
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}
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}
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}
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/* do this iteration
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*/
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cron_tick(&database);
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cron_tick(&database, secres1);
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/* sleep 1 minute
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/* sleep 1 or 60 seconds
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*/
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TargetTime += 60;
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TargetTime += (secres1 != 0) ? 1 : 60;
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runnum += 1;
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}
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}
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@ -187,29 +216,29 @@ run_reboot_jobs(db)
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static void
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cron_tick(db)
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cron_db *db;
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cron_tick(cron_db *db, int secres)
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{
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static struct tm lasttm;
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static time_t diff = 0, /* time difference in seconds from the last offset change */
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difflimit = 0; /* end point for the time zone correction */
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struct tm otztm; /* time in the old time zone */
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int otzminute, otzhour, otzdom, otzmonth, otzdow;
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int otzsecond, otzminute, otzhour, otzdom, otzmonth, otzdow;
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register struct tm *tm = localtime(&TargetTime);
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register int minute, hour, dom, month, dow;
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register int second, minute, hour, dom, month, dow;
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register user *u;
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register entry *e;
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/* make 0-based values out of these so we can use them as indicies
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*/
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second = (secres == 0) ? 0 : tm->tm_sec -FIRST_SECOND;
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minute = tm->tm_min -FIRST_MINUTE;
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hour = tm->tm_hour -FIRST_HOUR;
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dom = tm->tm_mday -FIRST_DOM;
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month = tm->tm_mon +1 /* 0..11 -> 1..12 */ -FIRST_MONTH;
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dow = tm->tm_wday -FIRST_DOW;
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Debug(DSCH, ("[%d] tick(%d,%d,%d,%d,%d)\n",
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getpid(), minute, hour, dom, month, dow))
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Debug(DSCH, ("[%d] tick(%d,%d,%d,%d,%d,%d)\n",
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getpid(), second, minute, hour, dom, month, dow))
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if (dst_enabled && last_time != 0
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&& TargetTime > last_time /* exclude stepping back */
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@ -262,6 +291,7 @@ cron_tick(db)
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/* make 0-based values out of these so we can use them as indicies
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*/
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otzsecond = (secres == 0) ? 0 : otztm.tm_sec -FIRST_SECOND;
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otzminute = otztm.tm_min -FIRST_MINUTE;
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otzhour = otztm.tm_hour -FIRST_HOUR;
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otzdom = otztm.tm_mday -FIRST_DOM;
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@ -283,7 +313,8 @@ cron_tick(db)
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e->uid, e->gid, e->cmd))
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if ( diff != 0 && (e->flags & (RUN_AT|NOT_UNTIL)) ) {
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if (bit_test(e->minute, otzminute)
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if (bit_test(e->second, otzsecond)
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&& bit_test(e->minute, otzminute)
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&& bit_test(e->hour, otzhour)
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&& bit_test(e->month, otzmonth)
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&& ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
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@ -302,7 +333,8 @@ cron_tick(db)
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continue;
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}
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if (bit_test(e->minute, minute)
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if (bit_test(e->second, second)
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&& bit_test(e->minute, minute)
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&& bit_test(e->hour, hour)
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&& bit_test(e->month, month)
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&& ( ((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
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@ -332,38 +364,74 @@ cron_tick(db)
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* that's something sysadmin's know to expect what with crashing computers..
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*/
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static void
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cron_sync() {
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register struct tm *tm;
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cron_sync(int secres) {
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struct tm *tm;
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TargetTime = time((time_t*)0);
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tm = localtime(&TargetTime);
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TargetTime += (60 - tm->tm_sec);
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if (secres != 0) {
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TargetTime += 1;
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} else {
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tm = localtime(&TargetTime);
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TargetTime += (60 - tm->tm_sec);
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}
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}
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static int
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timespec_subtract(struct timespec *result, struct timespec *x,
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struct timespec *y)
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{
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time_t nsec;
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/* Perform the carry for the later subtraction by updating y. */
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if (x->tv_nsec < y->tv_nsec) {
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nsec = (y->tv_nsec - x->tv_nsec) / 10000000 + 1;
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y->tv_nsec -= 1000000000 * nsec;
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y->tv_sec += nsec;
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}
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if (x->tv_nsec - y->tv_nsec > 1000000000) {
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nsec = (x->tv_nsec - y->tv_nsec) / 1000000000;
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y->tv_nsec += 1000000000 * nsec;
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y->tv_sec -= nsec;
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}
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/* tv_nsec is certainly positive. */
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result->tv_sec = x->tv_sec - y->tv_sec;
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result->tv_nsec = x->tv_nsec - y->tv_nsec;
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/* Return True if result is negative. */
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return (x->tv_sec < y->tv_sec);
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}
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static void
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cron_sleep(db)
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cron_db *db;
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cron_sleep(cron_db *db, int secres)
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{
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int seconds_to_wait = 0;
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int seconds_to_wait;
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int rval;
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struct timespec ctime, ttime, stime, remtime;
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/*
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* Loop until we reach the top of the next minute, sleep when possible.
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*/
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for (;;) {
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seconds_to_wait = (int) (TargetTime - time((time_t*)0));
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clock_gettime(CLOCK_REALTIME, &ctime);
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ttime.tv_sec = TargetTime;
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ttime.tv_nsec = 0;
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timespec_subtract(&stime, &ttime, &ctime);
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/*
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* If the seconds_to_wait value is insane, jump the cron
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*/
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if (seconds_to_wait < -600 || seconds_to_wait > 600) {
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if (stime.tv_sec < -600 || stime.tv_sec > 600) {
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cron_clean(db);
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cron_sync();
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cron_sync(secres);
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continue;
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}
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seconds_to_wait = (stime.tv_nsec > 0) ? stime.tv_sec + 1 :
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stime.tv_sec;
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Debug(DSCH, ("[%d] TargetTime=%ld, sec-to-wait=%d\n",
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getpid(), (long)TargetTime, seconds_to_wait))
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@ -372,13 +440,19 @@ cron_sleep(db)
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* to run, break
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*/
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if (seconds_to_wait <= 0)
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if (stime.tv_sec < 0)
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break;
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if (job_runqueue() == 0) {
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Debug(DSCH, ("[%d] sleeping for %d seconds\n",
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getpid(), seconds_to_wait))
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sleep(seconds_to_wait);
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for (;;) {
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rval = nanosleep(&stime, &remtime);
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if (rval == 0 || errno != EINTR)
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break;
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stime.tv_sec = remtime.tv_sec;
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stime.tv_nsec = remtime.tv_nsec;
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}
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}
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}
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}
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@ -484,3 +558,17 @@ parse_args(argc, argv)
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}
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}
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static int
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run_at_secres(cron_db *db)
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{
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user *u;
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entry *e;
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for (u = db->head; u != NULL; u = u->next) {
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for (e = u->crontab; e != NULL; e = e->next) {
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if ((e->flags & SEC_RES) != 0)
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return 1;
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}
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}
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return 0;
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}
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@ -124,6 +124,10 @@
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LineNumber = ln; \
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}
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#define FIRST_SECOND 0
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#define LAST_SECOND 59
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#define SECOND_COUNT (LAST_SECOND - FIRST_SECOND + 1)
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#define FIRST_MINUTE 0
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#define LAST_MINUTE 59
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#define MINUTE_COUNT (LAST_MINUTE - FIRST_MINUTE + 1)
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@ -165,6 +169,7 @@ typedef struct _entry {
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#endif
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char **envp;
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char *cmd;
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bitstr_t bit_decl(second, SECOND_COUNT);
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bitstr_t bit_decl(minute, MINUTE_COUNT);
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bitstr_t bit_decl(hour, HOUR_COUNT);
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bitstr_t bit_decl(dom, DOM_COUNT);
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@ -176,6 +181,7 @@ typedef struct _entry {
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#define WHEN_REBOOT 0x04
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#define RUN_AT 0x08
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#define NOT_UNTIL 0x10
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#define SEC_RES 0x20
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time_t lastrun;
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} entry;
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@ -232,6 +232,8 @@ string meaning
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@daily Run once a day, "0 0 * * *".
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@midnight (same as @daily)
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@hourly Run once an hour, "0 * * * *".
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@every_minute Run once a minute, "*/1 * * * *".
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@every_second Run once a second.
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.Ed
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.Sh EXAMPLE CRON FILE
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.Bd -literal
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@ -151,6 +151,7 @@ load_entry(file, error_func, pw, envp)
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e->flags |= WHEN_REBOOT;
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} else if (!strcmp("yearly", cmd) || !strcmp("annually", cmd)){
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Debug(DPARS, ("load_entry()...yearly shortcut\n"))
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bit_set(e->second, 0);
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bit_set(e->minute, 0);
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bit_set(e->hour, 0);
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bit_set(e->dom, 0);
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@ -159,6 +160,7 @@ load_entry(file, error_func, pw, envp)
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e->flags |= DOW_STAR;
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} else if (!strcmp("monthly", cmd)) {
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Debug(DPARS, ("load_entry()...monthly shortcut\n"))
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bit_set(e->second, 0);
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bit_set(e->minute, 0);
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bit_set(e->hour, 0);
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bit_set(e->dom, 0);
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@ -167,6 +169,7 @@ load_entry(file, error_func, pw, envp)
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e->flags |= DOW_STAR;
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} else if (!strcmp("weekly", cmd)) {
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Debug(DPARS, ("load_entry()...weekly shortcut\n"))
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bit_set(e->second, 0);
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bit_set(e->minute, 0);
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bit_set(e->hour, 0);
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bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
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@ -175,6 +178,7 @@ load_entry(file, error_func, pw, envp)
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bit_set(e->dow, 0);
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} else if (!strcmp("daily", cmd) || !strcmp("midnight", cmd)) {
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Debug(DPARS, ("load_entry()...daily shortcut\n"))
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bit_set(e->second, 0);
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bit_set(e->minute, 0);
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bit_set(e->hour, 0);
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bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
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@ -182,11 +186,29 @@ load_entry(file, error_func, pw, envp)
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bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
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} else if (!strcmp("hourly", cmd)) {
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Debug(DPARS, ("load_entry()...hourly shortcut\n"))
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bit_set(e->second, 0);
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bit_set(e->minute, 0);
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bit_nset(e->hour, 0, (LAST_HOUR-FIRST_HOUR+1));
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bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
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bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
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bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
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} else if (!strcmp("every_minute", cmd)) {
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Debug(DPARS, ("load_entry()...every_minute shortcut\n"))
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bit_set(e->second, 0);
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bit_nset(e->minute, 0, (LAST_MINUTE-FIRST_MINUTE+1));
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bit_nset(e->hour, 0, (LAST_HOUR-FIRST_HOUR+1));
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bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
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bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
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bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
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} else if (!strcmp("every_second", cmd)) {
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Debug(DPARS, ("load_entry()...every_second shortcut\n"))
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e->flags |= SEC_RES;
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bit_nset(e->second, 0, (LAST_SECOND-FIRST_SECOND+1));
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bit_nset(e->minute, 0, (LAST_MINUTE-FIRST_MINUTE+1));
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bit_nset(e->hour, 0, (LAST_HOUR-FIRST_HOUR+1));
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bit_nset(e->dom, 0, (LAST_DOM-FIRST_DOM+1));
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bit_nset(e->month, 0, (LAST_MONTH-FIRST_MONTH+1));
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bit_nset(e->dow, 0, (LAST_DOW-FIRST_DOW+1));
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} else {
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ecode = e_timespec;
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goto eof;
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@ -201,6 +223,7 @@ load_entry(file, error_func, pw, envp)
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}
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} else {
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Debug(DPARS, ("load_entry()...about to parse numerics\n"))
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bit_set(e->second, 0);
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ch = get_list(e->minute, FIRST_MINUTE, LAST_MINUTE,
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PPC_NULL, ch, file);
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Loading…
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Block a user