void
do_command(entry *e, user *u) {
Debug(DPROC, ("[%ld] do_command(%s, (%s,%ld,%ld))\n",
(long)getpid(), e->cmd, u->name,
(long)e->pwd->pw_uid, (long)e->pwd->pw_gid));
/* fork to become asynchronous -- parent process is done immediately,
* and continues to run the normal cron code, which means return to
* tick(). the child and grandchild don't leave this function, alive.
*
* vfork() is unsuitable, since we have much to do, and the parent
* needs to be able to run off and fork other processes.
*/
switch (fork()) {
case -1:
log_it("CRON", getpid(), "error", "can't fork");
break;
case 0:
/* child process */
acquire_daemonlock(1);
child_process(e);
Debug(DPROC, ("[%ld] child process done, exiting\n",
(long)getpid()));
_exit(OK_EXIT);
break;
default:
/* parent process */
break;
}
Debug(DPROC, ("[%ld] main process returning to work\n",(long)getpid()));
}
void
do_command (entry * e, user * u)
{
Debug (DPROC, ("[%d] do_command(%s, (%s,%d,%d))\n",
getpid (), e->cmd, u->name, e->uid, e->gid));
/* fork to become asynchronous -- parent process is done immediately,
* and continues to run the normal cron code, which means return to
* tick(). the child and grandchild don't leave this function, alive.
*
* vfork() is unsuitable, since we have much to do, and the parent
* needs to be able to run off and fork other processes.
*/
switch (fork ())
{
case -1:
log_it ("CRON", getpid (), "error", "can't fork");
break;
case 0:
/* child process */
acquire_daemonlock (1);
child_process (e, u);
Debug (DPROC, ("[%d] child process done, exiting\n", getpid ()));
#ifndef USE_SIGCHLD
/* remember current time. This is not entirely correct because
* the job might have been a catch-up job in that case we
* should only save its timestamp but we don't have access to
* the parent's CatchUpList variable
* we only have to do this here if we don't use SIGCHLD, otherwise
* the timestamp is saved correctly in our parent's sigchld_handler.
*/
save_lastrun (NULL);
#endif
_exit (OK_EXIT);
break;
default:
/* parent process */
break;
}
Debug (DPROC, ("[%d] main process returning to work\n", getpid ()));
}
int
main (int argc, char *argv[])
{
cron_db database;
char *config_file; /*Name of our configuration file; NULL if none */
struct sigaction my_sigaction;
/* We need to put Program_Name in its own storage because later we will
* modify argv[0] in an attempt to change the process name.
*/
ProcessName = argv[0];
ProgramName = strdup (argv[0]);
#if HAVE_SETLINEBUF
setlinebuf (stdout);
setlinebuf (stderr);
#endif /*HAVE_SETLINEBUF */
parse_args (argc, argv, &pass_environment, &config_file);
read_config (config_file, &allow_only_root, &log_syslog, &allow_file,
&deny_file, &crondir, &spool_dir, &log_file, &syscrontab,
&lastrun_file, &pidfile, &mailprog, &mailargs);
#ifdef USE_SIGCHLD
memset (&my_sigaction, 0, sizeof (my_sigaction));
my_sigaction.sa_handler = sigchld_handler;
my_sigaction.sa_flags |= SA_NOCLDSTOP | SA_NODEFER;
if (sigaction (SIGCHLD, &my_sigaction, NULL))
perror ("sigaction");
#else
(void) signal (SIGCHLD, SIG_IGN);
#endif
memset (&my_sigaction, 0, sizeof (my_sigaction));
my_sigaction.sa_handler = sigterm_handler;
if (sigaction (SIGTERM, &my_sigaction, NULL))
perror ("sigaction");
memset (&my_sigaction, 0, sizeof (my_sigaction));
my_sigaction.sa_handler = sighup_handler;
if (sigaction (SIGHUP, &my_sigaction, NULL))
perror ("sigaction");
acquire_daemonlock (0);
set_cron_uid ();
set_cron_cwd ();
#if HAVE_SETENV
if (!pass_environment)
setenv ("PATH", _PATH_DEFPATH, 1);
#endif
/* if there are no debug flags turned on, fork as a daemon should. */
#if DEBUGGING
if (DebugFlags)
{
#else
if (0)
{
#endif
(void) fprintf (stderr, "[%d] cron started\n", getpid ());
}
else
{
switch (fork ())
{
case -1:
log_it ("CRON", getpid (), "DEATH", "can't fork");
exit (0);
break;
case 0:
/* child process */
log_it ("CRON", getpid (), "STARTUP", "fork ok");
(void) setsid ();
break;
default:
/* parent process should just die */
_exit (0);
}
}
acquire_daemonlock (0);
/* initialize waiting for busy disk */
init_diskload ();
database.head = NULL;
database.tail = NULL;
database.mtime = (time_t) 0;
Debug (DMISC, ("about to load database"));
load_database (&database);
Debug (DMISC, ("about to build catch up list"));
build_cu_list (&database, &CatchUpList);
Debug (DMISC, ("about to run reboot jobs"));
run_reboot_jobs (&database);
while (TRUE)
{
cron_sync ();
# if DEBUGGING
if (!(DebugFlags & DTEST))
# endif /*DEBUGGING*/
cron_sleep ();
load_database (&database);
/* first catch up any jobs that are on the CatchUpList */
if (CatchUpList && (!jhead))
CatchUpList = run_cu_list (CatchUpList);
/* then run the regular jobs for this minute */
cron_tick (&database);
}
}
static void
run_reboot_jobs (cron_db * db)
{
register user *u;
register entry *e;
for (u = db->head; u != NULL; u = u->next)
{
for (e = u->crontab; e != NULL; e = e->next)
{
if (e->flags & WHEN_REBOOT)
{
job_add (e, u);
}
}
}
(void) job_runqueue ();
}
static void
cron_tick (cron_db * db)
{
register struct tm *tm = localtime (&TargetTime);
register int minute, hour, dom, month, dow;
register user *u;
register entry *e;
/* make 0-based values out of these so we can use them as indicies
*/
minute = tm->tm_min - FIRST_MINUTE;
hour = tm->tm_hour - FIRST_HOUR;
dom = tm->tm_mday - FIRST_DOM;
month = tm->tm_mon + 1 /* 0..11 -> 1..12 */ - FIRST_MONTH;
dow = tm->tm_wday - FIRST_DOW;
Debug (DSCH, ("[%d] tick(%d,%d,%d,%d,%d)\n",
getpid (), minute, hour, dom, month, dow));
/* the dom/dow situation is odd. '* * 1,15 * Sun' will run on the
* first and fifteenth AND every Sunday; '* * * * Sun' will run *only*
* on Sundays; '* * 1,15 * *' will run *only* the 1st and 15th. this
* is why we keep 'e->dow_star' and 'e->dom_star'. yes, it's bizarre.
* like many bizarre things, it's the standard.
*/
for (u = db->head; u != NULL; u = u->next)
{
for (e = u->crontab; e != NULL; e = e->next)
{
Debug (DSCH | DEXT, ("user [%s:%d:%d:...] cmd=\"%s\"\n",
env_get ("LOGNAME", e->envp),
e->uid, e->gid, e->cmd));
if (bit_test (e->minute, minute)
&& bit_test (e->hour, hour)
&& bit_test (e->month, month)
&& (((e->flags & DOM_STAR) || (e->flags & DOW_STAR))
? (bit_test (e->dow, dow) && bit_test (e->dom, dom))
: (bit_test (e->dow, dow) || bit_test (e->dom, dom))))
{
job_add (e, u);
}
}
}
}
/* the task here is to figure out how long it's going to be until :00 of the
* following minute and initialize TargetTime to this value. TargetTime
* will subsequently slide 60 seconds at a time, with correction applied
* implicitly in cron_sleep(). it would be nice to let cron execute in
* the "current minute" before going to sleep, but by restarting cron you
* could then get it to execute a given minute's jobs more than once.
* instead we have the chance of missing a minute's jobs completely, but
* that's something sysadmin's know to expect what with crashing computers..
*
* Patch from <*****@*****.**>:
* Do cron_sync() before each cron_sleep(), to handle changes to the system
* time.
*/
static void
cron_sync (void)
{
register struct tm *tm;
TargetTime = time ((time_t *) 0);
tm = localtime (&TargetTime);
TargetTime += (60 - tm->tm_sec);
}
static void
cron_sleep (void)
{
register int seconds_to_wait;
do
{
seconds_to_wait = (int) (TargetTime - time ((time_t *) 0));
Debug (DSCH, ("[%d] TargetTime=%ld, sec-to-wait=%d\n",
getpid (), TargetTime, seconds_to_wait));
/* if we intend to sleep, this means that it's finally
* time to empty the job queue (execute it).
*
* if we run any jobs, we'll probably screw up our timing,
* so go recompute.
*
* note that we depend here on the left-to-right nature
* of &&, and the short-circuiting.
*/
}
while (seconds_to_wait > 0 && job_runqueue ());
while (seconds_to_wait > 0)
{
Debug (DSCH, ("[%d] sleeping for %d seconds\n",
getpid (), seconds_to_wait));
seconds_to_wait = (int) sleep ((unsigned int) seconds_to_wait);
}
}
#ifdef USE_SIGCHLD
static RETSIGTYPE
sigchld_handler (int x)
{
WAIT_T waiter;
pid_t pid;
for (;;)
{
#if 1
pid = waitpid (-1, &waiter, WNOHANG);
#else
pid = wait3 (&waiter, WNOHANG, (struct rusage *) 0);
#endif
switch (pid)
{
case -1:
Debug (DPROC, ("[%d] sigchld...no children\n", getpid ()));
return;
case 0:
Debug (DPROC, ("[%d] sigchld...no dead kids\n", getpid ()));
return;
default:
Debug (DPROC,
("[%d] sigchld...pid #%d died, stat=%d\n",
getpid (), pid, WEXITSTATUS (waiter)));
save_lastrun (CatchUpList);
}
}
}
int
main(int argc, char *argv[]) {
struct sigaction sact;
cron_db database;
setprogname(argv[0]);
(void)setlocale(LC_ALL, "");
(void)setvbuf(stdout, NULL, _IOLBF, 0);
(void)setvbuf(stderr, NULL, _IOLBF, 0);
NoFork = 0;
parse_args(argc, argv);
(void)memset(&sact, 0, sizeof sact);
(void)sigemptyset(&sact.sa_mask);
sact.sa_flags = 0;
#ifdef SA_RESTART
sact.sa_flags |= SA_RESTART;
#endif
sact.sa_handler = sigchld_handler;
(void) sigaction(SIGCHLD, &sact, NULL);
sact.sa_handler = sighup_handler;
(void) sigaction(SIGHUP, &sact, NULL);
sact.sa_handler = quit;
(void) sigaction(SIGINT, &sact, NULL);
(void) sigaction(SIGTERM, &sact, NULL);
acquire_daemonlock(0);
set_cron_uid();
set_cron_cwd();
if (setenv("PATH", _PATH_DEFPATH, 1) < 0) {
log_it("CRON", getpid(), "DEATH", "can't malloc");
exit(1);
}
/* if there are no debug flags turned on, fork as a daemon should.
*/
if (DebugFlags) {
#if DEBUGGING
(void)fprintf(stderr, "[%ld] cron started\n", (long)getpid());
#endif
} else if (NoFork == 0) {
if (daemon(1, 0)) {
log_it("CRON",getpid(),"DEATH","can't fork");
exit(1);
}
}
acquire_daemonlock(0);
database.head = NULL;
database.tail = NULL;
database.mtime = (time_t) 0;
load_database(&database);
set_time(TRUE);
run_reboot_jobs(&database);
timeRunning = virtualTime = clockTime;
/*
* Too many clocks, not enough time (Al. Einstein)
* These clocks are in minutes since the epoch, adjusted for timezone.
* virtualTime: is the time it *would* be if we woke up
* promptly and nobody ever changed the clock. It is
* monotonically increasing... unless a timejump happens.
* At the top of the loop, all jobs for 'virtualTime' have run.
* timeRunning: is the time we last awakened.
* clockTime: is the time when set_time was last called.
*/
for (;;) {
int timeDiff;
enum timejump wakeupKind;
/* ... wait for the time (in minutes) to change ... */
do {
cron_sleep(timeRunning + 1);
set_time(FALSE);
} while (clockTime == timeRunning);
timeRunning = clockTime;
/*
* Calculate how the current time differs from our virtual
* clock. Classify the change into one of 4 cases.
*/
timeDiff = timeRunning - virtualTime;
/* shortcut for the most common case */
if (timeDiff == 1) {
virtualTime = timeRunning;
find_jobs(virtualTime, &database, TRUE, TRUE);
} else {
if (timeDiff > (3*MINUTE_COUNT) ||
timeDiff < -(3*MINUTE_COUNT))
wakeupKind = large;
else if (timeDiff > 5)
wakeupKind = medium;
else if (timeDiff > 0)
wakeupKind = small;
else
wakeupKind = negative;
switch (wakeupKind) {
case small:
/*
* case 1: timeDiff is a small positive number
* (wokeup late) run jobs for each virtual
* minute until caught up.
*/
Debug(DSCH, ("[%ld], normal case %d minutes to go\n",
(long)getpid(), timeDiff));
do {
if (job_runqueue())
(void)sleep(10);
virtualTime++;
find_jobs(virtualTime, &database,
TRUE, TRUE);
} while (virtualTime < timeRunning);
break;
case medium:
/*
* case 2: timeDiff is a medium-sized positive
* number, for example because we went to DST
* run wildcard jobs once, then run any
* fixed-time jobs that would otherwise be
* skipped if we use up our minute (possible,
* if there are a lot of jobs to run) go
* around the loop again so that wildcard jobs
* have a chance to run, and we do our
* housekeeping.
*/
Debug(DSCH, ("[%ld], DST begins %d minutes to go\n",
(long)getpid(), timeDiff));
/* run wildcard jobs for current minute */
find_jobs(timeRunning, &database, TRUE, FALSE);
/* run fixed-time jobs for each minute missed */
do {
if (job_runqueue())
(void)sleep(10);
virtualTime++;
find_jobs(virtualTime, &database,
FALSE, TRUE);
set_time(FALSE);
} while (virtualTime < timeRunning &&
clockTime == timeRunning);
break;
case negative:
/*
* case 3: timeDiff is a small or medium-sized
* negative num, eg. because of DST ending.
* Just run the wildcard jobs. The fixed-time
* jobs probably have already run, and should
* not be repeated. Virtual time does not
* change until we are caught up.
*/
Debug(DSCH, ("[%ld], DST ends %d minutes to go\n",
(long)getpid(), timeDiff));
find_jobs(timeRunning, &database, TRUE, FALSE);
break;
default:
/*
* other: time has changed a *lot*,
* jump virtual time, and run everything
*/
Debug(DSCH, ("[%ld], clock jumped\n",
(long)getpid()));
virtualTime = timeRunning;
find_jobs(timeRunning, &database, TRUE, TRUE);
}
}
/* Jobs to be run (if any) are loaded; clear the queue. */
(void)job_runqueue();
/* Check to see if we received a signal while running jobs. */
if (got_sighup) {
got_sighup = 0;
log_close();
}
if (got_sigchld) {
got_sigchld = 0;
sigchld_reaper();
}
load_database(&database);
}
}
