+#if !defined(lint) && !defined(LINT)
+static char rcsid[] = "$Header: /home/local/site/cron2.1/orig/RCS/crond.c,v 2.2 1992/05/13 05:56:35 rich Exp $";
+#endif
+
+/* Copyright 1988,1990 by Paul Vixie
+ * All rights reserved
+ *
+ * Distribute freely, except: don't remove my name from the source or
+ * documentation (don't take credit for my work), mark your changes (don't
+ * get me blamed for your possible bugs), don't alter or remove this
+ * notice. May be sold if buildable source is provided to buyer. No
+ * warrantee of any kind, express or implied, is included with this
+ * software; use at your own risk, responsibility for damages (if any) to
+ * anyone resulting from the use of this software rests entirely with the
+ * user.
+ *
+ * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
+ * I'll try to keep a version up to date. I can be reached as follows:
+ * Paul Vixie, 329 Noe Street, San Francisco, CA, 94114, (415) 864-7013,
+ * paul@vixie.sf.ca.us || {hoptoad,pacbell,decwrl,crash}!vixie!paul
+ */
+
+
+#define MAIN_PROGRAM
+
+
+#include "cron.h"
+#include <sys/time.h>
+#include <sys/signal.h>
+#include <sys/types.h>
+#if defined(BSD)
+# include <sys/wait.h>
+# include <sys/resource.h>
+#endif /*BSD*/
+
+extern int fork(), unlink();
+extern time_t time();
+extern void exit();
+extern unsigned sleep();
+
+void
+usage()
+{
+ (void) fprintf(stderr, "usage: %s [-x debugflag[,...]]\n", ProgramName);
+ (void) exit(ERROR_EXIT);
+}
+
+
+int
+main(argc, argv)
+ int argc;
+ char *argv[];
+{
+ extern void set_cron_uid(), be_different(), load_database(),
+ set_cron_cwd(), open_logfile();
+
+ static void cron_tick(), cron_sleep(), cron_sync(),
+ sigchld_handler(), parse_args(), run_reboot_jobs();
+
+ auto cron_db database;
+
+ ProgramName = argv[0];
+
+#if defined(BSD)
+ setlinebuf(stdout);
+ setlinebuf(stderr);
+#endif
+
+ parse_args(argc, argv);
+
+# if DEBUGGING
+ /* if there are no debug flags turned on, fork as a daemon should.
+ */
+ if (DebugFlags)
+ {
+ (void) fprintf(stderr, "[%d] crond started\n", getpid());
+ }
+ else
+# endif /*DEBUGGING*/
+ {
+ switch (fork())
+ {
+ case -1:
+ log_it("CROND",getpid(),"DEATH","can't fork");
+ exit(0);
+ break;
+ case 0:
+ /* child process */
+ be_different();
+ break;
+ default:
+ /* parent process should just die */
+ _exit(0);
+ }
+ }
+
+#if defined(BSD)
+ (void) signal(SIGCHLD, sigchld_handler);
+#endif /*BSD*/
+
+#if defined(ATT)
+ (void) signal(SIGCLD, SIG_IGN);
+#endif /*ATT*/
+
+ acquire_daemonlock();
+ set_cron_uid();
+ set_cron_cwd();
+ database.head = NULL;
+ database.tail = NULL;
+ database.mtime = (time_t) 0;
+ load_database(&database);
+ run_reboot_jobs(&database);
+ cron_sync();
+ while (TRUE)
+ {
+# if DEBUGGING
+ if (!(DebugFlags & DTEST))
+# endif /*DEBUGGING*/
+ cron_sleep();
+
+ load_database(&database);
+
+ /* do this iteration
+ */
+ cron_tick(&database);
+
+ /* sleep 1 minute
+ */
+ TargetTime += 60;
+ }
+}
+
+
+static void
+run_reboot_jobs(db)
+ cron_db *db;
+{
+ extern void job_add();
+ extern int job_runqueue();
+ 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->cmd, u);
+ }
+ }
+ }
+ (void) job_runqueue();
+}
+
+
+static void
+cron_tick(db)
+ cron_db *db;
+{
+ extern void job_add();
+ extern char *env_get();
+ extern struct tm *localtime();
+ register struct tm *tm = localtime(&TargetTime);
+ local 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) {
+ Debug(DSCH|DEXT, ("user [%s:%d:%d:...]\n",
+ env_get(USERENV,u->envp), u->uid, u->gid))
+ for (e = u->crontab; e != NULL; e = e->next) {
+ Debug(DSCH|DEXT, ("entry [%s]\n", 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->cmd, 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 crond 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..
+ */
+static void
+cron_sync()
+{
+ extern struct tm *localtime();
+ register struct tm *tm;
+
+ TargetTime = time((time_t*)0);
+ tm = localtime(&TargetTime);
+ TargetTime += (60 - tm->tm_sec);
+}
+
+
+static void
+cron_sleep()
+{
+ extern void do_command();
+ extern int job_runqueue();
+ 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());
+
+ if (seconds_to_wait > 0)
+ {
+ Debug(DSCH, ("[%d] sleeping for %d seconds\n",
+ getpid(), seconds_to_wait))
+ (void) sleep((unsigned int) seconds_to_wait);
+ }
+}
+
+
+#if defined(BSD)
+static void
+sigchld_handler()
+{
+ union wait waiter;
+ int pid;
+
+ for (;;)
+ {
+ pid = wait3(&waiter, WNOHANG, (struct rusage *)0);
+ 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, waiter.w_status))
+ }
+ }
+}
+#endif /*BSD*/
+
+
+static void
+parse_args(argc, argv)
+ int argc;
+ char *argv[];
+{
+ extern int optind, getopt();
+ extern void usage();
+ extern char *optarg;
+
+ int argch;
+
+ while (EOF != (argch = getopt(argc, argv, "x:")))
+ {
+ switch (argch)
+ {
+ default:
+ usage();
+ case 'x':
+ if (!set_debug_flags(optarg))
+ usage();
+ break;
+ }
+ }
+}
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