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cronie/src/cron.c

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/* Copyright 1988,1990,1993,1994 by Paul Vixie
* All rights reserved
*/
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1997,2000 by Internet Software Consortium, Inc.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Modified 2010/09/12 by Colin Dean, Durham University IT Service,
* to add clustering support.
*/
#include "config.h"
#define MAIN_PROGRAM
#include <errno.h>
#include <langinfo.h>
#include <locale.h>
#include <pwd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <sys/time.h>
#ifdef WITH_INOTIFY
# include <sys/inotify.h>
#endif
#ifdef HAVE_SYS_FCNTL_H
# include <sys/fcntl.h>
#endif
#include "cronie_common.h"
#include "funcs.h"
#include "globals.h"
#include "pathnames.h"
#if defined WITH_INOTIFY
int inotify_enabled;
#else
# define inotify_enabled 0
#endif
enum timejump { negative, small, medium, large };
static void usage(void) ATTRIBUTE_NORETURN,
run_reboot_jobs(cron_db *),
find_jobs(int, cron_db *, int, int, long),
set_time(int),
cron_sleep(int, cron_db *),
sigchld_handler(int),
sighup_handler(int ATTRIBUTE_UNUSED),
sigchld_reaper(void),
sigintterm_handler(int ATTRIBUTE_UNUSED), parse_args(int c, char *v[]);
static volatile sig_atomic_t got_sighup, got_sigchld, got_sigintterm;
static int timeRunning, virtualTime, clockTime;
static long GMToff;
static int DisableInotify;
#if defined WITH_INOTIFY
/*
* Note that inotify isn't safe to use with clustering, as changes made
* to a shared filesystem on one system cannot be relied on to be notified
* on another system, so use of inotify is disabled at runtime if run with
* clustering enabled.
*/
# if defined ENABLE_SYSCRONTAB
# define NUM_WATCHES 3
int wd[NUM_WATCHES];
const char *watchpaths[NUM_WATCHES] = {SPOOL_DIR, SYS_CROND_DIR, SYSCRONTAB};
# else
# define NUM_WATCHES 2
int wd[NUM_WATCHES];
const char *watchpaths[NUM_WATCHES] = {SPOOL_DIR, SYS_CROND_DIR};
# endif
static void reset_watches(void) {
size_t i;
for (i = 0; i < sizeof (wd) / sizeof (wd[0]); ++i) {
wd[i] = -2;
}
}
void set_cron_unwatched(int fd) {
size_t i;
for (i = 0; i < sizeof (wd) / sizeof (wd[0]); ++i) {
if (wd[i] > 0) {
inotify_rm_watch(fd, wd[i]);
wd[i] = -1;
}
}
}
void set_cron_watched(int fd) {
pid_t pid = getpid();
size_t i;
if (fd < 0) {
inotify_enabled = 0;
return;
}
for (i = 0; i < sizeof (wd) / sizeof (wd[0]); ++i) {
int w;
w = inotify_add_watch(fd, watchpaths[i],
IN_CREATE | IN_CLOSE_WRITE | IN_ATTRIB | IN_MODIFY | IN_MOVED_TO |
IN_MOVED_FROM | IN_MOVE_SELF | IN_DELETE | IN_DELETE_SELF);
if (w < 0 && errno != ENOENT) {
if (wd[i] != -1) {
log_it("CRON", pid, "This directory or file can't be watched",
watchpaths[i], errno);
log_it("CRON", pid, "INFO", "running without inotify support",
0);
}
inotify_enabled = 0;
set_cron_unwatched(fd);
return;
}
wd[i] = w;
}
if (!inotify_enabled) {
log_it("CRON", pid, "INFO", "running with inotify support", 0);
}
inotify_enabled = 1;
}
#endif
static void handle_signals(cron_db * database) {
if (got_sighup) {
got_sighup = 0;
#if defined WITH_INOTIFY
/* watches must be reinstated on reload */
if (inotify_enabled && (EnableClustering != 1)) {
set_cron_unwatched(database->ifd);
reset_watches();
inotify_enabled = 0;
}
#endif
database->mtime = (time_t) 0;
log_close();
}
if (got_sigchld) {
got_sigchld = 0;
sigchld_reaper();
}
}
static void usage(void) {
const char **dflags;
fprintf(stderr, "Usage:\n");
fprintf(stderr, " %s [options]\n", ProgramName);
fprintf(stderr, "\n");
fprintf(stderr, "Options:\n");
fprintf(stderr, " -h print this message \n");
fprintf(stderr, " -i deamon runs without inotify support\n");
fprintf(stderr, " -m <comm> off, or specify preferred client for sending mails\n");
fprintf(stderr, " -n run in foreground\n");
fprintf(stderr, " -p permit any crontab\n");
fprintf(stderr, " -P use PATH=\"%s\"\n", _PATH_DEFPATH);
fprintf(stderr, " -c enable clustering support\n");
fprintf(stderr, " -s log into syslog instead of sending mails\n");
fprintf(stderr, " -V print version and exit\n");
fprintf(stderr, " -x <flag> print debug information\n");
fprintf(stderr, "\n");
fprintf(stderr, "Debugging flags are: ");
for (dflags = DebugFlagNames; *dflags; dflags++)
fprintf(stderr, "%s%s", *dflags, dflags[1] ? "," : "\n");
exit(ERROR_EXIT);
}
int main(int argc, char *argv[]) {
struct sigaction sact;
cron_db database;
int fd;
char *cs;
pid_t pid = getpid();
long oldGMToff;
struct timeval tv;
struct timezone tz;
char buf[256];
if ((ProgramName=strrchr(argv[0], '/')) == NULL) {
ProgramName = argv[0];
}
else {
++ProgramName;
}
MailCmd[0] = '\0';
cron_default_mail_charset[0] = '\0';
setlocale(LC_ALL, "");
#if defined(BSD)
setlinebuf(stdout);
setlinebuf(stderr);
#endif
SyslogOutput = 0;
NoFork = 0;
ChangePath = 1;
parse_args(argc, argv);
memset((char *) &sact, 0, sizeof sact);
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 = sigintterm_handler;
(void) sigaction(SIGINT, &sact, NULL);
(void) sigaction(SIGTERM, &sact, NULL);
acquire_daemonlock(0);
set_cron_uid();
check_spool_dir();
if (ChangePath) {
if (setenv("PATH", _PATH_DEFPATH, 1) < 0) {
log_it("CRON", pid, "DEATH", "can't setenv PATH",
errno);
exit(1);
}
}
/* Get the default locale character set for the mail
* "Content-Type: ...; charset=" header
*/
setlocale(LC_ALL, ""); /* set locale to system defaults or to
* that specified by any LC_* env vars */
if ((cs = nl_langinfo(CODESET)) != NULL)
strncpy(cron_default_mail_charset, cs, MAX_ENVSTR-1);
else
strcpy(cron_default_mail_charset, "US-ASCII");
/* 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) {
switch (fork()) {
case -1:
log_it("CRON", pid, "DEATH", "can't fork", errno);
exit(0);
break;
case 0:
/* child process */
(void) setsid();
if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) >= 0) {
(void) dup2(fd, STDIN);
(void) dup2(fd, STDOUT);
(void) dup2(fd, STDERR);
if (fd != STDERR)
(void) close(fd);
}
break;
default:
/* parent process should just die */
_exit(0);
}
}
log_it("CRON", getpid(), "STARTUP", PACKAGE_VERSION, 0);
if (!SyslogOutput && MailCmd[0] == '\0' && access("/usr/sbin/sendmail", X_OK) != 0) {
SyslogOutput=1;
log_it("CRON", pid, "INFO","Syslog will be used instead of sendmail.", 0);
}
pid = getpid();
/* obtain a random scaling factor for RANDOM_DELAY */
if (gettimeofday(&tv, &tz) != 0)
tv.tv_usec = 0;
srandom((unsigned int)(pid + tv.tv_usec));
RandomScale = (double)random() / (double)RAND_MAX;
snprintf(buf, sizeof(buf), "RANDOM_DELAY will be scaled with factor %d%% if used.", (int)(RandomScale*100));
log_it("CRON", pid, "INFO", buf, 0);
acquire_daemonlock(0);
database.head = NULL;
database.tail = NULL;
database.mtime = (time_t) 0;
load_database(&database);
fd = -1;
#if defined WITH_INOTIFY
if (DisableInotify || EnableClustering) {
log_it("CRON", getpid(), "No inotify - daemon runs with -i or -c option",
"", 0);
}
else {
reset_watches();
database.ifd = fd = inotify_init();
fcntl(fd, F_SETFD, FD_CLOEXEC);
if (fd < 0)
log_it("CRON", pid, "INFO", "Inotify init failed", errno);
set_cron_watched(fd);
}
#endif
set_time(TRUE);
run_reboot_jobs(&database);
timeRunning = virtualTime = clockTime;
oldGMToff = GMToff;
/*
* 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.
*/
while (!got_sigintterm) {
int timeDiff;
enum timejump wakeupKind;
/* ... wait for the time (in minutes) to change ... */
do {
cron_sleep(timeRunning + 1, &database);
set_time(FALSE);
} while (!got_sigintterm && clockTime == timeRunning);
if (got_sigintterm)
break;
timeRunning = clockTime;
/*
* Calculate how the current time differs from our virtual
* clock. Classify the change into one of 4 cases.
*/
timeDiff = timeRunning - virtualTime;
check_orphans(&database);
#if defined WITH_INOTIFY
if (inotify_enabled) {
check_inotify_database(&database);
}
else {
if (load_database(&database) && (EnableClustering != 1))
/* try reinstating the watches */
set_cron_watched(fd);
}
#else
load_database(&database);
#endif
/* shortcut for the most common case */
if (timeDiff == 1) {
virtualTime = timeRunning;
oldGMToff = GMToff;
find_jobs(virtualTime, &database, TRUE, TRUE, oldGMToff);
}
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) pid, timeDiff));
do {
if (job_runqueue())
sleep(10);
virtualTime++;
if (virtualTime >= timeRunning)
/* always run also the other timezone jobs in the last step */
oldGMToff = GMToff;
find_jobs(virtualTime, &database, TRUE, TRUE, oldGMToff);
} 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) pid, timeDiff));
/* run wildcard jobs for current minute */
find_jobs(timeRunning, &database, TRUE, FALSE, GMToff);
/* run fixed-time jobs for each minute missed */
do {
if (job_runqueue())
sleep(10);
virtualTime++;
if (virtualTime >= timeRunning)
/* always run also the other timezone jobs in the last step */
oldGMToff = GMToff;
find_jobs(virtualTime, &database, FALSE, TRUE, oldGMToff);
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) pid, timeDiff));
find_jobs(timeRunning, &database, TRUE, FALSE, GMToff);
break;
default:
/*
* other: time has changed a *lot*,
* jump virtual time, and run everything
*/
Debug(DSCH, ("[%ld], clock jumped\n", (long) pid));
virtualTime = timeRunning;
oldGMToff = GMToff;
find_jobs(timeRunning, &database, TRUE, TRUE, GMToff);
}
}
/* Jobs to be run (if any) are loaded; clear the queue. */
job_runqueue();
handle_signals(&database);
}
#if defined WITH_INOTIFY
if (inotify_enabled && (EnableClustering != 1))
set_cron_unwatched(fd);
if (fd >= 0 && close(fd) < 0)
log_it("CRON", pid, "INFO", "Inotify close failed", errno);
#endif
log_it("CRON", pid, "INFO", "Shutting down", 0);
(void) unlink(_PATH_CRON_PID);
return 0;
}
static void run_reboot_jobs(cron_db * db) {
user *u;
entry *e;
int reboot;
pid_t pid = getpid();
/* lock exist - skip reboot jobs */
if (access(REBOOT_LOCK, F_OK) == 0) {
log_it("CRON", pid, "INFO",
"@reboot jobs will be run at computer's startup.", 0);
return;
}
/* lock doesn't exist - create lock, run reboot jobs */
if ((reboot = creat(REBOOT_LOCK, S_IRUSR & S_IWUSR)) < 0)
log_it("CRON", pid, "INFO", "Can't create lock for reboot jobs.",
errno);
else
close(reboot);
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 find_jobs(int vtime, cron_db * db, int doWild, int doNonWild, long vGMToff) {
char *orig_tz, *job_tz;
struct tm *tm;
int minute, hour, dom, month, dow;
user *u;
entry *e;
/* The support for the job-specific timezones is not perfect. There will
* be jobs missed or run twice during the DST change in the job timezone.
* It is recommended not to schedule any jobs during the hour when
* the DST changes happen if job-specific timezones are used.
*
* Make 0-based values out of tm values so we can use them as indicies
*/
#define maketime(tz1, tz2) do { \
char *t = tz1; \
if (t != NULL && *t != '\0') { \
setenv("TZ", t, 1); \
tm = localtime(&virtualGMTSecond); \
} else { if ((tz2) != NULL) \
setenv("TZ", (tz2), 1); \
else \
unsetenv("TZ"); \
tm = gmtime(&virtualSecond); \
} \
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; \
} while (0)
orig_tz = getenv("TZ");
/* 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) {
time_t virtualSecond = (time_t)(vtime - e->delay) * (time_t)SECONDS_PER_MINUTE;
time_t virtualGMTSecond = virtualSecond - vGMToff;
job_tz = env_get("CRON_TZ", e->envp);
maketime(job_tz, orig_tz);
/* here we test whether time is NOW */
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))
)
) {
if (job_tz != NULL && vGMToff != GMToff)
/* do not try to run the jobs from different timezones
* during the DST switch of the default timezone.
*/
continue;
if ((doNonWild &&
!(e->flags & (MIN_STAR | HR_STAR))) ||
(doWild && (e->flags & (MIN_STAR | HR_STAR))))
job_add(e, u); /*will add job, if it isn't in queue already for NOW. */
}
}
}
if (orig_tz != NULL)
setenv("TZ", orig_tz, 1);
else
unsetenv("TZ");
}
/*
* Set StartTime and clockTime to the current time.
* These are used for computing what time it really is right now.
* Note that clockTime is a unix wallclock time converted to minutes.
*/
static void set_time(int initialize) {
struct tm tm;
static int isdst;
StartTime = time(NULL);
/* We adjust the time to GMT so we can catch DST changes. */
tm = *localtime(&StartTime);
if (initialize || tm.tm_isdst != isdst) {
isdst = tm.tm_isdst;
GMToff = get_gmtoff(&StartTime, &tm);
Debug(DSCH, ("[%ld] GMToff=%ld\n", (long) getpid(), (long) GMToff));
}
clockTime = (int)((StartTime + GMToff) / (time_t) SECONDS_PER_MINUTE);
}
/*
* Try to just hit the next minute.
*/
static void cron_sleep(int target, cron_db * db) {
time_t t1, t2;
int seconds_to_wait;
t1 = time(NULL) + GMToff;
seconds_to_wait = (int) (target * SECONDS_PER_MINUTE - t1) + 1;
Debug(DSCH, ("[%ld] Target time=%ld, sec-to-wait=%d\n",
(long) getpid(), (long) target * SECONDS_PER_MINUTE,
seconds_to_wait));
while (seconds_to_wait > 0 && seconds_to_wait < 65) {
sleep((unsigned int) seconds_to_wait);
if (got_sigintterm)
return;
/*
* Check to see if we were interrupted by a signal.
* If so, service the signal(s) then continue sleeping
* where we left off.
*/
handle_signals(db);
t2 = time(NULL) + GMToff;
seconds_to_wait -= (int) (t2 - t1);
t1 = t2;
}
}
static void sighup_handler(int x ATTRIBUTE_UNUSED) {
got_sighup = 1;
}
static void sigchld_handler(int x ATTRIBUTE_UNUSED) {
got_sigchld = 1;
}
static void sigintterm_handler(int x ATTRIBUTE_UNUSED) {
got_sigintterm = 1;
}
static void sigchld_reaper(void) {
WAIT_T waiter;
PID_T pid;
do {
pid = waitpid(-1, &waiter, WNOHANG);
switch (pid) {
case -1:
if (errno == EINTR)
continue;
Debug(DPROC, ("[%ld] sigchld...no children\n", (long) getpid()));
break;
case 0:
Debug(DPROC, ("[%ld] sigchld...no dead kids\n", (long) getpid()));
break;
default:
Debug(DPROC,
("[%ld] sigchld...pid #%ld died, stat=%d\n",
(long) getpid(), (long) pid, WEXITSTATUS(waiter)));
break;
}
} while (pid > 0);
}
static void parse_args(int argc, char *argv[]) {
int argch;
while (-1 != (argch = getopt(argc, argv, "hnpsiPx:m:cV"))) {
switch (argch) {
case 'x':
if (!set_debug_flags(optarg))
usage();
break;
case 'n':
NoFork = 1;
break;
case 'p':
PermitAnyCrontab = 1;
break;
case 's':
SyslogOutput = 1;
break;
case 'i':
DisableInotify = 1;
break;
case 'P':
ChangePath = 0;
break;
case 'm':
strncpy(MailCmd, optarg, MAX_COMMAND);
break;
case 'c':
EnableClustering = 1;
break;
case 'V':
puts(PACKAGE_STRING);
exit(EXIT_SUCCESS);
case 'h':
default:
usage();
break;
}
}
}
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