1 /* vi: set sw=4 ts=4: */
3 * crond -d[#] -c <crondir> -f -b
5 * run as root, but NOT setuid root
7 * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
9 * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
11 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
14 #include <sys/syslog.h>
18 #define CRONTABS "/var/spool/cron/crontabs"
21 #define TMPDIR "/var/spool/cron"
24 #define SENDMAIL "sendmail"
27 #define SENDMAIL_ARGS "-ti", "oem"
30 #define CRONUPDATE "cron.update"
33 #define MAXLINES 256 /* max lines in non-root crontabs */
36 typedef struct CronFile {
37 struct CronFile *cf_Next;
38 struct CronLine *cf_LineBase;
39 char *cf_User; /* username */
40 int cf_Ready; /* bool: one or more jobs ready */
41 int cf_Running; /* bool: one or more jobs running */
42 int cf_Deleted; /* marked for deletion, ignore */
45 typedef struct CronLine {
46 struct CronLine *cl_Next;
47 char *cl_Shell; /* shell command */
48 pid_t cl_Pid; /* running pid, 0, or armed (-1) */
49 int cl_MailFlag; /* running pid is for mail */
50 int cl_MailPos; /* 'empty file' size */
51 char cl_Mins[60]; /* 0-59 */
52 char cl_Hrs[24]; /* 0-23 */
53 char cl_Days[32]; /* 1-31 */
54 char cl_Mons[12]; /* 0-11 */
55 char cl_Dow[7]; /* 0-6, beginning sunday */
64 #if ENABLE_DEBUG_CROND_OPTION
65 static unsigned DebugOpt;
68 static unsigned LogLevel = 8;
69 static const char *LogFile;
70 static const char *CDir = CRONTABS;
72 static void startlogger(void);
74 static void CheckUpdates(void);
75 static void SynchronizeDir(void);
76 static int TestJobs(time_t t1, time_t t2);
77 static void RunJobs(void);
78 static int CheckJobs(void);
80 static void RunJob(const char *user, CronLine * line);
82 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
83 static void EndJob(const char *user, CronLine * line);
85 #define EndJob(user, line) line->cl_Pid = 0
88 static void DeleteFile(const char *userName);
90 static CronFile *FileBase;
93 static void crondlog(const char *ctl, ...)
97 int level = (int) (ctl[0] & 0xf);
98 int type = level == 20 ?
99 LOG_ERR : ((ctl[0] & 0100) ? LOG_WARNING : LOG_NOTICE);
104 if (level >= LogLevel) {
106 #if ENABLE_DEBUG_CROND_OPTION
108 vfprintf(stderr, fmt, va);
112 vsyslog(type, fmt, va);
114 #if !ENABLE_DEBUG_CROND_OPTION
115 int logfd = open(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0600);
117 int logfd = open3_or_warn(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0600);
120 vdprintf(logfd, fmt, va);
131 int crond_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
132 int crond_main(int ac, char **av)
135 char *lopt, *Lopt, *copt;
136 USE_DEBUG_CROND_OPTION(char *dopt;)
138 opt_complementary = "f-b:b-f:S-L:L-S" USE_DEBUG_CROND_OPTION(":d-l");
139 opterr = 0; /* disable getopt 'errors' message. */
140 opt = getopt32(av, "l:L:fbSc:" USE_DEBUG_CROND_OPTION("d:"),
141 &lopt, &Lopt, &copt USE_DEBUG_CROND_OPTION(, &dopt));
142 if (opt & 1) /* -l */
143 LogLevel = xatou(lopt);
144 if (opt & 2) /* -L */
147 if (opt & 32) /* -c */
150 #if ENABLE_DEBUG_CROND_OPTION
151 if (opt & 64) { /* -d */
152 DebugOpt = xatou(dopt);
157 /* close stdin and stdout, stderr.
158 * close unused descriptors - don't need.
159 * optional detach from controlling terminal
162 bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, av);
165 signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */
167 startlogger(); /* need if syslog mode selected */
170 * main loop - synchronize to 1 second after the minute, minimum sleep
173 crondlog("\011%s " BB_VER " started, log level %d\n",
174 applet_name, LogLevel);
179 time_t t1 = time(NULL);
183 short sleep_time = 60;
185 write_pidfile("/var/run/crond.pid");
187 sleep((sleep_time + 1) - (short) (time(NULL) % sleep_time));
193 * The file 'cron.update' is checked to determine new cron
194 * jobs. The directory is rescanned once an hour to deal
197 * check for disparity. Disparities over an hour either way
198 * result in resynchronization. A reverse-indexed disparity
199 * less then an hour causes us to effectively sleep until we
200 * match the original time (i.e. no re-execution of jobs that
201 * have just been run). A forward-indexed disparity less then
202 * an hour causes intermediate jobs to be run, but only once
205 * when running jobs, the inequality used is greater but not
206 * equal to t1, and less then or equal to t2.
214 #if ENABLE_DEBUG_CROND_OPTION
216 crondlog("\005Wakeup dt=%d\n", dt);
218 if (dt < -60 * 60 || dt > 60 * 60) {
220 crondlog("\111time disparity of %d minutes detected\n", dt / 60);
225 if (CheckJobs() > 0) {
234 return 0; /* not reached */
237 static int ChangeUser(const char *user)
243 * Obtain password entry and change privileges
245 pas = getpwnam(user);
247 crondlog("\011failed to get uid for %s", user);
250 setenv("USER", pas->pw_name, 1);
251 setenv("HOME", pas->pw_dir, 1);
252 setenv("SHELL", DEFAULT_SHELL, 1);
255 * Change running state to the user in question
257 err_msg = change_identity_e2str(pas);
259 crondlog("\011%s for user %s", err_msg, user);
262 if (chdir(pas->pw_dir) < 0) {
263 crondlog("\011chdir failed: %s: %m", pas->pw_dir);
264 if (chdir(TMPDIR) < 0) {
265 crondlog("\011chdir failed: %s: %m", TMPDIR);
272 static void startlogger(void)
275 openlog(applet_name, LOG_CONS | LOG_PID, LOG_CRON);
277 #if ENABLE_DEBUG_CROND_OPTION
278 else { /* test logfile */
281 logfd = open3_or_warn(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0600);
290 static const char DowAry[] ALIGN1 =
291 "sun""mon""tue""wed""thu""fri""sat"
292 /* "Sun""Mon""Tue""Wed""Thu""Fri""Sat" */
295 static const char MonAry[] ALIGN1 =
296 "jan""feb""mar""apr""may""jun""jul""aug""sep""oct""nov""dec"
297 /* "Jan""Feb""Mar""Apr""May""Jun""Jul""Aug""Sep""Oct""Nov""Dec" */
300 static char *ParseField(char *user, char *ary, int modvalue, int off,
301 const char *names, char *ptr)
302 /* 'names' is a pointer to a set of 3-char abbreviations */
312 while (*ptr != ' ' && *ptr != '\t' && *ptr != '\n') {
315 /* Handle numeric digit or symbol or '*' */
318 n1 = 0; /* everything will be filled */
322 } else if (*ptr >= '0' && *ptr <= '9') {
324 n1 = strtol(ptr, &ptr, 10) + off;
326 n2 = strtol(ptr, &ptr, 10) + off;
332 for (i = 0; names[i]; i += 3) {
333 /* was using strncmp before... */
334 if (strncasecmp(ptr, &names[i], 3) == 0) {
347 /* handle optional range '-' */
350 crondlog("\111failed user %s parsing %s\n", user, base);
353 if (*ptr == '-' && n2 < 0) {
359 * collapse single-value ranges, handle skipmark, and fill
360 * in the character array appropriately.
367 skip = strtol(ptr + 1, &ptr, 10);
370 * fill array, using a failsafe is the easiest way to prevent
380 n1 = (n1 + 1) % modvalue;
383 ary[n1 % modvalue] = 1;
387 while (n1 != n2 && --failsafe);
390 crondlog("\111failed user %s parsing %s\n", user, base);
402 if (*ptr != ' ' && *ptr != '\t' && *ptr != '\n') {
403 crondlog("\111failed user %s parsing %s\n", user, base);
407 while (*ptr == ' ' || *ptr == '\t' || *ptr == '\n') {
410 #if ENABLE_DEBUG_CROND_OPTION
414 for (i = 0; i < modvalue; ++i) {
415 crondlog("\005%d", ary[i]);
424 static void FixDayDow(CronLine * line)
430 for (i = 0; i < (int)(ARRAY_SIZE(line->cl_Dow)); ++i) {
431 if (line->cl_Dow[i] == 0) {
436 for (i = 0; i < (int)(ARRAY_SIZE(line->cl_Days)); ++i) {
437 if (line->cl_Days[i] == 0) {
442 if (weekUsed && !daysUsed) {
443 memset(line->cl_Days, 0, sizeof(line->cl_Days));
445 if (daysUsed && !weekUsed) {
446 memset(line->cl_Dow, 0, sizeof(line->cl_Dow));
452 static void SynchronizeFile(const char *fileName)
454 int maxEntries = MAXLINES;
458 if (strcmp(fileName, "root") == 0) {
461 maxLines = maxEntries * 10;
466 DeleteFile(fileName);
468 fi = fopen(fileName, "r");
472 if (fstat(fileno(fi), &sbuf) == 0 && sbuf.st_uid == DaemonUid) {
473 CronFile *file = xzalloc(sizeof(CronFile));
476 file->cf_User = strdup(fileName);
477 pline = &file->cf_LineBase;
479 while (fgets(buf, sizeof(buf), fi) != NULL && --maxLines) {
484 if (buf[0] == 0 || buf[0] == '#') {
487 if (--maxEntries == 0) {
490 memset(&line, 0, sizeof(line));
492 #if ENABLE_DEBUG_CROND_OPTION
494 crondlog("\111User %s Entry %s\n", fileName, buf);
498 /* parse date ranges */
499 ptr = ParseField(file->cf_User, line.cl_Mins, 60, 0, NULL, buf);
500 ptr = ParseField(file->cf_User, line.cl_Hrs, 24, 0, NULL, ptr);
501 ptr = ParseField(file->cf_User, line.cl_Days, 32, 0, NULL, ptr);
502 ptr = ParseField(file->cf_User, line.cl_Mons, 12, -1, MonAry, ptr);
503 ptr = ParseField(file->cf_User, line.cl_Dow, 7, 0, DowAry, ptr);
511 * fix days and dow - if one is not * and the other
512 * is *, the other is set to 0, and vise-versa
517 *pline = xzalloc(sizeof(CronLine));
521 (*pline)->cl_Shell = strdup(ptr);
523 #if ENABLE_DEBUG_CROND_OPTION
525 crondlog("\111 Command %s\n", ptr);
529 pline = &((*pline)->cl_Next);
533 file->cf_Next = FileBase;
536 if (maxLines == 0 || maxEntries == 0) {
537 crondlog("\111Maximum number of lines reached for user %s\n", fileName);
545 static void CheckUpdates(void)
550 fi = fopen(CRONUPDATE, "r");
553 while (fgets(buf, sizeof(buf), fi) != NULL) {
554 SynchronizeFile(strtok(buf, " \t\r\n"));
560 static void SynchronizeDir(void)
562 /* Attempt to delete the database. */
567 for (file = FileBase; file && file->cf_Deleted; file = file->cf_Next);
571 DeleteFile(file->cf_User);
575 * Remove cron update file
577 * Re-chdir, in case directory was renamed & deleted, or otherwise
580 * scan directory and add associated users
584 if (chdir(CDir) < 0) {
585 crondlog("\311cannot find %s\n", CDir);
588 DIR *dir = opendir(".");
592 while ((den = readdir(dir))) {
593 if (strchr(den->d_name, '.') != NULL) {
596 if (getpwnam(den->d_name)) {
597 SynchronizeFile(den->d_name);
599 crondlog("\007ignoring %s\n", den->d_name);
604 crondlog("\311cannot open current dir!\n");
611 * DeleteFile() - delete user database
613 * Note: multiple entries for same user may exist if we were unable to
614 * completely delete a database due to running processes.
617 static void DeleteFile(const char *userName)
619 CronFile **pfile = &FileBase;
622 while ((file = *pfile) != NULL) {
623 if (strcmp(userName, file->cf_User) == 0) {
624 CronLine **pline = &file->cf_LineBase;
627 file->cf_Running = 0;
628 file->cf_Deleted = 1;
630 while ((line = *pline) != NULL) {
631 if (line->cl_Pid > 0) {
632 file->cf_Running = 1;
633 pline = &line->cl_Next;
635 *pline = line->cl_Next;
636 free(line->cl_Shell);
640 if (file->cf_Running == 0) {
641 *pfile = file->cf_Next;
645 pfile = &file->cf_Next;
648 pfile = &file->cf_Next;
656 * determine which jobs need to be run. Under normal conditions, the
657 * period is about a minute (one scan). Worst case it will be one
661 static int TestJobs(time_t t1, time_t t2)
666 /* Find jobs > t1 and <= t2 */
668 for (t = t1 - t1 % 60; t <= t2; t += 60) {
670 struct tm *tp = localtime(&t);
674 for (file = FileBase; file; file = file->cf_Next) {
675 #if ENABLE_DEBUG_CROND_OPTION
677 crondlog("\005FILE %s:\n", file->cf_User);
679 if (file->cf_Deleted)
681 for (line = file->cf_LineBase; line; line = line->cl_Next) {
682 #if ENABLE_DEBUG_CROND_OPTION
684 crondlog("\005 LINE %s\n", line->cl_Shell);
686 if (line->cl_Mins[tp->tm_min] && line->cl_Hrs[tp->tm_hour] &&
687 (line->cl_Days[tp->tm_mday] || line->cl_Dow[tp->tm_wday])
688 && line->cl_Mons[tp->tm_mon]) {
689 #if ENABLE_DEBUG_CROND_OPTION
691 crondlog("\005 JobToDo: %d %s\n",
692 line->cl_Pid, line->cl_Shell);
695 if (line->cl_Pid > 0) {
696 crondlog("\010 process already running: %s %s\n",
697 file->cf_User, line->cl_Shell);
698 } else if (line->cl_Pid == 0) {
711 static void RunJobs(void)
716 for (file = FileBase; file; file = file->cf_Next) {
717 if (file->cf_Ready) {
720 for (line = file->cf_LineBase; line; line = line->cl_Next) {
721 if (line->cl_Pid < 0) {
723 RunJob(file->cf_User, line);
725 crondlog("\010USER %s pid %3d cmd %s\n",
726 file->cf_User, line->cl_Pid, line->cl_Shell);
727 if (line->cl_Pid < 0) {
730 else if (line->cl_Pid > 0) {
731 file->cf_Running = 1;
740 * CheckJobs() - check for job completion
742 * Check for job completion, return number of jobs still running after
746 static int CheckJobs(void)
750 int nStillRunning = 0;
752 for (file = FileBase; file; file = file->cf_Next) {
753 if (file->cf_Running) {
754 file->cf_Running = 0;
756 for (line = file->cf_LineBase; line; line = line->cl_Next) {
757 if (line->cl_Pid > 0) {
759 int r = wait4(line->cl_Pid, &status, WNOHANG, NULL);
761 if (r < 0 || r == line->cl_Pid) {
762 EndJob(file->cf_User, line);
764 file->cf_Running = 1;
767 file->cf_Running = 1;
772 nStillRunning += file->cf_Running;
774 return nStillRunning;
778 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
780 ForkJob(const char *user, CronLine * line, int mailFd,
781 const char *prog, const char *cmd, const char *arg, const char *mailf)
783 /* Fork as the user in question and run program */
790 /* Change running state to the user in question */
792 if (ChangeUser(user) < 0) {
795 #if ENABLE_DEBUG_CROND_OPTION
797 crondlog("\005Child Running %s\n", prog);
802 dup2(mailFd, mailf != NULL);
803 dup2((mailf ? mailFd : 1), 2);
806 execl(prog, prog, cmd, arg, NULL);
807 crondlog("\024cannot exec, user %s cmd %s %s %s\n", user, prog, cmd, arg);
809 fdprintf(1, "Exec failed: %s -c %s\n", prog, arg);
812 } else if (pid < 0) {
814 crondlog("\024cannot fork, user %s\n", user);
820 /* PARENT, FORK SUCCESS
821 * rename mail-file based on pid of process
825 snprintf(mailFile2, sizeof(mailFile2), TMPDIR "/cron.%s.%d", user, pid);
826 rename(mailf, mailFile2);
829 * Close the mail file descriptor.. we can't just leave it open in
830 * a structure, closing it later, because we might run out of descriptors
838 static void RunJob(const char *user, CronLine * line)
844 line->cl_MailFlag = 0;
846 /* open mail file - owner root so nobody can screw with it. */
848 snprintf(mailFile, sizeof(mailFile), TMPDIR "/cron.%s.%d", user, getpid());
849 mailFd = open(mailFile, O_CREAT | O_TRUNC | O_WRONLY | O_EXCL | O_APPEND, 0600);
852 line->cl_MailFlag = 1;
853 fdprintf(mailFd, "To: %s\nSubject: cron: %s\n\n", user,
855 line->cl_MailPos = lseek(mailFd, 0, SEEK_CUR);
857 crondlog("\024cannot create mail file user %s file %s, output to /dev/null\n", user, mailFile);
860 ForkJob(user, line, mailFd, DEFAULT_SHELL, "-c", line->cl_Shell, mailFile);
864 * EndJob - called when job terminates and when mail terminates
867 static void EndJob(const char *user, CronLine * line)
875 if (line->cl_Pid <= 0) {
881 * End of job and no mail file
882 * End of sendmail job
885 snprintf(mailFile, sizeof(mailFile), TMPDIR "/cron.%s.%d", user, line->cl_Pid);
888 if (line->cl_MailFlag != 1) {
891 line->cl_MailFlag = 0;
894 * End of primary job - check for mail file. If size has increased and
895 * the file is still valid, we sendmail it.
898 mailFd = open(mailFile, O_RDONLY);
904 if (fstat(mailFd, &sbuf) < 0 || sbuf.st_uid != DaemonUid
905 || sbuf.st_nlink != 0 || sbuf.st_size == line->cl_MailPos
906 || !S_ISREG(sbuf.st_mode)
911 ForkJob(user, line, mailFd, SENDMAIL, SENDMAIL_ARGS, NULL);
914 /* crond without sendmail */
916 static void RunJob(const char *user, CronLine * line)
918 /* Fork as the user in question and run program */
924 /* Change running state to the user in question */
926 if (ChangeUser(user) < 0) {
929 #if ENABLE_DEBUG_CROND_OPTION
931 crondlog("\005Child Running %s\n", DEFAULT_SHELL);
935 execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", line->cl_Shell, NULL);
936 crondlog("\024cannot exec, user %s cmd %s -c %s\n", user,
937 DEFAULT_SHELL, line->cl_Shell);
939 } else if (pid < 0) {
941 crondlog("\024cannot, user %s\n", user);
946 #endif /* ENABLE_FEATURE_CROND_CALL_SENDMAIL */