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.
17 /* glibc frees previous setenv'ed value when we do next setenv()
18 * of the same variable. uclibc does not do this! */
19 #if (defined(__GLIBC__) && !defined(__UCLIBC__)) /* || OTHER_SAFE_LIBC... */
20 # define SETENV_LEAKS 0
22 # define SETENV_LEAKS 1
26 #define TMPDIR CONFIG_FEATURE_CROND_DIR
27 #define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs"
29 # define SENDMAIL "sendmail"
32 # define SENDMAIL_ARGS "-ti", NULL
35 # define CRONUPDATE "cron.update"
38 # define MAXLINES 256 /* max lines in non-root crontabs */
42 typedef struct CronFile {
43 struct CronFile *cf_Next;
44 struct CronLine *cf_LineBase;
45 char *cf_User; /* username */
46 smallint cf_Ready; /* bool: one or more jobs ready */
47 smallint cf_Running; /* bool: one or more jobs running */
48 smallint cf_Deleted; /* marked for deletion, ignore */
51 typedef struct CronLine {
52 struct CronLine *cl_Next;
53 char *cl_Shell; /* shell command */
54 pid_t cl_Pid; /* running pid, 0, or armed (-1) */
55 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
56 int cl_MailPos; /* 'empty file' size */
57 char *cl_MailTo; /* whom to mail results */
58 smallint cl_MailFlag; /* running pid is for mail */
60 /* ordered by size, not in natural order. makes code smaller: */
61 char cl_Dow[7]; /* 0-6, beginning sunday */
62 char cl_Mons[12]; /* 0-11 */
63 char cl_Hrs[24]; /* 0-23 */
64 char cl_Days[32]; /* 1-31 */
65 char cl_Mins[60]; /* 0-59 */
79 OPT_d = (1 << 6) * ENABLE_FEATURE_CROND_D,
81 #if ENABLE_FEATURE_CROND_D
82 #define DebugOpt (option_mask32 & OPT_d)
89 unsigned LogLevel; /* = 8; */
91 const char *CDir; /* = CRONTABS; */
98 #define G (*(struct globals*)&bb_common_bufsiz1)
99 #define LogLevel (G.LogLevel )
100 #define LogFile (G.LogFile )
101 #define CDir (G.CDir )
102 #define FileBase (G.FileBase )
103 #define env_var_user (G.env_var_user )
104 #define env_var_home (G.env_var_home )
105 #define INIT_G() do { \
111 /* 0 is the most verbose, default 8 */
117 /* level >= 20 is "error" */
120 static void crondlog(const char *ctl, ...) __attribute__ ((format (printf, 1, 2)));
121 static void crondlog(const char *ctl, ...)
124 int level = (ctl[0] & 0x1f);
127 if (level >= (int)LogLevel) {
128 /* Debug mode: all to (non-redirected) stderr, */
129 /* Syslog mode: all to syslog (logmode = LOGMODE_SYSLOG), */
130 if (!DebugOpt && LogFile) {
131 /* Otherwise (log to file): we reopen log file at every write: */
132 int logfd = open3_or_warn(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0666);
134 xmove_fd(logfd, STDERR_FILENO);
136 /* When we log to syslog, level > 8 is logged at LOG_ERR
137 * syslog level, level <= 8 is logged at LOG_INFO. */
139 bb_verror_msg(ctl + 1, va, /* strerr: */ NULL);
142 vasprintf(&msg, ctl + 1, va);
143 bb_info_msg("%s: %s", applet_name, msg);
153 /* We set environment *before* vfork (because we want to use vfork),
154 * so we cannot use setenv() - repeated calls to setenv() may leak memory!
155 * Using putenv(), and freeing memory after unsetenv() won't leak */
156 static void safe_setenv(char **pvar_val, const char *var, const char *val)
158 char *var_val = *pvar_val;
161 bb_unsetenv_and_free(var_val);
163 *pvar_val = xasprintf("%s=%s", var, val);
168 static void SetEnv(struct passwd *pas)
171 safe_setenv(&env_var_user, "USER", pas->pw_name);
172 safe_setenv(&env_var_home, "HOME", pas->pw_dir);
173 /* if we want to set user's shell instead: */
174 /*safe_setenv(env_var_shell, "SHELL", pas->pw_shell);*/
176 xsetenv("USER", pas->pw_name);
177 xsetenv("HOME", pas->pw_dir);
179 /* currently, we use constant one: */
180 /*setenv("SHELL", DEFAULT_SHELL, 1); - done earlier */
183 static void ChangeUser(struct passwd *pas)
185 /* careful: we're after vfork! */
186 change_identity(pas); /* - initgroups, setgid, setuid */
187 if (chdir(pas->pw_dir) < 0) {
188 crondlog(WARN9 "chdir(%s)", pas->pw_dir);
189 if (chdir(TMPDIR) < 0) {
190 crondlog(DIE9 "chdir(%s)", TMPDIR); /* exits */
195 static const char DowAry[] ALIGN1 =
196 "sun""mon""tue""wed""thu""fri""sat"
197 /* "Sun""Mon""Tue""Wed""Thu""Fri""Sat" */
200 static const char MonAry[] ALIGN1 =
201 "jan""feb""mar""apr""may""jun""jul""aug""sep""oct""nov""dec"
202 /* "Jan""Feb""Mar""Apr""May""Jun""Jul""Aug""Sep""Oct""Nov""Dec" */
205 static void ParseField(char *user, char *ary, int modvalue, int off,
206 const char *names, char *ptr)
207 /* 'names' is a pointer to a set of 3-char abbreviations */
213 // this can't happen due to config_read()
220 /* Handle numeric digit or symbol or '*' */
222 n1 = 0; /* everything will be filled */
226 } else if (isdigit(*ptr)) {
229 n1 = strtol(ptr, &endp, 10) + off;
231 n2 = strtol(ptr, &endp, 10) + off;
233 ptr = endp; /* gcc likes temp var for &endp */
238 for (i = 0; names[i]; i += 3) {
239 /* was using strncmp before... */
240 if (strncasecmp(ptr, &names[i], 3) == 0) {
253 /* handle optional range '-' */
257 if (*ptr == '-' && n2 < 0) {
263 * collapse single-value ranges, handle skipmark, and fill
264 * in the character array appropriately.
271 skip = strtol(ptr + 1, &endp, 10);
272 ptr = endp; /* gcc likes temp var for &endp */
276 * fill array, using a failsafe is the easiest way to prevent
285 n1 = (n1 + 1) % modvalue;
288 ary[n1 % modvalue] = 1;
291 if (--failsafe == 0) {
307 crondlog(WARN9 "user %s: parse error at %s", user, base);
311 if (DebugOpt && (LogLevel <= 5)) { /* like LVL5 */
312 /* can't use crondlog, it inserts '\n' */
314 for (i = 0; i < modvalue; ++i)
315 fprintf(stderr, "%d", (unsigned char)ary[i]);
316 bb_putchar_stderr('\n');
320 static void FixDayDow(CronLine *line)
326 for (i = 0; i < ARRAY_SIZE(line->cl_Dow); ++i) {
327 if (line->cl_Dow[i] == 0) {
332 for (i = 0; i < ARRAY_SIZE(line->cl_Days); ++i) {
333 if (line->cl_Days[i] == 0) {
338 if (weekUsed != daysUsed) {
340 memset(line->cl_Days, 0, sizeof(line->cl_Days));
342 memset(line->cl_Dow, 0, sizeof(line->cl_Dow));
347 * DeleteFile() - delete user database
349 * Note: multiple entries for same user may exist if we were unable to
350 * completely delete a database due to running processes.
352 static void DeleteFile(const char *userName)
354 CronFile **pfile = &FileBase;
357 while ((file = *pfile) != NULL) {
358 if (strcmp(userName, file->cf_User) == 0) {
359 CronLine **pline = &file->cf_LineBase;
362 file->cf_Running = 0;
363 file->cf_Deleted = 1;
365 while ((line = *pline) != NULL) {
366 if (line->cl_Pid > 0) {
367 file->cf_Running = 1;
368 pline = &line->cl_Next;
370 *pline = line->cl_Next;
371 free(line->cl_Shell);
375 if (file->cf_Running == 0) {
376 *pfile = file->cf_Next;
380 pfile = &file->cf_Next;
383 pfile = &file->cf_Next;
388 static void SynchronizeFile(const char *fileName)
390 struct parser_t *parser;
394 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
401 DeleteFile(fileName);
402 parser = config_open(fileName);
406 maxLines = (strcmp(fileName, "root") == 0) ? 65535 : MAXLINES;
408 if (fstat(fileno(parser->fp), &sbuf) == 0 && sbuf.st_uid == DaemonUid) {
409 CronFile *file = xzalloc(sizeof(CronFile));
413 file->cf_User = xstrdup(fileName);
414 pline = &file->cf_LineBase;
421 n = config_read(parser, tokens, 6, 1, "# \t", PARSE_NORMAL | PARSE_KEEP_COPY);
426 crondlog(LVL5 "user:%s entry:%s", fileName, parser->data);
428 /* check if line is setting MAILTO= */
429 if (0 == strncmp(tokens[0], "MAILTO=", 7)) {
430 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
432 mailTo = (tokens[0][7]) ? xstrdup(&tokens[0][7]) : NULL;
433 #endif /* otherwise just ignore such lines */
436 /* check if a minimum of tokens is specified */
439 *pline = line = xzalloc(sizeof(*line));
440 /* parse date ranges */
441 ParseField(file->cf_User, line->cl_Mins, 60, 0, NULL, tokens[0]);
442 ParseField(file->cf_User, line->cl_Hrs, 24, 0, NULL, tokens[1]);
443 ParseField(file->cf_User, line->cl_Days, 32, 0, NULL, tokens[2]);
444 ParseField(file->cf_User, line->cl_Mons, 12, -1, MonAry, tokens[3]);
445 ParseField(file->cf_User, line->cl_Dow, 7, 0, DowAry, tokens[4]);
447 * fix days and dow - if one is not "*" and the other
448 * is "*", the other is set to 0, and vise-versa
451 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
452 /* copy mailto (can be NULL) */
453 line->cl_MailTo = xstrdup(mailTo);
456 line->cl_Shell = xstrdup(tokens[5]);
458 crondlog(LVL5 " command:%s", tokens[5]);
460 pline = &line->cl_Next;
461 //bb_error_msg("M[%s]F[%s][%s][%s][%s][%s][%s]", mailTo, tokens[0], tokens[1], tokens[2], tokens[3], tokens[4], tokens[5]);
465 file->cf_Next = FileBase;
469 crondlog(WARN9 "user %s: too many lines", fileName);
472 config_close(parser);
475 static void CheckUpdates(void)
480 fi = fopen_for_read(CRONUPDATE);
483 while (fgets(buf, sizeof(buf), fi) != NULL) {
484 /* use first word only */
485 SynchronizeFile(strtok(buf, " \t\r\n"));
491 static void SynchronizeDir(void)
494 /* Attempt to delete the database. */
496 for (file = FileBase; file; file = file->cf_Next) {
497 if (!file->cf_Deleted) {
498 DeleteFile(file->cf_User);
504 * Remove cron update file
506 * Re-chdir, in case directory was renamed & deleted, or otherwise
509 * scan directory and add associated users
512 if (chdir(CDir) < 0) {
513 crondlog(DIE9 "chdir(%s)", CDir);
516 DIR *dir = opendir(".");
520 crondlog(DIE9 "chdir(%s)", "."); /* exits */
521 while ((den = readdir(dir)) != NULL) {
522 if (strchr(den->d_name, '.') != NULL) {
525 if (getpwnam(den->d_name)) {
526 SynchronizeFile(den->d_name);
528 crondlog(LVL7 "ignoring %s", den->d_name);
536 * Determine which jobs need to be run. Under normal conditions, the
537 * period is about a minute (one scan). Worst case it will be one
540 static int TestJobs(time_t t1, time_t t2)
545 /* Find jobs > t1 and <= t2 */
547 for (t = t1 - t1 % 60; t <= t2; t += 60) {
556 for (file = FileBase; file; file = file->cf_Next) {
558 crondlog(LVL5 "file %s:", file->cf_User);
559 if (file->cf_Deleted)
561 for (line = file->cf_LineBase; line; line = line->cl_Next) {
563 crondlog(LVL5 " line %s", line->cl_Shell);
564 if (line->cl_Mins[ptm->tm_min] && line->cl_Hrs[ptm->tm_hour]
565 && (line->cl_Days[ptm->tm_mday] || line->cl_Dow[ptm->tm_wday])
566 && line->cl_Mons[ptm->tm_mon]
569 crondlog(LVL5 " job: %d %s",
570 (int)line->cl_Pid, line->cl_Shell);
572 if (line->cl_Pid > 0) {
573 crondlog(LVL8 "user %s: process already running: %s",
574 file->cf_User, line->cl_Shell);
575 } else if (line->cl_Pid == 0) {
587 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
589 ForkJob(const char *user, CronLine *line, int mailFd,
590 const char *prog, const char *cmd, const char *arg,
591 const char *mail_filename);
593 * EndJob - called when job terminates and when mail terminates
595 static void EndJob(const char *user, CronLine *line)
602 if (line->cl_Pid <= 0) {
608 * End of job and no mail file
609 * End of sendmail job
611 snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, line->cl_Pid);
614 if (line->cl_MailFlag == 0) {
617 line->cl_MailFlag = 0;
620 * End of primary job - check for mail file. If size has increased and
621 * the file is still valid, we sendmail it.
623 mailFd = open(mailFile, O_RDONLY);
629 if (fstat(mailFd, &sbuf) < 0 || sbuf.st_uid != DaemonUid
630 || sbuf.st_nlink != 0 || sbuf.st_size == line->cl_MailPos
631 || !S_ISREG(sbuf.st_mode)
637 ForkJob(user, line, mailFd, SENDMAIL, SENDMAIL_ARGS, NULL);
640 # define EndJob(user, line) ((line)->cl_Pid = 0)
644 * Check for job completion, return number of jobs still running after
647 static int CheckJobs(void)
651 int nStillRunning = 0;
653 for (file = FileBase; file; file = file->cf_Next) {
654 if (file->cf_Running) {
655 file->cf_Running = 0;
657 for (line = file->cf_LineBase; line; line = line->cl_Next) {
659 if (line->cl_Pid <= 0)
662 r = waitpid(line->cl_Pid, &status, WNOHANG);
663 if (r < 0 || r == line->cl_Pid) {
664 EndJob(file->cf_User, line);
666 file->cf_Running = 1;
669 file->cf_Running = 1;
673 nStillRunning += file->cf_Running;
675 return nStillRunning;
678 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
680 // TODO: sendmail should be _run-time_ option, not compile-time!
683 ForkJob(const char *user, CronLine *line, int mailFd,
684 const char *prog, const char *cmd, const char *arg,
685 const char *mail_filename)
690 /* prepare things before vfork */
691 pas = getpwnam(user);
693 crondlog(WARN9 "can't get uid for %s", user);
701 /* change running state to the user in question */
704 crondlog(LVL5 "child running %s", prog);
707 xmove_fd(mailFd, mail_filename ? 1 : 0);
710 /* crond 3.0pl1-100 puts tasks in separate process groups */
712 execlp(prog, prog, cmd, arg, (char *) NULL);
713 crondlog(ERR20 "can't exec, user %s cmd %s %s %s", user, prog, cmd, arg);
715 fdprintf(1, "Exec failed: %s -c %s\n", prog, arg);
723 crondlog(ERR20 "can't vfork");
727 unlink(mail_filename);
730 /* PARENT, FORK SUCCESS */
732 /* rename mail-file based on pid of process */
733 char *mailFile2 = xasprintf("%s/cron.%s.%d", TMPDIR, user, (int)pid);
734 rename(mail_filename, mailFile2); // TODO: xrename?
740 * Close the mail file descriptor.. we can't just leave it open in
741 * a structure, closing it later, because we might run out of descriptors
748 static void RunJob(const char *user, CronLine *line)
754 line->cl_MailFlag = 0;
756 if (line->cl_MailTo) {
757 /* open mail file - owner root so nobody can screw with it. */
758 snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, getpid());
759 mailFd = open(mailFile, O_CREAT | O_TRUNC | O_WRONLY | O_EXCL | O_APPEND, 0600);
762 line->cl_MailFlag = 1;
763 fdprintf(mailFd, "To: %s\nSubject: cron: %s\n\n", line->cl_MailTo,
765 line->cl_MailPos = lseek(mailFd, 0, SEEK_CUR);
767 crondlog(ERR20 "can't create mail file %s for user %s, "
768 "discarding output", mailFile, user);
772 ForkJob(user, line, mailFd, DEFAULT_SHELL, "-c", line->cl_Shell, mailFile);
775 #else /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */
777 static void RunJob(const char *user, CronLine *line)
782 /* prepare things before vfork */
783 pas = getpwnam(user);
785 crondlog(WARN9 "can't get uid for %s", user);
790 /* fork as the user in question and run program */
794 /* change running state to the user in question */
797 crondlog(LVL5 "child running %s", DEFAULT_SHELL);
799 /* crond 3.0pl1-100 puts tasks in separate process groups */
801 execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", line->cl_Shell, (char *) NULL);
802 crondlog(ERR20 "can't exec, user %s cmd %s %s %s", user,
803 DEFAULT_SHELL, "-c", line->cl_Shell);
808 crondlog(ERR20 "can't vfork");
815 #endif /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */
817 static void RunJobs(void)
822 for (file = FileBase; file; file = file->cf_Next) {
827 for (line = file->cf_LineBase; line; line = line->cl_Next) {
828 if (line->cl_Pid >= 0)
831 RunJob(file->cf_User, line);
832 crondlog(LVL8 "USER %s pid %3d cmd %s",
833 file->cf_User, (int)line->cl_Pid, line->cl_Shell);
834 if (line->cl_Pid < 0) {
836 } else if (line->cl_Pid > 0) {
837 file->cf_Running = 1;
843 int crond_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
844 int crond_main(int argc UNUSED_PARAM, char **argv)
853 /* "-b after -f is ignored", and so on for every pair a-b */
854 opt_complementary = "f-b:b-f:S-L:L-S" IF_FEATURE_CROND_D(":d-l")
855 ":l+:d+"; /* -l and -d have numeric param */
856 opts = getopt32(argv, "l:L:fbSc:" IF_FEATURE_CROND_D("d:"),
857 &LogLevel, &LogFile, &CDir
858 IF_FEATURE_CROND_D(,&LogLevel));
859 /* both -d N and -l N set the same variable: LogLevel */
861 if (!(opts & OPT_f)) {
862 /* close stdin, stdout, stderr.
863 * close unused descriptors - don't need them. */
864 bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
867 if (!(opts & OPT_d) && LogFile == NULL) {
868 /* logging to syslog */
869 openlog(applet_name, LOG_CONS | LOG_PID, LOG_CRON);
870 logmode = LOGMODE_SYSLOG;
874 //signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */
875 xsetenv("SHELL", DEFAULT_SHELL); /* once, for all future children */
876 crondlog(LVL8 "crond (busybox "BB_VER") started, log level %d", LogLevel);
878 write_pidfile("/var/run/crond.pid");
880 /* main loop - synchronize to 1 second after the minute, minimum sleep
890 sleep((sleep_time + 1) - (time(NULL) % sleep_time));
893 dt = (long)t2 - (long)t1;
896 * The file 'cron.update' is checked to determine new cron
897 * jobs. The directory is rescanned once an hour to deal
900 * Check for time jump. Disparities over an hour either way
901 * result in resynchronization. A negative disparity
902 * less than an hour causes us to effectively sleep until we
903 * match the original time (i.e. no re-execution of jobs that
904 * have just been run). A positive disparity less than
905 * an hour causes intermediate jobs to be run, but only once
908 * When running jobs, the inequality used is greater but not
909 * equal to t1, and less then or equal to t2.
917 crondlog(LVL5 "wakeup dt=%ld", dt);
918 if (dt < -60 * 60 || dt > 60 * 60) {
919 crondlog(WARN9 "time disparity of %ld minutes detected", dt / 60);
920 /* and we do not run any jobs in this case */
922 /* Usual case: time advances forwad, as expected */
926 if (CheckJobs() > 0) {
932 /* else: time jumped back, do not run any jobs */
935 return 0; /* not reached */