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"
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_lines;
46 smallint cf_wants_starting; /* bool: one or more jobs ready */
47 smallint cf_has_running; /* bool: one or more jobs running */
48 smallint cf_deleted; /* marked for deletion (but still has running jobs) */
51 typedef struct CronLine {
52 struct CronLine *cl_next;
53 char *cl_cmd; /* shell command */
54 pid_t cl_pid; /* >0:running, <0:needs to be started in this minute, 0:dormant */
55 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
56 int cl_empty_mail_size; /* size of mail header only, 0 if no mailfile */
57 char *cl_mailto; /* whom to mail results, may be NULL */
59 /* ordered by size, not in natural order. makes code smaller: */
60 char cl_Dow[7]; /* 0-6, beginning sunday */
61 char cl_Mons[12]; /* 0-11 */
62 char cl_Hrs[24]; /* 0-23 */
63 char cl_Days[32]; /* 1-31 */
64 char cl_Mins[60]; /* 0-59 */
78 OPT_d = (1 << 6) * ENABLE_FEATURE_CROND_D,
80 #if ENABLE_FEATURE_CROND_D
81 # define DebugOpt (option_mask32 & OPT_d)
88 unsigned log_level; /* = 8; */
89 time_t crontab_dir_mtime;
90 const char *log_filename;
91 const char *crontab_dir_name; /* = CRONTABS; */
98 #define G (*(struct globals*)&bb_common_bufsiz1)
99 #define INIT_G() do { \
101 G.crontab_dir_name = CRONTABS; \
105 /* 0 is the most verbose, default 8 */
111 /* level >= 20 is "error" */
114 static void crondlog(const char *ctl, ...) __attribute__ ((format (printf, 1, 2)));
115 static void crondlog(const char *ctl, ...)
118 int level = (ctl[0] & 0x1f);
121 if (level >= (int)G.log_level) {
122 /* Debug mode: all to (non-redirected) stderr, */
123 /* Syslog mode: all to syslog (logmode = LOGMODE_SYSLOG), */
124 if (!DebugOpt && G.log_filename) {
125 /* Otherwise (log to file): we reopen log file at every write: */
126 int logfd = open3_or_warn(G.log_filename, O_WRONLY | O_CREAT | O_APPEND, 0666);
128 xmove_fd(logfd, STDERR_FILENO);
130 /* When we log to syslog, level > 8 is logged at LOG_ERR
131 * syslog level, level <= 8 is logged at LOG_INFO. */
133 bb_verror_msg(ctl + 1, va, /* strerr: */ NULL);
136 vasprintf(&msg, ctl + 1, va);
137 bb_info_msg("%s: %s", applet_name, msg);
146 static const char DowAry[] ALIGN1 =
147 "sun""mon""tue""wed""thu""fri""sat"
148 /* "Sun""Mon""Tue""Wed""Thu""Fri""Sat" */
151 static const char MonAry[] ALIGN1 =
152 "jan""feb""mar""apr""may""jun""jul""aug""sep""oct""nov""dec"
153 /* "Jan""Feb""Mar""Apr""May""Jun""Jul""Aug""Sep""Oct""Nov""Dec" */
156 static void ParseField(char *user, char *ary, int modvalue, int off,
157 const char *names, char *ptr)
158 /* 'names' is a pointer to a set of 3-char abbreviations */
164 // this can't happen due to config_read()
171 /* Handle numeric digit or symbol or '*' */
173 n1 = 0; /* everything will be filled */
177 } else if (isdigit(*ptr)) {
180 n1 = strtol(ptr, &endp, 10) + off;
182 n2 = strtol(ptr, &endp, 10) + off;
184 ptr = endp; /* gcc likes temp var for &endp */
189 for (i = 0; names[i]; i += 3) {
190 /* was using strncmp before... */
191 if (strncasecmp(ptr, &names[i], 3) == 0) {
204 /* handle optional range '-' */
208 if (*ptr == '-' && n2 < 0) {
214 * collapse single-value ranges, handle skipmark, and fill
215 * in the character array appropriately.
222 skip = strtol(ptr + 1, &endp, 10);
223 ptr = endp; /* gcc likes temp var for &endp */
227 * fill array, using a failsafe is the easiest way to prevent
236 n1 = (n1 + 1) % modvalue;
239 ary[n1 % modvalue] = 1;
242 if (--failsafe == 0) {
258 crondlog(WARN9 "user %s: parse error at %s", user, base);
262 if (DebugOpt && (G.log_level <= 5)) { /* like LVL5 */
263 /* can't use crondlog, it inserts '\n' */
265 for (i = 0; i < modvalue; ++i)
266 fprintf(stderr, "%d", (unsigned char)ary[i]);
267 bb_putchar_stderr('\n');
271 static void FixDayDow(CronLine *line)
277 for (i = 0; i < ARRAY_SIZE(line->cl_Dow); ++i) {
278 if (line->cl_Dow[i] == 0) {
283 for (i = 0; i < ARRAY_SIZE(line->cl_Days); ++i) {
284 if (line->cl_Days[i] == 0) {
289 if (weekUsed != daysUsed) {
291 memset(line->cl_Days, 0, sizeof(line->cl_Days));
293 memset(line->cl_Dow, 0, sizeof(line->cl_Dow));
298 * delete_cronfile() - delete user database
300 * Note: multiple entries for same user may exist if we were unable to
301 * completely delete a database due to running processes.
303 //FIXME: we will start a new job even if the old job is running
304 //if crontab was reloaded: crond thinks that "new" job is different from "old"
305 //even if they are in fact completely the same. Example
308 // 0-59 * * * * long_running_job2
309 //User edits crontab to:
310 // 0-59 * * * * job1_updated
311 // 0-59 * * * * long_running_job2
312 //Bug: crond can now start another long_running_job2 even if old one
314 //OTOH most other versions of cron do not wait for job termination anyway,
315 //they end up with multiple copies of jobs if they don't terminate soon enough.
316 static void delete_cronfile(const char *userName)
318 CronFile **pfile = &G.cron_files;
321 while ((file = *pfile) != NULL) {
322 if (strcmp(userName, file->cf_username) == 0) {
323 CronLine **pline = &file->cf_lines;
326 file->cf_has_running = 0;
327 file->cf_deleted = 1;
329 while ((line = *pline) != NULL) {
330 if (line->cl_pid > 0) {
331 file->cf_has_running = 1;
332 pline = &line->cl_next;
334 *pline = line->cl_next;
339 if (file->cf_has_running == 0) {
340 *pfile = file->cf_next;
341 free(file->cf_username);
346 pfile = &file->cf_next;
350 static void load_crontab(const char *fileName)
352 struct parser_t *parser;
356 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
360 delete_cronfile(fileName);
362 if (!getpwnam(fileName)) {
363 crondlog(LVL7 "ignoring file '%s' (no such user)", fileName);
367 parser = config_open(fileName);
371 maxLines = (strcmp(fileName, "root") == 0) ? 65535 : MAXLINES;
373 if (fstat(fileno(parser->fp), &sbuf) == 0 && sbuf.st_uid == DAEMON_UID) {
374 CronFile *file = xzalloc(sizeof(CronFile));
378 file->cf_username = xstrdup(fileName);
379 pline = &file->cf_lines;
386 n = config_read(parser, tokens, 6, 1, "# \t", PARSE_NORMAL | PARSE_KEEP_COPY);
391 crondlog(LVL5 "user:%s entry:%s", fileName, parser->data);
393 /* check if line is setting MAILTO= */
394 if (0 == strncmp(tokens[0], "MAILTO=", 7)) {
395 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
397 mailTo = (tokens[0][7]) ? xstrdup(&tokens[0][7]) : NULL;
398 #endif /* otherwise just ignore such lines */
401 /* check if a minimum of tokens is specified */
404 *pline = line = xzalloc(sizeof(*line));
405 /* parse date ranges */
406 ParseField(file->cf_username, line->cl_Mins, 60, 0, NULL, tokens[0]);
407 ParseField(file->cf_username, line->cl_Hrs, 24, 0, NULL, tokens[1]);
408 ParseField(file->cf_username, line->cl_Days, 32, 0, NULL, tokens[2]);
409 ParseField(file->cf_username, line->cl_Mons, 12, -1, MonAry, tokens[3]);
410 ParseField(file->cf_username, line->cl_Dow, 7, 0, DowAry, tokens[4]);
412 * fix days and dow - if one is not "*" and the other
413 * is "*", the other is set to 0, and vise-versa
416 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
417 /* copy mailto (can be NULL) */
418 line->cl_mailto = xstrdup(mailTo);
421 line->cl_cmd = xstrdup(tokens[5]);
423 crondlog(LVL5 " command:%s", tokens[5]);
425 pline = &line->cl_next;
426 //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]);
430 file->cf_next = G.cron_files;
434 crondlog(WARN9 "user %s: too many lines", fileName);
437 config_close(parser);
440 static void process_cron_update_file(void)
445 fi = fopen_for_read(CRONUPDATE);
448 while (fgets(buf, sizeof(buf), fi) != NULL) {
449 /* use first word only */
450 skip_non_whitespace(buf)[0] = '\0';
457 static void rescan_crontab_dir(void)
461 /* Delete all files until we only have ones with running jobs (or none) */
463 for (file = G.cron_files; file; file = file->cf_next) {
464 if (!file->cf_deleted) {
465 delete_cronfile(file->cf_username);
470 /* Remove cron update file */
472 /* Re-chdir, in case directory was renamed & deleted */
473 if (chdir(G.crontab_dir_name) < 0) {
474 crondlog(DIE9 "chdir(%s)", G.crontab_dir_name);
477 /* Scan directory and add associated users */
479 DIR *dir = opendir(".");
483 crondlog(DIE9 "chdir(%s)", "."); /* exits */
484 while ((den = readdir(dir)) != NULL) {
485 if (strchr(den->d_name, '.') != NULL) {
488 load_crontab(den->d_name);
495 /* We set environment *before* vfork (because we want to use vfork),
496 * so we cannot use setenv() - repeated calls to setenv() may leak memory!
497 * Using putenv(), and freeing memory after unsetenv() won't leak */
498 static void safe_setenv(char **pvar_val, const char *var, const char *val)
500 char *var_val = *pvar_val;
503 bb_unsetenv_and_free(var_val);
505 *pvar_val = xasprintf("%s=%s", var, val);
510 static void set_env_vars(struct passwd *pas)
513 safe_setenv(&G.env_var_user, "USER", pas->pw_name);
514 safe_setenv(&G.env_var_home, "HOME", pas->pw_dir);
515 /* if we want to set user's shell instead: */
516 /*safe_setenv(G.env_var_shell, "SHELL", pas->pw_shell);*/
518 xsetenv("USER", pas->pw_name);
519 xsetenv("HOME", pas->pw_dir);
521 /* currently, we use constant one: */
522 /*setenv("SHELL", DEFAULT_SHELL, 1); - done earlier */
525 static void change_user(struct passwd *pas)
527 /* careful: we're after vfork! */
528 change_identity(pas); /* - initgroups, setgid, setuid */
529 if (chdir(pas->pw_dir) < 0) {
530 crondlog(WARN9 "chdir(%s)", pas->pw_dir);
531 if (chdir(TMPDIR) < 0) {
532 crondlog(DIE9 "chdir(%s)", TMPDIR); /* exits */
537 // TODO: sendmail should be _run-time_ option, not compile-time!
538 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
541 fork_job(const char *user, int mailFd,
543 const char *shell_cmd /* if NULL, we run sendmail */
548 /* prepare things before vfork */
549 pas = getpwnam(user);
551 crondlog(WARN9 "can't get uid for %s", user);
559 /* initgroups, setgid, setuid, and chdir to home or TMPDIR */
562 crondlog(LVL5 "child running %s", prog);
565 xmove_fd(mailFd, shell_cmd ? 1 : 0);
568 /* crond 3.0pl1-100 puts tasks in separate process groups */
570 execlp(prog, prog, (shell_cmd ? "-c" : SENDMAIL_ARGS), shell_cmd, (char *) NULL);
571 crondlog(ERR20 "can't execute '%s' for user %s", prog, user);
573 fdprintf(1, "Exec failed: %s -c %s\n", prog, shell_cmd);
580 crondlog(ERR20 "can't vfork");
583 } /* else: PARENT, FORK SUCCESS */
586 * Close the mail file descriptor.. we can't just leave it open in
587 * a structure, closing it later, because we might run out of descriptors
595 static void start_one_job(const char *user, CronLine *line)
601 line->cl_empty_mail_size = 0;
603 if (line->cl_mailto) {
604 /* Open mail file (owner is root so nobody can screw with it) */
605 snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, getpid());
606 mailFd = open(mailFile, O_CREAT | O_TRUNC | O_WRONLY | O_EXCL | O_APPEND, 0600);
609 fdprintf(mailFd, "To: %s\nSubject: cron: %s\n\n", line->cl_mailto,
611 line->cl_empty_mail_size = lseek(mailFd, 0, SEEK_CUR);
613 crondlog(ERR20 "can't create mail file %s for user %s, "
614 "discarding output", mailFile, user);
618 line->cl_pid = fork_job(user, mailFd, DEFAULT_SHELL, line->cl_cmd);
620 if (line->cl_pid <= 0) {
623 /* rename mail-file based on pid of process */
624 char *mailFile2 = xasprintf("%s/cron.%s.%d", TMPDIR, user, (int)line->cl_pid);
625 rename(mailFile, mailFile2); // TODO: xrename?
632 * process_finished_job - called when job terminates and when mail terminates
634 static void process_finished_job(const char *user, CronLine *line)
647 if (line->cl_empty_mail_size <= 0) {
648 /* End of job and no mail file, or end of sendmail job */
653 * End of primary job - check for mail file.
654 * If size has changed and the file is still valid, we send it.
656 snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, (int)pid);
657 mailFd = open(mailFile, O_RDONLY);
663 if (fstat(mailFd, &sbuf) < 0
664 || sbuf.st_uid != DAEMON_UID
665 || sbuf.st_nlink != 0
666 || sbuf.st_size == line->cl_empty_mail_size
667 || !S_ISREG(sbuf.st_mode)
672 line->cl_empty_mail_size = 0;
673 /* if (line->cl_mailto) - always true if cl_empty_mail_size was nonzero */
674 line->cl_pid = fork_job(user, mailFd, SENDMAIL, NULL);
677 #else /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */
679 static void start_one_job(const char *user, CronLine *line)
684 pas = getpwnam(user);
686 crondlog(WARN9 "can't get uid for %s", user);
690 /* Prepare things before vfork */
693 /* Fork as the user in question and run program */
697 /* initgroups, setgid, setuid, and chdir to home or TMPDIR */
700 crondlog(LVL5 "child running %s", DEFAULT_SHELL);
702 /* crond 3.0pl1-100 puts tasks in separate process groups */
704 execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", line->cl_cmd, (char *) NULL);
705 crondlog(ERR20 "can't execute '%s' for user %s", DEFAULT_SHELL, user);
710 crondlog(ERR20 "can't vfork");
717 #define process_finished_job(user, line) ((line)->cl_pid = 0)
719 #endif /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */
722 * Determine which jobs need to be run. Under normal conditions, the
723 * period is about a minute (one scan). Worst case it will be one
726 static void flag_starting_jobs(time_t t1, time_t t2)
730 /* Find jobs > t1 and <= t2 */
732 for (t = t1 - t1 % 60; t <= t2; t += 60) {
741 for (file = G.cron_files; file; file = file->cf_next) {
743 crondlog(LVL5 "file %s:", file->cf_username);
744 if (file->cf_deleted)
746 for (line = file->cf_lines; line; line = line->cl_next) {
748 crondlog(LVL5 " line %s", line->cl_cmd);
749 if (line->cl_Mins[ptm->tm_min]
750 && line->cl_Hrs[ptm->tm_hour]
751 && (line->cl_Days[ptm->tm_mday] || line->cl_Dow[ptm->tm_wday])
752 && line->cl_Mons[ptm->tm_mon]
755 crondlog(LVL5 " job: %d %s",
756 (int)line->cl_pid, line->cl_cmd);
758 if (line->cl_pid > 0) {
759 crondlog(LVL8 "user %s: process already running: %s",
760 file->cf_username, line->cl_cmd);
761 } else if (line->cl_pid == 0) {
763 file->cf_wants_starting = 1;
771 static void start_jobs(void)
776 for (file = G.cron_files; file; file = file->cf_next) {
777 if (!file->cf_wants_starting)
780 file->cf_wants_starting = 0;
781 for (line = file->cf_lines; line; line = line->cl_next) {
783 if (line->cl_pid >= 0)
786 start_one_job(file->cf_username, line);
788 crondlog(LVL8 "USER %s pid %3d cmd %s",
789 file->cf_username, (int)pid, line->cl_cmd);
791 file->cf_wants_starting = 1;
794 file->cf_has_running = 1;
801 * Check for job completion, return number of jobs still running after
804 static int check_completions(void)
808 int num_still_running = 0;
810 for (file = G.cron_files; file; file = file->cf_next) {
811 if (!file->cf_has_running)
814 file->cf_has_running = 0;
815 for (line = file->cf_lines; line; line = line->cl_next) {
818 if (line->cl_pid <= 0)
821 r = waitpid(line->cl_pid, NULL, WNOHANG);
822 if (r < 0 || r == line->cl_pid) {
823 process_finished_job(file->cf_username, line);
824 if (line->cl_pid == 0) {
825 /* sendmail was not started for it */
828 /* else: sendmail was started, job is still running, fall thru */
830 /* else: r == 0: "process is still running" */
831 file->cf_has_running = 1;
833 //FIXME: if !file->cf_has_running && file->deleted: delete it!
834 //otherwise deleted entries will stay forever, right?
835 num_still_running += file->cf_has_running;
837 return num_still_running;
840 int crond_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
841 int crond_main(int argc UNUSED_PARAM, char **argv)
850 /* "-b after -f is ignored", and so on for every pair a-b */
851 opt_complementary = "f-b:b-f:S-L:L-S" IF_FEATURE_CROND_D(":d-l")
852 ":l+:d+"; /* -l and -d have numeric param */
853 opts = getopt32(argv, "l:L:fbSc:" IF_FEATURE_CROND_D("d:"),
854 &G.log_level, &G.log_filename, &G.crontab_dir_name
855 IF_FEATURE_CROND_D(,&G.log_level));
856 /* both -d N and -l N set the same variable: G.log_level */
858 if (!(opts & OPT_f)) {
859 /* close stdin, stdout, stderr.
860 * close unused descriptors - don't need them. */
861 bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
864 if (!(opts & OPT_d) && G.log_filename == NULL) {
865 /* logging to syslog */
866 openlog(applet_name, LOG_CONS | LOG_PID, LOG_CRON);
867 logmode = LOGMODE_SYSLOG;
870 xchdir(G.crontab_dir_name);
871 //signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */
872 xsetenv("SHELL", DEFAULT_SHELL); /* once, for all future children */
873 crondlog(LVL8 "crond (busybox "BB_VER") started, log level %d", G.log_level);
874 rescan_crontab_dir();
875 write_pidfile("/var/run/crond.pid");
888 /* Synchronize to 1 minute, minimum 1 second */
889 sleep(sleep_time - (time(NULL) % sleep_time) + 1);
892 dt = (long)t2 - (long)t1;
895 * The file 'cron.update' is checked to determine new cron
896 * jobs. The directory is rescanned once an hour to deal
899 * Check for time jump. Disparities over an hour either way
900 * result in resynchronization. A negative disparity
901 * less than an hour causes us to effectively sleep until we
902 * match the original time (i.e. no re-execution of jobs that
903 * have just been run). A positive disparity less than
904 * an hour causes intermediate jobs to be run, but only once
907 * When running jobs, the inequality used is greater but not
908 * equal to t1, and less then or equal to t2.
910 if (stat(G.crontab_dir_name, &sbuf) != 0)
911 sbuf.st_mtime = 0; /* force update (once) if dir was deleted */
912 if (G.crontab_dir_mtime != sbuf.st_mtime) {
913 G.crontab_dir_mtime = sbuf.st_mtime;
918 rescan_crontab_dir();
920 process_cron_update_file();
922 crondlog(LVL5 "wakeup dt=%ld", dt);
923 if (dt < -60 * 60 || dt > 60 * 60) {
924 crondlog(WARN9 "time disparity of %ld minutes detected", dt / 60);
925 /* and we do not run any jobs in this case */
927 /* Usual case: time advances forward, as expected */
928 flag_starting_jobs(t1, t2);
930 if (check_completions() > 0) {
931 /* some jobs are still running */
937 /* else: time jumped back, do not run any jobs */
940 return 0; /* not reached */