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1/* vi: set sw=4 ts=4: */
2/*
3 * crond -d[#] -c <crondir> -f -b
4 *
5 * run as root, but NOT setuid root
6 *
7 * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
8 * (version 2.3.2)
9 * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
10 *
11 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
12 */
13
14//usage:#define crond_trivial_usage
15//usage: "-fbS -l N " IF_FEATURE_CROND_D("-d N ") "-L LOGFILE -c DIR"
16//usage:#define crond_full_usage "\n\n"
17//usage: " -f Foreground"
18//usage: "\n -b Background (default)"
19//usage: "\n -S Log to syslog (default)"
20//usage: "\n -l Set log level. 0 is the most verbose, default 8"
21//usage: IF_FEATURE_CROND_D(
22//usage: "\n -d Set log level, log to stderr"
23//usage: )
24//usage: "\n -L Log to file"
25//usage: "\n -c Working dir"
26
27#include "libbb.h"
28#include <syslog.h>
29
30/* glibc frees previous setenv'ed value when we do next setenv()
31 * of the same variable. uclibc does not do this! */
32#if (defined(__GLIBC__) && !defined(__UCLIBC__)) /* || OTHER_SAFE_LIBC... */
33# define SETENV_LEAKS 0
34#else
35# define SETENV_LEAKS 1
36#endif
37
38
39#ifdef __BIONIC__
40#define TMPDIR "/data/local/tmp"
41#else
42#define TMPDIR CONFIG_FEATURE_CROND_DIR
43#endif
44#define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs"
45#ifndef SENDMAIL
46# define SENDMAIL "sendmail"
47#endif
48#ifndef SENDMAIL_ARGS
49# define SENDMAIL_ARGS "-ti"
50#endif
51#ifndef CRONUPDATE
52# define CRONUPDATE "cron.update"
53#endif
54#ifndef MAXLINES
55# define MAXLINES 256 /* max lines in non-root crontabs */
56#endif
57
58
59typedef struct CronFile {
60 struct CronFile *cf_next;
61 struct CronLine *cf_lines;
62 char *cf_username;
63 smallint cf_wants_starting; /* bool: one or more jobs ready */
64 smallint cf_has_running; /* bool: one or more jobs running */
65 smallint cf_deleted; /* marked for deletion (but still has running jobs) */
66} CronFile;
67
68typedef struct CronLine {
69 struct CronLine *cl_next;
70 char *cl_cmd; /* shell command */
71 pid_t cl_pid; /* >0:running, <0:needs to be started in this minute, 0:dormant */
72#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
73 int cl_empty_mail_size; /* size of mail header only, 0 if no mailfile */
74 char *cl_mailto; /* whom to mail results, may be NULL */
75#endif
76 /* ordered by size, not in natural order. makes code smaller: */
77 char cl_Dow[7]; /* 0-6, beginning sunday */
78 char cl_Mons[12]; /* 0-11 */
79 char cl_Hrs[24]; /* 0-23 */
80 char cl_Days[32]; /* 1-31 */
81 char cl_Mins[60]; /* 0-59 */
82} CronLine;
83
84
85#define DAEMON_UID 0
86
87
88enum {
89 OPT_l = (1 << 0),
90 OPT_L = (1 << 1),
91 OPT_f = (1 << 2),
92 OPT_b = (1 << 3),
93 OPT_S = (1 << 4),
94 OPT_c = (1 << 5),
95 OPT_d = (1 << 6) * ENABLE_FEATURE_CROND_D,
96};
97#if ENABLE_FEATURE_CROND_D
98# define DebugOpt (option_mask32 & OPT_d)
99#else
100# define DebugOpt 0
101#endif
102
103
104struct globals {
105 unsigned log_level; /* = 8; */
106 time_t crontab_dir_mtime;
107 const char *log_filename;
108 const char *crontab_dir_name; /* = CRONTABS; */
109 CronFile *cron_files;
110#if SETENV_LEAKS
111 char *env_var_user;
112 char *env_var_home;
113#endif
114} FIX_ALIASING;
115#define G (*(struct globals*)&bb_common_bufsiz1)
116#define INIT_G() do { \
117 G.log_level = 8; \
118 G.crontab_dir_name = CRONTABS; \
119} while (0)
120
121
122/* 0 is the most verbose, default 8 */
123#define LVL5 "\x05"
124#define LVL7 "\x07"
125#define LVL8 "\x08"
126#define WARN9 "\x49"
127#define DIE9 "\xc9"
128/* level >= 20 is "error" */
129#define ERR20 "\x14"
130
131static void crondlog(const char *ctl, ...) __attribute__ ((format (printf, 1, 2)));
132static void crondlog(const char *ctl, ...)
133{
134 va_list va;
135 int level = (ctl[0] & 0x1f);
136
137 va_start(va, ctl);
138 if (level >= (int)G.log_level) {
139 /* Debug mode: all to (non-redirected) stderr, */
140 /* Syslog mode: all to syslog (logmode = LOGMODE_SYSLOG), */
141 if (!DebugOpt && G.log_filename) {
142 /* Otherwise (log to file): we reopen log file at every write: */
143 int logfd = open_or_warn(G.log_filename, O_WRONLY | O_CREAT | O_APPEND);
144 if (logfd >= 0)
145 xmove_fd(logfd, STDERR_FILENO);
146 }
147 /* When we log to syslog, level > 8 is logged at LOG_ERR
148 * syslog level, level <= 8 is logged at LOG_INFO. */
149 if (level > 8) {
150 bb_verror_msg(ctl + 1, va, /* strerr: */ NULL);
151 } else {
152 char *msg = NULL;
153 vasprintf(&msg, ctl + 1, va);
154 bb_info_msg("%s: %s", applet_name, msg);
155 free(msg);
156 }
157 }
158 va_end(va);
159 if (ctl[0] & 0x80)
160 exit(20);
161}
162
163static const char DowAry[] ALIGN1 =
164 "sun""mon""tue""wed""thu""fri""sat"
165 /* "Sun""Mon""Tue""Wed""Thu""Fri""Sat" */
166;
167
168static const char MonAry[] ALIGN1 =
169 "jan""feb""mar""apr""may""jun""jul""aug""sep""oct""nov""dec"
170 /* "Jan""Feb""Mar""Apr""May""Jun""Jul""Aug""Sep""Oct""Nov""Dec" */
171;
172
173static void ParseField(char *user, char *ary, int modvalue, int off,
174 const char *names, char *ptr)
175/* 'names' is a pointer to a set of 3-char abbreviations */
176{
177 char *base = ptr;
178 int n1 = -1;
179 int n2 = -1;
180
181 // this can't happen due to config_read()
182 /*if (base == NULL)
183 return;*/
184
185 while (1) {
186 int skip = 0;
187
188 /* Handle numeric digit or symbol or '*' */
189 if (*ptr == '*') {
190 n1 = 0; /* everything will be filled */
191 n2 = modvalue - 1;
192 skip = 1;
193 ++ptr;
194 } else if (isdigit(*ptr)) {
195 char *endp;
196 if (n1 < 0) {
197 n1 = strtol(ptr, &endp, 10) + off;
198 } else {
199 n2 = strtol(ptr, &endp, 10) + off;
200 }
201 ptr = endp; /* gcc likes temp var for &endp */
202 skip = 1;
203 } else if (names) {
204 int i;
205
206 for (i = 0; names[i]; i += 3) {
207 /* was using strncmp before... */
208 if (strncasecmp(ptr, &names[i], 3) == 0) {
209 ptr += 3;
210 if (n1 < 0) {
211 n1 = i / 3;
212 } else {
213 n2 = i / 3;
214 }
215 skip = 1;
216 break;
217 }
218 }
219 }
220
221 /* handle optional range '-' */
222 if (skip == 0) {
223 goto err;
224 }
225 if (*ptr == '-' && n2 < 0) {
226 ++ptr;
227 continue;
228 }
229
230 /*
231 * collapse single-value ranges, handle skipmark, and fill
232 * in the character array appropriately.
233 */
234 if (n2 < 0) {
235 n2 = n1;
236 }
237 if (*ptr == '/') {
238 char *endp;
239 skip = strtol(ptr + 1, &endp, 10);
240 ptr = endp; /* gcc likes temp var for &endp */
241 }
242
243 /*
244 * fill array, using a failsafe is the easiest way to prevent
245 * an endless loop
246 */
247 {
248 int s0 = 1;
249 int failsafe = 1024;
250
251 --n1;
252 do {
253 n1 = (n1 + 1) % modvalue;
254
255 if (--s0 == 0) {
256 ary[n1 % modvalue] = 1;
257 s0 = skip;
258 }
259 if (--failsafe == 0) {
260 goto err;
261 }
262 } while (n1 != n2);
263 }
264 if (*ptr != ',') {
265 break;
266 }
267 ++ptr;
268 n1 = -1;
269 n2 = -1;
270 }
271
272 if (*ptr) {
273 err:
274 crondlog(WARN9 "user %s: parse error at %s", user, base);
275 return;
276 }
277
278 if (DebugOpt && (G.log_level <= 5)) { /* like LVL5 */
279 /* can't use crondlog, it inserts '\n' */
280 int i;
281 for (i = 0; i < modvalue; ++i)
282 fprintf(stderr, "%d", (unsigned char)ary[i]);
283 bb_putchar_stderr('\n');
284 }
285}
286
287static void FixDayDow(CronLine *line)
288{
289 unsigned i;
290 int weekUsed = 0;
291 int daysUsed = 0;
292
293 for (i = 0; i < ARRAY_SIZE(line->cl_Dow); ++i) {
294 if (line->cl_Dow[i] == 0) {
295 weekUsed = 1;
296 break;
297 }
298 }
299 for (i = 0; i < ARRAY_SIZE(line->cl_Days); ++i) {
300 if (line->cl_Days[i] == 0) {
301 daysUsed = 1;
302 break;
303 }
304 }
305 if (weekUsed != daysUsed) {
306 if (weekUsed)
307 memset(line->cl_Days, 0, sizeof(line->cl_Days));
308 else /* daysUsed */
309 memset(line->cl_Dow, 0, sizeof(line->cl_Dow));
310 }
311}
312
313/*
314 * delete_cronfile() - delete user database
315 *
316 * Note: multiple entries for same user may exist if we were unable to
317 * completely delete a database due to running processes.
318 */
319//FIXME: we will start a new job even if the old job is running
320//if crontab was reloaded: crond thinks that "new" job is different from "old"
321//even if they are in fact completely the same. Example
322//Crontab was:
323// 0-59 * * * * job1
324// 0-59 * * * * long_running_job2
325//User edits crontab to:
326// 0-59 * * * * job1_updated
327// 0-59 * * * * long_running_job2
328//Bug: crond can now start another long_running_job2 even if old one
329//is still running.
330//OTOH most other versions of cron do not wait for job termination anyway,
331//they end up with multiple copies of jobs if they don't terminate soon enough.
332static void delete_cronfile(const char *userName)
333{
334 CronFile **pfile = &G.cron_files;
335 CronFile *file;
336
337 while ((file = *pfile) != NULL) {
338 if (strcmp(userName, file->cf_username) == 0) {
339 CronLine **pline = &file->cf_lines;
340 CronLine *line;
341
342 file->cf_has_running = 0;
343 file->cf_deleted = 1;
344
345 while ((line = *pline) != NULL) {
346 if (line->cl_pid > 0) {
347 file->cf_has_running = 1;
348 pline = &line->cl_next;
349 } else {
350 *pline = line->cl_next;
351 free(line->cl_cmd);
352 free(line);
353 }
354 }
355 if (file->cf_has_running == 0) {
356 *pfile = file->cf_next;
357 free(file->cf_username);
358 free(file);
359 continue;
360 }
361 }
362 pfile = &file->cf_next;
363 }
364}
365
366static void load_crontab(const char *fileName)
367{
368 struct parser_t *parser;
369 struct stat sbuf;
370 int maxLines;
371 char *tokens[6];
372#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
373 char *mailTo = NULL;
374#endif
375
376 delete_cronfile(fileName);
377
378 if (!getpwnam(fileName)) {
379 crondlog(LVL7 "ignoring file '%s' (no such user)", fileName);
380 return;
381 }
382
383 parser = config_open(fileName);
384 if (!parser)
385 return;
386
387 maxLines = (strcmp(fileName, "root") == 0) ? 65535 : MAXLINES;
388
389 if (fstat(fileno(parser->fp), &sbuf) == 0 && sbuf.st_uid == DAEMON_UID) {
390 CronFile *file = xzalloc(sizeof(CronFile));
391 CronLine **pline;
392 int n;
393
394 file->cf_username = xstrdup(fileName);
395 pline = &file->cf_lines;
396
397 while (1) {
398 CronLine *line;
399
400 if (!--maxLines)
401 break;
402 n = config_read(parser, tokens, 6, 1, "# \t", PARSE_NORMAL | PARSE_KEEP_COPY);
403 if (!n)
404 break;
405
406 if (DebugOpt)
407 crondlog(LVL5 "user:%s entry:%s", fileName, parser->data);
408
409 /* check if line is setting MAILTO= */
410 if (0 == strncmp(tokens[0], "MAILTO=", 7)) {
411#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
412 free(mailTo);
413 mailTo = (tokens[0][7]) ? xstrdup(&tokens[0][7]) : NULL;
414#endif /* otherwise just ignore such lines */
415 continue;
416 }
417 /* check if a minimum of tokens is specified */
418 if (n < 6)
419 continue;
420 *pline = line = xzalloc(sizeof(*line));
421 /* parse date ranges */
422 ParseField(file->cf_username, line->cl_Mins, 60, 0, NULL, tokens[0]);
423 ParseField(file->cf_username, line->cl_Hrs, 24, 0, NULL, tokens[1]);
424 ParseField(file->cf_username, line->cl_Days, 32, 0, NULL, tokens[2]);
425 ParseField(file->cf_username, line->cl_Mons, 12, -1, MonAry, tokens[3]);
426 ParseField(file->cf_username, line->cl_Dow, 7, 0, DowAry, tokens[4]);
427 /*
428 * fix days and dow - if one is not "*" and the other
429 * is "*", the other is set to 0, and vise-versa
430 */
431 FixDayDow(line);
432#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
433 /* copy mailto (can be NULL) */
434 line->cl_mailto = xstrdup(mailTo);
435#endif
436 /* copy command */
437 line->cl_cmd = xstrdup(tokens[5]);
438 if (DebugOpt) {
439 crondlog(LVL5 " command:%s", tokens[5]);
440 }
441 pline = &line->cl_next;
442//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]);
443 }
444 *pline = NULL;
445
446 file->cf_next = G.cron_files;
447 G.cron_files = file;
448
449 if (maxLines == 0) {
450 crondlog(WARN9 "user %s: too many lines", fileName);
451 }
452 }
453 config_close(parser);
454}
455
456static void process_cron_update_file(void)
457{
458 FILE *fi;
459 char buf[256];
460
461 fi = fopen_for_read(CRONUPDATE);
462 if (fi != NULL) {
463 unlink(CRONUPDATE);
464 while (fgets(buf, sizeof(buf), fi) != NULL) {
465 /* use first word only */
466 skip_non_whitespace(buf)[0] = '\0';
467 load_crontab(buf);
468 }
469 fclose(fi);
470 }
471}
472
473static void rescan_crontab_dir(void)
474{
475 CronFile *file;
476
477 /* Delete all files until we only have ones with running jobs (or none) */
478 again:
479 for (file = G.cron_files; file; file = file->cf_next) {
480 if (!file->cf_deleted) {
481 delete_cronfile(file->cf_username);
482 goto again;
483 }
484 }
485
486 /* Remove cron update file */
487 unlink(CRONUPDATE);
488 /* Re-chdir, in case directory was renamed & deleted */
489 if (chdir(G.crontab_dir_name) < 0) {
490 crondlog(DIE9 "chdir(%s)", G.crontab_dir_name);
491 }
492
493 /* Scan directory and add associated users */
494 {
495 DIR *dir = opendir(".");
496 struct dirent *den;
497
498 if (!dir)
499 crondlog(DIE9 "chdir(%s)", "."); /* exits */
500 while ((den = readdir(dir)) != NULL) {
501 if (strchr(den->d_name, '.') != NULL) {
502 continue;
503 }
504 load_crontab(den->d_name);
505 }
506 closedir(dir);
507 }
508}
509
510#if SETENV_LEAKS
511/* We set environment *before* vfork (because we want to use vfork),
512 * so we cannot use setenv() - repeated calls to setenv() may leak memory!
513 * Using putenv(), and freeing memory after unsetenv() won't leak */
514static void safe_setenv(char **pvar_val, const char *var, const char *val)
515{
516 char *var_val = *pvar_val;
517
518 if (var_val) {
519 bb_unsetenv_and_free(var_val);
520 }
521 *pvar_val = xasprintf("%s=%s", var, val);
522 putenv(*pvar_val);
523}
524#endif
525
526static void set_env_vars(struct passwd *pas)
527{
528#if SETENV_LEAKS
529 safe_setenv(&G.env_var_user, "USER", pas->pw_name);
530 safe_setenv(&G.env_var_home, "HOME", pas->pw_dir);
531 /* if we want to set user's shell instead: */
532 /*safe_setenv(G.env_var_shell, "SHELL", pas->pw_shell);*/
533#else
534 xsetenv("USER", pas->pw_name);
535 xsetenv("HOME", pas->pw_dir);
536#endif
537 /* currently, we use constant one: */
538 /*setenv("SHELL", DEFAULT_SHELL, 1); - done earlier */
539}
540
541static void change_user(struct passwd *pas)
542{
543 /* careful: we're after vfork! */
544 change_identity(pas); /* - initgroups, setgid, setuid */
545 if (chdir(pas->pw_dir) < 0) {
546 crondlog(WARN9 "chdir(%s)", pas->pw_dir);
547 if (chdir(TMPDIR) < 0) {
548 crondlog(DIE9 "chdir(%s)", TMPDIR); /* exits */
549 }
550 }
551}
552
553// TODO: sendmail should be _run-time_ option, not compile-time!
554#if ENABLE_FEATURE_CROND_CALL_SENDMAIL
555
556static pid_t
557fork_job(const char *user, int mailFd,
558 const char *prog,
559 const char *shell_cmd /* if NULL, we run sendmail */
560) {
561 struct passwd *pas;
562 pid_t pid;
563
564 /* prepare things before vfork */
565 pas = getpwnam(user);
566 if (!pas) {
567 crondlog(WARN9 "can't get uid for %s", user);
568 goto err;
569 }
570 set_env_vars(pas);
571
572 pid = vfork();
573 if (pid == 0) {
574 /* CHILD */
575 /* initgroups, setgid, setuid, and chdir to home or TMPDIR */
576 change_user(pas);
577 if (DebugOpt) {
578 crondlog(LVL5 "child running %s", prog);
579 }
580 if (mailFd >= 0) {
581 xmove_fd(mailFd, shell_cmd ? 1 : 0);
582 dup2(1, 2);
583 }
584 /* crond 3.0pl1-100 puts tasks in separate process groups */
585 bb_setpgrp();
586 execlp(prog, prog, (shell_cmd ? "-c" : SENDMAIL_ARGS), shell_cmd, (char *) NULL);
587 crondlog(ERR20 "can't execute '%s' for user %s", prog, user);
588 if (shell_cmd) {
589 fdprintf(1, "Exec failed: %s -c %s\n", prog, shell_cmd);
590 }
591 _exit(EXIT_SUCCESS);
592 }
593
594 if (pid < 0) {
595 /* FORK FAILED */
596 crondlog(ERR20 "can't vfork");
597 err:
598 pid = 0;
599 } /* else: PARENT, FORK SUCCESS */
600
601 /*
602 * Close the mail file descriptor.. we can't just leave it open in
603 * a structure, closing it later, because we might run out of descriptors
604 */
605 if (mailFd >= 0) {
606 close(mailFd);
607 }
608 return pid;
609}
610
611static void start_one_job(const char *user, CronLine *line)
612{
613 char mailFile[128];
614 int mailFd = -1;
615
616 line->cl_pid = 0;
617 line->cl_empty_mail_size = 0;
618
619 if (line->cl_mailto) {
620 /* Open mail file (owner is root so nobody can screw with it) */
621 snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, getpid());
622 mailFd = open(mailFile, O_CREAT | O_TRUNC | O_WRONLY | O_EXCL | O_APPEND, 0600);
623
624 if (mailFd >= 0) {
625 fdprintf(mailFd, "To: %s\nSubject: cron: %s\n\n", line->cl_mailto,
626 line->cl_cmd);
627 line->cl_empty_mail_size = lseek(mailFd, 0, SEEK_CUR);
628 } else {
629 crondlog(ERR20 "can't create mail file %s for user %s, "
630 "discarding output", mailFile, user);
631 }
632 }
633
634 line->cl_pid = fork_job(user, mailFd, DEFAULT_SHELL, line->cl_cmd);
635 if (mailFd >= 0) {
636 if (line->cl_pid <= 0) {
637 unlink(mailFile);
638 } else {
639 /* rename mail-file based on pid of process */
640 char *mailFile2 = xasprintf("%s/cron.%s.%d", TMPDIR, user, (int)line->cl_pid);
641 rename(mailFile, mailFile2); // TODO: xrename?
642 free(mailFile2);
643 }
644 }
645}
646
647/*
648 * process_finished_job - called when job terminates and when mail terminates
649 */
650static void process_finished_job(const char *user, CronLine *line)
651{
652 pid_t pid;
653 int mailFd;
654 char mailFile[128];
655 struct stat sbuf;
656
657 pid = line->cl_pid;
658 line->cl_pid = 0;
659 if (pid <= 0) {
660 /* No job */
661 return;
662 }
663 if (line->cl_empty_mail_size <= 0) {
664 /* End of job and no mail file, or end of sendmail job */
665 return;
666 }
667
668 /*
669 * End of primary job - check for mail file.
670 * If size has changed and the file is still valid, we send it.
671 */
672 snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, (int)pid);
673 mailFd = open(mailFile, O_RDONLY);
674 unlink(mailFile);
675 if (mailFd < 0) {
676 return;
677 }
678
679 if (fstat(mailFd, &sbuf) < 0
680 || sbuf.st_uid != DAEMON_UID
681 || sbuf.st_nlink != 0
682 || sbuf.st_size == line->cl_empty_mail_size
683 || !S_ISREG(sbuf.st_mode)
684 ) {
685 close(mailFd);
686 return;
687 }
688 line->cl_empty_mail_size = 0;
689 /* if (line->cl_mailto) - always true if cl_empty_mail_size was nonzero */
690 line->cl_pid = fork_job(user, mailFd, SENDMAIL, NULL);
691}
692
693#else /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */
694
695static void start_one_job(const char *user, CronLine *line)
696{
697 struct passwd *pas;
698 pid_t pid;
699
700 pas = safegetpwnam(user);
701 if (!pas) {
702 crondlog(WARN9 "can't get uid for %s", user);
703 goto err;
704 }
705
706 /* Prepare things before vfork */
707 set_env_vars(pas);
708
709 /* Fork as the user in question and run program */
710 pid = vfork();
711 if (pid == 0) {
712 /* CHILD */
713 /* initgroups, setgid, setuid, and chdir to home or TMPDIR */
714 change_user(pas);
715 if (DebugOpt) {
716 crondlog(LVL5 "child running %s", DEFAULT_SHELL);
717 }
718 /* crond 3.0pl1-100 puts tasks in separate process groups */
719 bb_setpgrp();
720 execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", line->cl_cmd, (char *) NULL);
721 crondlog(ERR20 "can't execute '%s' for user %s", DEFAULT_SHELL, user);
722 _exit(EXIT_SUCCESS);
723 }
724 if (pid < 0) {
725 /* FORK FAILED */
726 crondlog(ERR20 "can't vfork");
727 err:
728 pid = 0;
729 }
730 line->cl_pid = pid;
731}
732
733#define process_finished_job(user, line) ((line)->cl_pid = 0)
734
735#endif /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */
736
737/*
738 * Determine which jobs need to be run. Under normal conditions, the
739 * period is about a minute (one scan). Worst case it will be one
740 * hour (60 scans).
741 */
742static void flag_starting_jobs(time_t t1, time_t t2)
743{
744 time_t t;
745
746 /* Find jobs > t1 and <= t2 */
747
748 for (t = t1 - t1 % 60; t <= t2; t += 60) {
749 struct tm *ptm;
750 CronFile *file;
751 CronLine *line;
752
753 if (t <= t1)
754 continue;
755
756 ptm = localtime(&t);
757 for (file = G.cron_files; file; file = file->cf_next) {
758 if (DebugOpt)
759 crondlog(LVL5 "file %s:", file->cf_username);
760 if (file->cf_deleted)
761 continue;
762 for (line = file->cf_lines; line; line = line->cl_next) {
763 if (DebugOpt)
764 crondlog(LVL5 " line %s", line->cl_cmd);
765 if (line->cl_Mins[ptm->tm_min]
766 && line->cl_Hrs[ptm->tm_hour]
767 && (line->cl_Days[ptm->tm_mday] || line->cl_Dow[ptm->tm_wday])
768 && line->cl_Mons[ptm->tm_mon]
769 ) {
770 if (DebugOpt) {
771 crondlog(LVL5 " job: %d %s",
772 (int)line->cl_pid, line->cl_cmd);
773 }
774 if (line->cl_pid > 0) {
775 crondlog(LVL8 "user %s: process already running: %s",
776 file->cf_username, line->cl_cmd);
777 } else if (line->cl_pid == 0) {
778 line->cl_pid = -1;
779 file->cf_wants_starting = 1;
780 }
781 }
782 }
783 }
784 }
785}
786
787static void start_jobs(void)
788{
789 CronFile *file;
790 CronLine *line;
791
792 for (file = G.cron_files; file; file = file->cf_next) {
793 if (!file->cf_wants_starting)
794 continue;
795
796 file->cf_wants_starting = 0;
797 for (line = file->cf_lines; line; line = line->cl_next) {
798 pid_t pid;
799 if (line->cl_pid >= 0)
800 continue;
801
802 start_one_job(file->cf_username, line);
803 pid = line->cl_pid;
804 crondlog(LVL8 "USER %s pid %3d cmd %s",
805 file->cf_username, (int)pid, line->cl_cmd);
806 if (pid < 0) {
807 file->cf_wants_starting = 1;
808 }
809 if (pid > 0) {
810 file->cf_has_running = 1;
811 }
812 }
813 }
814}
815
816/*
817 * Check for job completion, return number of jobs still running after
818 * all done.
819 */
820static int check_completions(void)
821{
822 CronFile *file;
823 CronLine *line;
824 int num_still_running = 0;
825
826 for (file = G.cron_files; file; file = file->cf_next) {
827 if (!file->cf_has_running)
828 continue;
829
830 file->cf_has_running = 0;
831 for (line = file->cf_lines; line; line = line->cl_next) {
832 int r;
833
834 if (line->cl_pid <= 0)
835 continue;
836
837 r = waitpid(line->cl_pid, NULL, WNOHANG);
838 if (r < 0 || r == line->cl_pid) {
839 process_finished_job(file->cf_username, line);
840 if (line->cl_pid == 0) {
841 /* sendmail was not started for it */
842 continue;
843 }
844 /* else: sendmail was started, job is still running, fall thru */
845 }
846 /* else: r == 0: "process is still running" */
847 file->cf_has_running = 1;
848 }
849//FIXME: if !file->cf_has_running && file->deleted: delete it!
850//otherwise deleted entries will stay forever, right?
851 num_still_running += file->cf_has_running;
852 }
853 return num_still_running;
854}
855
856int crond_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
857int crond_main(int argc UNUSED_PARAM, char **argv)
858{
859 time_t t2;
860 int rescan;
861 int sleep_time;
862 unsigned opts;
863
864 INIT_G();
865
866 /* "-b after -f is ignored", and so on for every pair a-b */
867 opt_complementary = "f-b:b-f:S-L:L-S" IF_FEATURE_CROND_D(":d-l")
868 /* -l and -d have numeric param */
869 ":l+" IF_FEATURE_CROND_D(":d+");
870 opts = getopt32(argv, "l:L:fbSc:" IF_FEATURE_CROND_D("d:"),
871 &G.log_level, &G.log_filename, &G.crontab_dir_name
872 IF_FEATURE_CROND_D(,&G.log_level));
873 /* both -d N and -l N set the same variable: G.log_level */
874
875 if (!(opts & OPT_f)) {
876 /* close stdin, stdout, stderr.
877 * close unused descriptors - don't need them. */
878 bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
879 }
880
881 if (!(opts & OPT_d) && G.log_filename == NULL) {
882 /* logging to syslog */
883 openlog(applet_name, LOG_CONS | LOG_PID, LOG_CRON);
884 logmode = LOGMODE_SYSLOG;
885 }
886
887 xchdir(G.crontab_dir_name);
888 //signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */
889 xsetenv("SHELL", DEFAULT_SHELL); /* once, for all future children */
890 crondlog(LVL8 "crond (busybox "BB_VER") started, log level %d", G.log_level);
891 rescan_crontab_dir();
892 write_pidfile(CONFIG_PID_FILE_PATH "/crond.pid");
893
894 /* Main loop */
895 t2 = time(NULL);
896 rescan = 60;
897 sleep_time = 60;
898 for (;;) {
899 struct stat sbuf;
900 time_t t1;
901 long dt;
902
903 t1 = t2;
904
905 /* Synchronize to 1 minute, minimum 1 second */
906 sleep(sleep_time - (time(NULL) % sleep_time) + 1);
907
908 t2 = time(NULL);
909 dt = (long)t2 - (long)t1;
910
911 /*
912 * The file 'cron.update' is checked to determine new cron
913 * jobs. The directory is rescanned once an hour to deal
914 * with any screwups.
915 *
916 * Check for time jump. Disparities over an hour either way
917 * result in resynchronization. A negative disparity
918 * less than an hour causes us to effectively sleep until we
919 * match the original time (i.e. no re-execution of jobs that
920 * have just been run). A positive disparity less than
921 * an hour causes intermediate jobs to be run, but only once
922 * in the worst case.
923 *
924 * When running jobs, the inequality used is greater but not
925 * equal to t1, and less then or equal to t2.
926 */
927 if (stat(G.crontab_dir_name, &sbuf) != 0)
928 sbuf.st_mtime = 0; /* force update (once) if dir was deleted */
929 if ((time_t) G.crontab_dir_mtime != (time_t) sbuf.st_mtime) {
930 G.crontab_dir_mtime = sbuf.st_mtime;
931 rescan = 1;
932 }
933 if (--rescan == 0) {
934 rescan = 60;
935 rescan_crontab_dir();
936 }
937 process_cron_update_file();
938 if (DebugOpt)
939 crondlog(LVL5 "wakeup dt=%ld", dt);
940 if (dt < -60 * 60 || dt > 60 * 60) {
941 crondlog(WARN9 "time disparity of %ld minutes detected", dt / 60);
942 /* and we do not run any jobs in this case */
943 } else if (dt > 0) {
944 /* Usual case: time advances forward, as expected */
945 flag_starting_jobs(t1, t2);
946 start_jobs();
947 if (check_completions() > 0) {
948 /* some jobs are still running */
949 sleep_time = 10;
950 } else {
951 sleep_time = 60;
952 }
953 }
954 /* else: time jumped back, do not run any jobs */
955 } /* for (;;) */
956
957 return 0; /* not reached */
958}
959
generated by cgit at 2024-05-16 02:12:52 (GMT)