/* vi: set sw=4 ts=4: */ /* * crond -d[#] -c <crondir> -f -b * * run as root, but NOT setuid root * * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com) * (version 2.3.2) * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002 * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ #include "libbb.h" #include <syslog.h> /* glibc frees previous setenv'ed value when we do next setenv() * of the same variable. uclibc does not do this! */ #if (defined(__GLIBC__) && !defined(__UCLIBC__)) /* || OTHER_SAFE_LIBC... */ # define SETENV_LEAKS 0 #else # define SETENV_LEAKS 1 #endif #define TMPDIR CONFIG_FEATURE_CROND_DIR #define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs" #ifndef SENDMAIL # define SENDMAIL "sendmail" #endif #ifndef SENDMAIL_ARGS # define SENDMAIL_ARGS "-ti" #endif #ifndef CRONUPDATE # define CRONUPDATE "cron.update" #endif #ifndef MAXLINES # define MAXLINES 256 /* max lines in non-root crontabs */ #endif typedef struct CronFile { struct CronFile *cf_next; struct CronLine *cf_lines; char *cf_username; smallint cf_wants_starting; /* bool: one or more jobs ready */ smallint cf_has_running; /* bool: one or more jobs running */ smallint cf_deleted; /* marked for deletion (but still has running jobs) */ } CronFile; typedef struct CronLine { struct CronLine *cl_next; char *cl_cmd; /* shell command */ pid_t cl_pid; /* >0:running, <0:needs to be started in this minute, 0:dormant */ #if ENABLE_FEATURE_CROND_CALL_SENDMAIL int cl_empty_mail_size; /* size of mail header only, 0 if no mailfile */ char *cl_mailto; /* whom to mail results, may be NULL */ #endif /* ordered by size, not in natural order. makes code smaller: */ char cl_Dow[7]; /* 0-6, beginning sunday */ char cl_Mons[12]; /* 0-11 */ char cl_Hrs[24]; /* 0-23 */ char cl_Days[32]; /* 1-31 */ char cl_Mins[60]; /* 0-59 */ } CronLine; #define DAEMON_UID 0 enum { OPT_l = (1 << 0), OPT_L = (1 << 1), OPT_f = (1 << 2), OPT_b = (1 << 3), OPT_S = (1 << 4), OPT_c = (1 << 5), OPT_d = (1 << 6) * ENABLE_FEATURE_CROND_D, }; #if ENABLE_FEATURE_CROND_D # define DebugOpt (option_mask32 & OPT_d) #else # define DebugOpt 0 #endif struct globals { unsigned log_level; /* = 8; */ time_t crontab_dir_mtime; const char *log_filename; const char *crontab_dir_name; /* = CRONTABS; */ CronFile *cron_files; #if SETENV_LEAKS char *env_var_user; char *env_var_home; #endif } FIX_ALIASING; #define G (*(struct globals*)&bb_common_bufsiz1) #define INIT_G() do { \ G.log_level = 8; \ G.crontab_dir_name = CRONTABS; \ } while (0) /* 0 is the most verbose, default 8 */ #define LVL5 "\x05" #define LVL7 "\x07" #define LVL8 "\x08" #define WARN9 "\x49" #define DIE9 "\xc9" /* level >= 20 is "error" */ #define ERR20 "\x14" static void crondlog(const char *ctl, ...) __attribute__ ((format (printf, 1, 2))); static void crondlog(const char *ctl, ...) { va_list va; int level = (ctl[0] & 0x1f); va_start(va, ctl); if (level >= (int)G.log_level) { /* Debug mode: all to (non-redirected) stderr, */ /* Syslog mode: all to syslog (logmode = LOGMODE_SYSLOG), */ if (!DebugOpt && G.log_filename) { /* Otherwise (log to file): we reopen log file at every write: */ int logfd = open_or_warn(G.log_filename, O_WRONLY | O_CREAT | O_APPEND); if (logfd >= 0) xmove_fd(logfd, STDERR_FILENO); } /* When we log to syslog, level > 8 is logged at LOG_ERR * syslog level, level <= 8 is logged at LOG_INFO. */ if (level > 8) { bb_verror_msg(ctl + 1, va, /* strerr: */ NULL); } else { char *msg = NULL; vasprintf(&msg, ctl + 1, va); bb_info_msg("%s: %s", applet_name, msg); free(msg); } } va_end(va); if (ctl[0] & 0x80) exit(20); } static const char DowAry[] ALIGN1 = "sun""mon""tue""wed""thu""fri""sat" /* "Sun""Mon""Tue""Wed""Thu""Fri""Sat" */ ; static const char MonAry[] ALIGN1 = "jan""feb""mar""apr""may""jun""jul""aug""sep""oct""nov""dec" /* "Jan""Feb""Mar""Apr""May""Jun""Jul""Aug""Sep""Oct""Nov""Dec" */ ; static void ParseField(char *user, char *ary, int modvalue, int off, const char *names, char *ptr) /* 'names' is a pointer to a set of 3-char abbreviations */ { char *base = ptr; int n1 = -1; int n2 = -1; // this can't happen due to config_read() /*if (base == NULL) return;*/ while (1) { int skip = 0; /* Handle numeric digit or symbol or '*' */ if (*ptr == '*') { n1 = 0; /* everything will be filled */ n2 = modvalue - 1; skip = 1; ++ptr; } else if (isdigit(*ptr)) { char *endp; if (n1 < 0) { n1 = strtol(ptr, &endp, 10) + off; } else { n2 = strtol(ptr, &endp, 10) + off; } ptr = endp; /* gcc likes temp var for &endp */ skip = 1; } else if (names) { int i; for (i = 0; names[i]; i += 3) { /* was using strncmp before... */ if (strncasecmp(ptr, &names[i], 3) == 0) { ptr += 3; if (n1 < 0) { n1 = i / 3; } else { n2 = i / 3; } skip = 1; break; } } } /* handle optional range '-' */ if (skip == 0) { goto err; } if (*ptr == '-' && n2 < 0) { ++ptr; continue; } /* * collapse single-value ranges, handle skipmark, and fill * in the character array appropriately. */ if (n2 < 0) { n2 = n1; } if (*ptr == '/') { char *endp; skip = strtol(ptr + 1, &endp, 10); ptr = endp; /* gcc likes temp var for &endp */ } /* * fill array, using a failsafe is the easiest way to prevent * an endless loop */ { int s0 = 1; int failsafe = 1024; --n1; do { n1 = (n1 + 1) % modvalue; if (--s0 == 0) { ary[n1 % modvalue] = 1; s0 = skip; } if (--failsafe == 0) { goto err; } } while (n1 != n2); } if (*ptr != ',') { break; } ++ptr; n1 = -1; n2 = -1; } if (*ptr) { err: crondlog(WARN9 "user %s: parse error at %s", user, base); return; } if (DebugOpt && (G.log_level <= 5)) { /* like LVL5 */ /* can't use crondlog, it inserts '\n' */ int i; for (i = 0; i < modvalue; ++i) fprintf(stderr, "%d", (unsigned char)ary[i]); bb_putchar_stderr('\n'); } } static void FixDayDow(CronLine *line) { unsigned i; int weekUsed = 0; int daysUsed = 0; for (i = 0; i < ARRAY_SIZE(line->cl_Dow); ++i) { if (line->cl_Dow[i] == 0) { weekUsed = 1; break; } } for (i = 0; i < ARRAY_SIZE(line->cl_Days); ++i) { if (line->cl_Days[i] == 0) { daysUsed = 1; break; } } if (weekUsed != daysUsed) { if (weekUsed) memset(line->cl_Days, 0, sizeof(line->cl_Days)); else /* daysUsed */ memset(line->cl_Dow, 0, sizeof(line->cl_Dow)); } } /* * delete_cronfile() - delete user database * * Note: multiple entries for same user may exist if we were unable to * completely delete a database due to running processes. */ //FIXME: we will start a new job even if the old job is running //if crontab was reloaded: crond thinks that "new" job is different from "old" //even if they are in fact completely the same. Example //Crontab was: // 0-59 * * * * job1 // 0-59 * * * * long_running_job2 //User edits crontab to: // 0-59 * * * * job1_updated // 0-59 * * * * long_running_job2 //Bug: crond can now start another long_running_job2 even if old one //is still running. //OTOH most other versions of cron do not wait for job termination anyway, //they end up with multiple copies of jobs if they don't terminate soon enough. static void delete_cronfile(const char *userName) { CronFile **pfile = &G.cron_files; CronFile *file; while ((file = *pfile) != NULL) { if (strcmp(userName, file->cf_username) == 0) { CronLine **pline = &file->cf_lines; CronLine *line; file->cf_has_running = 0; file->cf_deleted = 1; while ((line = *pline) != NULL) { if (line->cl_pid > 0) { file->cf_has_running = 1; pline = &line->cl_next; } else { *pline = line->cl_next; free(line->cl_cmd); free(line); } } if (file->cf_has_running == 0) { *pfile = file->cf_next; free(file->cf_username); free(file); continue; } } pfile = &file->cf_next; } } static void load_crontab(const char *fileName) { struct parser_t *parser; struct stat sbuf; int maxLines; char *tokens[6]; #if ENABLE_FEATURE_CROND_CALL_SENDMAIL char *mailTo = NULL; #endif delete_cronfile(fileName); if (!getpwnam(fileName)) { crondlog(LVL7 "ignoring file '%s' (no such user)", fileName); return; } parser = config_open(fileName); if (!parser) return; maxLines = (strcmp(fileName, "root") == 0) ? 65535 : MAXLINES; if (fstat(fileno(parser->fp), &sbuf) == 0 && sbuf.st_uid == DAEMON_UID) { CronFile *file = xzalloc(sizeof(CronFile)); CronLine **pline; int n; file->cf_username = xstrdup(fileName); pline = &file->cf_lines; while (1) { CronLine *line; if (!--maxLines) break; n = config_read(parser, tokens, 6, 1, "# \t", PARSE_NORMAL | PARSE_KEEP_COPY); if (!n) break; if (DebugOpt) crondlog(LVL5 "user:%s entry:%s", fileName, parser->data); /* check if line is setting MAILTO= */ if (0 == strncmp(tokens[0], "MAILTO=", 7)) { #if ENABLE_FEATURE_CROND_CALL_SENDMAIL free(mailTo); mailTo = (tokens[0][7]) ? xstrdup(&tokens[0][7]) : NULL; #endif /* otherwise just ignore such lines */ continue; } /* check if a minimum of tokens is specified */ if (n < 6) continue; *pline = line = xzalloc(sizeof(*line)); /* parse date ranges */ ParseField(file->cf_username, line->cl_Mins, 60, 0, NULL, tokens[0]); ParseField(file->cf_username, line->cl_Hrs, 24, 0, NULL, tokens[1]); ParseField(file->cf_username, line->cl_Days, 32, 0, NULL, tokens[2]); ParseField(file->cf_username, line->cl_Mons, 12, -1, MonAry, tokens[3]); ParseField(file->cf_username, line->cl_Dow, 7, 0, DowAry, tokens[4]); /* * fix days and dow - if one is not "*" and the other * is "*", the other is set to 0, and vise-versa */ FixDayDow(line); #if ENABLE_FEATURE_CROND_CALL_SENDMAIL /* copy mailto (can be NULL) */ line->cl_mailto = xstrdup(mailTo); #endif /* copy command */ line->cl_cmd = xstrdup(tokens[5]); if (DebugOpt) { crondlog(LVL5 " command:%s", tokens[5]); } pline = &line->cl_next; //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]); } *pline = NULL; file->cf_next = G.cron_files; G.cron_files = file; if (maxLines == 0) { crondlog(WARN9 "user %s: too many lines", fileName); } } config_close(parser); } static void process_cron_update_file(void) { FILE *fi; char buf[256]; fi = fopen_for_read(CRONUPDATE); if (fi != NULL) { unlink(CRONUPDATE); while (fgets(buf, sizeof(buf), fi) != NULL) { /* use first word only */ skip_non_whitespace(buf)[0] = '\0'; load_crontab(buf); } fclose(fi); } } static void rescan_crontab_dir(void) { CronFile *file; /* Delete all files until we only have ones with running jobs (or none) */ again: for (file = G.cron_files; file; file = file->cf_next) { if (!file->cf_deleted) { delete_cronfile(file->cf_username); goto again; } } /* Remove cron update file */ unlink(CRONUPDATE); /* Re-chdir, in case directory was renamed & deleted */ if (chdir(G.crontab_dir_name) < 0) { crondlog(DIE9 "chdir(%s)", G.crontab_dir_name); } /* Scan directory and add associated users */ { DIR *dir = opendir("."); struct dirent *den; if (!dir) crondlog(DIE9 "chdir(%s)", "."); /* exits */ while ((den = readdir(dir)) != NULL) { if (strchr(den->d_name, '.') != NULL) { continue; } load_crontab(den->d_name); } closedir(dir); } } #if SETENV_LEAKS /* We set environment *before* vfork (because we want to use vfork), * so we cannot use setenv() - repeated calls to setenv() may leak memory! * Using putenv(), and freeing memory after unsetenv() won't leak */ static void safe_setenv(char **pvar_val, const char *var, const char *val) { char *var_val = *pvar_val; if (var_val) { bb_unsetenv_and_free(var_val); } *pvar_val = xasprintf("%s=%s", var, val); putenv(*pvar_val); } #endif static void set_env_vars(struct passwd *pas) { #if SETENV_LEAKS safe_setenv(&G.env_var_user, "USER", pas->pw_name); safe_setenv(&G.env_var_home, "HOME", pas->pw_dir); /* if we want to set user's shell instead: */ /*safe_setenv(G.env_var_shell, "SHELL", pas->pw_shell);*/ #else xsetenv("USER", pas->pw_name); xsetenv("HOME", pas->pw_dir); #endif /* currently, we use constant one: */ /*setenv("SHELL", DEFAULT_SHELL, 1); - done earlier */ } static void change_user(struct passwd *pas) { /* careful: we're after vfork! */ change_identity(pas); /* - initgroups, setgid, setuid */ if (chdir(pas->pw_dir) < 0) { crondlog(WARN9 "chdir(%s)", pas->pw_dir); if (chdir(TMPDIR) < 0) { crondlog(DIE9 "chdir(%s)", TMPDIR); /* exits */ } } } // TODO: sendmail should be _run-time_ option, not compile-time! #if ENABLE_FEATURE_CROND_CALL_SENDMAIL static pid_t fork_job(const char *user, int mailFd, const char *prog, const char *shell_cmd /* if NULL, we run sendmail */ ) { struct passwd *pas; pid_t pid; /* prepare things before vfork */ pas = getpwnam(user); if (!pas) { crondlog(WARN9 "can't get uid for %s", user); goto err; } set_env_vars(pas); pid = vfork(); if (pid == 0) { /* CHILD */ /* initgroups, setgid, setuid, and chdir to home or TMPDIR */ change_user(pas); if (DebugOpt) { crondlog(LVL5 "child running %s", prog); } if (mailFd >= 0) { xmove_fd(mailFd, shell_cmd ? 1 : 0); dup2(1, 2); } /* crond 3.0pl1-100 puts tasks in separate process groups */ bb_setpgrp(); execlp(prog, prog, (shell_cmd ? "-c" : SENDMAIL_ARGS), shell_cmd, (char *) NULL); crondlog(ERR20 "can't execute '%s' for user %s", prog, user); if (shell_cmd) { fdprintf(1, "Exec failed: %s -c %s\n", prog, shell_cmd); } _exit(EXIT_SUCCESS); } if (pid < 0) { /* FORK FAILED */ crondlog(ERR20 "can't vfork"); err: pid = 0; } /* else: PARENT, FORK SUCCESS */ /* * Close the mail file descriptor.. we can't just leave it open in * a structure, closing it later, because we might run out of descriptors */ if (mailFd >= 0) { close(mailFd); } return pid; } static void start_one_job(const char *user, CronLine *line) { char mailFile[128]; int mailFd = -1; line->cl_pid = 0; line->cl_empty_mail_size = 0; if (line->cl_mailto) { /* Open mail file (owner is root so nobody can screw with it) */ snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, getpid()); mailFd = open(mailFile, O_CREAT | O_TRUNC | O_WRONLY | O_EXCL | O_APPEND, 0600); if (mailFd >= 0) { fdprintf(mailFd, "To: %s\nSubject: cron: %s\n\n", line->cl_mailto, line->cl_cmd); line->cl_empty_mail_size = lseek(mailFd, 0, SEEK_CUR); } else { crondlog(ERR20 "can't create mail file %s for user %s, " "discarding output", mailFile, user); } } line->cl_pid = fork_job(user, mailFd, DEFAULT_SHELL, line->cl_cmd); if (mailFd >= 0) { if (line->cl_pid <= 0) { unlink(mailFile); } else { /* rename mail-file based on pid of process */ char *mailFile2 = xasprintf("%s/cron.%s.%d", TMPDIR, user, (int)line->cl_pid); rename(mailFile, mailFile2); // TODO: xrename? free(mailFile2); } } } /* * process_finished_job - called when job terminates and when mail terminates */ static void process_finished_job(const char *user, CronLine *line) { pid_t pid; int mailFd; char mailFile[128]; struct stat sbuf; pid = line->cl_pid; line->cl_pid = 0; if (pid <= 0) { /* No job */ return; } if (line->cl_empty_mail_size <= 0) { /* End of job and no mail file, or end of sendmail job */ return; } /* * End of primary job - check for mail file. * If size has changed and the file is still valid, we send it. */ snprintf(mailFile, sizeof(mailFile), "%s/cron.%s.%d", TMPDIR, user, (int)pid); mailFd = open(mailFile, O_RDONLY); unlink(mailFile); if (mailFd < 0) { return; } if (fstat(mailFd, &sbuf) < 0 || sbuf.st_uid != DAEMON_UID || sbuf.st_nlink != 0 || sbuf.st_size == line->cl_empty_mail_size || !S_ISREG(sbuf.st_mode) ) { close(mailFd); return; } line->cl_empty_mail_size = 0; /* if (line->cl_mailto) - always true if cl_empty_mail_size was nonzero */ line->cl_pid = fork_job(user, mailFd, SENDMAIL, NULL); } #else /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */ static void start_one_job(const char *user, CronLine *line) { struct passwd *pas; pid_t pid; pas = getpwnam(user); if (!pas) { crondlog(WARN9 "can't get uid for %s", user); goto err; } /* Prepare things before vfork */ set_env_vars(pas); /* Fork as the user in question and run program */ pid = vfork(); if (pid == 0) { /* CHILD */ /* initgroups, setgid, setuid, and chdir to home or TMPDIR */ change_user(pas); if (DebugOpt) { crondlog(LVL5 "child running %s", DEFAULT_SHELL); } /* crond 3.0pl1-100 puts tasks in separate process groups */ bb_setpgrp(); execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", line->cl_cmd, (char *) NULL); crondlog(ERR20 "can't execute '%s' for user %s", DEFAULT_SHELL, user); _exit(EXIT_SUCCESS); } if (pid < 0) { /* FORK FAILED */ crondlog(ERR20 "can't vfork"); err: pid = 0; } line->cl_pid = pid; } #define process_finished_job(user, line) ((line)->cl_pid = 0) #endif /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */ /* * Determine which jobs need to be run. Under normal conditions, the * period is about a minute (one scan). Worst case it will be one * hour (60 scans). */ static void flag_starting_jobs(time_t t1, time_t t2) { time_t t; /* Find jobs > t1 and <= t2 */ for (t = t1 - t1 % 60; t <= t2; t += 60) { struct tm *ptm; CronFile *file; CronLine *line; if (t <= t1) continue; ptm = localtime(&t); for (file = G.cron_files; file; file = file->cf_next) { if (DebugOpt) crondlog(LVL5 "file %s:", file->cf_username); if (file->cf_deleted) continue; for (line = file->cf_lines; line; line = line->cl_next) { if (DebugOpt) crondlog(LVL5 " line %s", line->cl_cmd); if (line->cl_Mins[ptm->tm_min] && line->cl_Hrs[ptm->tm_hour] && (line->cl_Days[ptm->tm_mday] || line->cl_Dow[ptm->tm_wday]) && line->cl_Mons[ptm->tm_mon] ) { if (DebugOpt) { crondlog(LVL5 " job: %d %s", (int)line->cl_pid, line->cl_cmd); } if (line->cl_pid > 0) { crondlog(LVL8 "user %s: process already running: %s", file->cf_username, line->cl_cmd); } else if (line->cl_pid == 0) { line->cl_pid = -1; file->cf_wants_starting = 1; } } } } } } static void start_jobs(void) { CronFile *file; CronLine *line; for (file = G.cron_files; file; file = file->cf_next) { if (!file->cf_wants_starting) continue; file->cf_wants_starting = 0; for (line = file->cf_lines; line; line = line->cl_next) { pid_t pid; if (line->cl_pid >= 0) continue; start_one_job(file->cf_username, line); pid = line->cl_pid; crondlog(LVL8 "USER %s pid %3d cmd %s", file->cf_username, (int)pid, line->cl_cmd); if (pid < 0) { file->cf_wants_starting = 1; } if (pid > 0) { file->cf_has_running = 1; } } } } /* * Check for job completion, return number of jobs still running after * all done. */ static int check_completions(void) { CronFile *file; CronLine *line; int num_still_running = 0; for (file = G.cron_files; file; file = file->cf_next) { if (!file->cf_has_running) continue; file->cf_has_running = 0; for (line = file->cf_lines; line; line = line->cl_next) { int r; if (line->cl_pid <= 0) continue; r = waitpid(line->cl_pid, NULL, WNOHANG); if (r < 0 || r == line->cl_pid) { process_finished_job(file->cf_username, line); if (line->cl_pid == 0) { /* sendmail was not started for it */ continue; } /* else: sendmail was started, job is still running, fall thru */ } /* else: r == 0: "process is still running" */ file->cf_has_running = 1; } //FIXME: if !file->cf_has_running && file->deleted: delete it! //otherwise deleted entries will stay forever, right? num_still_running += file->cf_has_running; } return num_still_running; } int crond_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int crond_main(int argc UNUSED_PARAM, char **argv) { time_t t2; int rescan; int sleep_time; unsigned opts; INIT_G(); /* "-b after -f is ignored", and so on for every pair a-b */ opt_complementary = "f-b:b-f:S-L:L-S" IF_FEATURE_CROND_D(":d-l") ":l+:d+"; /* -l and -d have numeric param */ opts = getopt32(argv, "l:L:fbSc:" IF_FEATURE_CROND_D("d:"), &G.log_level, &G.log_filename, &G.crontab_dir_name IF_FEATURE_CROND_D(,&G.log_level)); /* both -d N and -l N set the same variable: G.log_level */ if (!(opts & OPT_f)) { /* close stdin, stdout, stderr. * close unused descriptors - don't need them. */ bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv); } if (!(opts & OPT_d) && G.log_filename == NULL) { /* logging to syslog */ openlog(applet_name, LOG_CONS | LOG_PID, LOG_CRON); logmode = LOGMODE_SYSLOG; } xchdir(G.crontab_dir_name); //signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */ xsetenv("SHELL", DEFAULT_SHELL); /* once, for all future children */ crondlog(LVL8 "crond (busybox "BB_VER") started, log level %d", G.log_level); rescan_crontab_dir(); write_pidfile("/var/run/crond.pid"); /* Main loop */ t2 = time(NULL); rescan = 60; sleep_time = 60; for (;;) { struct stat sbuf; time_t t1; long dt; t1 = t2; /* Synchronize to 1 minute, minimum 1 second */ sleep(sleep_time - (time(NULL) % sleep_time) + 1); t2 = time(NULL); dt = (long)t2 - (long)t1; /* * The file 'cron.update' is checked to determine new cron * jobs. The directory is rescanned once an hour to deal * with any screwups. * * Check for time jump. Disparities over an hour either way * result in resynchronization. A negative disparity * less than an hour causes us to effectively sleep until we * match the original time (i.e. no re-execution of jobs that * have just been run). A positive disparity less than * an hour causes intermediate jobs to be run, but only once * in the worst case. * * When running jobs, the inequality used is greater but not * equal to t1, and less then or equal to t2. */ if (stat(G.crontab_dir_name, &sbuf) != 0) sbuf.st_mtime = 0; /* force update (once) if dir was deleted */ if (G.crontab_dir_mtime != sbuf.st_mtime) { G.crontab_dir_mtime = sbuf.st_mtime; rescan = 1; } if (--rescan == 0) { rescan = 60; rescan_crontab_dir(); } process_cron_update_file(); if (DebugOpt) crondlog(LVL5 "wakeup dt=%ld", dt); if (dt < -60 * 60 || dt > 60 * 60) { crondlog(WARN9 "time disparity of %ld minutes detected", dt / 60); /* and we do not run any jobs in this case */ } else if (dt > 0) { /* Usual case: time advances forward, as expected */ flag_starting_jobs(t1, t2); start_jobs(); if (check_completions() > 0) { /* some jobs are still running */ sleep_time = 10; } else { sleep_time = 60; } } /* else: time jumped back, do not run any jobs */ } /* for (;;) */ return 0; /* not reached */ }