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- /* crond.c - daemon to execute scheduled commands.
- *
- * Copyright 2014 Ranjan Kumar <ranjankumar.bth@gmail.com>
- *
- * No Standard
- USE_CROND(NEWTOY(crond, "fbSl#<0=8d#<0L:c:[-bf][-LS][-ld]", TOYFLAG_USR|TOYFLAG_SBIN|TOYFLAG_NEEDROOT))
- config CROND
- bool "crond"
- default n
- help
- usage: crond [-fbS] [-l N] [-d N] [-L LOGFILE] [-c DIR]
- A daemon to execute scheduled commands.
- -b Background (default)
- -c crontab dir
- -d Set log level, log to stderr
- -f Foreground
- -l Set log level. 0 is the most verbose, default 8
- -S Log to syslog (default)
- -L Log to file
- */
- #define FOR_crond
- #include "toys.h"
- GLOBALS(
- char *crontabs_dir;
- char *logfile;
- int loglevel_d;
- int loglevel;
- time_t crontabs_dir_mtime;
- uint8_t flagd;
- )
- typedef struct _var {
- struct _var *next, *prev;
- char *name, *val;
- } VAR;
- typedef struct _job {
- struct _job *next, *prev;
- char min[60], hour[24], dom[31], mon[12], dow[7], *cmd;
- int isrunning, needstart, mailsize;
- pid_t pid;
- } JOB;
- typedef struct _cronfile {
- struct _cronfile *next, *prev;
- struct double_list *job, *var;
- char *username, *mailto;
- int invalid;
- } CRONFILE;
- static char days[]={"sun""mon""tue""wed""thu""fri""sat"};
- static char months[]={"jan""feb""mar""apr""may""jun""jul"
- "aug""sep""oct""nov""dec"};
- CRONFILE *gclist;
- #define LOG_EXIT 0
- #define LOG_LEVEL5 5
- #define LOG_LEVEL7 7
- #define LOG_LEVEL8 8
- #define LOG_LEVEL9 9 // warning
- #define LOG_ERROR 20
- static void loginfo(uint8_t loglevel, char *msg, ...)
- {
- va_list s, d;
- va_start(s, msg);
- va_copy(d, s);
- if (loglevel >= TT.loglevel) {
- int used;
- char *smsg;
- if (!TT.flagd && TT.logfile) {
- int fd = open(TT.logfile, O_WRONLY | O_CREAT | O_APPEND, 0666);
- if (fd==-1) perror_msg("'%s", TT.logfile);
- else {
- dup2(fd, 2);
- close(fd);
- }
- }
- used = vsnprintf(NULL, 0, msg, d);
- smsg = xzalloc(++used);
- vsnprintf(smsg, used, msg, s);
- if (TT.flagd || TT.logfile) {
- fflush(NULL);
- smsg[used-1] = '\n';
- writeall((loglevel > 8) ? 2 : 1, smsg, used);
- } else syslog((loglevel > 8) ? LOG_ERR : LOG_INFO, "%s", smsg);
- free(smsg);
- }
- va_end(d);
- va_end(s);
- if (!loglevel) exit(20);
- }
- /*
- * Names can also be used for the 'month' and 'day of week' fields
- * (First three letters of the particular day or month).
- */
- static int getindex(char *src, int size)
- {
- int i;
- char *field = (size == 12) ? months : days;
- // strings are not allowed for min, hour and dom fields.
- if (!(size == 7 || size == 12)) return -1;
- for (i = 0; field[i]; i += 3) {
- if (!strncasecmp(src, &field[i], 3))
- return (i/3);
- }
- return -1;
- }
- // set elements of minute, hour, day of month, month and day of week arrays.
- static void fillarray(char *dst, int start, int end, int skip)
- {
- int sk = 1;
- if (end < 0) {
- dst[start] = 1;
- return;
- }
- if (!skip) skip = 1;
- do {
- if (!--sk) {
- dst[start] = 1;
- sk = skip;
- }
- } while (start++ != end);
- }
- static long getval(char *num, long low, long high)
- {
- long val = strtol(num, &num, 10);
- if (*num || (val < low) || (val > high)) return -1;
- return val;
- }
- //static int parse_and_fillarray(char *dst, int size, char *src)
- static int parse_and_fillarray(char *dst, int min, int max, char *src)
- {
- int start, end, skip = 0;
- char *ptr = strchr(src, '/');
- if (ptr) {
- *ptr++ = 0;
- if ((skip = getval(ptr, min, (min ? max: max-1))) < 0) goto ERROR;
- }
- if (*src == '-' || *src == ',') goto ERROR;
- if (*src == '*') {
- if (*(src+1)) goto ERROR;
- fillarray(dst, 0, max-1, skip);
- } else {
- for (;;) {
- char *ctoken = strsep(&src, ","), *dtoken;
- if (!ctoken) break;
- if (!*ctoken) goto ERROR;
- // Get start position.
- dtoken = strsep(&ctoken, "-");
- if (isdigit(*dtoken)) {
- if ((start = getval(dtoken, min, (min ? max : max-1))) < 0) goto ERROR;
- start = min ? (start-1) : start;
- } else if ((start = getindex(dtoken, max)) < 0) goto ERROR;
- // Get end position.
- if (!ctoken) end = -1; // e.g. N1,N2,N3
- else if (*ctoken) {// e.g. N-M
- if (isdigit(*ctoken)) {
- if ((end = getval(ctoken, min, (min ? max : max-1))) < 0) goto ERROR;
- end = min ? (end-1) : end;
- } else if ((end = getindex(ctoken, max)) < 0) goto ERROR;
- if (end == start) end = -1;
- } else goto ERROR; // error condition 'N-'
- fillarray(dst, start, end, skip);
- }
- }
- if (TT.flagd && (TT.loglevel <= 5)) {
- for (start = 0; start < max; start++)
- fprintf(stderr, "%d", (unsigned char)dst[start]);
- fputc('\n', stderr);
- }
- return 0;
- ERROR:
- loginfo(LOG_LEVEL9, "parse error at %s", src);
- return -1;
- }
- static char *omitspace(char *line)
- {
- while (*line == ' ' || *line == '\t') line++;
- return line;
- }
- static void parse_line(char *line, CRONFILE *cfile)
- {
- int count = 0;
- char *name, *val, *tokens[5] = {0,};
- VAR *v;
- JOB *j;
- line = omitspace(line);
- if (!*line || *line == '#') return;
- /*
- * TODO: Enhancement to support 8 special strings
- * @reboot -> Run once at startup.
- * @yearly -> Run once a year (0 0 1 1 *).
- * @annually -> Same as above.
- * @monthly -> Run once a month (0 0 1 * *).
- * @weekly -> Run once a week (0 0 * * 0).
- * @daily -> Run once a day (0 0 * * *).
- * @midnight -> same as above.
- * @hourly -> Run once an hour (0 * * * *).
- */
- if (*line == '@') return;
- if (TT.flagd) loginfo(LOG_LEVEL5, "user:%s entry:%s", cfile->username, line);
- while (count<5) {
- int len = strcspn(line, " \t");
- if (line[len]) line[len++] = '\0';
- tokens[count++] = line;
- line += len;
- line = omitspace(line);
- if (!*line) break;
- }
- switch (count) {
- case 1: // form SHELL=/bin/sh
- name = tokens[0];
- if ((val = strchr(name, '='))) *val++ = 0;
- if (!val || !*val) return;
- break;
- case 2: // form SHELL =/bin/sh or SHELL= /bin/sh
- name = tokens[0];
- if ((val = strchr(name, '='))) {
- *val = 0;
- val = tokens[1];
- } else {
- if (*(tokens[1]) != '=') return;
- val = tokens[1] + 1;
- }
- if (!*val) return;
- break;
- case 3: // NAME = VAL
- name = tokens[0];
- val = tokens[2];
- if (*(tokens[1]) != '=') return;
- break;
- case 5:
- // don't have any cmd to execute.
- if (!*line) return;
- j = xzalloc(sizeof(JOB));
- if (parse_and_fillarray(j->min, 0, sizeof(j->min), tokens[0]))
- goto STOP_PARSING;
- if (parse_and_fillarray(j->hour, 0, sizeof(j->hour), tokens[1]))
- goto STOP_PARSING;
- if (parse_and_fillarray(j->dom, 1, sizeof(j->dom), tokens[2]))
- goto STOP_PARSING;
- if (parse_and_fillarray(j->mon, 1, sizeof(j->mon), tokens[3]))
- goto STOP_PARSING;
- if (parse_and_fillarray(j->dow, 0, sizeof(j->dow), tokens[4]))
- goto STOP_PARSING;
- j->cmd = xstrdup(line);
- if (TT.flagd) loginfo(LOG_LEVEL5, " command:%s", j->cmd);
- dlist_add_nomalloc((struct double_list **)&cfile->job, (struct double_list *)j);
- return;
- STOP_PARSING:
- free(j);
- return;
- default: return;
- }
- if (!strcmp(name, "MAILTO")) cfile->mailto = xstrdup(val);
- else {
- v = xzalloc(sizeof(VAR));
- v->name = xstrdup(name);
- v->val = xstrdup(val);
- dlist_add_nomalloc((struct double_list **)&cfile->var, (struct double_list *)v);
- }
- }
- static void free_jobs(JOB **jlist)
- {
- JOB *j = dlist_pop(jlist);
- free(j->cmd);
- free(j);
- }
- static void free_cronfile(CRONFILE **list)
- {
- CRONFILE *l = dlist_pop(list);
- VAR *v, *vnode = (VAR *)l->var;
- if (l->username != l->mailto) free(l->mailto);
- free(l->username);
- while (vnode && (v = dlist_pop(&vnode))) {
- free(v->name);
- free(v->val);
- free(v);
- }
- free(l);
- }
- /*
- * Iterate all cronfiles to identify the completed jobs and freed them.
- * If all jobs got completed for a cronfile, freed cronfile too.
- */
- static void remove_completed_jobs()
- {
- CRONFILE *lstart, *list = gclist;
- lstart = list;
- while (list) {
- int delete = 1;
- JOB *jstart, *jlist = (JOB *)list->job;
- list->invalid = 1;
- jstart = jlist;
- while (jlist) {
- jlist->isrunning = 0;
- if (jlist->pid > 0) {
- jlist->isrunning = 1;
- delete = 0;
- jlist = jlist->next;
- } else {
- if (jlist == jstart) { // if 1st node has to delete.
- jstart = jstart->next;
- free_jobs(&jlist);
- continue;
- } else free_jobs(&jlist);
- }
- if (jlist == jstart) break;
- }
- list->job = (struct double_list *)jlist;
- if (delete) {
- if (lstart == list) {
- lstart = lstart->next;
- free_cronfile(&list);
- continue;
- } else free_cronfile(&list);
- }
- list = list->next;
- if (lstart == list) break;
- }
- gclist = list;
- }
- // Scan cronfiles and prepare the list of cronfiles with their jobs.
- static void scan_cronfiles()
- {
- DIR *dp;
- struct dirent *entry;
- remove_completed_jobs();
- if (chdir(TT.crontabs_dir)) loginfo(LOG_EXIT, "chdir(%s)", TT.crontabs_dir);
- if (!(dp = opendir("."))) loginfo(LOG_EXIT, "chdir(%s)", ".");
- while ((entry = readdir(dp))) {
- CRONFILE *cfile;
- FILE *fp;
- char *line = 0;
- size_t allocated_length = 0;
- if (isdotdot(entry->d_name)) continue;
- if (!getpwnam(entry->d_name)) {
- loginfo(LOG_LEVEL7, "ignoring file '%s' (no such user)", entry->d_name);
- continue;
- }
- if (!(fp = fopen(entry->d_name, "r"))) continue;
- // one node for each user
- cfile = xzalloc(sizeof(CRONFILE));
- cfile->username = xstrdup(entry->d_name);
- while (getline(&line, &allocated_length, fp) > 0) {
- parse_line(line, cfile);
- }
- free(line);
- fclose(fp);
- // If there is no job for a cron, remove the VAR list.
- if (!cfile->job) {
- VAR *v, *vnode = (VAR *)cfile->var;
- free(cfile->username);
- if (cfile->mailto) free(cfile->mailto);
- while (vnode && (v = dlist_pop(&vnode))) {
- free(v->name);
- free(v->val);
- free(v);
- }
- free(cfile);
- } else {
- if (!cfile->mailto) cfile->mailto = cfile->username;
- dlist_add_nomalloc((struct double_list **)&gclist,
- (struct double_list *)cfile);
- }
- }
- closedir(dp);
- }
- /*
- * Set env variables, if any in the cronfile. Execute given job with the given
- * SHELL or Default SHELL and send an e-mail with respect to every successfully
- * completed job (as per the given param 'prog').
- */
- static void do_fork(CRONFILE *cfile, JOB *job, int fd, char *prog)
- {
- pid_t pid = vfork();
- if (pid == 0) {
- VAR *v, *vstart = (VAR *)cfile->var;
- struct passwd *pwd = getpwnam(cfile->username);
- if (!pwd) loginfo(LOG_LEVEL9, "can't get uid for %s", cfile->username);
- else {
- char *file = "/bin/sh";
- if (setenv("USER", pwd->pw_name, 1)) _exit(1);
- for (v = vstart; v;) {
- if (!strcmp("SHELL", v->name)) file = v->val;
- if (setenv(v->name, v->val, 1)) _exit(1);
- if ((v=v->next) == vstart) break;
- }
- if (!getenv("HOME")) {
- if (setenv("HOME", pwd->pw_dir, 1))
- _exit(1);
- }
- xsetuser(pwd);
- if (chdir(pwd->pw_dir)) loginfo(LOG_LEVEL9, "chdir(%s)", pwd->pw_dir);
- if (prog) file = prog;
- if (TT.flagd) loginfo(LOG_LEVEL5, "child running %s", file);
- if (fd >= 0) {
- int newfd = prog ? 0 : 1;
- if (fd != newfd) {
- dup2(fd, newfd);
- close(fd);
- }
- dup2(1, 2);
- }
- setpgrp();
- execlp(file, file, (prog ? "-ti" : "-c"), (prog ? NULL : job->cmd), (char *) NULL);
- loginfo(LOG_ERROR, "can't execute '%s' for user %s", file, cfile->username);
- if (!prog) dprintf(1, "Exec failed: %s -c %s\n", file, job->cmd);
- _exit(EXIT_SUCCESS);
- }
- }
- if (pid < 0) {
- loginfo(LOG_ERROR, "can't vfork");
- pid = 0;
- }
- if (fd >=0) close(fd);
- job->pid = pid;
- }
- // Send an e-mail for each successfully completed jobs.
- static void sendmail(CRONFILE *cfile, JOB *job)
- {
- pid_t pid = job->pid;
- int mailfd;
- struct stat sb;
- job->pid = 0;
- if (pid <=0 || job->mailsize <=0) {
- job->isrunning = 0;
- job->needstart = 1;
- return;
- }
- snprintf(toybuf, sizeof(toybuf), "/var/spool/cron/cron.%s.%d",
- cfile->username, (int)pid);
- mailfd = open(toybuf, O_RDONLY);
- unlink(toybuf);
- if (mailfd < 0) return;
- if (fstat(mailfd, &sb) == -1 || sb.st_uid != 0 || sb.st_nlink != 0
- || sb.st_size == job->mailsize || !S_ISREG(sb.st_mode)) {
- xclose(mailfd);
- return;
- }
- job->mailsize = 0;
- do_fork(cfile, job, mailfd, "sendmail");
- }
- // Count the number of jobs, which are not completed.
- static int count_running_jobs()
- {
- CRONFILE *cfile = gclist;
- JOB *job, *jstart;
- int count = 0;
- while (cfile) {
- job = jstart = (JOB *)cfile->job;
- while (job) {
- int ret;
- if (!job->isrunning || job->pid<=0) goto NEXT_JOB;
- job->isrunning = 0;
- ret = waitpid(job->pid, NULL, WNOHANG);
- if (ret < 0 || ret == job->pid) {
- sendmail(cfile, job);
- if (job->pid) count += (job->isrunning=1);
- else {
- job->isrunning = 0;
- job->needstart = 1;
- }
- }
- else count += (job->isrunning=1);
- NEXT_JOB:
- if ((job = job->next) == jstart) break;
- }
- if ((cfile = cfile->next) == gclist) break;
- }
- return count;
- }
- // Execute jobs one by one and prepare for the e-mail sending.
- static void execute_jobs(void)
- {
- CRONFILE *cfile = gclist;
- JOB *job, *jstart;
- while (cfile) {
- job = jstart = (JOB *)cfile->job;
- while (job) {
- if (job->needstart) {
- job->needstart = 0;
- if (job->pid < 0) {
- int mailfd = -1;
- job->mailsize = job->pid = 0;
- snprintf(toybuf, sizeof(toybuf), "/var/spool/cron/cron.%s.%d",
- cfile->username, getpid());
- if ((mailfd = open(toybuf, O_CREAT|O_TRUNC|O_WRONLY|O_EXCL|O_APPEND,
- 0600)) < 0) {
- loginfo(LOG_ERROR, "can't create mail file %s for user %s, "
- "discarding output", toybuf, cfile->username);
- } else {
- dprintf(mailfd, "To: %s\nSubject: cron: %s\n\n", cfile->mailto, job->cmd);
- job->mailsize = lseek(mailfd, 0, SEEK_CUR);
- }
- do_fork(cfile, job, mailfd, NULL);
- if (mailfd >= 0) {
- if (job->pid <= 0) unlink(toybuf);
- else {
- char *mailfile = xmprintf("/var/spool/cron/cron.%s.%d",
- cfile->username, (int)job->pid);
- rename(toybuf, mailfile);
- free(mailfile);
- }
- }
- loginfo(LOG_LEVEL8, "USER %s pid %3d cmd %s",
- cfile->username, job->pid, job->cmd);
- if (job->pid < 0) job->needstart = 1;
- else job->isrunning = 1;
- }
- }
- if ((job = job->next) == jstart) break;
- }
- if ((cfile = cfile->next) == gclist) break;
- }
- }
- // Identify jobs, which needs to be started at the given time interval.
- static void schedule_jobs(time_t ctime, time_t ptime)
- {
- time_t tm = ptime-ptime%60;
- for (; tm <= ctime; tm += 60) {
- struct tm *lt;
- CRONFILE *cfile = gclist;
- JOB *job, *jstart;
- if (tm <= ptime) continue;
- lt = localtime(&tm);
- while (cfile) {
- if (TT.flagd) loginfo(LOG_LEVEL5, "file %s:", cfile->username);
- if (cfile->invalid) goto NEXT_CRONFILE;
- job = jstart = (JOB *)cfile->job;
- while (job) {
- if (TT.flagd) loginfo(LOG_LEVEL5, " line %s", job->cmd);
- if (job->min[lt->tm_min] && job->hour[lt->tm_hour]
- && (job->dom[lt->tm_mday] || job->dow[lt->tm_wday])
- && job->mon[lt->tm_mon-1]) {
- if (TT.flagd)
- loginfo(LOG_LEVEL5, " job: %d %s\n", (int)job->pid, job->cmd);
- if (job->pid > 0) {
- loginfo(LOG_LEVEL8, "user %s: process already running: %s",
- cfile->username, job->cmd);
- } else if (!job->pid) {
- job->pid = -1;
- job->needstart = 1;
- job->isrunning = 0;
- }
- }
- if ((job = job->next) == jstart) break;
- }
- NEXT_CRONFILE:
- if ((cfile = cfile->next) == gclist) break;
- }
- }
- }
- void crond_main(void)
- {
- time_t ctime, ptime;
- int sleepfor = 60;
- struct stat sb;
- TT.flagd = (toys.optflags & FLAG_d);
- // Setting default params.
- if (TT.flagd) TT.loglevel = TT.loglevel_d;
- if (!(toys.optflags & (FLAG_f | FLAG_b))) toys.optflags |= FLAG_b;
- if (!(toys.optflags & (FLAG_S | FLAG_L))) toys.optflags |= FLAG_S;
- if ((toys.optflags & FLAG_c)
- && (TT.crontabs_dir[strlen(TT.crontabs_dir)-1] != '/'))
- TT.crontabs_dir = xmprintf("%s/", TT.crontabs_dir);
- if (!TT.crontabs_dir) TT.crontabs_dir = xstrdup("/var/spool/cron/crontabs/");
- if (toys.optflags & FLAG_b) daemon(0,0);
- if (!TT.flagd && !TT.logfile)
- openlog(toys.which->name, LOG_CONS | LOG_PID, LOG_CRON);
- // Set default shell once.
- if (setenv("SHELL", "/bin/sh", 1)) error_exit("Can't set default shell");
- xchdir(TT.crontabs_dir);
- loginfo(LOG_LEVEL8, "crond started, log level %d", TT.loglevel);
- if (stat(TT.crontabs_dir, &sb)) sb.st_mtime = 0;
- TT.crontabs_dir_mtime = sb.st_mtime;
- scan_cronfiles();
- ctime = time(NULL);
- while (1) {
- long tdiff;
- ptime = ctime;
- sleep(sleepfor - (ptime%sleepfor) +1);
- tdiff =(long) ((ctime = time(NULL)) - ptime);
- if (stat(TT.crontabs_dir, &sb)) sb.st_mtime = 0;
- if (TT.crontabs_dir_mtime != sb.st_mtime) {
- TT.crontabs_dir_mtime = sb.st_mtime;
- scan_cronfiles();
- }
- if (TT.flagd) loginfo(LOG_LEVEL5, "wakeup diff=%ld\n", tdiff);
- if (tdiff < -60 * 60 || tdiff > 60 * 60)
- loginfo(LOG_LEVEL9, "time disparity of %ld minutes detected", tdiff / 60);
- else if (tdiff > 0) {
- schedule_jobs(ctime, ptime);
- execute_jobs();
- if (count_running_jobs()) sleepfor = 10;
- else sleepfor = 60;
- }
- }
- }
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