| /* vi: set sw=4 ts=4: */ |
| /* |
| * 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. |
| */ |
| //config:config CROND |
| //config: bool "crond (14 kb)" |
| //config: default y |
| //config: select FEATURE_SYSLOG |
| //config: help |
| //config: Crond is a background daemon that parses individual crontab |
| //config: files and executes commands on behalf of the users in question. |
| //config: This is a port of dcron from slackware. It uses files of the |
| //config: format /var/spool/cron/crontabs/<username> files, for example: |
| //config: $ cat /var/spool/cron/crontabs/root |
| //config: # Run daily cron jobs at 4:40 every day: |
| //config: 40 4 * * * /etc/cron/daily > /dev/null 2>&1 |
| //config: |
| //config:config FEATURE_CROND_D |
| //config: bool "Support -d (redirect output to stderr)" |
| //config: depends on CROND |
| //config: default y |
| //config: help |
| //config: -d N sets loglevel (0:most verbose) and directs all output to stderr. |
| //config: |
| //config:config FEATURE_CROND_CALL_SENDMAIL |
| //config: bool "Report command output via email (using sendmail)" |
| //config: default y |
| //config: depends on CROND |
| //config: help |
| //config: Command output will be sent to corresponding user via email. |
| //config: |
| //config:config FEATURE_CROND_SPECIAL_TIMES |
| //config: bool "Support special times (@reboot, @daily, etc) in crontabs" |
| //config: default y |
| //config: depends on CROND |
| //config: help |
| //config: string meaning |
| //config: ------ ------- |
| //config: @reboot Run once, at startup |
| //config: @yearly Run once a year: "0 0 1 1 *" |
| //config: @annually Same as @yearly: "0 0 1 1 *" |
| //config: @monthly Run once a month: "0 0 1 * *" |
| //config: @weekly Run once a week: "0 0 * * 0" |
| //config: @daily Run once a day: "0 0 * * *" |
| //config: @midnight Same as @daily: "0 0 * * *" |
| //config: @hourly Run once an hour: "0 * * * *" |
| //config: |
| //config:config FEATURE_CROND_DIR |
| //config: string "crond spool directory" |
| //config: default "/var/spool/cron" |
| //config: depends on CROND || CRONTAB |
| //config: help |
| //config: Location of crond spool. |
| |
| //applet:IF_CROND(APPLET(crond, BB_DIR_USR_SBIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_CROND) += crond.o |
| |
| //usage:#define crond_trivial_usage |
| //usage: "-fbS -l N " IF_FEATURE_CROND_D("-d N ") "-L LOGFILE -c DIR" |
| //usage:#define crond_full_usage "\n\n" |
| //usage: " -f Foreground" |
| //usage: "\n -b Background (default)" |
| //usage: "\n -S Log to syslog (default)" |
| //usage: "\n -l N Set log level. Most verbose 0, default 8" |
| //usage: IF_FEATURE_CROND_D( |
| //usage: "\n -d N Set log level, log to stderr" |
| //usage: ) |
| //usage: "\n -L FILE Log to FILE" |
| //usage: "\n -c DIR Cron dir. Default:"CONFIG_FEATURE_CROND_DIR"/crontabs" |
| |
| #include "libbb.h" |
| #include "common_bufsiz.h" |
| #include <syslog.h> |
| |
| #if 0 |
| /* If libc tracks and reuses setenv()-allocated memory, ok to set this to 0 */ |
| /* Neither glibc nor uclibc do that! */ |
| # define SETENV_LEAKS 0 |
| #else |
| # define SETENV_LEAKS 1 |
| #endif |
| |
| |
| #define CRON_DIR CONFIG_FEATURE_CROND_DIR |
| #define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs" |
| #define CRON_REBOOT CONFIG_PID_FILE_PATH "/crond.reboot" |
| #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 */ |
| #define START_ME_REBOOT -2 |
| #define START_ME_NORMAL -1 |
| #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 |
| char *cl_shell; |
| /* 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, |
| }; |
| |
| struct globals { |
| unsigned log_level; /* = 8; */ |
| time_t crontab_dir_mtime; |
| const char *log_filename; |
| const char *crontab_dir_name; /* = CRONTABS; */ |
| CronFile *cron_files; |
| char *default_shell; |
| #if SETENV_LEAKS |
| char *env_var_user; |
| char *env_var_home; |
| char *env_var_shell; |
| char *env_var_logname; |
| #endif |
| } FIX_ALIASING; |
| #define G (*(struct globals*)bb_common_bufsiz1) |
| #define INIT_G() do { \ |
| setup_common_bufsiz(); \ |
| G.log_level = 8; \ |
| G.crontab_dir_name = CRONTABS; \ |
| } while (0) |
| |
| /* Log levels: |
| * 0 is the most verbose, default 8. |
| * For some reason, in fact only 5, 7 and 8 are used. |
| */ |
| static void crondlog(unsigned level, const char *msg, va_list va) |
| { |
| if (level >= G.log_level) { |
| /* |
| * We are called only for info meesages. |
| * Warnings/errors use plain bb_[p]error_msg's, which |
| * need not touch syslog_level |
| * (they are ok with LOG_ERR default). |
| */ |
| bb_vinfo_msg(msg, va); |
| } |
| } |
| |
| static void log5(const char *msg, ...) |
| { |
| va_list va; |
| va_start(va, msg); |
| crondlog(4, msg, va); |
| va_end(va); |
| } |
| |
| static void log7(const char *msg, ...) |
| { |
| va_list va; |
| va_start(va, msg); |
| crondlog(7, msg, va); |
| va_end(va); |
| } |
| |
| static void log8(const char *msg, ...) |
| { |
| va_list va; |
| va_start(va, msg); |
| crondlog(8, msg, va); |
| va_end(va); |
| } |
| |
| |
| static const char DowAry[] ALIGN1 = |
| "sun""mon""tue""wed""thu""fri""sat" |
| ; |
| |
| static const char MonAry[] ALIGN1 = |
| "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: |
| bb_error_msg("user %s: parse error at %s", user, base); |
| return; |
| } |
| |
| /* can't use log5 (it inserts newlines), open-coding it */ |
| if (G.log_level <= 5 && logmode != LOGMODE_SYSLOG) { |
| 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 |
| char *shell = NULL; |
| |
| delete_cronfile(fileName); |
| |
| if (!getpwnam(fileName)) { |
| log7("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) { |
| bb_error_msg("user %s: too many lines", fileName); |
| break; |
| } |
| |
| n = config_read(parser, tokens, 6, 1, "# \t", PARSE_NORMAL | PARSE_KEEP_COPY); |
| if (!n) |
| break; |
| |
| log5("user:%s entry:%s", fileName, parser->data); |
| |
| /* check if line is setting MAILTO= */ |
| if (is_prefixed_with(tokens[0], "MAILTO=")) { |
| #if ENABLE_FEATURE_CROND_CALL_SENDMAIL |
| free(mailTo); |
| mailTo = (tokens[0][7]) ? xstrdup(&tokens[0][7]) : NULL; |
| #endif /* otherwise just ignore such lines */ |
| continue; |
| } |
| if (is_prefixed_with(tokens[0], "SHELL=")) { |
| free(shell); |
| shell = xstrdup(&tokens[0][6]); |
| continue; |
| } |
| //TODO: handle HOME= too? "man crontab" says: |
| //name = value |
| // |
| //where the spaces around the equal-sign (=) are optional, and any subsequent |
| //non-leading spaces in value will be part of the value assigned to name. |
| //The value string may be placed in quotes (single or double, but matching) |
| //to preserve leading or trailing blanks. |
| // |
| //Several environment variables are set up automatically by the cron(8) daemon. |
| //SHELL is set to /bin/sh, and LOGNAME and HOME are set from the /etc/passwd |
| //line of the crontab's owner. HOME and SHELL may be overridden by settings |
| //in the crontab; LOGNAME may not. |
| |
| #if ENABLE_FEATURE_CROND_SPECIAL_TIMES |
| if (tokens[0][0] == '@') { |
| /* |
| * "@daily /a/script/to/run PARAM1 PARAM2..." |
| */ |
| typedef struct SpecialEntry { |
| const char *name; |
| const char tokens[8]; |
| } SpecialEntry; |
| static const SpecialEntry SpecAry[] = { |
| /* hour day month weekday */ |
| { "yearly", "0\0" "1\0" "1\0" "*" }, |
| { "annually", "0\0" "1\0" "1\0" "*" }, |
| { "monthly", "0\0" "1\0" "*\0" "*" }, |
| { "weekly", "0\0" "*\0" "*\0" "0" }, |
| { "daily", "0\0" "*\0" "*\0" "*" }, |
| { "midnight", "0\0" "*\0" "*\0" "*" }, |
| { "hourly", "*\0" "*\0" "*\0" "*" }, |
| { "reboot", "" }, |
| }; |
| const SpecialEntry *e = SpecAry; |
| |
| if (n < 2) |
| continue; |
| for (;;) { |
| if (strcmp(e->name, tokens[0] + 1) == 0) { |
| /* |
| * tokens[1] is only the first word of command, |
| * can'r use it. |
| * find the entire command in unmodified string: |
| */ |
| tokens[5] = skip_whitespace( |
| skip_non_whitespace( |
| skip_whitespace(parser->data))); |
| if (e->tokens[0]) { |
| char *et = (char*)e->tokens; |
| /* minute is "0" for all specials */ |
| tokens[0] = (char*)"0"; |
| tokens[1] = et; |
| tokens[2] = et + 2; |
| tokens[3] = et + 4; |
| tokens[4] = et + 6; |
| } |
| goto got_it; |
| } |
| if (!e->tokens[0]) |
| break; |
| e++; |
| } |
| continue; /* bad line (unrecognized '@foo') */ |
| } |
| #endif |
| /* check if a minimum of tokens is specified */ |
| if (n < 6) |
| continue; |
| IF_FEATURE_CROND_SPECIAL_TIMES( |
| got_it: |
| ) |
| *pline = line = xzalloc(sizeof(*line)); |
| #if ENABLE_FEATURE_CROND_SPECIAL_TIMES |
| if (tokens[0][0] == '@') { /* "@reboot" line */ |
| file->cf_wants_starting = 1; |
| line->cl_pid = START_ME_REBOOT; /* wants to start */ |
| /* line->cl_Mins/Hrs/etc stay zero: never match any time */ |
| } else |
| #endif |
| { |
| /* 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 |
| line->cl_shell = xstrdup(shell); |
| /* copy command */ |
| line->cl_cmd = xstrdup(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; |
| } |
| config_close(parser); |
| #if ENABLE_FEATURE_CROND_CALL_SENDMAIL |
| free(mailTo); |
| #endif |
| free(shell); |
| } |
| |
| 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 */ |
| xchdir(G.crontab_dir_name); |
| |
| /* Scan directory and add associated users */ |
| { |
| DIR *dir = opendir("."); |
| struct dirent *den; |
| |
| /* xopendir exists, but "can't open '.'" is not informative */ |
| if (!dir) |
| bb_error_msg_and_die("can't open '%s'", G.crontab_dir_name); |
| 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, const char *shell) |
| { |
| /* POSIX requires crond to set up at least HOME, LOGNAME, PATH, SHELL. |
| * We assume crond inherited suitable PATH. |
| */ |
| #if SETENV_LEAKS |
| safe_setenv(&G.env_var_logname, "LOGNAME", pas->pw_name); |
| safe_setenv(&G.env_var_user, "USER", pas->pw_name); |
| safe_setenv(&G.env_var_home, "HOME", pas->pw_dir); |
| safe_setenv(&G.env_var_shell, "SHELL", shell); |
| #else |
| xsetenv("LOGNAME", pas->pw_name); |
| xsetenv("USER", pas->pw_name); |
| xsetenv("HOME", pas->pw_dir); |
| xsetenv("SHELL", shell); |
| #endif |
| } |
| |
| static void change_user(struct passwd *pas) |
| { |
| /* careful: we're after vfork! */ |
| change_identity(pas); /* - initgroups, setgid, setuid */ |
| if (chdir(pas->pw_dir) < 0) { |
| bb_error_msg("can't change directory to '%s'", pas->pw_dir); |
| xchdir(CRON_DIR); |
| } |
| } |
| |
| // 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, CronLine *line, bool run_sendmail) |
| { |
| struct passwd *pas; |
| const char *shell, *prog; |
| smallint sv_logmode; |
| pid_t pid; |
| |
| /* prepare things before vfork */ |
| pas = getpwnam(user); |
| if (!pas) { |
| bb_error_msg("can't get uid for %s", user); |
| goto err; |
| } |
| |
| shell = line->cl_shell ? line->cl_shell : G.default_shell; |
| prog = run_sendmail ? SENDMAIL : shell; |
| |
| set_env_vars(pas, shell); |
| |
| sv_logmode = logmode; |
| pid = vfork(); |
| if (pid == 0) { |
| /* CHILD */ |
| /* initgroups, setgid, setuid, and chdir to home or CRON_DIR */ |
| change_user(pas); |
| log5("child running %s", prog); |
| if (mailFd >= 0) { |
| xmove_fd(mailFd, run_sendmail ? 0 : 1); |
| dup2(1, 2); |
| } |
| /* crond 3.0pl1-100 puts tasks in separate process groups */ |
| bb_setpgrp(); |
| if (!run_sendmail) |
| execlp(prog, prog, "-c", line->cl_cmd, (char *) NULL); |
| else |
| execlp(prog, prog, SENDMAIL_ARGS, (char *) NULL); |
| /* |
| * I want this error message on stderr too, |
| * even if other messages go only to syslog: |
| */ |
| logmode |= LOGMODE_STDIO; |
| bb_error_msg_and_die("can't execute '%s' for user %s", prog, user); |
| } |
| logmode = sv_logmode; |
| |
| if (pid < 0) { |
| bb_perror_msg("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 pid_t 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", CRON_DIR, 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 { |
| bb_error_msg("can't create mail file %s for user %s, " |
| "discarding output", mailFile, user); |
| } |
| } |
| |
| line->cl_pid = fork_job(user, mailFd, line, /*sendmail?*/ 0); |
| 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", CRON_DIR, user, (int)line->cl_pid); |
| rename(mailFile, mailFile2); // TODO: xrename? |
| free(mailFile2); |
| } |
| } |
| |
| return line->cl_pid; |
| } |
| |
| /* |
| * 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", CRON_DIR, 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, line, /*sendmail?*/ 1); |
| } |
| |
| #else /* !ENABLE_FEATURE_CROND_CALL_SENDMAIL */ |
| |
| static pid_t start_one_job(const char *user, CronLine *line) |
| { |
| const char *shell; |
| struct passwd *pas; |
| pid_t pid; |
| |
| pas = getpwnam(user); |
| if (!pas) { |
| bb_error_msg("can't get uid for %s", user); |
| goto err; |
| } |
| |
| /* Prepare things before vfork */ |
| shell = line->cl_shell ? line->cl_shell : G.default_shell; |
| set_env_vars(pas, shell); |
| |
| /* Fork as the user in question and run program */ |
| pid = vfork(); |
| if (pid == 0) { |
| /* CHILD */ |
| /* initgroups, setgid, setuid, and chdir to home or CRON_DIR */ |
| change_user(pas); |
| log5("child running %s", shell); |
| /* crond 3.0pl1-100 puts tasks in separate process groups */ |
| bb_setpgrp(); |
| execl(shell, shell, "-c", line->cl_cmd, (char *) NULL); |
| bb_error_msg_and_die("can't execute '%s' for user %s", shell, user); |
| } |
| if (pid < 0) { |
| bb_perror_msg("vfork"); |
| err: |
| pid = 0; |
| } |
| line->cl_pid = pid; |
| return 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) { |
| log5("file %s:", file->cf_username); |
| if (file->cf_deleted) |
| continue; |
| for (line = file->cf_lines; line; line = line->cl_next) { |
| log5(" 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] |
| ) { |
| log5(" job: %d %s", |
| (int)line->cl_pid, line->cl_cmd); |
| if (line->cl_pid > 0) { |
| log8("user %s: process already running: %s", |
| file->cf_username, line->cl_cmd); |
| } else if (line->cl_pid == 0) { |
| line->cl_pid = START_ME_NORMAL; |
| file->cf_wants_starting = 1; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| #if ENABLE_FEATURE_CROND_SPECIAL_TIMES |
| static int touch_reboot_file(void) |
| { |
| int fd = open(CRON_REBOOT, O_WRONLY | O_CREAT | O_EXCL | O_TRUNC, 0000); |
| if (fd >= 0) { |
| close(fd); |
| return 1; |
| } |
| /* File (presumably) exists - this is not the first run after reboot */ |
| return 0; |
| } |
| #endif |
| |
| static void start_jobs(int wants_start) |
| { |
| 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 != wants_start) |
| continue; |
| |
| pid = start_one_job(file->cf_username, line); |
| log8("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; |
| } |
| |
| static void reopen_logfile_to_stderr(void) |
| { |
| if (G.log_filename) { |
| int logfd = open_or_warn(G.log_filename, O_WRONLY | O_CREAT | O_APPEND); |
| if (logfd >= 0) |
| xmove_fd(logfd, STDERR_FILENO); |
| } |
| } |
| |
| int crond_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int crond_main(int argc UNUSED_PARAM, char **argv) |
| { |
| time_t t2; |
| unsigned rescan; |
| unsigned sleep_time; |
| unsigned opts; |
| |
| INIT_G(); |
| |
| opts = getopt32(argv, "^" |
| "l:L:fbSc:" IF_FEATURE_CROND_D("d:") |
| "\0" |
| /* "-b after -f is ignored", and so on for every pair a-b */ |
| "f-b:b-f:S-L:L-S" IF_FEATURE_CROND_D(":d-l") |
| /* -l and -d have numeric param */ |
| ":l+" 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; |
| } |
| |
| //signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */ |
| |
| reopen_logfile_to_stderr(); |
| xchdir(G.crontab_dir_name); |
| /* $SHELL, or current UID's shell, or DEFAULT_SHELL */ |
| /* Useful on Android where DEFAULT_SHELL /bin/sh may not exist */ |
| G.default_shell = xstrdup(get_shell_name()); |
| |
| log8("crond (busybox "BB_VER") started, log level %d", G.log_level); |
| rescan_crontab_dir(); |
| write_pidfile_std_path_and_ext("crond"); |
| #if ENABLE_FEATURE_CROND_SPECIAL_TIMES |
| if (touch_reboot_file()) |
| start_jobs(START_ME_REBOOT); /* start @reboot entries, if any */ |
| #endif |
| |
| /* Main loop */ |
| t2 = time(NULL); |
| rescan = 60; |
| sleep_time = 60; |
| for (;;) { |
| struct stat sbuf; |
| time_t t1; |
| long dt; |
| |
| /* Synchronize to 1 minute, minimum 1 second */ |
| t1 = t2; |
| sleep(sleep_time - (time(NULL) % sleep_time)); |
| t2 = time(NULL); |
| dt = (long)t2 - (long)t1; |
| |
| reopen_logfile_to_stderr(); |
| |
| /* |
| * 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(); |
| log5("wakeup dt=%ld", dt); |
| if (dt < -60 * 60 || dt > 60 * 60) { |
| bb_info_msg("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(START_ME_NORMAL); |
| sleep_time = 60; |
| if (check_completions() > 0) { |
| /* some jobs are still running */ |
| sleep_time = 10; |
| } |
| } |
| /* else: time jumped back, do not run any jobs */ |
| } /* for (;;) */ |
| |
| return 0; /* not reached */ |
| } |