/* Copyright 1988,1990,1993,1994 by Paul Vixie * All rights reserved * * Distribute freely, except: don't remove my name from the source or * documentation (don't take credit for my work), mark your changes (don't * get me blamed for your possible bugs), don't alter or remove this * notice. May be sold if buildable source is provided to buyer. No * warrantee of any kind, express or implied, is included with this * software; use at your own risk, responsibility for damages (if any) to * anyone resulting from the use of this software rests entirely with the * user. * * Send bug reports, bug fixes, enhancements, requests, flames, etc., and * I'll try to keep a version up to date. I can be reached as follows: * Paul Vixie uunet!decwrl!vixie!paul * From Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp */ #if !defined(lint) && !defined(LINT) static const char rcsid[] = "$FreeBSD$"; #endif /* crontab - install and manage per-user crontab files * vix 02may87 [RCS has the rest of the log] * vix 26jan87 [original] */ #define MAIN_PROGRAM #include "cron.h" #include #include #include #include #include #ifdef USE_UTIMES # include #else # include # include #endif #if defined(POSIX) # include #endif #define NHEADER_LINES 3 enum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace }; #if DEBUGGING static char *Options[] = { "???", "list", "delete", "edit", "replace" }; #endif static PID_T Pid; static char User[MAX_UNAME], RealUser[MAX_UNAME]; static char Filename[MAX_FNAME]; static FILE *NewCrontab; static int CheckErrorCount; static enum opt_t Option; static struct passwd *pw; static void list_cmd __P((void)), delete_cmd __P((void)), edit_cmd __P((void)), poke_daemon __P((void)), check_error __P((char *)), parse_args __P((int c, char *v[])); static int replace_cmd __P((void)); static void usage(msg) char *msg; { fprintf(stderr, "crontab: usage error: %s\n", msg); fprintf(stderr, "%s\n%s\n", "usage: crontab [-u user] file", " crontab [-u user] { -e | -l | -r }"); exit(ERROR_EXIT); } int main(argc, argv) int argc; char *argv[]; { int exitstatus; Pid = getpid(); ProgramName = argv[0]; #if defined(POSIX) setlocale(LC_ALL, ""); #endif #if defined(BSD) setlinebuf(stderr); #endif parse_args(argc, argv); /* sets many globals, opens a file */ set_cron_uid(); set_cron_cwd(); if (!allowed(User)) { warnx("you (%s) are not allowed to use this program", User); log_it(RealUser, Pid, "AUTH", "crontab command not allowed"); exit(ERROR_EXIT); } exitstatus = OK_EXIT; switch (Option) { case opt_list: list_cmd(); break; case opt_delete: delete_cmd(); break; case opt_edit: edit_cmd(); break; case opt_replace: if (replace_cmd() < 0) exitstatus = ERROR_EXIT; break; case opt_unknown: break; } exit(exitstatus); /*NOTREACHED*/ } static void parse_args(argc, argv) int argc; char *argv[]; { int argch; if (!(pw = getpwuid(getuid()))) errx(ERROR_EXIT, "your UID isn't in the passwd file, bailing out"); (void) strncpy(User, pw->pw_name, (sizeof User)-1); User[(sizeof User)-1] = '\0'; strcpy(RealUser, User); Filename[0] = '\0'; Option = opt_unknown; while ((argch = getopt(argc, argv, "u:lerx:")) != -1) { switch (argch) { case 'x': if (!set_debug_flags(optarg)) usage("bad debug option"); break; case 'u': if (getuid() != ROOT_UID) errx(ERROR_EXIT, "must be privileged to use -u"); if (!(pw = getpwnam(optarg))) errx(ERROR_EXIT, "user `%s' unknown", optarg); (void) strncpy(User, pw->pw_name, (sizeof User)-1); User[(sizeof User)-1] = '\0'; break; case 'l': if (Option != opt_unknown) usage("only one operation permitted"); Option = opt_list; break; case 'r': if (Option != opt_unknown) usage("only one operation permitted"); Option = opt_delete; break; case 'e': if (Option != opt_unknown) usage("only one operation permitted"); Option = opt_edit; break; default: usage("unrecognized option"); } } endpwent(); if (Option != opt_unknown) { if (argv[optind] != NULL) { usage("no arguments permitted after this option"); } } else { if (argv[optind] != NULL) { Option = opt_replace; (void) strncpy (Filename, argv[optind], (sizeof Filename)-1); Filename[(sizeof Filename)-1] = '\0'; } else { usage("file name must be specified for replace"); } } if (Option == opt_replace) { /* we have to open the file here because we're going to * chdir(2) into /var/cron before we get around to * reading the file. */ if (!strcmp(Filename, "-")) { NewCrontab = stdin; } else { /* relinquish the setuid status of the binary during * the open, lest nonroot users read files they should * not be able to read. we can't use access() here * since there's a race condition. thanks go out to * Arnt Gulbrandsen for spotting * the race. */ if (swap_uids() < OK) err(ERROR_EXIT, "swapping uids"); if (!(NewCrontab = fopen(Filename, "r"))) err(ERROR_EXIT, "%s", Filename); if (swap_uids() < OK) err(ERROR_EXIT, "swapping uids back"); } } Debug(DMISC, ("user=%s, file=%s, option=%s\n", User, Filename, Options[(int)Option])) } static void list_cmd() { char n[MAX_FNAME]; FILE *f; int ch, x; log_it(RealUser, Pid, "LIST", User); (void) sprintf(n, CRON_TAB(User)); if (!(f = fopen(n, "r"))) { if (errno == ENOENT) errx(ERROR_EXIT, "no crontab for %s", User); else err(ERROR_EXIT, "%s", n); } /* file is open. copy to stdout, close. */ Set_LineNum(1) /* ignore the top few comments since we probably put them there. */ for (x = 0; x < NHEADER_LINES; x++) { ch = get_char(f); if (EOF == ch) break; if ('#' != ch) { putchar(ch); break; } while (EOF != (ch = get_char(f))) if (ch == '\n') break; if (EOF == ch) break; } while (EOF != (ch = get_char(f))) putchar(ch); fclose(f); } static void delete_cmd() { char n[MAX_FNAME]; int ch, first; if (isatty(STDIN_FILENO)) { (void)fprintf(stderr, "remove crontab for %s? ", User); first = ch = getchar(); while (ch != '\n' && ch != EOF) ch = getchar(); if (first != 'y' && first != 'Y') return; } log_it(RealUser, Pid, "DELETE", User); (void) sprintf(n, CRON_TAB(User)); if (unlink(n)) { if (errno == ENOENT) errx(ERROR_EXIT, "no crontab for %s", User); else err(ERROR_EXIT, "%s", n); } poke_daemon(); } static void check_error(msg) char *msg; { CheckErrorCount++; fprintf(stderr, "\"%s\":%d: %s\n", Filename, LineNumber-1, msg); } static void edit_cmd() { char n[MAX_FNAME], q[MAX_TEMPSTR], *editor; FILE *f; int ch, t, x; struct stat statbuf, fsbuf; time_t mtime; WAIT_T waiter; PID_T pid, xpid; mode_t um; log_it(RealUser, Pid, "BEGIN EDIT", User); (void) sprintf(n, CRON_TAB(User)); if (!(f = fopen(n, "r"))) { if (errno != ENOENT) err(ERROR_EXIT, "%s", n); warnx("no crontab for %s - using an empty one", User); if (!(f = fopen(_PATH_DEVNULL, "r"))) err(ERROR_EXIT, _PATH_DEVNULL); } um = umask(077); (void) sprintf(Filename, "/tmp/crontab.XXXXXXXXXX"); if ((t = mkstemp(Filename)) == -1) { warn("%s", Filename); (void) umask(um); goto fatal; } (void) umask(um); #ifdef HAS_FCHOWN if (fchown(t, getuid(), getgid()) < 0) { #else if (chown(Filename, getuid(), getgid()) < 0) { #endif warn("fchown"); goto fatal; } if (!(NewCrontab = fdopen(t, "r+"))) { warn("fdopen"); goto fatal; } Set_LineNum(1) /* ignore the top few comments since we probably put them there. */ for (x = 0; x < NHEADER_LINES; x++) { ch = get_char(f); if (EOF == ch) break; if ('#' != ch) { putc(ch, NewCrontab); break; } while (EOF != (ch = get_char(f))) if (ch == '\n') break; if (EOF == ch) break; } /* copy the rest of the crontab (if any) to the temp file. */ if (EOF != ch) while (EOF != (ch = get_char(f))) putc(ch, NewCrontab); fclose(f); if (fflush(NewCrontab)) err(ERROR_EXIT, "%s", Filename); if (fstat(t, &fsbuf) < 0) { warn("unable to fstat temp file"); goto fatal; } again: if (stat(Filename, &statbuf) < 0) { warn("stat"); fatal: unlink(Filename); exit(ERROR_EXIT); } if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) errx(ERROR_EXIT, "temp file must be edited in place"); mtime = statbuf.st_mtime; if ((!(editor = getenv("VISUAL"))) && (!(editor = getenv("EDITOR"))) ) { editor = EDITOR; } /* we still have the file open. editors will generally rewrite the * original file rather than renaming/unlinking it and starting a * new one; even backup files are supposed to be made by copying * rather than by renaming. if some editor does not support this, * then don't use it. the security problems are more severe if we * close and reopen the file around the edit. */ switch (pid = fork()) { case -1: warn("fork"); goto fatal; case 0: /* child */ if (setuid(getuid()) < 0) err(ERROR_EXIT, "setuid(getuid())"); if (chdir("/tmp") < 0) err(ERROR_EXIT, "chdir(/tmp)"); if (strlen(editor) + strlen(Filename) + 2 >= MAX_TEMPSTR) errx(ERROR_EXIT, "editor or filename too long"); execlp(editor, editor, Filename, (char *)NULL); err(ERROR_EXIT, "%s", editor); /*NOTREACHED*/ default: /* parent */ break; } /* parent */ { void (*f[4])(); f[0] = signal(SIGHUP, SIG_IGN); f[1] = signal(SIGINT, SIG_IGN); f[2] = signal(SIGTERM, SIG_IGN); xpid = wait(&waiter); signal(SIGHUP, f[0]); signal(SIGINT, f[1]); signal(SIGTERM, f[2]); } if (xpid != pid) { warnx("wrong PID (%d != %d) from \"%s\"", xpid, pid, editor); goto fatal; } if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) { warnx("\"%s\" exited with status %d", editor, WEXITSTATUS(waiter)); goto fatal; } if (WIFSIGNALED(waiter)) { warnx("\"%s\" killed; signal %d (%score dumped)", editor, WTERMSIG(waiter), WCOREDUMP(waiter) ?"" :"no "); goto fatal; } if (stat(Filename, &statbuf) < 0) { warn("stat"); goto fatal; } if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) errx(ERROR_EXIT, "temp file must be edited in place"); if (mtime == statbuf.st_mtime) { warnx("no changes made to crontab"); goto remove; } warnx("installing new crontab"); switch (replace_cmd()) { case 0: break; case -1: for (;;) { printf("Do you want to retry the same edit? "); fflush(stdout); q[0] = '\0'; (void) fgets(q, sizeof q, stdin); switch (islower(q[0]) ? q[0] : tolower(q[0])) { case 'y': goto again; case 'n': goto abandon; default: fprintf(stderr, "Enter Y or N\n"); } } /*NOTREACHED*/ case -2: abandon: warnx("edits left in %s", Filename); goto done; default: warnx("panic: bad switch() in replace_cmd()"); goto fatal; } remove: unlink(Filename); done: log_it(RealUser, Pid, "END EDIT", User); } /* returns 0 on success * -1 on syntax error * -2 on install error */ static int replace_cmd() { char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME]; FILE *tmp; int ch, eof; entry *e; time_t now = time(NULL); char **envp = env_init(); if (envp == NULL) { warnx("cannot allocate memory"); return (-2); } (void) sprintf(n, "tmp.%d", Pid); (void) sprintf(tn, CRON_TAB(n)); if (!(tmp = fopen(tn, "w+"))) { warn("%s", tn); return (-2); } /* write a signature at the top of the file. * * VERY IMPORTANT: make sure NHEADER_LINES agrees with this code. */ fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n"); fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now)); fprintf(tmp, "# (Cron version -- %s)\n", rcsid); /* copy the crontab to the tmp */ rewind(NewCrontab); Set_LineNum(1) while (EOF != (ch = get_char(NewCrontab))) putc(ch, tmp); ftruncate(fileno(tmp), ftell(tmp)); fflush(tmp); rewind(tmp); if (ferror(tmp)) { warnx("error while writing new crontab to %s", tn); fclose(tmp); unlink(tn); return (-2); } /* check the syntax of the file being installed. */ /* BUG: was reporting errors after the EOF if there were any errors * in the file proper -- kludged it by stopping after first error. * vix 31mar87 */ Set_LineNum(1 - NHEADER_LINES) CheckErrorCount = 0; eof = FALSE; while (!CheckErrorCount && !eof) { switch (load_env(envstr, tmp)) { case ERR: eof = TRUE; break; case FALSE: e = load_entry(tmp, check_error, pw, envp); if (e) free(e); break; case TRUE: break; } } if (CheckErrorCount != 0) { warnx("errors in crontab file, can't install"); fclose(tmp); unlink(tn); return (-1); } #ifdef HAS_FCHOWN if (fchown(fileno(tmp), ROOT_UID, -1) < OK) #else if (chown(tn, ROOT_UID, -1) < OK) #endif { warn("chown"); fclose(tmp); unlink(tn); return (-2); } #ifdef HAS_FCHMOD if (fchmod(fileno(tmp), 0600) < OK) #else if (chmod(tn, 0600) < OK) #endif { warn("chown"); fclose(tmp); unlink(tn); return (-2); } if (fclose(tmp) == EOF) { warn("fclose"); unlink(tn); return (-2); } (void) sprintf(n, CRON_TAB(User)); if (rename(tn, n)) { warn("error renaming %s to %s", tn, n); unlink(tn); return (-2); } log_it(RealUser, Pid, "REPLACE", User); poke_daemon(); return (0); } static void poke_daemon() { #ifdef USE_UTIMES struct timeval tvs[2]; struct timezone tz; (void) gettimeofday(&tvs[0], &tz); tvs[1] = tvs[0]; if (utimes(SPOOL_DIR, tvs) < OK) { warn("can't update mtime on spooldir %s", SPOOL_DIR); return; } #else if (utime(SPOOL_DIR, NULL) < OK) { warn("can't update mtime on spooldir %s", SPOOL_DIR); return; } #endif /*USE_UTIMES*/ }