1 /* Copyright 1988,1990,1993,1994 by Paul Vixie 2 * All rights reserved 3 * 4 * Distribute freely, except: don't remove my name from the source or 5 * documentation (don't take credit for my work), mark your changes (don't 6 * get me blamed for your possible bugs), don't alter or remove this 7 * notice. May be sold if buildable source is provided to buyer. No 8 * warrantee of any kind, express or implied, is included with this 9 * software; use at your own risk, responsibility for damages (if any) to 10 * anyone resulting from the use of this software rests entirely with the 11 * user. 12 * 13 * Send bug reports, bug fixes, enhancements, requests, flames, etc., and 14 * I'll try to keep a version up to date. I can be reached as follows: 15 * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul 16 * From Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp 17 */ 18 19 #if !defined(lint) && !defined(LINT) 20 static const char rcsid[] = 21 "$FreeBSD$"; 22 #endif 23 24 /* crontab - install and manage per-user crontab files 25 * vix 02may87 [RCS has the rest of the log] 26 * vix 26jan87 [original] 27 */ 28 29 #define MAIN_PROGRAM 30 31 #include "cron.h" 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <paths.h> 35 #include <sys/file.h> 36 #include <sys/stat.h> 37 #ifdef USE_UTIMES 38 # include <sys/time.h> 39 #else 40 # include <time.h> 41 # include <utime.h> 42 #endif 43 #if defined(POSIX) 44 # include <locale.h> 45 #endif 46 47 48 #define NHEADER_LINES 3 49 50 51 enum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace }; 52 53 #if DEBUGGING 54 static char *Options[] = { "???", "list", "delete", "edit", "replace" }; 55 #endif 56 57 58 static PID_T Pid; 59 static char User[MAX_UNAME], RealUser[MAX_UNAME]; 60 static char Filename[MAX_FNAME]; 61 static FILE *NewCrontab; 62 static int CheckErrorCount; 63 static enum opt_t Option; 64 static struct passwd *pw; 65 static void list_cmd __P((void)), 66 delete_cmd __P((void)), 67 edit_cmd __P((void)), 68 poke_daemon __P((void)), 69 check_error __P((char *)), 70 parse_args __P((int c, char *v[])); 71 static int replace_cmd __P((void)); 72 73 74 static void 75 usage(msg) 76 char *msg; 77 { 78 fprintf(stderr, "crontab: usage error: %s\n", msg); 79 fprintf(stderr, "%s\n%s\n", 80 "usage: crontab [-u user] file", 81 " crontab [-u user] { -e | -l | -r }"); 82 exit(ERROR_EXIT); 83 } 84 85 86 int 87 main(argc, argv) 88 int argc; 89 char *argv[]; 90 { 91 int exitstatus; 92 93 Pid = getpid(); 94 ProgramName = argv[0]; 95 96 #if defined(POSIX) 97 setlocale(LC_ALL, ""); 98 #endif 99 100 #if defined(BSD) 101 setlinebuf(stderr); 102 #endif 103 parse_args(argc, argv); /* sets many globals, opens a file */ 104 set_cron_uid(); 105 set_cron_cwd(); 106 if (!allowed(User)) { 107 warnx("you (%s) are not allowed to use this program", User); 108 log_it(RealUser, Pid, "AUTH", "crontab command not allowed"); 109 exit(ERROR_EXIT); 110 } 111 exitstatus = OK_EXIT; 112 switch (Option) { 113 case opt_list: list_cmd(); 114 break; 115 case opt_delete: delete_cmd(); 116 break; 117 case opt_edit: edit_cmd(); 118 break; 119 case opt_replace: if (replace_cmd() < 0) 120 exitstatus = ERROR_EXIT; 121 break; 122 case opt_unknown: 123 break; 124 } 125 exit(exitstatus); 126 /*NOTREACHED*/ 127 } 128 129 130 static void 131 parse_args(argc, argv) 132 int argc; 133 char *argv[]; 134 { 135 int argch; 136 137 if (!(pw = getpwuid(getuid()))) 138 errx(ERROR_EXIT, "your UID isn't in the passwd file, bailing out"); 139 (void) strncpy(User, pw->pw_name, (sizeof User)-1); 140 User[(sizeof User)-1] = '\0'; 141 strcpy(RealUser, User); 142 Filename[0] = '\0'; 143 Option = opt_unknown; 144 while ((argch = getopt(argc, argv, "u:lerx:")) != -1) { 145 switch (argch) { 146 case 'x': 147 if (!set_debug_flags(optarg)) 148 usage("bad debug option"); 149 break; 150 case 'u': 151 if (getuid() != ROOT_UID) 152 errx(ERROR_EXIT, "must be privileged to use -u"); 153 if (!(pw = getpwnam(optarg))) 154 errx(ERROR_EXIT, "user `%s' unknown", optarg); 155 (void) strncpy(User, pw->pw_name, (sizeof User)-1); 156 User[(sizeof User)-1] = '\0'; 157 break; 158 case 'l': 159 if (Option != opt_unknown) 160 usage("only one operation permitted"); 161 Option = opt_list; 162 break; 163 case 'r': 164 if (Option != opt_unknown) 165 usage("only one operation permitted"); 166 Option = opt_delete; 167 break; 168 case 'e': 169 if (Option != opt_unknown) 170 usage("only one operation permitted"); 171 Option = opt_edit; 172 break; 173 default: 174 usage("unrecognized option"); 175 } 176 } 177 178 endpwent(); 179 180 if (Option != opt_unknown) { 181 if (argv[optind] != NULL) { 182 usage("no arguments permitted after this option"); 183 } 184 } else { 185 if (argv[optind] != NULL) { 186 Option = opt_replace; 187 (void) strncpy (Filename, argv[optind], (sizeof Filename)-1); 188 Filename[(sizeof Filename)-1] = '\0'; 189 190 } else { 191 usage("file name must be specified for replace"); 192 } 193 } 194 195 if (Option == opt_replace) { 196 /* we have to open the file here because we're going to 197 * chdir(2) into /var/cron before we get around to 198 * reading the file. 199 */ 200 if (!strcmp(Filename, "-")) { 201 NewCrontab = stdin; 202 } else { 203 /* relinquish the setuid status of the binary during 204 * the open, lest nonroot users read files they should 205 * not be able to read. we can't use access() here 206 * since there's a race condition. thanks go out to 207 * Arnt Gulbrandsen <agulbra@pvv.unit.no> for spotting 208 * the race. 209 */ 210 211 if (swap_uids() < OK) 212 err(ERROR_EXIT, "swapping uids"); 213 if (!(NewCrontab = fopen(Filename, "r"))) 214 err(ERROR_EXIT, "%s", Filename); 215 if (swap_uids() < OK) 216 err(ERROR_EXIT, "swapping uids back"); 217 } 218 } 219 220 Debug(DMISC, ("user=%s, file=%s, option=%s\n", 221 User, Filename, Options[(int)Option])) 222 } 223 224 225 static void 226 list_cmd() { 227 char n[MAX_FNAME]; 228 FILE *f; 229 int ch, x; 230 231 log_it(RealUser, Pid, "LIST", User); 232 (void) sprintf(n, CRON_TAB(User)); 233 if (!(f = fopen(n, "r"))) { 234 if (errno == ENOENT) 235 errx(ERROR_EXIT, "no crontab for %s", User); 236 else 237 err(ERROR_EXIT, "%s", n); 238 } 239 240 /* file is open. copy to stdout, close. 241 */ 242 Set_LineNum(1) 243 244 /* ignore the top few comments since we probably put them there. 245 */ 246 for (x = 0; x < NHEADER_LINES; x++) { 247 ch = get_char(f); 248 if (EOF == ch) 249 break; 250 if ('#' != ch) { 251 putchar(ch); 252 break; 253 } 254 while (EOF != (ch = get_char(f))) 255 if (ch == '\n') 256 break; 257 if (EOF == ch) 258 break; 259 } 260 261 while (EOF != (ch = get_char(f))) 262 putchar(ch); 263 fclose(f); 264 } 265 266 267 static void 268 delete_cmd() { 269 char n[MAX_FNAME]; 270 int ch, first; 271 272 if (isatty(STDIN_FILENO)) { 273 (void)fprintf(stderr, "remove crontab for %s? ", User); 274 first = ch = getchar(); 275 while (ch != '\n' && ch != EOF) 276 ch = getchar(); 277 if (first != 'y' && first != 'Y') 278 return; 279 } 280 281 log_it(RealUser, Pid, "DELETE", User); 282 (void) sprintf(n, CRON_TAB(User)); 283 if (unlink(n)) { 284 if (errno == ENOENT) 285 errx(ERROR_EXIT, "no crontab for %s", User); 286 else 287 err(ERROR_EXIT, "%s", n); 288 } 289 poke_daemon(); 290 } 291 292 293 static void 294 check_error(msg) 295 char *msg; 296 { 297 CheckErrorCount++; 298 fprintf(stderr, "\"%s\":%d: %s\n", Filename, LineNumber-1, msg); 299 } 300 301 302 static void 303 edit_cmd() { 304 char n[MAX_FNAME], q[MAX_TEMPSTR], *editor; 305 FILE *f; 306 int ch, t, x; 307 struct stat statbuf, fsbuf; 308 time_t mtime; 309 WAIT_T waiter; 310 PID_T pid, xpid; 311 mode_t um; 312 313 log_it(RealUser, Pid, "BEGIN EDIT", User); 314 (void) sprintf(n, CRON_TAB(User)); 315 if (!(f = fopen(n, "r"))) { 316 if (errno != ENOENT) 317 err(ERROR_EXIT, "%s", n); 318 warnx("no crontab for %s - using an empty one", User); 319 if (!(f = fopen(_PATH_DEVNULL, "r"))) 320 err(ERROR_EXIT, _PATH_DEVNULL); 321 } 322 323 um = umask(077); 324 (void) sprintf(Filename, "/tmp/crontab.XXXXXXXXXX"); 325 if ((t = mkstemp(Filename)) == -1) { 326 warn("%s", Filename); 327 (void) umask(um); 328 goto fatal; 329 } 330 (void) umask(um); 331 #ifdef HAS_FCHOWN 332 if (fchown(t, getuid(), getgid()) < 0) { 333 #else 334 if (chown(Filename, getuid(), getgid()) < 0) { 335 #endif 336 warn("fchown"); 337 goto fatal; 338 } 339 if (!(NewCrontab = fdopen(t, "r+"))) { 340 warn("fdopen"); 341 goto fatal; 342 } 343 344 Set_LineNum(1) 345 346 /* ignore the top few comments since we probably put them there. 347 */ 348 for (x = 0; x < NHEADER_LINES; x++) { 349 ch = get_char(f); 350 if (EOF == ch) 351 break; 352 if ('#' != ch) { 353 putc(ch, NewCrontab); 354 break; 355 } 356 while (EOF != (ch = get_char(f))) 357 if (ch == '\n') 358 break; 359 if (EOF == ch) 360 break; 361 } 362 363 /* copy the rest of the crontab (if any) to the temp file. 364 */ 365 if (EOF != ch) 366 while (EOF != (ch = get_char(f))) 367 putc(ch, NewCrontab); 368 fclose(f); 369 if (fflush(NewCrontab)) 370 err(ERROR_EXIT, "%s", Filename); 371 if (fstat(t, &fsbuf) < 0) { 372 warn("unable to fstat temp file"); 373 goto fatal; 374 } 375 again: 376 if (stat(Filename, &statbuf) < 0) { 377 warn("stat"); 378 fatal: unlink(Filename); 379 exit(ERROR_EXIT); 380 } 381 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 382 errx(ERROR_EXIT, "temp file must be edited in place"); 383 mtime = statbuf.st_mtime; 384 385 if ((!(editor = getenv("VISUAL"))) 386 && (!(editor = getenv("EDITOR"))) 387 ) { 388 editor = EDITOR; 389 } 390 391 /* we still have the file open. editors will generally rewrite the 392 * original file rather than renaming/unlinking it and starting a 393 * new one; even backup files are supposed to be made by copying 394 * rather than by renaming. if some editor does not support this, 395 * then don't use it. the security problems are more severe if we 396 * close and reopen the file around the edit. 397 */ 398 399 switch (pid = fork()) { 400 case -1: 401 warn("fork"); 402 goto fatal; 403 case 0: 404 /* child */ 405 if (setuid(getuid()) < 0) 406 err(ERROR_EXIT, "setuid(getuid())"); 407 if (chdir("/tmp") < 0) 408 err(ERROR_EXIT, "chdir(/tmp)"); 409 if (strlen(editor) + strlen(Filename) + 2 >= MAX_TEMPSTR) 410 errx(ERROR_EXIT, "editor or filename too long"); 411 execlp(editor, editor, Filename, (char *)NULL); 412 err(ERROR_EXIT, "%s", editor); 413 /*NOTREACHED*/ 414 default: 415 /* parent */ 416 break; 417 } 418 419 /* parent */ 420 { 421 void (*f[4])(); 422 f[0] = signal(SIGHUP, SIG_IGN); 423 f[1] = signal(SIGINT, SIG_IGN); 424 f[2] = signal(SIGTERM, SIG_IGN); 425 xpid = wait(&waiter); 426 signal(SIGHUP, f[0]); 427 signal(SIGINT, f[1]); 428 signal(SIGTERM, f[2]); 429 } 430 if (xpid != pid) { 431 warnx("wrong PID (%d != %d) from \"%s\"", xpid, pid, editor); 432 goto fatal; 433 } 434 if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) { 435 warnx("\"%s\" exited with status %d", editor, WEXITSTATUS(waiter)); 436 goto fatal; 437 } 438 if (WIFSIGNALED(waiter)) { 439 warnx("\"%s\" killed; signal %d (%score dumped)", 440 editor, WTERMSIG(waiter), WCOREDUMP(waiter) ?"" :"no "); 441 goto fatal; 442 } 443 if (stat(Filename, &statbuf) < 0) { 444 warn("stat"); 445 goto fatal; 446 } 447 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 448 errx(ERROR_EXIT, "temp file must be edited in place"); 449 if (mtime == statbuf.st_mtime) { 450 warnx("no changes made to crontab"); 451 goto remove; 452 } 453 warnx("installing new crontab"); 454 switch (replace_cmd()) { 455 case 0: 456 break; 457 case -1: 458 for (;;) { 459 printf("Do you want to retry the same edit? "); 460 fflush(stdout); 461 q[0] = '\0'; 462 (void) fgets(q, sizeof q, stdin); 463 switch (islower(q[0]) ? q[0] : tolower(q[0])) { 464 case 'y': 465 goto again; 466 case 'n': 467 goto abandon; 468 default: 469 fprintf(stderr, "Enter Y or N\n"); 470 } 471 } 472 /*NOTREACHED*/ 473 case -2: 474 abandon: 475 warnx("edits left in %s", Filename); 476 goto done; 477 default: 478 warnx("panic: bad switch() in replace_cmd()"); 479 goto fatal; 480 } 481 remove: 482 unlink(Filename); 483 done: 484 log_it(RealUser, Pid, "END EDIT", User); 485 } 486 487 488 /* returns 0 on success 489 * -1 on syntax error 490 * -2 on install error 491 */ 492 static int 493 replace_cmd() { 494 char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME]; 495 FILE *tmp; 496 int ch, eof; 497 entry *e; 498 time_t now = time(NULL); 499 char **envp = env_init(); 500 501 if (envp == NULL) { 502 warnx("cannot allocate memory"); 503 return (-2); 504 } 505 506 (void) sprintf(n, "tmp.%d", Pid); 507 (void) sprintf(tn, CRON_TAB(n)); 508 if (!(tmp = fopen(tn, "w+"))) { 509 warn("%s", tn); 510 return (-2); 511 } 512 513 /* write a signature at the top of the file. 514 * 515 * VERY IMPORTANT: make sure NHEADER_LINES agrees with this code. 516 */ 517 fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n"); 518 fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now)); 519 fprintf(tmp, "# (Cron version -- %s)\n", rcsid); 520 521 /* copy the crontab to the tmp 522 */ 523 rewind(NewCrontab); 524 Set_LineNum(1) 525 while (EOF != (ch = get_char(NewCrontab))) 526 putc(ch, tmp); 527 ftruncate(fileno(tmp), ftell(tmp)); 528 fflush(tmp); rewind(tmp); 529 530 if (ferror(tmp)) { 531 warnx("error while writing new crontab to %s", tn); 532 fclose(tmp); unlink(tn); 533 return (-2); 534 } 535 536 /* check the syntax of the file being installed. 537 */ 538 539 /* BUG: was reporting errors after the EOF if there were any errors 540 * in the file proper -- kludged it by stopping after first error. 541 * vix 31mar87 542 */ 543 Set_LineNum(1 - NHEADER_LINES) 544 CheckErrorCount = 0; eof = FALSE; 545 while (!CheckErrorCount && !eof) { 546 switch (load_env(envstr, tmp)) { 547 case ERR: 548 eof = TRUE; 549 break; 550 case FALSE: 551 e = load_entry(tmp, check_error, pw, envp); 552 if (e) 553 free(e); 554 break; 555 case TRUE: 556 break; 557 } 558 } 559 560 if (CheckErrorCount != 0) { 561 warnx("errors in crontab file, can't install"); 562 fclose(tmp); unlink(tn); 563 return (-1); 564 } 565 566 #ifdef HAS_FCHOWN 567 if (fchown(fileno(tmp), ROOT_UID, -1) < OK) 568 #else 569 if (chown(tn, ROOT_UID, -1) < OK) 570 #endif 571 { 572 warn("chown"); 573 fclose(tmp); unlink(tn); 574 return (-2); 575 } 576 577 #ifdef HAS_FCHMOD 578 if (fchmod(fileno(tmp), 0600) < OK) 579 #else 580 if (chmod(tn, 0600) < OK) 581 #endif 582 { 583 warn("chown"); 584 fclose(tmp); unlink(tn); 585 return (-2); 586 } 587 588 if (fclose(tmp) == EOF) { 589 warn("fclose"); 590 unlink(tn); 591 return (-2); 592 } 593 594 (void) sprintf(n, CRON_TAB(User)); 595 if (rename(tn, n)) { 596 warn("error renaming %s to %s", tn, n); 597 unlink(tn); 598 return (-2); 599 } 600 log_it(RealUser, Pid, "REPLACE", User); 601 602 poke_daemon(); 603 604 return (0); 605 } 606 607 608 static void 609 poke_daemon() { 610 #ifdef USE_UTIMES 611 struct timeval tvs[2]; 612 struct timezone tz; 613 614 (void) gettimeofday(&tvs[0], &tz); 615 tvs[1] = tvs[0]; 616 if (utimes(SPOOL_DIR, tvs) < OK) { 617 warn("can't update mtime on spooldir %s", SPOOL_DIR); 618 return; 619 } 620 #else 621 if (utime(SPOOL_DIR, NULL) < OK) { 622 warn("can't update mtime on spooldir %s", SPOOL_DIR); 623 return; 624 } 625 #endif /*USE_UTIMES*/ 626 } 627