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 * 17 * From Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp 18 * $FreeBSD: src/usr.sbin/cron/crontab/crontab.c,v 1.12.2.4 2001/06/16 03:18:37 peter Exp $ 19 * $DragonFly: src/usr.sbin/cron/crontab/crontab.c,v 1.5 2004/12/18 22:48:03 swildner Exp $ 20 */ 21 22 /* crontab - install and manage per-user crontab files 23 * vix 02may87 [RCS has the rest of the log] 24 * vix 26jan87 [original] 25 */ 26 27 static char version[] = "$DragonFly: src/usr.sbin/cron/crontab/crontab.c,v 1.5 2004/12/18 22:48:03 swildner Exp $"; 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(void), 66 delete_cmd(void), 67 edit_cmd(void), 68 poke_daemon(void), 69 check_error(char *), 70 parse_args(int c, char *v[]); 71 static int replace_cmd(void); 72 73 74 static void 75 usage(char *msg) 76 { 77 fprintf(stderr, "crontab: usage error: %s\n", msg); 78 fprintf(stderr, "%s\n%s\n", 79 "usage: crontab [-u user] file", 80 " crontab [-u user] { -e | -l | -r }"); 81 exit(ERROR_EXIT); 82 } 83 84 85 int 86 main(int argc, char **argv) 87 { 88 int exitstatus; 89 90 Pid = getpid(); 91 ProgramName = argv[0]; 92 93 #if defined(POSIX) 94 setlocale(LC_ALL, ""); 95 #endif 96 97 #if defined(BSD) 98 setlinebuf(stderr); 99 #endif 100 parse_args(argc, argv); /* sets many globals, opens a file */ 101 set_cron_uid(); 102 set_cron_cwd(); 103 if (!allowed(User)) { 104 warnx("you (%s) are not allowed to use this program", User); 105 log_it(RealUser, Pid, "AUTH", "crontab command not allowed"); 106 exit(ERROR_EXIT); 107 } 108 exitstatus = OK_EXIT; 109 switch (Option) { 110 case opt_list: list_cmd(); 111 break; 112 case opt_delete: delete_cmd(); 113 break; 114 case opt_edit: edit_cmd(); 115 break; 116 case opt_replace: if (replace_cmd() < 0) 117 exitstatus = ERROR_EXIT; 118 break; 119 case opt_unknown: 120 break; 121 } 122 exit(0); 123 /*NOTREACHED*/ 124 } 125 126 127 static void 128 parse_args(int argc, char **argv) 129 { 130 int argch; 131 132 if (!(pw = getpwuid(getuid()))) 133 errx(ERROR_EXIT, "your UID isn't in the passwd file, bailing out"); 134 strncpy(User, pw->pw_name, (sizeof User)-1); 135 User[(sizeof User)-1] = '\0'; 136 strcpy(RealUser, User); 137 Filename[0] = '\0'; 138 Option = opt_unknown; 139 while ((argch = getopt(argc, argv, "u:lerx:")) != -1) { 140 switch (argch) { 141 case 'x': 142 if (!set_debug_flags(optarg)) 143 usage("bad debug option"); 144 break; 145 case 'u': 146 if (getuid() != ROOT_UID) 147 errx(ERROR_EXIT, "must be privileged to use -u"); 148 if (!(pw = getpwnam(optarg))) 149 errx(ERROR_EXIT, "user `%s' unknown", optarg); 150 strncpy(User, pw->pw_name, (sizeof User)-1); 151 User[(sizeof User)-1] = '\0'; 152 break; 153 case 'l': 154 if (Option != opt_unknown) 155 usage("only one operation permitted"); 156 Option = opt_list; 157 break; 158 case 'r': 159 if (Option != opt_unknown) 160 usage("only one operation permitted"); 161 Option = opt_delete; 162 break; 163 case 'e': 164 if (Option != opt_unknown) 165 usage("only one operation permitted"); 166 Option = opt_edit; 167 break; 168 default: 169 usage("unrecognized option"); 170 } 171 } 172 173 endpwent(); 174 175 if (Option != opt_unknown) { 176 if (argv[optind] != NULL) { 177 usage("no arguments permitted after this option"); 178 } 179 } else { 180 if (argv[optind] != NULL) { 181 Option = opt_replace; 182 strncpy (Filename, argv[optind], (sizeof Filename)-1); 183 Filename[(sizeof Filename)-1] = '\0'; 184 185 } else { 186 usage("file name must be specified for replace"); 187 } 188 } 189 190 if (Option == opt_replace) { 191 /* we have to open the file here because we're going to 192 * chdir(2) into /var/cron before we get around to 193 * reading the file. 194 */ 195 if (!strcmp(Filename, "-")) { 196 NewCrontab = stdin; 197 } else { 198 /* relinquish the setuid status of the binary during 199 * the open, lest nonroot users read files they should 200 * not be able to read. we can't use access() here 201 * since there's a race condition. thanks go out to 202 * Arnt Gulbrandsen <agulbra@pvv.unit.no> for spotting 203 * the race. 204 */ 205 206 if (swap_uids() < OK) 207 err(ERROR_EXIT, "swapping uids"); 208 if (!(NewCrontab = fopen(Filename, "r"))) 209 err(ERROR_EXIT, "%s", Filename); 210 if (swap_uids() < OK) 211 err(ERROR_EXIT, "swapping uids back"); 212 } 213 } 214 215 Debug(DMISC, ("user=%s, file=%s, option=%s\n", 216 User, Filename, Options[(int)Option])) 217 } 218 219 220 static void 221 list_cmd(void) 222 { 223 char n[MAX_FNAME]; 224 FILE *f; 225 int ch, x; 226 227 log_it(RealUser, Pid, "LIST", User); 228 sprintf(n, CRON_TAB(User)); 229 if (!(f = fopen(n, "r"))) { 230 if (errno == ENOENT) 231 errx(ERROR_EXIT, "no crontab for %s", User); 232 else 233 err(ERROR_EXIT, "%s", n); 234 } 235 236 /* file is open. copy to stdout, close. 237 */ 238 Set_LineNum(1) 239 240 /* ignore the top few comments since we probably put them there. 241 */ 242 for (x = 0; x < NHEADER_LINES; x++) { 243 ch = get_char(f); 244 if (EOF == ch) 245 break; 246 if ('#' != ch) { 247 putchar(ch); 248 break; 249 } 250 while (EOF != (ch = get_char(f))) 251 if (ch == '\n') 252 break; 253 if (EOF == ch) 254 break; 255 } 256 257 while (EOF != (ch = get_char(f))) 258 putchar(ch); 259 fclose(f); 260 } 261 262 263 static void 264 delete_cmd(void) 265 { 266 char n[MAX_FNAME]; 267 int ch, first; 268 269 if (isatty(STDIN_FILENO)) { 270 fprintf(stderr, "remove crontab for %s? ", User); 271 first = ch = getchar(); 272 while (ch != '\n' && ch != EOF) 273 ch = getchar(); 274 if (first != 'y' && first != 'Y') 275 return; 276 } 277 278 log_it(RealUser, Pid, "DELETE", User); 279 sprintf(n, CRON_TAB(User)); 280 if (unlink(n)) { 281 if (errno == ENOENT) 282 errx(ERROR_EXIT, "no crontab for %s", User); 283 else 284 err(ERROR_EXIT, "%s", n); 285 } 286 poke_daemon(); 287 } 288 289 290 static void 291 check_error(char *msg) 292 { 293 CheckErrorCount++; 294 fprintf(stderr, "\"%s\":%d: %s\n", Filename, LineNumber-1, msg); 295 } 296 297 298 static void 299 edit_cmd(void) 300 { 301 char n[MAX_FNAME], q[MAX_TEMPSTR], *editor; 302 FILE *f; 303 int ch, t, x; 304 struct stat statbuf, fsbuf; 305 time_t mtime; 306 WAIT_T waiter; 307 PID_T pid, xpid; 308 mode_t um; 309 310 log_it(RealUser, Pid, "BEGIN EDIT", User); 311 sprintf(n, CRON_TAB(User)); 312 if (!(f = fopen(n, "r"))) { 313 if (errno != ENOENT) 314 err(ERROR_EXIT, "%s", n); 315 warnx("no crontab for %s - using an empty one", User); 316 if (!(f = fopen(_PATH_DEVNULL, "r"))) 317 err(ERROR_EXIT, _PATH_DEVNULL); 318 } 319 320 um = umask(077); 321 sprintf(Filename, "/tmp/crontab.XXXXXXXXXX"); 322 if ((t = mkstemp(Filename)) == -1) { 323 warn("%s", Filename); 324 umask(um); 325 goto fatal; 326 } 327 umask(um); 328 #ifdef HAS_FCHOWN 329 if (fchown(t, getuid(), getgid()) < 0) { 330 #else 331 if (chown(Filename, getuid(), getgid()) < 0) { 332 #endif 333 warn("fchown"); 334 goto fatal; 335 } 336 if (!(NewCrontab = fdopen(t, "r+"))) { 337 warn("fdopen"); 338 goto fatal; 339 } 340 341 Set_LineNum(1) 342 343 /* ignore the top few comments since we probably put them there. 344 */ 345 for (x = 0; x < NHEADER_LINES; x++) { 346 ch = get_char(f); 347 if (EOF == ch) 348 break; 349 if ('#' != ch) { 350 putc(ch, NewCrontab); 351 break; 352 } 353 while (EOF != (ch = get_char(f))) 354 if (ch == '\n') 355 break; 356 if (EOF == ch) 357 break; 358 } 359 360 /* copy the rest of the crontab (if any) to the temp file. 361 */ 362 if (EOF != ch) 363 while (EOF != (ch = get_char(f))) 364 putc(ch, NewCrontab); 365 fclose(f); 366 if (fflush(NewCrontab)) 367 err(ERROR_EXIT, "%s", Filename); 368 if (fstat(t, &fsbuf) < 0) { 369 warn("unable to fstat temp file"); 370 goto fatal; 371 } 372 again: 373 if (stat(Filename, &statbuf) < 0) { 374 warn("stat"); 375 fatal: unlink(Filename); 376 exit(ERROR_EXIT); 377 } 378 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 379 errx(ERROR_EXIT, "temp file must be edited in place"); 380 mtime = statbuf.st_mtime; 381 382 if ((!(editor = getenv("VISUAL"))) 383 && (!(editor = getenv("EDITOR"))) 384 ) { 385 editor = EDITOR; 386 } 387 388 /* we still have the file open. editors will generally rewrite the 389 * original file rather than renaming/unlinking it and starting a 390 * new one; even backup files are supposed to be made by copying 391 * rather than by renaming. if some editor does not support this, 392 * then don't use it. the security problems are more severe if we 393 * close and reopen the file around the edit. 394 */ 395 396 switch (pid = fork()) { 397 case -1: 398 warn("fork"); 399 goto fatal; 400 case 0: 401 /* child */ 402 if (setuid(getuid()) < 0) 403 err(ERROR_EXIT, "setuid(getuid())"); 404 if (chdir("/tmp") < 0) 405 err(ERROR_EXIT, "chdir(/tmp)"); 406 if (strlen(editor) + strlen(Filename) + 2 >= MAX_TEMPSTR) 407 errx(ERROR_EXIT, "editor or filename too long"); 408 execlp(editor, editor, Filename, NULL); 409 err(ERROR_EXIT, "%s", editor); 410 /*NOTREACHED*/ 411 default: 412 /* parent */ 413 break; 414 } 415 416 /* parent */ 417 { 418 void (*f[4])(); 419 f[0] = signal(SIGHUP, SIG_IGN); 420 f[1] = signal(SIGINT, SIG_IGN); 421 f[2] = signal(SIGTERM, SIG_IGN); 422 xpid = wait(&waiter); 423 signal(SIGHUP, f[0]); 424 signal(SIGINT, f[1]); 425 signal(SIGTERM, f[2]); 426 } 427 if (xpid != pid) { 428 warnx("wrong PID (%d != %d) from \"%s\"", xpid, pid, editor); 429 goto fatal; 430 } 431 if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) { 432 warnx("\"%s\" exited with status %d", editor, WEXITSTATUS(waiter)); 433 goto fatal; 434 } 435 if (WIFSIGNALED(waiter)) { 436 warnx("\"%s\" killed; signal %d (%score dumped)", 437 editor, WTERMSIG(waiter), WCOREDUMP(waiter) ?"" :"no "); 438 goto fatal; 439 } 440 if (stat(Filename, &statbuf) < 0) { 441 warn("stat"); 442 goto fatal; 443 } 444 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 445 errx(ERROR_EXIT, "temp file must be edited in place"); 446 if (mtime == statbuf.st_mtime) { 447 warnx("no changes made to crontab"); 448 goto remove; 449 } 450 warnx("installing new crontab"); 451 switch (replace_cmd()) { 452 case 0: 453 break; 454 case -1: 455 for (;;) { 456 printf("Do you want to retry the same edit? "); 457 fflush(stdout); 458 q[0] = '\0'; 459 fgets(q, sizeof q, stdin); 460 switch (islower(q[0]) ? q[0] : tolower(q[0])) { 461 case 'y': 462 goto again; 463 case 'n': 464 goto abandon; 465 default: 466 fprintf(stderr, "Enter Y or N\n"); 467 } 468 } 469 /*NOTREACHED*/ 470 case -2: 471 abandon: 472 warnx("edits left in %s", Filename); 473 goto done; 474 default: 475 warnx("panic: bad switch() in replace_cmd()"); 476 goto fatal; 477 } 478 remove: 479 unlink(Filename); 480 done: 481 log_it(RealUser, Pid, "END EDIT", User); 482 } 483 484 485 /* returns 0 on success 486 * -1 on syntax error 487 * -2 on install error 488 */ 489 static int 490 replace_cmd(void) 491 { 492 char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME]; 493 FILE *tmp; 494 int ch, eof; 495 entry *e; 496 time_t now = time(NULL); 497 char **envp = env_init(); 498 499 if (envp == NULL) { 500 warnx("cannot allocate memory"); 501 return (-2); 502 } 503 504 sprintf(n, "tmp.%d", Pid); 505 sprintf(tn, CRON_TAB(n)); 506 if (!(tmp = fopen(tn, "w+"))) { 507 warn("%s", tn); 508 return (-2); 509 } 510 511 /* write a signature at the top of the file. 512 * 513 * VERY IMPORTANT: make sure NHEADER_LINES agrees with this code. 514 */ 515 fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n"); 516 fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now)); 517 fprintf(tmp, "# (Cron version -- %s)\n", version); 518 519 /* copy the crontab to the tmp 520 */ 521 rewind(NewCrontab); 522 Set_LineNum(1) 523 while (EOF != (ch = get_char(NewCrontab))) 524 putc(ch, tmp); 525 ftruncate(fileno(tmp), ftell(tmp)); 526 fflush(tmp); rewind(tmp); 527 528 if (ferror(tmp)) { 529 warnx("error while writing new crontab to %s", tn); 530 fclose(tmp); unlink(tn); 531 return (-2); 532 } 533 534 /* check the syntax of the file being installed. 535 */ 536 537 /* BUG: was reporting errors after the EOF if there were any errors 538 * in the file proper -- kludged it by stopping after first error. 539 * vix 31mar87 540 */ 541 Set_LineNum(1 - NHEADER_LINES) 542 CheckErrorCount = 0; eof = FALSE; 543 while (!CheckErrorCount && !eof) { 544 switch (load_env(envstr, tmp)) { 545 case ERR: 546 eof = TRUE; 547 break; 548 case FALSE: 549 e = load_entry(tmp, check_error, pw, envp); 550 if (e) 551 free(e); 552 break; 553 case TRUE: 554 break; 555 } 556 } 557 558 if (CheckErrorCount != 0) { 559 warnx("errors in crontab file, can't install"); 560 fclose(tmp); unlink(tn); 561 return (-1); 562 } 563 564 #ifdef HAS_FCHOWN 565 if (fchown(fileno(tmp), ROOT_UID, -1) < OK) 566 #else 567 if (chown(tn, ROOT_UID, -1) < OK) 568 #endif 569 { 570 warn("chown"); 571 fclose(tmp); unlink(tn); 572 return (-2); 573 } 574 575 #ifdef HAS_FCHMOD 576 if (fchmod(fileno(tmp), 0600) < OK) 577 #else 578 if (chmod(tn, 0600) < OK) 579 #endif 580 { 581 warn("chown"); 582 fclose(tmp); unlink(tn); 583 return (-2); 584 } 585 586 if (fclose(tmp) == EOF) { 587 warn("fclose"); 588 unlink(tn); 589 return (-2); 590 } 591 592 sprintf(n, CRON_TAB(User)); 593 if (rename(tn, n)) { 594 warn("error renaming %s to %s", tn, n); 595 unlink(tn); 596 return (-2); 597 } 598 log_it(RealUser, Pid, "REPLACE", User); 599 600 poke_daemon(); 601 602 return (0); 603 } 604 605 606 static void 607 poke_daemon(void) 608 { 609 #ifdef USE_UTIMES 610 struct timeval tvs[2]; 611 struct timezone tz; 612 613 gettimeofday(&tvs[0], &tz); 614 tvs[1] = tvs[0]; 615 if (utimes(SPOOL_DIR, tvs) < OK) { 616 warn("can't update mtime on spooldir %s", SPOOL_DIR); 617 return; 618 } 619 #else 620 if (utime(SPOOL_DIR, NULL) < OK) { 621 warn("can't update mtime on spooldir %s", SPOOL_DIR); 622 return; 623 } 624 #endif /*USE_UTIMES*/ 625 } 626