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