crontab.c revision 135165
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) 20static const char rcsid[] = 21 "$FreeBSD: head/usr.sbin/cron/crontab/crontab.c 135165 2004-09-13 18:39:04Z dds $"; 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 51enum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace }; 52 53#if DEBUGGING 54static char *Options[] = { "???", "list", "delete", "edit", "replace" }; 55#endif 56 57 58static PID_T Pid; 59static char User[MAX_UNAME], RealUser[MAX_UNAME]; 60static char Filename[MAX_FNAME]; 61static FILE *NewCrontab; 62static int CheckErrorCount; 63static enum opt_t Option; 64static struct passwd *pw; 65static 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[])); 71static int replace_cmd __P((void)); 72 73 74static void 75usage(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 86int 87main(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 130static void 131parse_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 225static void 226list_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 267static void 268delete_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 293static void 294check_error(msg) 295 char *msg; 296{ 297 CheckErrorCount++; 298 fprintf(stderr, "\"%s\":%d: %s\n", Filename, LineNumber-1, msg); 299} 300 301 302static void 303edit_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 int syntax_error = 0; 313 314 log_it(RealUser, Pid, "BEGIN EDIT", User); 315 (void) sprintf(n, CRON_TAB(User)); 316 if (!(f = fopen(n, "r"))) { 317 if (errno != ENOENT) 318 err(ERROR_EXIT, "%s", n); 319 warnx("no crontab for %s - using an empty one", User); 320 if (!(f = fopen(_PATH_DEVNULL, "r"))) 321 err(ERROR_EXIT, _PATH_DEVNULL); 322 } 323 324 um = umask(077); 325 (void) sprintf(Filename, "/tmp/crontab.XXXXXXXXXX"); 326 if ((t = mkstemp(Filename)) == -1) { 327 warn("%s", Filename); 328 (void) umask(um); 329 goto fatal; 330 } 331 (void) umask(um); 332#ifdef HAS_FCHOWN 333 if (fchown(t, getuid(), getgid()) < 0) { 334#else 335 if (chown(Filename, getuid(), getgid()) < 0) { 336#endif 337 warn("fchown"); 338 goto fatal; 339 } 340 if (!(NewCrontab = fdopen(t, "r+"))) { 341 warn("fdopen"); 342 goto fatal; 343 } 344 345 Set_LineNum(1) 346 347 /* ignore the top few comments since we probably put them there. 348 */ 349 for (x = 0; x < NHEADER_LINES; x++) { 350 ch = get_char(f); 351 if (EOF == ch) 352 break; 353 if ('#' != ch) { 354 putc(ch, NewCrontab); 355 break; 356 } 357 while (EOF != (ch = get_char(f))) 358 if (ch == '\n') 359 break; 360 if (EOF == ch) 361 break; 362 } 363 364 /* copy the rest of the crontab (if any) to the temp file. 365 */ 366 if (EOF != ch) 367 while (EOF != (ch = get_char(f))) 368 putc(ch, NewCrontab); 369 fclose(f); 370 if (fflush(NewCrontab)) 371 err(ERROR_EXIT, "%s", Filename); 372 if (fstat(t, &fsbuf) < 0) { 373 warn("unable to fstat temp file"); 374 goto fatal; 375 } 376 again: 377 if (stat(Filename, &statbuf) < 0) { 378 warn("stat"); 379 fatal: unlink(Filename); 380 exit(ERROR_EXIT); 381 } 382 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 383 errx(ERROR_EXIT, "temp file must be edited in place"); 384 mtime = statbuf.st_mtime; 385 386 if ((!(editor = getenv("VISUAL"))) 387 && (!(editor = getenv("EDITOR"))) 388 ) { 389 editor = EDITOR; 390 } 391 392 /* we still have the file open. editors will generally rewrite the 393 * original file rather than renaming/unlinking it and starting a 394 * new one; even backup files are supposed to be made by copying 395 * rather than by renaming. if some editor does not support this, 396 * then don't use it. the security problems are more severe if we 397 * close and reopen the file around the edit. 398 */ 399 400 switch (pid = fork()) { 401 case -1: 402 warn("fork"); 403 goto fatal; 404 case 0: 405 /* child */ 406 if (setuid(getuid()) < 0) 407 err(ERROR_EXIT, "setuid(getuid())"); 408 if (chdir("/tmp") < 0) 409 err(ERROR_EXIT, "chdir(/tmp)"); 410 if (strlen(editor) + strlen(Filename) + 2 >= MAX_TEMPSTR) 411 errx(ERROR_EXIT, "editor or filename too long"); 412 execlp(editor, editor, Filename, (char *)NULL); 413 err(ERROR_EXIT, "%s", editor); 414 /*NOTREACHED*/ 415 default: 416 /* parent */ 417 break; 418 } 419 420 /* parent */ 421 { 422 void (*f[4])(); 423 f[0] = signal(SIGHUP, SIG_IGN); 424 f[1] = signal(SIGINT, SIG_IGN); 425 f[2] = signal(SIGTERM, SIG_IGN); 426 xpid = wait(&waiter); 427 signal(SIGHUP, f[0]); 428 signal(SIGINT, f[1]); 429 signal(SIGTERM, f[2]); 430 } 431 if (xpid != pid) { 432 warnx("wrong PID (%d != %d) from \"%s\"", xpid, pid, editor); 433 goto fatal; 434 } 435 if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) { 436 warnx("\"%s\" exited with status %d", editor, WEXITSTATUS(waiter)); 437 goto fatal; 438 } 439 if (WIFSIGNALED(waiter)) { 440 warnx("\"%s\" killed; signal %d (%score dumped)", 441 editor, WTERMSIG(waiter), WCOREDUMP(waiter) ?"" :"no "); 442 goto fatal; 443 } 444 if (stat(Filename, &statbuf) < 0) { 445 warn("stat"); 446 goto fatal; 447 } 448 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 449 errx(ERROR_EXIT, "temp file must be edited in place"); 450 if (mtime == statbuf.st_mtime && !syntax_error) { 451 warnx("no changes made to crontab"); 452 goto remove; 453 } 454 warnx("installing new crontab"); 455 switch (replace_cmd()) { 456 case 0: /* Success */ 457 break; 458 case -1: /* Syntax error */ 459 for (;;) { 460 printf("Do you want to retry the same edit? "); 461 fflush(stdout); 462 q[0] = '\0'; 463 (void) fgets(q, sizeof q, stdin); 464 switch (islower(q[0]) ? q[0] : tolower(q[0])) { 465 case 'y': 466 syntax_error = 1; 467 goto again; 468 case 'n': 469 goto abandon; 470 default: 471 fprintf(stderr, "Enter Y or N\n"); 472 } 473 } 474 /*NOTREACHED*/ 475 case -2: /* Install error */ 476 abandon: 477 warnx("edits left in %s", Filename); 478 goto done; 479 default: 480 warnx("panic: bad switch() in replace_cmd()"); 481 goto fatal; 482 } 483 remove: 484 unlink(Filename); 485 done: 486 log_it(RealUser, Pid, "END EDIT", User); 487} 488 489 490/* returns 0 on success 491 * -1 on syntax error 492 * -2 on install error 493 */ 494static int 495replace_cmd() { 496 char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME]; 497 FILE *tmp; 498 int ch, eof; 499 entry *e; 500 time_t now = time(NULL); 501 char **envp = env_init(); 502 503 if (envp == NULL) { 504 warnx("cannot allocate memory"); 505 return (-2); 506 } 507 508 (void) sprintf(n, "tmp.%d", Pid); 509 (void) sprintf(tn, CRON_TAB(n)); 510 if (!(tmp = fopen(tn, "w+"))) { 511 warn("%s", tn); 512 return (-2); 513 } 514 515 /* write a signature at the top of the file. 516 * 517 * VERY IMPORTANT: make sure NHEADER_LINES agrees with this code. 518 */ 519 fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n"); 520 fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now)); 521 fprintf(tmp, "# (Cron version -- %s)\n", rcsid); 522 523 /* copy the crontab to the tmp 524 */ 525 rewind(NewCrontab); 526 Set_LineNum(1) 527 while (EOF != (ch = get_char(NewCrontab))) 528 putc(ch, tmp); 529 ftruncate(fileno(tmp), ftell(tmp)); 530 fflush(tmp); rewind(tmp); 531 532 if (ferror(tmp)) { 533 warnx("error while writing new crontab to %s", tn); 534 fclose(tmp); unlink(tn); 535 return (-2); 536 } 537 538 /* check the syntax of the file being installed. 539 */ 540 541 /* BUG: was reporting errors after the EOF if there were any errors 542 * in the file proper -- kludged it by stopping after first error. 543 * vix 31mar87 544 */ 545 Set_LineNum(1 - NHEADER_LINES) 546 CheckErrorCount = 0; eof = FALSE; 547 while (!CheckErrorCount && !eof) { 548 switch (load_env(envstr, tmp)) { 549 case ERR: 550 eof = TRUE; 551 break; 552 case FALSE: 553 e = load_entry(tmp, check_error, pw, envp); 554 if (e) 555 free(e); 556 break; 557 case TRUE: 558 break; 559 } 560 } 561 562 if (CheckErrorCount != 0) { 563 warnx("errors in crontab file, can't install"); 564 fclose(tmp); unlink(tn); 565 return (-1); 566 } 567 568#ifdef HAS_FCHOWN 569 if (fchown(fileno(tmp), ROOT_UID, -1) < OK) 570#else 571 if (chown(tn, ROOT_UID, -1) < OK) 572#endif 573 { 574 warn("chown"); 575 fclose(tmp); unlink(tn); 576 return (-2); 577 } 578 579#ifdef HAS_FCHMOD 580 if (fchmod(fileno(tmp), 0600) < OK) 581#else 582 if (chmod(tn, 0600) < OK) 583#endif 584 { 585 warn("chown"); 586 fclose(tmp); unlink(tn); 587 return (-2); 588 } 589 590 if (fclose(tmp) == EOF) { 591 warn("fclose"); 592 unlink(tn); 593 return (-2); 594 } 595 596 (void) sprintf(n, CRON_TAB(User)); 597 if (rename(tn, n)) { 598 warn("error renaming %s to %s", tn, n); 599 unlink(tn); 600 return (-2); 601 } 602 log_it(RealUser, Pid, "REPLACE", User); 603 604 poke_daemon(); 605 606 return (0); 607} 608 609 610static void 611poke_daemon() { 612#ifdef USE_UTIMES 613 struct timeval tvs[2]; 614 struct timezone tz; 615 616 (void) gettimeofday(&tvs[0], &tz); 617 tvs[1] = tvs[0]; 618 if (utimes(SPOOL_DIR, tvs) < OK) { 619 warn("can't update mtime on spooldir %s", SPOOL_DIR); 620 return; 621 } 622#else 623 if (utime(SPOOL_DIR, NULL) < OK) { 624 warn("can't update mtime on spooldir %s", SPOOL_DIR); 625 return; 626 } 627#endif /*USE_UTIMES*/ 628} 629