crontab.c revision 69793
11590Srgrimes/* Copyright 1988,1990,1993,1994 by Paul Vixie 21590Srgrimes * All rights reserved 31590Srgrimes * 41590Srgrimes * Distribute freely, except: don't remove my name from the source or 51590Srgrimes * documentation (don't take credit for my work), mark your changes (don't 61590Srgrimes * get me blamed for your possible bugs), don't alter or remove this 71590Srgrimes * notice. May be sold if buildable source is provided to buyer. No 81590Srgrimes * warrantee of any kind, express or implied, is included with this 91590Srgrimes * software; use at your own risk, responsibility for damages (if any) to 101590Srgrimes * anyone resulting from the use of this software rests entirely with the 111590Srgrimes * user. 121590Srgrimes * 131590Srgrimes * Send bug reports, bug fixes, enhancements, requests, flames, etc., and 141590Srgrimes * I'll try to keep a version up to date. I can be reached as follows: 151590Srgrimes * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul 161590Srgrimes * From Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp 171590Srgrimes */ 181590Srgrimes 191590Srgrimes#if !defined(lint) && !defined(LINT) 201590Srgrimesstatic const char rcsid[] = 211590Srgrimes "$FreeBSD: head/usr.sbin/cron/crontab/crontab.c 69793 2000-12-09 09:35:55Z obrien $"; 221590Srgrimes#endif 231590Srgrimes 241590Srgrimes/* crontab - install and manage per-user crontab files 251590Srgrimes * vix 02may87 [RCS has the rest of the log] 261590Srgrimes * vix 26jan87 [original] 271590Srgrimes */ 281590Srgrimes 291590Srgrimes#define MAIN_PROGRAM 301590Srgrimes 311590Srgrimes#include "cron.h" 321590Srgrimes#include <errno.h> 331590Srgrimes#include <fcntl.h> 341590Srgrimes#include <paths.h> 351590Srgrimes#include <sys/file.h> 361590Srgrimes#include <sys/stat.h> 371590Srgrimes#ifdef USE_UTIMES 3861575Sroberto# include <sys/time.h> 391590Srgrimes#else 4061575Sroberto# include <time.h> 4161575Sroberto# include <utime.h> 421590Srgrimes#endif 43116333Smarkm#if defined(POSIX) 4493604Sobrien# include <locale.h> 4593604Sobrien#endif 461590Srgrimes 471590Srgrimes 481590Srgrimes#define NHEADER_LINES 3 491590Srgrimes 501590Srgrimes 511590Srgrimesenum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace }; 521590Srgrimes 531590Srgrimes#if DEBUGGING 541590Srgrimesstatic char *Options[] = { "???", "list", "delete", "edit", "replace" }; 551590Srgrimes#endif 561590Srgrimes 571590Srgrimes 588874Srgrimesstatic PID_T Pid; 591590Srgrimesstatic char User[MAX_UNAME], RealUser[MAX_UNAME]; 601590Srgrimesstatic char Filename[MAX_FNAME]; 611590Srgrimesstatic FILE *NewCrontab; 621590Srgrimesstatic int CheckErrorCount; 631590Srgrimesstatic enum opt_t Option; 64116333Smarkmstatic struct passwd *pw; 651590Srgrimesstatic void list_cmd __P((void)), 6691400Sdwmalone delete_cmd __P((void)), 6791400Sdwmalone edit_cmd __P((void)), 681590Srgrimes poke_daemon __P((void)), 691590Srgrimes check_error __P((char *)), 701590Srgrimes parse_args __P((int c, char *v[])); 711590Srgrimesstatic int replace_cmd __P((void)); 721590Srgrimes 731590Srgrimes 741590Srgrimesstatic void 751590Srgrimesusage(msg) 761590Srgrimes char *msg; 771590Srgrimes{ 781590Srgrimes fprintf(stderr, "crontab: usage error: %s\n", msg); 791590Srgrimes fprintf(stderr, "%s\n%s\n", 801590Srgrimes "usage: crontab [-u user] file", 811590Srgrimes " crontab [-u user] { -e | -l | -r }"); 821590Srgrimes exit(ERROR_EXIT); 831590Srgrimes} 841590Srgrimes 851590Srgrimes 86144526Stjrint 87144526Stjrmain(argc, argv) 881590Srgrimes int argc; 891590Srgrimes char *argv[]; 90116333Smarkm{ 911590Srgrimes int exitstatus; 92144526Stjr 931590Srgrimes Pid = getpid(); 941590Srgrimes ProgramName = argv[0]; 951590Srgrimes 961590Srgrimes#if defined(POSIX) 971590Srgrimes setlocale(LC_ALL, ""); 981590Srgrimes#endif 991590Srgrimes 100144526Stjr#if defined(BSD) 101144526Stjr setlinebuf(stderr); 102144526Stjr#endif 103144526Stjr parse_args(argc, argv); /* sets many globals, opens a file */ 104144526Stjr set_cron_uid(); 1051590Srgrimes set_cron_cwd(); 1061590Srgrimes if (!allowed(User)) { 1071590Srgrimes warnx("you (%s) are not allowed to use this program", User); 108144526Stjr log_it(RealUser, Pid, "AUTH", "crontab command not allowed"); 1091590Srgrimes 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(0); 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; 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 while (EOF != (ch = get_char(f))) 244 putchar(ch); 245 fclose(f); 246} 247 248 249static void 250delete_cmd() { 251 char n[MAX_FNAME]; 252 int ch, first; 253 254 if (isatty(STDIN_FILENO)) { 255 (void)fprintf(stderr, "remove crontab for %s? ", User); 256 first = ch = getchar(); 257 while (ch != '\n' && ch != EOF) 258 ch = getchar(); 259 if (first != 'y' && first != 'Y') 260 return; 261 } 262 263 log_it(RealUser, Pid, "DELETE", User); 264 (void) sprintf(n, CRON_TAB(User)); 265 if (unlink(n)) { 266 if (errno == ENOENT) 267 errx(ERROR_EXIT, "no crontab for %s", User); 268 else 269 err(ERROR_EXIT, "%s", n); 270 } 271 poke_daemon(); 272} 273 274 275static void 276check_error(msg) 277 char *msg; 278{ 279 CheckErrorCount++; 280 fprintf(stderr, "\"%s\":%d: %s\n", Filename, LineNumber-1, msg); 281} 282 283 284static void 285edit_cmd() { 286 char n[MAX_FNAME], q[MAX_TEMPSTR], *editor; 287 FILE *f; 288 int ch, t, x; 289 struct stat statbuf, fsbuf; 290 time_t mtime; 291 WAIT_T waiter; 292 PID_T pid, xpid; 293 mode_t um; 294 295 log_it(RealUser, Pid, "BEGIN EDIT", User); 296 (void) sprintf(n, CRON_TAB(User)); 297 if (!(f = fopen(n, "r"))) { 298 if (errno != ENOENT) 299 err(ERROR_EXIT, "%s", n); 300 warnx("no crontab for %s - using an empty one", User); 301 if (!(f = fopen(_PATH_DEVNULL, "r"))) 302 err(ERROR_EXIT, _PATH_DEVNULL); 303 } 304 305 um = umask(077); 306 (void) sprintf(Filename, "/tmp/crontab.XXXXXXXXXX"); 307 if ((t = mkstemp(Filename)) == -1) { 308 warn("%s", Filename); 309 (void) umask(um); 310 goto fatal; 311 } 312 (void) umask(um); 313#ifdef HAS_FCHOWN 314 if (fchown(t, getuid(), getgid()) < 0) { 315#else 316 if (chown(Filename, getuid(), getgid()) < 0) { 317#endif 318 warn("fchown"); 319 goto fatal; 320 } 321 if (!(NewCrontab = fdopen(t, "r+"))) { 322 warn("fdopen"); 323 goto fatal; 324 } 325 326 Set_LineNum(1) 327 328 /* ignore the top few comments since we probably put them there. 329 */ 330 for (x = 0; x < NHEADER_LINES; x++) { 331 ch = get_char(f); 332 if (EOF == ch) 333 break; 334 if ('#' != ch) { 335 putc(ch, NewCrontab); 336 break; 337 } 338 while (EOF != (ch = get_char(f))) 339 if (ch == '\n') 340 break; 341 if (EOF == ch) 342 break; 343 } 344 345 /* copy the rest of the crontab (if any) to the temp file. 346 */ 347 if (EOF != ch) 348 while (EOF != (ch = get_char(f))) 349 putc(ch, NewCrontab); 350 fclose(f); 351 if (fflush(NewCrontab)) 352 err(ERROR_EXIT, "%s", Filename); 353 if (fstat(t, &fsbuf) < 0) { 354 warn("unable to fstat temp file"); 355 goto fatal; 356 } 357 again: 358 if (stat(Filename, &statbuf) < 0) { 359 warn("stat"); 360 fatal: unlink(Filename); 361 exit(ERROR_EXIT); 362 } 363 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 364 errx(ERROR_EXIT, "temp file must be edited in place"); 365 mtime = statbuf.st_mtime; 366 367 if ((!(editor = getenv("VISUAL"))) 368 && (!(editor = getenv("EDITOR"))) 369 ) { 370 editor = EDITOR; 371 } 372 373 /* we still have the file open. editors will generally rewrite the 374 * original file rather than renaming/unlinking it and starting a 375 * new one; even backup files are supposed to be made by copying 376 * rather than by renaming. if some editor does not support this, 377 * then don't use it. the security problems are more severe if we 378 * close and reopen the file around the edit. 379 */ 380 381 switch (pid = fork()) { 382 case -1: 383 warn("fork"); 384 goto fatal; 385 case 0: 386 /* child */ 387 if (setuid(getuid()) < 0) 388 err(ERROR_EXIT, "setuid(getuid())"); 389 if (chdir("/tmp") < 0) 390 err(ERROR_EXIT, "chdir(/tmp)"); 391 if (strlen(editor) + strlen(Filename) + 2 >= MAX_TEMPSTR) 392 errx(ERROR_EXIT, "editor or filename too long"); 393 execlp(editor, editor, Filename, NULL); 394 err(ERROR_EXIT, "%s", editor); 395 /*NOTREACHED*/ 396 default: 397 /* parent */ 398 break; 399 } 400 401 /* parent */ 402 { 403 void (*f[4])(); 404 f[0] = signal(SIGHUP, SIG_IGN); 405 f[1] = signal(SIGINT, SIG_IGN); 406 f[2] = signal(SIGTERM, SIG_IGN); 407 xpid = wait(&waiter); 408 signal(SIGHUP, f[0]); 409 signal(SIGINT, f[1]); 410 signal(SIGTERM, f[2]); 411 } 412 if (xpid != pid) { 413 warnx("wrong PID (%d != %d) from \"%s\"", xpid, pid, editor); 414 goto fatal; 415 } 416 if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) { 417 warnx("\"%s\" exited with status %d", editor, WEXITSTATUS(waiter)); 418 goto fatal; 419 } 420 if (WIFSIGNALED(waiter)) { 421 warnx("\"%s\" killed; signal %d (%score dumped)", 422 editor, WTERMSIG(waiter), WCOREDUMP(waiter) ?"" :"no "); 423 goto fatal; 424 } 425 if (stat(Filename, &statbuf) < 0) { 426 warn("stat"); 427 goto fatal; 428 } 429 if (statbuf.st_dev != fsbuf.st_dev || statbuf.st_ino != fsbuf.st_ino) 430 errx(ERROR_EXIT, "temp file must be edited in place"); 431 if (mtime == statbuf.st_mtime) { 432 warnx("no changes made to crontab"); 433 goto remove; 434 } 435 warnx("installing new crontab"); 436 switch (replace_cmd()) { 437 case 0: 438 break; 439 case -1: 440 for (;;) { 441 printf("Do you want to retry the same edit? "); 442 fflush(stdout); 443 q[0] = '\0'; 444 (void) fgets(q, sizeof q, stdin); 445 switch (islower(q[0]) ? q[0] : tolower(q[0])) { 446 case 'y': 447 goto again; 448 case 'n': 449 goto abandon; 450 default: 451 fprintf(stderr, "Enter Y or N\n"); 452 } 453 } 454 /*NOTREACHED*/ 455 case -2: 456 abandon: 457 warnx("edits left in %s", Filename); 458 goto done; 459 default: 460 warnx("panic: bad switch() in replace_cmd()"); 461 goto fatal; 462 } 463 remove: 464 unlink(Filename); 465 done: 466 log_it(RealUser, Pid, "END EDIT", User); 467} 468 469 470/* returns 0 on success 471 * -1 on syntax error 472 * -2 on install error 473 */ 474static int 475replace_cmd() { 476 char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME]; 477 FILE *tmp; 478 int ch, eof; 479 entry *e; 480 time_t now = time(NULL); 481 char **envp = env_init(); 482 483 if (envp == NULL) { 484 warnx("cannot allocate memory"); 485 return (-2); 486 } 487 488 (void) sprintf(n, "tmp.%d", Pid); 489 (void) sprintf(tn, CRON_TAB(n)); 490 if (!(tmp = fopen(tn, "w+"))) { 491 warn("%s", tn); 492 return (-2); 493 } 494 495 /* write a signature at the top of the file. 496 * 497 * VERY IMPORTANT: make sure NHEADER_LINES agrees with this code. 498 */ 499 fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n"); 500 fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now)); 501 fprintf(tmp, "# (Cron version -- %s)\n", rcsid); 502 503 /* copy the crontab to the tmp 504 */ 505 rewind(NewCrontab); 506 Set_LineNum(1) 507 while (EOF != (ch = get_char(NewCrontab))) 508 putc(ch, tmp); 509 ftruncate(fileno(tmp), ftell(tmp)); 510 fflush(tmp); rewind(tmp); 511 512 if (ferror(tmp)) { 513 warnx("error while writing new crontab to %s", tn); 514 fclose(tmp); unlink(tn); 515 return (-2); 516 } 517 518 /* check the syntax of the file being installed. 519 */ 520 521 /* BUG: was reporting errors after the EOF if there were any errors 522 * in the file proper -- kludged it by stopping after first error. 523 * vix 31mar87 524 */ 525 Set_LineNum(1 - NHEADER_LINES) 526 CheckErrorCount = 0; eof = FALSE; 527 while (!CheckErrorCount && !eof) { 528 switch (load_env(envstr, tmp)) { 529 case ERR: 530 eof = TRUE; 531 break; 532 case FALSE: 533 e = load_entry(tmp, check_error, pw, envp); 534 if (e) 535 free(e); 536 break; 537 case TRUE: 538 break; 539 } 540 } 541 542 if (CheckErrorCount != 0) { 543 warnx("errors in crontab file, can't install"); 544 fclose(tmp); unlink(tn); 545 return (-1); 546 } 547 548#ifdef HAS_FCHOWN 549 if (fchown(fileno(tmp), ROOT_UID, -1) < OK) 550#else 551 if (chown(tn, ROOT_UID, -1) < OK) 552#endif 553 { 554 warn("chown"); 555 fclose(tmp); unlink(tn); 556 return (-2); 557 } 558 559#ifdef HAS_FCHMOD 560 if (fchmod(fileno(tmp), 0600) < OK) 561#else 562 if (chmod(tn, 0600) < OK) 563#endif 564 { 565 warn("chown"); 566 fclose(tmp); unlink(tn); 567 return (-2); 568 } 569 570 if (fclose(tmp) == EOF) { 571 warn("fclose"); 572 unlink(tn); 573 return (-2); 574 } 575 576 (void) sprintf(n, CRON_TAB(User)); 577 if (rename(tn, n)) { 578 warn("error renaming %s to %s", tn, n); 579 unlink(tn); 580 return (-2); 581 } 582 log_it(RealUser, Pid, "REPLACE", User); 583 584 poke_daemon(); 585 586 return (0); 587} 588 589 590static void 591poke_daemon() { 592#ifdef USE_UTIMES 593 struct timeval tvs[2]; 594 struct timezone tz; 595 596 (void) gettimeofday(&tvs[0], &tz); 597 tvs[1] = tvs[0]; 598 if (utimes(SPOOL_DIR, tvs) < OK) { 599 warn("can't update mtime on spooldir %s", SPOOL_DIR); 600 return; 601 } 602#else 603 if (utime(SPOOL_DIR, NULL) < OK) { 604 warn("can't update mtime on spooldir %s", SPOOL_DIR); 605 return; 606 } 607#endif /*USE_UTIMES*/ 608} 609