1 /*- 2 * Copyright (c) 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 static char copyright[] = 10 "@(#) Copyright (c) 1990, 1993, 1994\n\ 11 The Regents of the University of California. All rights reserved.\n"; 12 #endif /* not lint */ 13 14 #ifndef lint 15 static char sccsid[] = "@(#)mail.local.c 8.20 (Berkeley) 05/22/95"; 16 #endif /* not lint */ 17 18 /* 19 * This is not intended to compile on System V derived systems 20 * such as Solaris or HP-UX, since they use a totally different 21 * approach to mailboxes (essentially, they have a setgid program 22 * rather than setuid, and they rely on the ability to "give away" 23 * files to do their work). IT IS NOT A BUG that this doesn't 24 * compile on such architectures. 25 */ 26 27 #include <sys/param.h> 28 #include <sys/stat.h> 29 #include <sys/socket.h> 30 31 #include <netinet/in.h> 32 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <netdb.h> 36 #include <pwd.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <string.h> 40 #include <sysexits.h> 41 #include <syslog.h> 42 #include <time.h> 43 #include <unistd.h> 44 #include <ctype.h> 45 46 #if __STDC__ 47 #include <stdarg.h> 48 #else 49 #include <varargs.h> 50 #endif 51 52 #ifndef LOCK_EX 53 # include <sys/file.h> 54 #endif 55 56 #ifdef BSD4_4 57 # include "pathnames.h" 58 #endif 59 60 #ifndef __P 61 # ifdef __STDC__ 62 # define __P(protos) protos 63 # else 64 # define __P(protos) () 65 # define const 66 # endif 67 #endif 68 #ifndef __dead 69 # if defined(__GNUC__) && (__GNUC__ < 2 || __GNUC_MINOR__ < 5) && !defined(__STRICT_ANSI__) 70 # define __dead __volatile 71 # else 72 # define __dead 73 # endif 74 #endif 75 76 #ifndef BSD4_4 77 # define _BSD_VA_LIST_ va_list 78 extern char *strerror __P((int)); 79 extern int snprintf __P((char *, int, const char *, ...)); 80 #endif 81 82 /* 83 * If you don't have setreuid, and you have saved uids, and you have 84 * a seteuid() call that doesn't try to emulate using setuid(), then 85 * you can try defining USE_SETEUID. 86 */ 87 #ifdef USE_SETEUID 88 # define setreuid(r, e) seteuid(e) 89 #endif 90 91 #ifndef _PATH_LOCTMP 92 # define _PATH_LOCTMP "/tmp/local.XXXXXX" 93 #endif 94 #ifndef _PATH_MAILDIR 95 # define _PATH_MAILDIR "/var/spool/mail" 96 #endif 97 98 #ifndef S_ISREG 99 # define S_ISREG(mode) (((mode) & _S_IFMT) == S_IFREG) 100 #endif 101 102 int eval = EX_OK; /* sysexits.h error value. */ 103 104 void deliver __P((int, char *)); 105 void e_to_sys __P((int)); 106 __dead void err __P((const char *, ...)); 107 void notifybiff __P((char *)); 108 int store __P((char *)); 109 void usage __P((void)); 110 void vwarn __P((const char *, _BSD_VA_LIST_)); 111 void warn __P((const char *, ...)); 112 113 int 114 main(argc, argv) 115 int argc; 116 char *argv[]; 117 { 118 struct passwd *pw; 119 int ch, fd; 120 uid_t uid; 121 char *from; 122 extern char *optarg; 123 extern int optind; 124 125 /* make sure we have some open file descriptors */ 126 for (fd = 10; fd < 30; fd++) 127 (void) close(fd); 128 129 /* use a reasonable umask */ 130 (void) umask(0077); 131 132 #ifdef LOG_MAIL 133 openlog("mail.local", 0, LOG_MAIL); 134 #else 135 openlog("mail.local", 0); 136 #endif 137 138 from = NULL; 139 while ((ch = getopt(argc, argv, "df:r:")) != EOF) 140 switch(ch) { 141 case 'd': /* Backward compatible. */ 142 break; 143 case 'f': 144 case 'r': /* Backward compatible. */ 145 if (from != NULL) { 146 warn("multiple -f options"); 147 usage(); 148 } 149 from = optarg; 150 break; 151 case '?': 152 default: 153 usage(); 154 } 155 argc -= optind; 156 argv += optind; 157 158 if (!*argv) 159 usage(); 160 161 /* 162 * If from not specified, use the name from getlogin() if the 163 * uid matches, otherwise, use the name from the password file 164 * corresponding to the uid. 165 */ 166 uid = getuid(); 167 if (!from && (!(from = getlogin()) || 168 !(pw = getpwnam(from)) || pw->pw_uid != uid)) 169 from = (pw = getpwuid(uid)) ? pw->pw_name : "???"; 170 171 /* 172 * There is no way to distinguish the error status of one delivery 173 * from the rest of the deliveries. So, if we failed hard on one 174 * or more deliveries, but had no failures on any of the others, we 175 * return a hard failure. If we failed temporarily on one or more 176 * deliveries, we return a temporary failure regardless of the other 177 * failures. This results in the delivery being reattempted later 178 * at the expense of repeated failures and multiple deliveries. 179 */ 180 for (fd = store(from); *argv; ++argv) 181 deliver(fd, *argv); 182 exit(eval); 183 } 184 185 int 186 store(from) 187 char *from; 188 { 189 FILE *fp; 190 time_t tval; 191 int fd, eline; 192 char line[2048]; 193 char tmpbuf[sizeof _PATH_LOCTMP + 1]; 194 195 strcpy(tmpbuf, _PATH_LOCTMP); 196 if ((fd = mkstemp(tmpbuf)) == -1 || (fp = fdopen(fd, "w+")) == NULL) { 197 e_to_sys(errno); 198 err("unable to open temporary file"); 199 } 200 (void)unlink(tmpbuf); 201 202 (void)time(&tval); 203 (void)fprintf(fp, "From %s %s", from, ctime(&tval)); 204 205 line[0] = '\0'; 206 for (eline = 1; fgets(line, sizeof(line), stdin);) { 207 if (line[0] == '\n') 208 eline = 1; 209 else { 210 if (eline && line[0] == 'F' && 211 !memcmp(line, "From ", 5)) 212 (void)putc('>', fp); 213 eline = 0; 214 } 215 (void)fprintf(fp, "%s", line); 216 if (ferror(fp)) { 217 e_to_sys(errno); 218 err("temporary file write error"); 219 } 220 } 221 222 /* If message not newline terminated, need an extra. */ 223 if (!strchr(line, '\n')) 224 (void)putc('\n', fp); 225 /* Output a newline; note, empty messages are allowed. */ 226 (void)putc('\n', fp); 227 228 if (fflush(fp) == EOF || ferror(fp)) { 229 e_to_sys(errno); 230 err("temporary file write error"); 231 } 232 return (fd); 233 } 234 235 void 236 deliver(fd, name) 237 int fd; 238 char *name; 239 { 240 struct stat fsb, sb; 241 struct passwd *pw; 242 int mbfd, nr, nw, off; 243 char *p; 244 char biffmsg[100], buf[8*1024], path[MAXPATHLEN]; 245 off_t curoff; 246 247 /* 248 * Disallow delivery to unknown names -- special mailboxes can be 249 * handled in the sendmail aliases file. 250 */ 251 if (!(pw = getpwnam(name))) { 252 if (eval != EX_TEMPFAIL) 253 eval = EX_UNAVAILABLE; 254 warn("unknown name: %s", name); 255 return; 256 } 257 258 /* 259 * Keep name reasonably short to avoid buffer overruns. 260 * This isn't necessary on BSD because of the proper 261 * definition of snprintf(), but it can cause problems 262 * on other systems. 263 * Also, clear out any bogus characters. 264 */ 265 266 if (strlen(name) > 40) 267 name[40] = '\0'; 268 for (p = name; *p != '\0'; p++) 269 { 270 if (!isascii(*p)) 271 *p &= 0x7f; 272 else if (!isprint(*p)) 273 *p = '.'; 274 } 275 276 (void)snprintf(path, sizeof(path), "%s/%s", _PATH_MAILDIR, name); 277 278 /* 279 * If the mailbox is linked or a symlink, fail. There's an obvious 280 * race here, that the file was replaced with a symbolic link after 281 * the lstat returned, but before the open. We attempt to detect 282 * this by comparing the original stat information and information 283 * returned by an fstat of the file descriptor returned by the open. 284 * 285 * NB: this is a symptom of a larger problem, that the mail spooling 286 * directory is writeable by the wrong users. If that directory is 287 * writeable, system security is compromised for other reasons, and 288 * it cannot be fixed here. 289 * 290 * If we created the mailbox, set the owner/group. If that fails, 291 * just return. Another process may have already opened it, so we 292 * can't unlink it. Historically, binmail set the owner/group at 293 * each mail delivery. We no longer do this, assuming that if the 294 * ownership or permissions were changed there was a reason. 295 * 296 * XXX 297 * open(2) should support flock'ing the file. 298 */ 299 tryagain: 300 lockmbox(path); 301 if (lstat(path, &sb)) { 302 mbfd = open(path, 303 O_APPEND|O_CREAT|O_EXCL|O_WRONLY, S_IRUSR|S_IWUSR); 304 if (mbfd == -1) { 305 if (errno == EEXIST) 306 goto tryagain; 307 } else if (fchown(mbfd, pw->pw_uid, pw->pw_gid)) { 308 e_to_sys(errno); 309 warn("chown %u.%u: %s", pw->pw_uid, pw->pw_gid, name); 310 goto err1; 311 } 312 } else if (sb.st_nlink != 1 || !S_ISREG(sb.st_mode)) { 313 e_to_sys(errno); 314 warn("%s: irregular file", path); 315 goto err0; 316 } else if (sb.st_uid != pw->pw_uid) { 317 warn("%s: wrong ownership (%d)", path, sb.st_uid); 318 unlockmbox(); 319 return; 320 } else { 321 mbfd = open(path, O_APPEND|O_WRONLY, 0); 322 if (mbfd != -1 && 323 (fstat(mbfd, &fsb) || fsb.st_nlink != 1 || 324 !S_ISREG(fsb.st_mode) || sb.st_dev != fsb.st_dev || 325 sb.st_ino != fsb.st_ino || sb.st_uid != fsb.st_uid)) { 326 warn("%s: file changed after open", path); 327 goto err1; 328 } 329 } 330 331 if (mbfd == -1) { 332 e_to_sys(errno); 333 warn("%s: %s", path, strerror(errno)); 334 goto err0; 335 } 336 337 /* Wait until we can get a lock on the file. */ 338 if (flock(mbfd, LOCK_EX)) { 339 e_to_sys(errno); 340 warn("%s: %s", path, strerror(errno)); 341 goto err1; 342 } 343 344 /* Get the starting offset of the new message for biff. */ 345 curoff = lseek(mbfd, (off_t)0, SEEK_END); 346 (void)snprintf(biffmsg, sizeof(biffmsg), 347 sizeof curoff > sizeof(long) ? "%s@%qd\n" : "%s@%ld\n", 348 name, curoff); 349 350 /* Copy the message into the file. */ 351 if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) { 352 e_to_sys(errno); 353 warn("temporary file: %s", strerror(errno)); 354 goto err1; 355 } 356 if (setreuid(0, pw->pw_uid) < 0) { 357 e_to_sys(errno); 358 warn("setreuid(0, %d): %s (r=%d, e=%d)", 359 pw->pw_uid, strerror(errno), getuid(), geteuid()); 360 goto err1; 361 } 362 #ifdef DEBUG 363 printf("new euid = %d\n", geteuid()); 364 #endif 365 while ((nr = read(fd, buf, sizeof(buf))) > 0) 366 for (off = 0; off < nr; off += nw) 367 if ((nw = write(mbfd, buf + off, nr - off)) < 0) { 368 e_to_sys(errno); 369 warn("%s: %s", path, strerror(errno)); 370 goto err3; 371 } 372 if (nr < 0) { 373 e_to_sys(errno); 374 warn("temporary file: %s", strerror(errno)); 375 goto err3; 376 } 377 378 /* Flush to disk, don't wait for update. */ 379 if (fsync(mbfd)) { 380 e_to_sys(errno); 381 warn("%s: %s", path, strerror(errno)); 382 err3: 383 if (setreuid(0, 0) < 0) { 384 e_to_sys(errno); 385 warn("setreuid(0, 0): %s", strerror(errno)); 386 } 387 #ifdef DEBUG 388 printf("reset euid = %d\n", geteuid()); 389 #endif 390 err2: (void)ftruncate(mbfd, curoff); 391 err1: (void)close(mbfd); 392 err0: unlockmbox(); 393 return; 394 } 395 396 /* Close and check -- NFS doesn't write until the close. */ 397 if (close(mbfd)) { 398 e_to_sys(errno); 399 warn("%s: %s", path, strerror(errno)); 400 unlockmbox(); 401 return; 402 } 403 404 if (setreuid(0, 0) < 0) { 405 e_to_sys(errno); 406 warn("setreuid(0, 0): %s", strerror(errno)); 407 } 408 #ifdef DEBUG 409 printf("reset euid = %d\n", geteuid()); 410 #endif 411 unlockmbox(); 412 notifybiff(biffmsg); 413 } 414 415 /* 416 * user.lock files are necessary for compatibility with other 417 * systems, e.g., when the mail spool file is NFS exported. 418 * Alas, mailbox locking is more than just a local matter. 419 * EPA 11/94. 420 */ 421 422 char lockname[MAXPATHLEN]; 423 int locked = 0; 424 425 lockmbox(path) 426 char *path; 427 { 428 int statfailed = 0; 429 430 if (locked) 431 return; 432 sprintf(lockname, "%s.lock", path); 433 for (;; sleep(5)) { 434 int fd; 435 struct stat st; 436 time_t now; 437 438 fd = open(lockname, O_WRONLY|O_EXCL|O_CREAT, 0); 439 if (fd >= 0) { 440 locked = 1; 441 close(fd); 442 return; 443 } 444 if (stat(lockname, &st) < 0) { 445 if (statfailed++ > 5) 446 return; 447 continue; 448 } 449 statfailed = 0; 450 time(&now); 451 if (now < st.st_ctime + 300) 452 continue; 453 unlink(lockname); 454 } 455 } 456 457 unlockmbox() 458 { 459 if (!locked) 460 return; 461 unlink(lockname); 462 locked = 0; 463 } 464 465 void 466 notifybiff(msg) 467 char *msg; 468 { 469 static struct sockaddr_in addr; 470 static int f = -1; 471 struct hostent *hp; 472 struct servent *sp; 473 int len; 474 475 if (!addr.sin_family) { 476 /* Be silent if biff service not available. */ 477 if (!(sp = getservbyname("biff", "udp"))) 478 return; 479 if (!(hp = gethostbyname("localhost"))) { 480 warn("localhost: %s", strerror(errno)); 481 return; 482 } 483 addr.sin_family = hp->h_addrtype; 484 memcpy(&addr.sin_addr, hp->h_addr, hp->h_length); 485 addr.sin_port = sp->s_port; 486 } 487 if (f < 0 && (f = socket(AF_INET, SOCK_DGRAM, 0)) == -1) { 488 warn("socket: %s", strerror(errno)); 489 return; 490 } 491 len = strlen(msg) + 1; 492 if (sendto(f, msg, len, 0, (struct sockaddr *)&addr, sizeof(addr)) 493 != len) 494 warn("sendto biff: %s", strerror(errno)); 495 } 496 497 void 498 usage() 499 { 500 eval = EX_USAGE; 501 err("usage: mail.local [-f from] user ..."); 502 } 503 504 #if __STDC__ 505 void 506 err(const char *fmt, ...) 507 #else 508 void 509 err(fmt, va_alist) 510 const char *fmt; 511 va_dcl 512 #endif 513 { 514 va_list ap; 515 516 #if __STDC__ 517 va_start(ap, fmt); 518 #else 519 va_start(ap); 520 #endif 521 vwarn(fmt, ap); 522 va_end(ap); 523 524 exit(eval); 525 } 526 527 void 528 #if __STDC__ 529 warn(const char *fmt, ...) 530 #else 531 warn(fmt, va_alist) 532 const char *fmt; 533 va_dcl 534 #endif 535 { 536 va_list ap; 537 538 #if __STDC__ 539 va_start(ap, fmt); 540 #else 541 va_start(ap); 542 #endif 543 vwarn(fmt, ap); 544 va_end(ap); 545 } 546 547 void 548 vwarn(fmt, ap) 549 const char *fmt; 550 _BSD_VA_LIST_ ap; 551 { 552 /* 553 * Log the message to stderr. 554 * 555 * Don't use LOG_PERROR as an openlog() flag to do this, 556 * it's not portable enough. 557 */ 558 if (eval != EX_USAGE) 559 (void)fprintf(stderr, "mail.local: "); 560 (void)vfprintf(stderr, fmt, ap); 561 (void)fprintf(stderr, "\n"); 562 563 #ifndef ultrix 564 /* Log the message to syslog. */ 565 vsyslog(LOG_ERR, fmt, ap); 566 #else 567 { 568 char fmtbuf[10240]; 569 570 (void) sprintf(fmtbuf, fmt, ap); 571 syslog(LOG_ERR, "%s", fmtbuf); 572 } 573 #endif 574 } 575 576 /* 577 * e_to_sys -- 578 * Guess which errno's are temporary. Gag me. 579 */ 580 void 581 e_to_sys(num) 582 int num; 583 { 584 /* Temporary failures override hard errors. */ 585 if (eval == EX_TEMPFAIL) 586 return; 587 588 switch(num) { /* Hopefully temporary errors. */ 589 #ifdef EAGAIN 590 case EAGAIN: /* Resource temporarily unavailable */ 591 #endif 592 #ifdef EDQUOT 593 case EDQUOT: /* Disc quota exceeded */ 594 #endif 595 #ifdef EBUSY 596 case EBUSY: /* Device busy */ 597 #endif 598 #ifdef EPROCLIM 599 case EPROCLIM: /* Too many processes */ 600 #endif 601 #ifdef EUSERS 602 case EUSERS: /* Too many users */ 603 #endif 604 #ifdef ECONNABORTED 605 case ECONNABORTED: /* Software caused connection abort */ 606 #endif 607 #ifdef ECONNREFUSED 608 case ECONNREFUSED: /* Connection refused */ 609 #endif 610 #ifdef ECONNRESET 611 case ECONNRESET: /* Connection reset by peer */ 612 #endif 613 #ifdef EDEADLK 614 case EDEADLK: /* Resource deadlock avoided */ 615 #endif 616 #ifdef EFBIG 617 case EFBIG: /* File too large */ 618 #endif 619 #ifdef EHOSTDOWN 620 case EHOSTDOWN: /* Host is down */ 621 #endif 622 #ifdef EHOSTUNREACH 623 case EHOSTUNREACH: /* No route to host */ 624 #endif 625 #ifdef EMFILE 626 case EMFILE: /* Too many open files */ 627 #endif 628 #ifdef ENETDOWN 629 case ENETDOWN: /* Network is down */ 630 #endif 631 #ifdef ENETRESET 632 case ENETRESET: /* Network dropped connection on reset */ 633 #endif 634 #ifdef ENETUNREACH 635 case ENETUNREACH: /* Network is unreachable */ 636 #endif 637 #ifdef ENFILE 638 case ENFILE: /* Too many open files in system */ 639 #endif 640 #ifdef ENOBUFS 641 case ENOBUFS: /* No buffer space available */ 642 #endif 643 #ifdef ENOMEM 644 case ENOMEM: /* Cannot allocate memory */ 645 #endif 646 #ifdef ENOSPC 647 case ENOSPC: /* No space left on device */ 648 #endif 649 #ifdef EROFS 650 case EROFS: /* Read-only file system */ 651 #endif 652 #ifdef ESTALE 653 case ESTALE: /* Stale NFS file handle */ 654 #endif 655 #ifdef ETIMEDOUT 656 case ETIMEDOUT: /* Connection timed out */ 657 #endif 658 #if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN && EWOULDBLOCK != EDEADLK 659 case EWOULDBLOCK: /* Operation would block. */ 660 #endif 661 eval = EX_TEMPFAIL; 662 break; 663 default: 664 eval = EX_UNAVAILABLE; 665 break; 666 } 667 } 668 669 #ifndef BSD4_4 670 671 char * 672 strerror(eno) 673 int eno; 674 { 675 extern int sys_nerr; 676 extern char *sys_errlist[]; 677 static char ebuf[60]; 678 679 if (eno >= 0 && eno <= sys_nerr) 680 return sys_errlist[eno]; 681 (void) sprintf(ebuf, "Error %d", eno); 682 return ebuf; 683 } 684 685 #if __STDC__ 686 snprintf(char *buf, int bufsiz, const char *fmt, ...) 687 #else 688 snprintf(buf, bufsiz, fmt, va_alist) 689 char *buf; 690 int bufsiz; 691 const char *fmt; 692 va_dcl 693 #endif 694 { 695 va_list ap; 696 697 #if __STDC__ 698 va_start(ap, fmt); 699 #else 700 va_start(ap); 701 #endif 702 vsprintf(buf, fmt, ap); 703 va_end(ap); 704 } 705 706 #endif 707 708 #ifdef ultrix 709 710 /* 711 * Copyright (c) 1987, 1993 712 * The Regents of the University of California. All rights reserved. 713 * 714 * Redistribution and use in source and binary forms, with or without 715 * modification, are permitted provided that the following conditions 716 * are met: 717 * 1. Redistributions of source code must retain the above copyright 718 * notice, this list of conditions and the following disclaimer. 719 * 2. Redistributions in binary form must reproduce the above copyright 720 * notice, this list of conditions and the following disclaimer in the 721 * documentation and/or other materials provided with the distribution. 722 * 3. All advertising materials mentioning features or use of this software 723 * must display the following acknowledgement: 724 * This product includes software developed by the University of 725 * California, Berkeley and its contributors. 726 * 4. Neither the name of the University nor the names of its contributors 727 * may be used to endorse or promote products derived from this software 728 * without specific prior written permission. 729 * 730 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 731 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 732 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 733 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 734 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 735 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 736 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 737 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 738 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 739 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 740 * SUCH DAMAGE. 741 */ 742 743 #if defined(LIBC_SCCS) && !defined(lint) 744 static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93"; 745 #endif /* LIBC_SCCS and not lint */ 746 747 #include <sys/types.h> 748 #include <sys/stat.h> 749 #include <fcntl.h> 750 #include <errno.h> 751 #include <stdio.h> 752 #include <ctype.h> 753 754 static int _gettemp(); 755 756 mkstemp(path) 757 char *path; 758 { 759 int fd; 760 761 return (_gettemp(path, &fd) ? fd : -1); 762 } 763 764 /* 765 char * 766 mktemp(path) 767 char *path; 768 { 769 return(_gettemp(path, (int *)NULL) ? path : (char *)NULL); 770 } 771 */ 772 773 static 774 _gettemp(path, doopen) 775 char *path; 776 register int *doopen; 777 { 778 extern int errno; 779 register char *start, *trv; 780 struct stat sbuf; 781 u_int pid; 782 783 pid = getpid(); 784 for (trv = path; *trv; ++trv); /* extra X's get set to 0's */ 785 while (*--trv == 'X') { 786 *trv = (pid % 10) + '0'; 787 pid /= 10; 788 } 789 790 /* 791 * check the target directory; if you have six X's and it 792 * doesn't exist this runs for a *very* long time. 793 */ 794 for (start = trv + 1;; --trv) { 795 if (trv <= path) 796 break; 797 if (*trv == '/') { 798 *trv = '\0'; 799 if (stat(path, &sbuf)) 800 return(0); 801 if (!S_ISDIR(sbuf.st_mode)) { 802 errno = ENOTDIR; 803 return(0); 804 } 805 *trv = '/'; 806 break; 807 } 808 } 809 810 for (;;) { 811 if (doopen) { 812 if ((*doopen = 813 open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0) 814 return(1); 815 if (errno != EEXIST) 816 return(0); 817 } 818 else if (stat(path, &sbuf)) 819 return(errno == ENOENT ? 1 : 0); 820 821 /* tricky little algorithm for backward compatibility */ 822 for (trv = start;;) { 823 if (!*trv) 824 return(0); 825 if (*trv == 'z') 826 *trv++ = 'a'; 827 else { 828 if (isdigit(*trv)) 829 *trv = 'a'; 830 else 831 ++*trv; 832 break; 833 } 834 } 835 } 836 /*NOTREACHED*/ 837 } 838 839 #endif 840