1 /* $NetBSD: getcap.c,v 1.12 1997/05/17 19:29:18 pk Exp $ */ 2 3 /*- 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Casey Leedom of Lawrence Livermore National Laboratory. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 #if 0 41 static char sccsid[] = "@(#)getcap.c 8.3 (Berkeley) 3/25/94"; 42 #else 43 static char rcsid[] = "$NetBSD: getcap.c,v 1.12 1997/05/17 19:29:18 pk Exp $"; 44 #endif 45 #endif /* LIBC_SCCS and not lint */ 46 47 #include <sys/types.h> 48 49 #include <ctype.h> 50 #include <db.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <limits.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #define BFRAG 1024 60 #define BSIZE 1024 61 #define ESC ('[' & 037) /* ASCII ESC */ 62 #define MAX_RECURSION 32 /* maximum getent recursion */ 63 #define SFRAG 100 /* cgetstr mallocs in SFRAG chunks */ 64 65 #define RECOK (char)0 66 #define TCERR (char)1 67 #define SHADOW (char)2 68 69 static size_t topreclen; /* toprec length */ 70 static char *toprec; /* Additional record specified by cgetset() */ 71 static int gottoprec; /* Flag indicating retrieval of toprecord */ 72 73 static int cdbget __P((DB *, char **, char *)); 74 static int getent __P((char **, u_int *, char **, int, char *, int, char *)); 75 static int nfcmp __P((char *, char *)); 76 77 /* 78 * Cgetset() allows the addition of a user specified buffer to be added 79 * to the database array, in effect "pushing" the buffer on top of the 80 * virtual database. 0 is returned on success, -1 on failure. 81 */ 82 int 83 cgetset(ent) 84 char *ent; 85 { 86 if (ent == NULL) { 87 if (toprec) 88 free(toprec); 89 toprec = NULL; 90 topreclen = 0; 91 return (0); 92 } 93 topreclen = strlen(ent); 94 if ((toprec = malloc (topreclen + 1)) == NULL) { 95 errno = ENOMEM; 96 return (-1); 97 } 98 gottoprec = 0; 99 (void)strcpy(toprec, ent); /* XXX: strcpy is safe */ 100 return (0); 101 } 102 103 /* 104 * Cgetcap searches the capability record buf for the capability cap with 105 * type `type'. A pointer to the value of cap is returned on success, NULL 106 * if the requested capability couldn't be found. 107 * 108 * Specifying a type of ':' means that nothing should follow cap (:cap:). 109 * In this case a pointer to the terminating ':' or NUL will be returned if 110 * cap is found. 111 * 112 * If (cap, '@') or (cap, terminator, '@') is found before (cap, terminator) 113 * return NULL. 114 */ 115 char * 116 cgetcap(buf, cap, type) 117 char *buf, *cap; 118 int type; 119 { 120 register char *bp, *cp; 121 122 bp = buf; 123 for (;;) { 124 /* 125 * Skip past the current capability field - it's either the 126 * name field if this is the first time through the loop, or 127 * the remainder of a field whose name failed to match cap. 128 */ 129 for (;;) 130 if (*bp == '\0') 131 return (NULL); 132 else 133 if (*bp++ == ':') 134 break; 135 136 /* 137 * Try to match (cap, type) in buf. 138 */ 139 for (cp = cap; *cp == *bp && *bp != '\0'; cp++, bp++) 140 continue; 141 if (*cp != '\0') 142 continue; 143 if (*bp == '@') 144 return (NULL); 145 if (type == ':') { 146 if (*bp != '\0' && *bp != ':') 147 continue; 148 return(bp); 149 } 150 if (*bp != type) 151 continue; 152 bp++; 153 return (*bp == '@' ? NULL : bp); 154 } 155 /* NOTREACHED */ 156 } 157 158 /* 159 * Cgetent extracts the capability record name from the NULL terminated file 160 * array db_array and returns a pointer to a malloc'd copy of it in buf. 161 * Buf must be retained through all subsequent calls to cgetcap, cgetnum, 162 * cgetflag, and cgetstr, but may then be free'd. 0 is returned on success, 163 * -1 if the requested record couldn't be found, -2 if a system error was 164 * encountered (couldn't open/read a file, etc.), and -3 if a potential 165 * reference loop is detected. 166 */ 167 int 168 cgetent(buf, db_array, name) 169 char **buf, **db_array, *name; 170 { 171 u_int dummy; 172 173 return (getent(buf, &dummy, db_array, -1, name, 0, NULL)); 174 } 175 176 /* 177 * Getent implements the functions of cgetent. If fd is non-negative, 178 * *db_array has already been opened and fd is the open file descriptor. We 179 * do this to save time and avoid using up file descriptors for tc= 180 * recursions. 181 * 182 * Getent returns the same success/failure codes as cgetent. On success, a 183 * pointer to a malloc'ed capability record with all tc= capabilities fully 184 * expanded and its length (not including trailing ASCII NUL) are left in 185 * *cap and *len. 186 * 187 * Basic algorithm: 188 * + Allocate memory incrementally as needed in chunks of size BFRAG 189 * for capability buffer. 190 * + Recurse for each tc=name and interpolate result. Stop when all 191 * names interpolated, a name can't be found, or depth exceeds 192 * MAX_RECURSION. 193 */ 194 static int 195 getent(cap, len, db_array, fd, name, depth, nfield) 196 char **cap, **db_array, *name, *nfield; 197 u_int *len; 198 int fd, depth; 199 { 200 DB *capdbp; 201 DBT key, data; 202 register char *r_end, *rp, **db_p; 203 int myfd, eof, foundit, retval, clen; 204 char *record, *cbuf; 205 int tc_not_resolved; 206 char pbuf[_POSIX_PATH_MAX]; 207 208 /* 209 * Return with ``loop detected'' error if we've recursed more than 210 * MAX_RECURSION times. 211 */ 212 if (depth > MAX_RECURSION) 213 return (-3); 214 215 /* 216 * Check if we have a top record from cgetset(). 217 */ 218 if (depth == 0 && toprec != NULL && cgetmatch(toprec, name) == 0) { 219 if ((record = malloc (topreclen + BFRAG)) == NULL) { 220 errno = ENOMEM; 221 return (-2); 222 } 223 (void)strcpy(record, toprec); /* XXX: strcpy is safe */ 224 myfd = 0; 225 db_p = db_array; 226 rp = record + topreclen + 1; 227 r_end = rp + BFRAG; 228 goto tc_exp; 229 } 230 /* 231 * Allocate first chunk of memory. 232 */ 233 if ((record = malloc(BFRAG)) == NULL) { 234 errno = ENOMEM; 235 return (-2); 236 } 237 r_end = record + BFRAG; 238 foundit = 0; 239 /* 240 * Loop through database array until finding the record. 241 */ 242 243 for (db_p = db_array; *db_p != NULL; db_p++) { 244 eof = 0; 245 246 /* 247 * Open database if not already open. 248 */ 249 250 if (fd >= 0) { 251 (void)lseek(fd, (off_t)0, L_SET); 252 myfd = 0; 253 } else { 254 (void)snprintf(pbuf, sizeof(pbuf), "%s.db", *db_p); 255 if ((capdbp = dbopen(pbuf, O_RDONLY, 0, DB_HASH, 0)) 256 != NULL) { 257 free(record); 258 retval = cdbget(capdbp, &record, name); 259 if (retval < 0) { 260 /* no record available */ 261 (void)capdbp->close(capdbp); 262 return (retval); 263 } 264 /* save the data; close frees it */ 265 clen = strlen(record); 266 cbuf = malloc(clen + 1); 267 memcpy(cbuf, record, clen + 1); 268 if (capdbp->close(capdbp) < 0) { 269 free(cbuf); 270 return (-2); 271 } 272 *len = clen; 273 *cap = cbuf; 274 return (retval); 275 } else { 276 fd = open(*db_p, O_RDONLY, 0); 277 if (fd < 0) { 278 /* No error on unfound file. */ 279 continue; 280 } 281 myfd = 1; 282 } 283 } 284 /* 285 * Find the requested capability record ... 286 */ 287 { 288 char buf[BUFSIZ]; 289 register char *b_end, *bp; 290 register int c; 291 292 /* 293 * Loop invariants: 294 * There is always room for one more character in record. 295 * R_end always points just past end of record. 296 * Rp always points just past last character in record. 297 * B_end always points just past last character in buf. 298 * Bp always points at next character in buf. 299 */ 300 b_end = buf; 301 bp = buf; 302 for (;;) { 303 304 /* 305 * Read in a line implementing (\, newline) 306 * line continuation. 307 */ 308 rp = record; 309 for (;;) { 310 if (bp >= b_end) { 311 int n; 312 313 n = read(fd, buf, sizeof(buf)); 314 if (n <= 0) { 315 if (myfd) 316 (void)close(fd); 317 if (n < 0) { 318 free(record); 319 return (-2); 320 } else { 321 fd = -1; 322 eof = 1; 323 break; 324 } 325 } 326 b_end = buf+n; 327 bp = buf; 328 } 329 330 c = *bp++; 331 if (c == '\n') { 332 if (rp > record && *(rp-1) == '\\') { 333 rp--; 334 continue; 335 } else 336 break; 337 } 338 *rp++ = c; 339 340 /* 341 * Enforce loop invariant: if no room 342 * left in record buffer, try to get 343 * some more. 344 */ 345 if (rp >= r_end) { 346 u_int pos; 347 size_t newsize; 348 349 pos = rp - record; 350 newsize = r_end - record + BFRAG; 351 record = realloc(record, newsize); 352 if (record == NULL) { 353 errno = ENOMEM; 354 if (myfd) 355 (void)close(fd); 356 return (-2); 357 } 358 r_end = record + newsize; 359 rp = record + pos; 360 } 361 } 362 /* loop invariant let's us do this */ 363 *rp++ = '\0'; 364 365 /* 366 * If encountered eof check next file. 367 */ 368 if (eof) 369 break; 370 371 /* 372 * Toss blank lines and comments. 373 */ 374 if (*record == '\0' || *record == '#') 375 continue; 376 377 /* 378 * See if this is the record we want ... 379 */ 380 if (cgetmatch(record, name) == 0) { 381 if (nfield == NULL || !nfcmp(nfield, record)) { 382 foundit = 1; 383 break; /* found it! */ 384 } 385 } 386 } 387 } 388 if (foundit) 389 break; 390 } 391 392 if (!foundit) 393 return (-1); 394 395 /* 396 * Got the capability record, but now we have to expand all tc=name 397 * references in it ... 398 */ 399 tc_exp: { 400 register char *newicap, *s; 401 register int newilen; 402 u_int ilen; 403 int diff, iret, tclen; 404 char *icap, *scan, *tc, *tcstart, *tcend; 405 406 /* 407 * Loop invariants: 408 * There is room for one more character in record. 409 * R_end points just past end of record. 410 * Rp points just past last character in record. 411 * Scan points at remainder of record that needs to be 412 * scanned for tc=name constructs. 413 */ 414 scan = record; 415 tc_not_resolved = 0; 416 for (;;) { 417 if ((tc = cgetcap(scan, "tc", '=')) == NULL) 418 break; 419 420 /* 421 * Find end of tc=name and stomp on the trailing `:' 422 * (if present) so we can use it to call ourselves. 423 */ 424 s = tc; 425 for (;;) 426 if (*s == '\0') 427 break; 428 else 429 if (*s++ == ':') { 430 *(s - 1) = '\0'; 431 break; 432 } 433 tcstart = tc - 3; 434 tclen = s - tcstart; 435 tcend = s; 436 437 iret = getent(&icap, &ilen, db_p, fd, tc, depth+1, 438 NULL); 439 newicap = icap; /* Put into a register. */ 440 newilen = ilen; 441 if (iret != 0) { 442 /* an error */ 443 if (iret < -1) { 444 if (myfd) 445 (void)close(fd); 446 free(record); 447 return (iret); 448 } 449 if (iret == 1) 450 tc_not_resolved = 1; 451 /* couldn't resolve tc */ 452 if (iret == -1) { 453 *(s - 1) = ':'; 454 scan = s - 1; 455 tc_not_resolved = 1; 456 continue; 457 458 } 459 } 460 /* not interested in name field of tc'ed record */ 461 s = newicap; 462 for (;;) 463 if (*s == '\0') 464 break; 465 else 466 if (*s++ == ':') 467 break; 468 newilen -= s - newicap; 469 newicap = s; 470 471 /* make sure interpolated record is `:'-terminated */ 472 s += newilen; 473 if (*(s-1) != ':') { 474 *s = ':'; /* overwrite NUL with : */ 475 newilen++; 476 } 477 478 /* 479 * Make sure there's enough room to insert the 480 * new record. 481 */ 482 diff = newilen - tclen; 483 if (diff >= r_end - rp) { 484 u_int pos, tcpos, tcposend; 485 size_t newsize; 486 487 pos = rp - record; 488 newsize = r_end - record + diff + BFRAG; 489 tcpos = tcstart - record; 490 tcposend = tcend - record; 491 record = realloc(record, newsize); 492 if (record == NULL) { 493 errno = ENOMEM; 494 if (myfd) 495 (void)close(fd); 496 free(icap); 497 return (-2); 498 } 499 r_end = record + newsize; 500 rp = record + pos; 501 tcstart = record + tcpos; 502 tcend = record + tcposend; 503 } 504 505 /* 506 * Insert tc'ed record into our record. 507 */ 508 s = tcstart + newilen; 509 bcopy(tcend, s, rp - tcend); 510 bcopy(newicap, tcstart, newilen); 511 rp += diff; 512 free(icap); 513 514 /* 515 * Start scan on `:' so next cgetcap works properly 516 * (cgetcap always skips first field). 517 */ 518 scan = s-1; 519 } 520 521 } 522 /* 523 * Close file (if we opened it), give back any extra memory, and 524 * return capability, length and success. 525 */ 526 if (myfd) 527 (void)close(fd); 528 *len = rp - record - 1; /* don't count NUL */ 529 if (r_end > rp) 530 if ((record = 531 realloc(record, (size_t)(rp - record))) == NULL) { 532 errno = ENOMEM; 533 return (-2); 534 } 535 536 *cap = record; 537 if (tc_not_resolved) 538 return (1); 539 return (0); 540 } 541 542 static int 543 cdbget(capdbp, bp, name) 544 DB *capdbp; 545 char **bp, *name; 546 { 547 DBT key, data; 548 char *buf; 549 int st; 550 551 key.data = name; 552 key.size = strlen(name); 553 554 for (;;) { 555 /* Get the reference. */ 556 switch(capdbp->get(capdbp, &key, &data, 0)) { 557 case -1: 558 return (-2); 559 case 1: 560 return (-1); 561 } 562 563 /* If not an index to another record, leave. */ 564 if (((char *)data.data)[0] != SHADOW) 565 break; 566 567 key.data = (char *)data.data + 1; 568 key.size = data.size - 1; 569 } 570 571 *bp = (char *)data.data + 1; 572 return (((char *)(data.data))[0] == TCERR ? 1 : 0); 573 } 574 575 /* 576 * Cgetmatch will return 0 if name is one of the names of the capability 577 * record buf, -1 if not. 578 */ 579 int 580 cgetmatch(buf, name) 581 char *buf, *name; 582 { 583 register char *np, *bp; 584 585 /* 586 * Start search at beginning of record. 587 */ 588 bp = buf; 589 for (;;) { 590 /* 591 * Try to match a record name. 592 */ 593 np = name; 594 for (;;) 595 if (*np == '\0') 596 if (*bp == '|' || *bp == ':' || *bp == '\0') 597 return (0); 598 else 599 break; 600 else 601 if (*bp++ != *np++) 602 break; 603 604 /* 605 * Match failed, skip to next name in record. 606 */ 607 bp--; /* a '|' or ':' may have stopped the match */ 608 for (;;) 609 if (*bp == '\0' || *bp == ':') 610 return (-1); /* match failed totally */ 611 else 612 if (*bp++ == '|') 613 break; /* found next name */ 614 } 615 } 616 617 618 619 620 621 int 622 cgetfirst(buf, db_array) 623 char **buf, **db_array; 624 { 625 (void)cgetclose(); 626 return (cgetnext(buf, db_array)); 627 } 628 629 static FILE *pfp; 630 static int slash; 631 static char **dbp; 632 633 int 634 cgetclose() 635 { 636 if (pfp != NULL) { 637 (void)fclose(pfp); 638 pfp = NULL; 639 } 640 dbp = NULL; 641 gottoprec = 0; 642 slash = 0; 643 return(0); 644 } 645 646 /* 647 * Cgetnext() gets either the first or next entry in the logical database 648 * specified by db_array. It returns 0 upon completion of the database, 1 649 * upon returning an entry with more remaining, and -1 if an error occurs. 650 */ 651 int 652 cgetnext(bp, db_array) 653 register char **bp; 654 char **db_array; 655 { 656 size_t len; 657 int status, i, done; 658 char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE]; 659 u_int dummy; 660 661 if (dbp == NULL) 662 dbp = db_array; 663 664 if (pfp == NULL && (pfp = fopen(*dbp, "r")) == NULL) { 665 (void)cgetclose(); 666 return (-1); 667 } 668 for(;;) { 669 if (toprec && !gottoprec) { 670 gottoprec = 1; 671 line = toprec; 672 } else { 673 line = fgetln(pfp, &len); 674 if (line == NULL && pfp) { 675 (void)fclose(pfp); 676 if (ferror(pfp)) { 677 (void)cgetclose(); 678 return (-1); 679 } else { 680 if (*++dbp == NULL) { 681 (void)cgetclose(); 682 return (0); 683 } else if ((pfp = 684 fopen(*dbp, "r")) == NULL) { 685 (void)cgetclose(); 686 return (-1); 687 } else 688 continue; 689 } 690 } else 691 line[len - 1] = '\0'; 692 if (len == 1) { 693 slash = 0; 694 continue; 695 } 696 if (isspace(*line) || 697 *line == ':' || *line == '#' || slash) { 698 if (line[len - 2] == '\\') 699 slash = 1; 700 else 701 slash = 0; 702 continue; 703 } 704 if (line[len - 2] == '\\') 705 slash = 1; 706 else 707 slash = 0; 708 } 709 710 711 /* 712 * Line points to a name line. 713 */ 714 i = 0; 715 done = 0; 716 np = nbuf; 717 for (;;) { 718 for (cp = line; *cp != '\0'; cp++) { 719 if (*cp == ':') { 720 *np++ = ':'; 721 done = 1; 722 break; 723 } 724 if (*cp == '\\') 725 break; 726 *np++ = *cp; 727 } 728 if (done) { 729 *np = '\0'; 730 break; 731 } else { /* name field extends beyond the line */ 732 line = fgetln(pfp, &len); 733 if (line == NULL && pfp) { 734 (void)fclose(pfp); 735 if (ferror(pfp)) { 736 (void)cgetclose(); 737 return (-1); 738 } 739 } else 740 line[len - 1] = '\0'; 741 } 742 } 743 rp = buf; 744 for(cp = nbuf; *cp != '\0'; cp++) 745 if (*cp == '|' || *cp == ':') 746 break; 747 else 748 *rp++ = *cp; 749 750 *rp = '\0'; 751 /* 752 * XXX 753 * Last argument of getent here should be nbuf if we want true 754 * sequential access in the case of duplicates. 755 * With NULL, getent will return the first entry found 756 * rather than the duplicate entry record. This is a 757 * matter of semantics that should be resolved. 758 */ 759 status = getent(bp, &dummy, db_array, -1, buf, 0, NULL); 760 if (status == -2 || status == -3) 761 (void)cgetclose(); 762 763 return (status + 1); 764 } 765 /* NOTREACHED */ 766 } 767 768 /* 769 * Cgetstr retrieves the value of the string capability cap from the 770 * capability record pointed to by buf. A pointer to a decoded, NUL 771 * terminated, malloc'd copy of the string is returned in the char * 772 * pointed to by str. The length of the string not including the trailing 773 * NUL is returned on success, -1 if the requested string capability 774 * couldn't be found, -2 if a system error was encountered (storage 775 * allocation failure). 776 */ 777 int 778 cgetstr(buf, cap, str) 779 char *buf, *cap; 780 char **str; 781 { 782 register u_int m_room; 783 register char *bp, *mp; 784 int len; 785 char *mem; 786 787 /* 788 * Find string capability cap 789 */ 790 bp = cgetcap(buf, cap, '='); 791 if (bp == NULL) 792 return (-1); 793 794 /* 795 * Conversion / storage allocation loop ... Allocate memory in 796 * chunks SFRAG in size. 797 */ 798 if ((mem = malloc(SFRAG)) == NULL) { 799 errno = ENOMEM; 800 return (-2); /* couldn't even allocate the first fragment */ 801 } 802 m_room = SFRAG; 803 mp = mem; 804 805 while (*bp != ':' && *bp != '\0') { 806 /* 807 * Loop invariants: 808 * There is always room for one more character in mem. 809 * Mp always points just past last character in mem. 810 * Bp always points at next character in buf. 811 */ 812 if (*bp == '^') { 813 bp++; 814 if (*bp == ':' || *bp == '\0') 815 break; /* drop unfinished escape */ 816 *mp++ = *bp++ & 037; 817 } else if (*bp == '\\') { 818 bp++; 819 if (*bp == ':' || *bp == '\0') 820 break; /* drop unfinished escape */ 821 if ('0' <= *bp && *bp <= '7') { 822 register int n, i; 823 824 n = 0; 825 i = 3; /* maximum of three octal digits */ 826 do { 827 n = n * 8 + (*bp++ - '0'); 828 } while (--i && '0' <= *bp && *bp <= '7'); 829 *mp++ = n; 830 } 831 else switch (*bp++) { 832 case 'b': case 'B': 833 *mp++ = '\b'; 834 break; 835 case 't': case 'T': 836 *mp++ = '\t'; 837 break; 838 case 'n': case 'N': 839 *mp++ = '\n'; 840 break; 841 case 'f': case 'F': 842 *mp++ = '\f'; 843 break; 844 case 'r': case 'R': 845 *mp++ = '\r'; 846 break; 847 case 'e': case 'E': 848 *mp++ = ESC; 849 break; 850 case 'c': case 'C': 851 *mp++ = ':'; 852 break; 853 default: 854 /* 855 * Catches '\', '^', and 856 * everything else. 857 */ 858 *mp++ = *(bp-1); 859 break; 860 } 861 } else 862 *mp++ = *bp++; 863 m_room--; 864 865 /* 866 * Enforce loop invariant: if no room left in current 867 * buffer, try to get some more. 868 */ 869 if (m_room == 0) { 870 size_t size = mp - mem; 871 872 if ((mem = realloc(mem, size + SFRAG)) == NULL) 873 return (-2); 874 m_room = SFRAG; 875 mp = mem + size; 876 } 877 } 878 *mp++ = '\0'; /* loop invariant let's us do this */ 879 m_room--; 880 len = mp - mem - 1; 881 882 /* 883 * Give back any extra memory and return value and success. 884 */ 885 if (m_room != 0) 886 if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL) 887 return (-2); 888 *str = mem; 889 return (len); 890 } 891 892 /* 893 * Cgetustr retrieves the value of the string capability cap from the 894 * capability record pointed to by buf. The difference between cgetustr() 895 * and cgetstr() is that cgetustr does not decode escapes but rather treats 896 * all characters literally. A pointer to a NUL terminated malloc'd 897 * copy of the string is returned in the char pointed to by str. The 898 * length of the string not including the trailing NUL is returned on success, 899 * -1 if the requested string capability couldn't be found, -2 if a system 900 * error was encountered (storage allocation failure). 901 */ 902 int 903 cgetustr(buf, cap, str) 904 char *buf, *cap, **str; 905 { 906 register u_int m_room; 907 register char *bp, *mp; 908 int len; 909 char *mem; 910 911 /* 912 * Find string capability cap 913 */ 914 if ((bp = cgetcap(buf, cap, '=')) == NULL) 915 return (-1); 916 917 /* 918 * Conversion / storage allocation loop ... Allocate memory in 919 * chunks SFRAG in size. 920 */ 921 if ((mem = malloc(SFRAG)) == NULL) { 922 errno = ENOMEM; 923 return (-2); /* couldn't even allocate the first fragment */ 924 } 925 m_room = SFRAG; 926 mp = mem; 927 928 while (*bp != ':' && *bp != '\0') { 929 /* 930 * Loop invariants: 931 * There is always room for one more character in mem. 932 * Mp always points just past last character in mem. 933 * Bp always points at next character in buf. 934 */ 935 *mp++ = *bp++; 936 m_room--; 937 938 /* 939 * Enforce loop invariant: if no room left in current 940 * buffer, try to get some more. 941 */ 942 if (m_room == 0) { 943 size_t size = mp - mem; 944 945 if ((mem = realloc(mem, size + SFRAG)) == NULL) 946 return (-2); 947 m_room = SFRAG; 948 mp = mem + size; 949 } 950 } 951 *mp++ = '\0'; /* loop invariant let's us do this */ 952 m_room--; 953 len = mp - mem - 1; 954 955 /* 956 * Give back any extra memory and return value and success. 957 */ 958 if (m_room != 0) 959 if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL) 960 return (-2); 961 *str = mem; 962 return (len); 963 } 964 965 /* 966 * Cgetnum retrieves the value of the numeric capability cap from the 967 * capability record pointed to by buf. The numeric value is returned in 968 * the long pointed to by num. 0 is returned on success, -1 if the requested 969 * numeric capability couldn't be found. 970 */ 971 int 972 cgetnum(buf, cap, num) 973 char *buf, *cap; 974 long *num; 975 { 976 register long n; 977 register int base, digit; 978 register char *bp; 979 980 /* 981 * Find numeric capability cap 982 */ 983 bp = cgetcap(buf, cap, '#'); 984 if (bp == NULL) 985 return (-1); 986 987 /* 988 * Look at value and determine numeric base: 989 * 0x... or 0X... hexadecimal, 990 * else 0... octal, 991 * else decimal. 992 */ 993 if (*bp == '0') { 994 bp++; 995 if (*bp == 'x' || *bp == 'X') { 996 bp++; 997 base = 16; 998 } else 999 base = 8; 1000 } else 1001 base = 10; 1002 1003 /* 1004 * Conversion loop ... 1005 */ 1006 n = 0; 1007 for (;;) { 1008 if ('0' <= *bp && *bp <= '9') 1009 digit = *bp - '0'; 1010 else if ('a' <= *bp && *bp <= 'f') 1011 digit = 10 + *bp - 'a'; 1012 else if ('A' <= *bp && *bp <= 'F') 1013 digit = 10 + *bp - 'A'; 1014 else 1015 break; 1016 1017 if (digit >= base) 1018 break; 1019 1020 n = n * base + digit; 1021 bp++; 1022 } 1023 1024 /* 1025 * Return value and success. 1026 */ 1027 *num = n; 1028 return (0); 1029 } 1030 1031 1032 /* 1033 * Compare name field of record. 1034 */ 1035 static int 1036 nfcmp(nf, rec) 1037 char *nf, *rec; 1038 { 1039 char *cp, tmp; 1040 int ret; 1041 1042 for (cp = rec; *cp != ':'; cp++) 1043 ; 1044 1045 tmp = *(cp + 1); 1046 *(cp + 1) = '\0'; 1047 ret = strcmp(nf, rec); 1048 *(cp + 1) = tmp; 1049 1050 return (ret); 1051 } 1052