getcap.c revision 1.4 1 /*-
2 * Copyright (c) 1992 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Casey Leedom of Lawrence Livermore National Laboratory.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #if defined(LIBC_SCCS) && !defined(lint)
38 /*static char *sccsid = "from: @(#)getcap.c 5.15 (Berkeley) 3/19/93";*/
39 static char *rcsid = "$Id: getcap.c,v 1.4 1993/08/26 00:44:35 jtc Exp $";
40 #endif /* LIBC_SCCS and not lint */
41
42 #include <sys/types.h>
43
44 #include <ctype.h>
45 #include <db.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <limits.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53
54 #define BFRAG 1024
55 #define BSIZE 1024
56 #define ESC ('[' & 037) /* ASCII ESC */
57 #define MAX_RECURSION 32 /* maximum getent recursion */
58 #define SFRAG 100 /* cgetstr mallocs in SFRAG chunks */
59
60 #define RECOK (char)0
61 #define TCERR (char)1
62 #define SHADOW (char)2
63
64 static size_t topreclen; /* toprec length */
65 static char *toprec; /* Additional record specified by cgetset() */
66 static int gottoprec; /* Flag indicating retrieval of toprecord */
67
68 static int cdbget __P((DB *, char **, char *));
69 static int getent __P((char **, u_int *, char **, int, char *, int, char *));
70 static int nfcmp __P((char *, char *));
71
72 /*
73 * Cgetset() allows the addition of a user specified buffer to be added
74 * to the database array, in effect "pushing" the buffer on top of the
75 * virtual database. 0 is returned on success, -1 on failure.
76 */
77 int
78 cgetset(ent)
79 char *ent;
80 {
81 if (ent == NULL) {
82 if (toprec)
83 free(toprec);
84 toprec = NULL;
85 topreclen = 0;
86 return (0);
87 }
88 topreclen = strlen(ent);
89 if ((toprec = malloc (topreclen + 1)) == NULL) {
90 errno = ENOMEM;
91 return (-1);
92 }
93 gottoprec = 0;
94 (void)strcpy(toprec, ent);
95 return (0);
96 }
97
98 /*
99 * Cgetcap searches the capability record buf for the capability cap with
100 * type `type'. A pointer to the value of cap is returned on success, NULL
101 * if the requested capability couldn't be found.
102 *
103 * Specifying a type of ':' means that nothing should follow cap (:cap:).
104 * In this case a pointer to the terminating ':' or NUL will be returned if
105 * cap is found.
106 *
107 * If (cap, '@') or (cap, terminator, '@') is found before (cap, terminator)
108 * return NULL.
109 */
110 char *
111 cgetcap(buf, cap, type)
112 char *buf, *cap;
113 int type;
114 {
115 register char *bp, *cp;
116
117 bp = buf;
118 for (;;) {
119 /*
120 * Skip past the current capability field - it's either the
121 * name field if this is the first time through the loop, or
122 * the remainder of a field whose name failed to match cap.
123 */
124 for (;;)
125 if (*bp == '\0')
126 return (NULL);
127 else
128 if (*bp++ == ':')
129 break;
130
131 /*
132 * Try to match (cap, type) in buf.
133 */
134 for (cp = cap; *cp == *bp && *bp != '\0'; cp++, bp++)
135 continue;
136 if (*cp != '\0')
137 continue;
138 if (*bp == '@')
139 return (NULL);
140 if (type == ':') {
141 if (*bp != '\0' && *bp != ':')
142 continue;
143 return(bp);
144 }
145 if (*bp != type)
146 continue;
147 bp++;
148 return (*bp == '@' ? NULL : bp);
149 }
150 /* NOTREACHED */
151 }
152
153 /*
154 * Cgetent extracts the capability record name from the NULL terminated file
155 * array db_array and returns a pointer to a malloc'd copy of it in buf.
156 * Buf must be retained through all subsequent calls to cgetcap, cgetnum,
157 * cgetflag, and cgetstr, but may then be free'd. 0 is returned on success,
158 * -1 if the requested record couldn't be found, -2 if a system error was
159 * encountered (couldn't open/read a file, etc.), and -3 if a potential
160 * reference loop is detected.
161 */
162 int
163 cgetent(buf, db_array, name)
164 char **buf, **db_array, *name;
165 {
166 u_int dummy;
167
168 return (getent(buf, &dummy, db_array, -1, name, 0, NULL));
169 }
170
171 /*
172 * Getent implements the functions of cgetent. If fd is non-negative,
173 * *db_array has already been opened and fd is the open file descriptor. We
174 * do this to save time and avoid using up file descriptors for tc=
175 * recursions.
176 *
177 * Getent returns the same success/failure codes as cgetent. On success, a
178 * pointer to a malloc'ed capability record with all tc= capabilities fully
179 * expanded and its length (not including trailing ASCII NUL) are left in
180 * *cap and *len.
181 *
182 * Basic algorithm:
183 * + Allocate memory incrementally as needed in chunks of size BFRAG
184 * for capability buffer.
185 * + Recurse for each tc=name and interpolate result. Stop when all
186 * names interpolated, a name can't be found, or depth exceeds
187 * MAX_RECURSION.
188 */
189 static int
190 getent(cap, len, db_array, fd, name, depth, nfield)
191 char **cap, **db_array, *name, *nfield;
192 u_int *len;
193 int fd, depth;
194 {
195 DB *capdbp;
196 DBT key, data;
197 register char *r_end, *rp, **db_p;
198 int myfd, eof, foundit, retval;
199 char *record;
200 int tc_not_resolved;
201 char pbuf[_POSIX_PATH_MAX];
202
203 /*
204 * Return with ``loop detected'' error if we've recursed more than
205 * MAX_RECURSION times.
206 */
207 if (depth > MAX_RECURSION)
208 return (-3);
209
210 /*
211 * Check if we have a top record from cgetset().
212 */
213 if (depth == 0 && toprec != NULL && cgetmatch(toprec, name) == 0) {
214 if ((record = malloc (topreclen + BFRAG)) == NULL) {
215 errno = ENOMEM;
216 return (-2);
217 }
218 (void)strcpy(record, toprec);
219 myfd = 0;
220 db_p = db_array;
221 rp = record + topreclen + 1;
222 r_end = rp + BFRAG;
223 goto tc_exp;
224 }
225 /*
226 * Allocate first chunk of memory.
227 */
228 if ((record = malloc(BFRAG)) == NULL) {
229 errno = ENOMEM;
230 return (-2);
231 }
232 r_end = record + BFRAG;
233 foundit = 0;
234 /*
235 * Loop through database array until finding the record.
236 */
237
238 for (db_p = db_array; *db_p != NULL; db_p++) {
239 eof = 0;
240
241 /*
242 * Open database if not already open.
243 */
244
245 if (fd >= 0) {
246 (void)lseek(fd, (off_t)0, L_SET);
247 myfd = 0;
248 } else {
249 (void)snprintf(pbuf, sizeof(pbuf), "%s.db", *db_p);
250 if ((capdbp = dbopen(pbuf, O_RDONLY, 0, DB_HASH, 0))
251 != NULL) {
252 free(record);
253 retval = cdbget(capdbp, &record, name);
254 if (capdbp->close(capdbp) < 0)
255 return (-2);
256 *len = strlen(record);
257 *cap = malloc(*len + 1);
258 memmove(*cap, record, *len + 1);
259 return (retval);
260 } else {
261 fd = open(*db_p, O_RDONLY, 0);
262 if (fd < 0) {
263 /* No error on unfound file. */
264 if (errno == ENOENT)
265 continue;
266 free(record);
267 return (-2);
268 }
269 myfd = 1;
270 }
271 }
272 /*
273 * Find the requested capability record ...
274 */
275 {
276 char buf[BUFSIZ];
277 register char *b_end, *bp;
278 register int c;
279
280 /*
281 * Loop invariants:
282 * There is always room for one more character in record.
283 * R_end always points just past end of record.
284 * Rp always points just past last character in record.
285 * B_end always points just past last character in buf.
286 * Bp always points at next character in buf.
287 */
288 b_end = buf;
289 bp = buf;
290 for (;;) {
291
292 /*
293 * Read in a line implementing (\, newline)
294 * line continuation.
295 */
296 rp = record;
297 for (;;) {
298 if (bp >= b_end) {
299 int n;
300
301 n = read(fd, buf, sizeof(buf));
302 if (n <= 0) {
303 if (myfd)
304 (void)close(fd);
305 if (n < 0) {
306 free(record);
307 return (-2);
308 } else {
309 fd = -1;
310 eof = 1;
311 break;
312 }
313 }
314 b_end = buf+n;
315 bp = buf;
316 }
317
318 c = *bp++;
319 if (c == '\n') {
320 if (rp > record && *(rp-1) == '\\') {
321 rp--;
322 continue;
323 } else
324 break;
325 }
326 *rp++ = c;
327
328 /*
329 * Enforce loop invariant: if no room
330 * left in record buffer, try to get
331 * some more.
332 */
333 if (rp >= r_end) {
334 u_int pos;
335 size_t newsize;
336
337 pos = rp - record;
338 newsize = r_end - record + BFRAG;
339 record = realloc(record, newsize);
340 if (record == NULL) {
341 errno = ENOMEM;
342 if (myfd)
343 (void)close(fd);
344 return (-2);
345 }
346 r_end = record + newsize;
347 rp = record + pos;
348 }
349 }
350 /* loop invariant let's us do this */
351 *rp++ = '\0';
352
353 /*
354 * If encountered eof check next file.
355 */
356 if (eof)
357 break;
358
359 /*
360 * Toss blank lines and comments.
361 */
362 if (*record == '\0' || *record == '#')
363 continue;
364
365 /*
366 * See if this is the record we want ...
367 */
368 if (cgetmatch(record, name) == 0) {
369 if (nfield == NULL || !nfcmp(nfield, record)) {
370 foundit = 1;
371 break; /* found it! */
372 }
373 }
374 }
375 }
376 if (foundit)
377 break;
378 }
379
380 if (!foundit)
381 return (-1);
382
383 /*
384 * Got the capability record, but now we have to expand all tc=name
385 * references in it ...
386 */
387 tc_exp: {
388 register char *newicap, *s;
389 register int newilen;
390 u_int ilen;
391 int diff, iret, tclen;
392 char *icap, *scan, *tc, *tcstart, *tcend;
393
394 /*
395 * Loop invariants:
396 * There is room for one more character in record.
397 * R_end points just past end of record.
398 * Rp points just past last character in record.
399 * Scan points at remainder of record that needs to be
400 * scanned for tc=name constructs.
401 */
402 scan = record;
403 tc_not_resolved = 0;
404 for (;;) {
405 if ((tc = cgetcap(scan, "tc", '=')) == NULL)
406 break;
407
408 /*
409 * Find end of tc=name and stomp on the trailing `:'
410 * (if present) so we can use it to call ourselves.
411 */
412 s = tc;
413 for (;;)
414 if (*s == '\0')
415 break;
416 else
417 if (*s++ == ':') {
418 *(s - 1) = '\0';
419 break;
420 }
421 tcstart = tc - 3;
422 tclen = s - tcstart;
423 tcend = s;
424
425 iret = getent(&icap, &ilen, db_p, fd, tc, depth+1,
426 NULL);
427 newicap = icap; /* Put into a register. */
428 newilen = ilen;
429 if (iret != 0) {
430 /* an error */
431 if (iret < -1) {
432 if (myfd)
433 (void)close(fd);
434 free(record);
435 return (iret);
436 }
437 if (iret == 1)
438 tc_not_resolved = 1;
439 /* couldn't resolve tc */
440 if (iret == -1) {
441 *(s - 1) = ':';
442 scan = s - 1;
443 tc_not_resolved = 1;
444 continue;
445
446 }
447 }
448 /* not interested in name field of tc'ed record */
449 s = newicap;
450 for (;;)
451 if (*s == '\0')
452 break;
453 else
454 if (*s++ == ':')
455 break;
456 newilen -= s - newicap;
457 newicap = s;
458
459 /* make sure interpolated record is `:'-terminated */
460 s += newilen;
461 if (*(s-1) != ':') {
462 *s = ':'; /* overwrite NUL with : */
463 newilen++;
464 }
465
466 /*
467 * Make sure there's enough room to insert the
468 * new record.
469 */
470 diff = newilen - tclen;
471 if (diff >= r_end - rp) {
472 u_int pos, tcpos, tcposend;
473 size_t newsize;
474
475 pos = rp - record;
476 newsize = r_end - record + diff + BFRAG;
477 tcpos = tcstart - record;
478 tcposend = tcend - record;
479 record = realloc(record, newsize);
480 if (record == NULL) {
481 errno = ENOMEM;
482 if (myfd)
483 (void)close(fd);
484 free(icap);
485 return (-2);
486 }
487 r_end = record + newsize;
488 rp = record + pos;
489 tcstart = record + tcpos;
490 tcend = record + tcposend;
491 }
492
493 /*
494 * Insert tc'ed record into our record.
495 */
496 s = tcstart + newilen;
497 bcopy(tcend, s, rp - tcend);
498 bcopy(newicap, tcstart, newilen);
499 rp += diff;
500 free(icap);
501
502 /*
503 * Start scan on `:' so next cgetcap works properly
504 * (cgetcap always skips first field).
505 */
506 scan = s-1;
507 }
508
509 }
510 /*
511 * Close file (if we opened it), give back any extra memory, and
512 * return capability, length and success.
513 */
514 if (myfd)
515 (void)close(fd);
516 *len = rp - record - 1; /* don't count NUL */
517 if (r_end > rp)
518 if ((record =
519 realloc(record, (size_t)(rp - record))) == NULL) {
520 errno = ENOMEM;
521 return (-2);
522 }
523
524 *cap = record;
525 if (tc_not_resolved)
526 return (1);
527 return (0);
528 }
529
530 static int
531 cdbget(capdbp, bp, name)
532 DB *capdbp;
533 char **bp, *name;
534 {
535 DBT key, data;
536 char *buf;
537 int st;
538
539 key.data = name;
540 key.size = strlen(name);
541
542 for (;;) {
543 /* Get the reference. */
544 switch(capdbp->get(capdbp, &key, &data, 0)) {
545 case -1:
546 return (-2);
547 case 1:
548 return (-1);
549 }
550
551 /* If not an index to another record, leave. */
552 if (((char *)data.data)[0] != SHADOW)
553 break;
554
555 key.data = (char *)data.data + 1;
556 key.size = data.size - 1;
557 }
558
559 *bp = (char *)data.data + 1;
560 return (((char *)(data.data))[0] == TCERR ? 1 : 0);
561 }
562
563 /*
564 * Cgetmatch will return 0 if name is one of the names of the capability
565 * record buf, -1 if not.
566 */
567 int
568 cgetmatch(buf, name)
569 char *buf, *name;
570 {
571 register char *np, *bp;
572
573 /*
574 * Start search at beginning of record.
575 */
576 bp = buf;
577 for (;;) {
578 /*
579 * Try to match a record name.
580 */
581 np = name;
582 for (;;)
583 if (*np == '\0')
584 if (*bp == '|' || *bp == ':' || *bp == '\0')
585 return (0);
586 else
587 break;
588 else
589 if (*bp++ != *np++)
590 break;
591
592 /*
593 * Match failed, skip to next name in record.
594 */
595 bp--; /* a '|' or ':' may have stopped the match */
596 for (;;)
597 if (*bp == '\0' || *bp == ':')
598 return (-1); /* match failed totally */
599 else
600 if (*bp++ == '|')
601 break; /* found next name */
602 }
603 }
604
605
606
607
608
609 int
610 cgetfirst(buf, db_array)
611 char **buf, **db_array;
612 {
613 (void)cgetclose();
614 return (cgetnext(buf, db_array));
615 }
616
617 static FILE *pfp;
618 static int slash;
619 static char **dbp;
620
621 int
622 cgetclose()
623 {
624 if (pfp != NULL) {
625 (void)fclose(pfp);
626 pfp = NULL;
627 }
628 dbp = NULL;
629 gottoprec = 0;
630 slash = 0;
631 return(0);
632 }
633
634 /*
635 * Cgetnext() gets either the first or next entry in the logical database
636 * specified by db_array. It returns 0 upon completion of the database, 1
637 * upon returning an entry with more remaining, and -1 if an error occurs.
638 */
639 int
640 cgetnext(bp, db_array)
641 register char **bp;
642 char **db_array;
643 {
644 size_t len;
645 int status, i, done;
646 char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE];
647 u_int dummy;
648
649 if (dbp == NULL)
650 dbp = db_array;
651
652 if (pfp == NULL && (pfp = fopen(*dbp, "r")) == NULL) {
653 (void)cgetclose();
654 return (-1);
655 }
656 for(;;) {
657 if (toprec && !gottoprec) {
658 gottoprec = 1;
659 line = toprec;
660 } else {
661 line = fgetline(pfp, &len);
662 if (line == NULL && pfp) {
663 (void)fclose(pfp);
664 if (ferror(pfp)) {
665 (void)cgetclose();
666 return (-1);
667 } else {
668 if (*++dbp == NULL) {
669 (void)cgetclose();
670 return (0);
671 } else if ((pfp =
672 fopen(*dbp, "r")) == NULL) {
673 (void)cgetclose();
674 return (-1);
675 } else
676 continue;
677 }
678 }
679 if (len == 0) {
680 slash = 0;
681 continue;
682 }
683 if (isspace(*line) ||
684 *line == ':' || *line == '#' || slash) {
685 if (line[len - 1] == '\\')
686 slash = 1;
687 else
688 slash = 0;
689 continue;
690 }
691 if (line[len - 1] == '\\')
692 slash = 1;
693 else
694 slash = 0;
695 }
696
697
698 /*
699 * Line points to a name line.
700 */
701 i = 0;
702 done = 0;
703 np = nbuf;
704 for (;;) {
705 for (cp = line; *cp != '\0'; cp++) {
706 if (*cp == ':') {
707 *np++ = ':';
708 done = 1;
709 break;
710 }
711 if (*cp == '\\')
712 break;
713 *np++ = *cp;
714 }
715 if (done) {
716 *np = '\0';
717 break;
718 } else { /* name field extends beyond the line */
719 line = fgetline(pfp, &len);
720 if (line == NULL && pfp) {
721 (void)fclose(pfp);
722 if (ferror(pfp)) {
723 (void)cgetclose();
724 return (-1);
725 }
726 }
727 }
728 }
729 rp = buf;
730 for(cp = nbuf; *cp != NULL; cp++)
731 if (*cp == '|' || *cp == ':')
732 break;
733 else
734 *rp++ = *cp;
735
736 *rp = '\0';
737 /*
738 * XXX
739 * Last argument of getent here should be nbuf if we want true
740 * sequential access in the case of duplicates.
741 * With NULL, getent will return the first entry found
742 * rather than the duplicate entry record. This is a
743 * matter of semantics that should be resolved.
744 */
745 status = getent(bp, &dummy, db_array, -1, buf, 0, NULL);
746 if (status == -2 || status == -3)
747 (void)cgetclose();
748
749 return (status + 1);
750 }
751 /* NOTREACHED */
752 }
753
754 /*
755 * Cgetstr retrieves the value of the string capability cap from the
756 * capability record pointed to by buf. A pointer to a decoded, NUL
757 * terminated, malloc'd copy of the string is returned in the char *
758 * pointed to by str. The length of the string not including the trailing
759 * NUL is returned on success, -1 if the requested string capability
760 * couldn't be found, -2 if a system error was encountered (storage
761 * allocation failure).
762 */
763 int
764 cgetstr(buf, cap, str)
765 char *buf, *cap;
766 char **str;
767 {
768 register u_int m_room;
769 register char *bp, *mp;
770 int len;
771 char *mem;
772
773 /*
774 * Find string capability cap
775 */
776 bp = cgetcap(buf, cap, '=');
777 if (bp == NULL)
778 return (-1);
779
780 /*
781 * Conversion / storage allocation loop ... Allocate memory in
782 * chunks SFRAG in size.
783 */
784 if ((mem = malloc(SFRAG)) == NULL) {
785 errno = ENOMEM;
786 return (-2); /* couldn't even allocate the first fragment */
787 }
788 m_room = SFRAG;
789 mp = mem;
790
791 while (*bp != ':' && *bp != '\0') {
792 /*
793 * Loop invariants:
794 * There is always room for one more character in mem.
795 * Mp always points just past last character in mem.
796 * Bp always points at next character in buf.
797 */
798 if (*bp == '^') {
799 bp++;
800 if (*bp == ':' || *bp == '\0')
801 break; /* drop unfinished escape */
802 *mp++ = *bp++ & 037;
803 } else if (*bp == '\\') {
804 bp++;
805 if (*bp == ':' || *bp == '\0')
806 break; /* drop unfinished escape */
807 if ('0' <= *bp && *bp <= '7') {
808 register int n, i;
809
810 n = 0;
811 i = 3; /* maximum of three octal digits */
812 do {
813 n = n * 8 + (*bp++ - '0');
814 } while (--i && '0' <= *bp && *bp <= '7');
815 *mp++ = n;
816 }
817 else switch (*bp++) {
818 case 'b': case 'B':
819 *mp++ = '\b';
820 break;
821 case 't': case 'T':
822 *mp++ = '\t';
823 break;
824 case 'n': case 'N':
825 *mp++ = '\n';
826 break;
827 case 'f': case 'F':
828 *mp++ = '\f';
829 break;
830 case 'r': case 'R':
831 *mp++ = '\r';
832 break;
833 case 'e': case 'E':
834 *mp++ = ESC;
835 break;
836 case 'c': case 'C':
837 *mp++ = ':';
838 break;
839 default:
840 /*
841 * Catches '\', '^', and
842 * everything else.
843 */
844 *mp++ = *(bp-1);
845 break;
846 }
847 } else
848 *mp++ = *bp++;
849 m_room--;
850
851 /*
852 * Enforce loop invariant: if no room left in current
853 * buffer, try to get some more.
854 */
855 if (m_room == 0) {
856 size_t size = mp - mem;
857
858 if ((mem = realloc(mem, size + SFRAG)) == NULL)
859 return (-2);
860 m_room = SFRAG;
861 mp = mem + size;
862 }
863 }
864 *mp++ = '\0'; /* loop invariant let's us do this */
865 m_room--;
866 len = mp - mem - 1;
867
868 /*
869 * Give back any extra memory and return value and success.
870 */
871 if (m_room != 0)
872 if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
873 return (-2);
874 *str = mem;
875 return (len);
876 }
877
878 /*
879 * Cgetustr retrieves the value of the string capability cap from the
880 * capability record pointed to by buf. The difference between cgetustr()
881 * and cgetstr() is that cgetustr does not decode escapes but rather treats
882 * all characters literally. A pointer to a NUL terminated malloc'd
883 * copy of the string is returned in the char pointed to by str. The
884 * length of the string not including the trailing NUL is returned on success,
885 * -1 if the requested string capability couldn't be found, -2 if a system
886 * error was encountered (storage allocation failure).
887 */
888 int
889 cgetustr(buf, cap, str)
890 char *buf, *cap, **str;
891 {
892 register u_int m_room;
893 register char *bp, *mp;
894 int len;
895 char *mem;
896
897 /*
898 * Find string capability cap
899 */
900 if ((bp = cgetcap(buf, cap, '=')) == NULL)
901 return (-1);
902
903 /*
904 * Conversion / storage allocation loop ... Allocate memory in
905 * chunks SFRAG in size.
906 */
907 if ((mem = malloc(SFRAG)) == NULL) {
908 errno = ENOMEM;
909 return (-2); /* couldn't even allocate the first fragment */
910 }
911 m_room = SFRAG;
912 mp = mem;
913
914 while (*bp != ':' && *bp != '\0') {
915 /*
916 * Loop invariants:
917 * There is always room for one more character in mem.
918 * Mp always points just past last character in mem.
919 * Bp always points at next character in buf.
920 */
921 *mp++ = *bp++;
922 m_room--;
923
924 /*
925 * Enforce loop invariant: if no room left in current
926 * buffer, try to get some more.
927 */
928 if (m_room == 0) {
929 size_t size = mp - mem;
930
931 if ((mem = realloc(mem, size + SFRAG)) == NULL)
932 return (-2);
933 m_room = SFRAG;
934 mp = mem + size;
935 }
936 }
937 *mp++ = '\0'; /* loop invariant let's us do this */
938 m_room--;
939 len = mp - mem - 1;
940
941 /*
942 * Give back any extra memory and return value and success.
943 */
944 if (m_room != 0)
945 if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
946 return (-2);
947 *str = mem;
948 return (len);
949 }
950
951 /*
952 * Cgetnum retrieves the value of the numeric capability cap from the
953 * capability record pointed to by buf. The numeric value is returned in
954 * the long pointed to by num. 0 is returned on success, -1 if the requested
955 * numeric capability couldn't be found.
956 */
957 int
958 cgetnum(buf, cap, num)
959 char *buf, *cap;
960 long *num;
961 {
962 register long n;
963 register int base, digit;
964 register char *bp;
965
966 /*
967 * Find numeric capability cap
968 */
969 bp = cgetcap(buf, cap, '#');
970 if (bp == NULL)
971 return (-1);
972
973 /*
974 * Look at value and determine numeric base:
975 * 0x... or 0X... hexadecimal,
976 * else 0... octal,
977 * else decimal.
978 */
979 if (*bp == '0') {
980 bp++;
981 if (*bp == 'x' || *bp == 'X') {
982 bp++;
983 base = 16;
984 } else
985 base = 8;
986 } else
987 base = 10;
988
989 /*
990 * Conversion loop ...
991 */
992 n = 0;
993 for (;;) {
994 if ('0' <= *bp && *bp <= '9')
995 digit = *bp - '0';
996 else if ('a' <= *bp && *bp <= 'f')
997 digit = 10 + *bp - 'a';
998 else if ('A' <= *bp && *bp <= 'F')
999 digit = 10 + *bp - 'A';
1000 else
1001 break;
1002
1003 if (digit >= base)
1004 break;
1005
1006 n = n * base + digit;
1007 bp++;
1008 }
1009
1010 /*
1011 * Return value and success.
1012 */
1013 *num = n;
1014 return (0);
1015 }
1016
1017
1018 /*
1019 * Compare name field of record.
1020 */
1021 static int
1022 nfcmp(nf, rec)
1023 char *nf, *rec;
1024 {
1025 char *cp, tmp;
1026 int ret;
1027
1028 for (cp = rec; *cp != ':'; cp++)
1029 ;
1030
1031 tmp = *(cp + 1);
1032 *(cp + 1) = '\0';
1033 ret = strcmp(nf, rec);
1034 *(cp + 1) = tmp;
1035
1036 return (ret);
1037 }
1038