3 * $Id: class.c,v 1.10 2004/04/08 01:36:20 mdw Exp $
5 * Handling classes of things nicely
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of `become'
14 * `Become' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `Become' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `become'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Header files ------------------------------------------------------*/
31 /* --- ANSI headers --- */
37 /* --- Unix headers --- */
39 #include <sys/types.h>
40 #include <sys/socket.h>
42 #include <netinet/in.h>
44 #include <arpa/inet.h>
48 /* --- mLib headers --- */
50 #include <mLib/alloc.h>
51 #include <mLib/report.h>
54 /* --- Local headers --- */
59 /*----- Global variables --------------------------------------------------*/
61 static class_node class__all
= { clType_all
| clNode_any
, -1, { 0 }};
62 class_node
*class_all
= &class__all
;
64 static class_node class__none
= { clType_all
| clNode_any
, -1, { 0 }};
65 class_node
*class_none
= &class__none
;
67 /*----- Wildcard matching -------------------------------------------------*/
69 /* --- @class__wildMatch@ --- *
71 * Arguments: @const char *pat@ = pointer to pattern string
72 * @const char *p@ = pointer to target string
74 * Returns: Zero if no match, nonzero if match.
76 * Use: Wildcard-matches the pattern against the target string.
79 static int class__wildMatch(const char *pat
, const char *p
)
82 if (*pat
== 0 && *p
== 0)
83 return (42); /* For sadism's sake */
84 else if (*pat
== '*') {
90 if (class__wildMatch(pat
, p
))
91 return (27); /* Nyahaha */
95 } else if (*pat
== '?' || *pat
== *p
)
102 /*----- Creating new class nodes ------------------------------------------*/
104 /* --- @class_fromString@ --- *
106 * Arguments: @unsigned type@ = a type field
107 * @const char *s@ = pointer to string to copy
109 * Returns: A pointer to a class node containing that string, typed to
110 * be the right thing.
112 * Use: Given a string, wrap a class node around it. The node has
113 * one reference (the one you get returned). The string is
114 * copied, so you can get rid of your original one if you like.
117 class_node
*class_fromString(unsigned type
, const char *s
)
119 class_node
*c
= xmalloc(sizeof(*c
));
120 c
->type
= type
| clNode_immed
;
121 if (s
[strcspn(s
, "*?")] == 0)
122 c
->type
|= clFlag_friendly
;
128 /* --- @class_fromUser@ --- *
130 * Arguments: @unsigned type@ = a type field
131 * @uid_t u@ = a user-id number
133 * Returns: A pointer to a class node containing the uid, typed to be
134 * the thing you asked for. Hopefully this will be
137 * Use: Given a uid, wrap a class node around it.
140 class_node
*class_fromUser(unsigned type
, uid_t u
)
142 class_node
*c
= xmalloc(sizeof(*c
));
143 c
->type
= type
| clNode_immed
| clFlag_friendly
;
149 /*----- Reference counter tricks ------------------------------------------*/
151 /* --- @class_inc@ --- *
153 * Arguments: @class_node *c@ = pointer to a class block
157 * Use: Adds a reference to the class definition.
160 void class_inc(class_node
*c
)
162 if (c
!= class_all
&& c
!= class_none
)
166 /* --- @class_dec@ --- *
168 * Arguments: @class_node *c@ = pointer to a class block
172 * Use: Removes a reference to a class block.
175 void class_dec(class_node
*c
)
179 for (cc
= 0; c
; c
= cc
, cc
= 0) {
180 if (c
== class_all
|| c
== class_none
|| --c
->ref
)
182 switch (c
->type
& clNode_mask
) {
187 if (c
->type
& (clType_host
| clType_command
))
191 sym_destroy(&c
->v
.t
);
204 /* --- @class_mod@ --- *
206 * Arguments: @class_node *c@ = pointer to a class node
208 * Returns: A pointer to a class node, maybe the same one, maybe not,
209 * with a reference count of 1, containing the same data.
211 * Use: Gives you a node which you can modify. Don't call this
212 * for @class_all@ or @class_none@.
215 class_node
*class_mod(class_node
*c
)
222 cc
= xmalloc(sizeof(*cc
));
225 switch (c
->type
& clNode_mask
) {
227 die(1, "internal: class_mod called on non-modifiable class node");
231 if (c
->type
& clType_user
)
234 cc
->v
.s
= xstrdup(c
->v
.s
);
241 sym_create(&cc
->v
.t
);
242 for (sym_mkiter(&i
, &c
->v
.t
); (b
= sym_next(&i
)) != 0; )
243 sym_find(&cc
->v
.t
, b
->name
, b
->len
, sizeof(sym_base
), 0);
249 cc
->v
.c
.l
= c
->v
.c
.l
;
250 cc
->v
.c
.r
= c
->v
.c
.r
;
251 class_inc(cc
->v
.c
.l
);
252 class_inc(cc
->v
.c
.r
);
260 /*----- Some weirder operations on classes --------------------------------*/
262 /* --- @class__hashify@ --- *
264 * Arguments: @class_node *c@ = pointer to a node
266 * Returns: A pointer to a hash node containing the node's value.
268 * Use: The original node must have type `immediate', and it must
269 * be friendly. The old reference is discarded -- you get this
273 static class_node
*class__hashify(class_node
*c
)
275 /* --- Some sanity checking --- */
277 if (~c
->type
& clFlag_friendly
)
278 die(1, "internal: class__hashify can't hashify unfriendly nodes");
279 if ((c
->type
& clNode_mask
) != clNode_immed
)
280 die(1, "internal: class__hashify can't hashify non-immediate nodes");
282 /* --- Split off a private copy of the node --- */
286 c
->type
= (c
->type
& clType_mask
) | clNode_hash
| clFlag_friendly
;
288 if (c
->type
& clType_user
) {
291 sym_find(&c
->v
.t
, (char *)&u
, sizeof(u
), sizeof(sym_base
), 0);
295 sym_find(&c
->v
.t
, s
, -1, sizeof(sym_base
), 0);
302 /*----- Arithmetic on classes ---------------------------------------------*/
304 /* --- @class__binop@ --- *
306 * Arguments: @class_node *l@ = left argument
307 * @class_node *r@ = right argument
308 * @unsigned op@ = the binop code
310 * Returns: A class node representing the result of a binary operation
313 * Use: Performs a binary operation on classes. If the types don't
314 * match, then a null pointer is returned. Both @l@ and @r@
315 * may be modified, and will be decremented before they get
316 * returned to you. If you don't want that to happen, ensure
317 * that you've claimed a reference to the original versions.
319 * If both nodes are `friendly' (see below), then an attempt is
320 * made to combine them sensibly using a hashtable.
322 * If one or both nodes is/are unfriendly, a binop node is
323 * created with type @op@ to allow the matcher to decide on
324 * membership appropriately at match time.
326 * A friendly node is one which can be placed in a hash table to
327 * speed up searching. It's friendly, because it doesn't mind
328 * living with other nodes. Uid numbers are friendly.
329 * Wildcarded strings aren't. Hashtables are trivially
333 class_node
*class__binop(class_node
*l
, class_node
*r
, int op
)
335 unsigned type
= l
->type
& r
->type
& clType_mask
;
336 unsigned lnode
= l
->type
& clNode_mask
, rnode
= r
->type
& clNode_mask
;
338 /* --- Check for compatible types --- */
346 /* --- Handle `friendly' nodes --- */
348 if ((l
->type
& r
->type
& clFlag_friendly
)) {
350 /* --- Consider promoting an item to a hash --- *
352 * If both are immediate nodes, and they're both `friendly', we can
353 * profitably hash them together.
355 * Life gets complicated when we do subtraction, because it's not
356 * commutative. In this case, I have to promote the left operand anyway.
359 if (lnode
== clNode_immed
&&
360 (rnode
== clNode_immed
|| op
== clNode_diff
)) {
362 /* --- Quick check for triviality --- *
364 * There are some more short-cuts I can employ if the values are
368 if (rnode
== clNode_immed
) {
370 /* --- See whether the two items are equal --- */
372 int eq
= (type
& clType_user ?
373 l
->v
.u
== r
->v
.u
: strcmp(l
->v
.s
, r
->v
.s
) == 0);
375 /* --- Now do something appropriate --- */
404 /* --- Turn @l@ into a hash containing itself --- */
406 l
= class__hashify(l
);
410 /* --- Otherwise, make @l@ the hash --- *
412 * Both @l@ and @r@ are friendly. Since they're not both immediates,
413 * one must be a hash.
416 else if ((l
->type
& clNode_mask
) == clNode_immed
) {
420 tn
= l
, l
= r
, r
= tn
;
421 tt
= lnode
, lnode
= rnode
, rnode
= tt
;
424 /* --- Now merge @r@ with @l@ --- */
430 /* --- The union operation isn't hard --- */
433 if (rnode
== clNode_immed
) {
434 if (type
& clType_user
) {
435 sym_find(&l
->v
.t
, (char *)&r
->v
.u
,
436 sizeof(r
->v
.u
), sizeof(sym_base
), 0);
438 sym_find(&l
->v
.t
, r
->v
.s
, -1, sizeof(sym_base
), 0);
443 for (sym_mkiter(&i
, &r
->v
.t
); (b
= sym_next(&i
)) != 0; )
444 sym_find(&l
->v
.t
, b
->name
, b
->len
, sizeof(sym_base
), 0);
448 /* --- Set difference is similar in spirit --- */
451 if (rnode
== clNode_immed
) {
454 if (type
& clType_user
)
455 f
= sym_find(&l
->v
.t
, (char *)&r
->v
.u
, sizeof(r
->v
.u
), 0, 0);
457 f
= sym_find(&l
->v
.t
, r
->v
.s
, -1, 0, 0);
459 sym_remove(&l
->v
.t
, f
);
464 for (sym_mkiter(&i
, &r
->v
.t
); (b
= sym_next(&i
)) != 0; ) {
465 if ((f
= sym_find(&l
->v
.t
, b
->name
, b
->len
, 0, 0)) != 0)
466 sym_remove(&l
->v
.t
, f
);
471 /* --- Intersection is wild and wacky --- */
474 if (rnode
== clNode_immed
) {
477 if (type
& clType_user
)
478 f
= sym_find(&l
->v
.t
, (char *)&r
->v
.u
, sizeof(r
->v
.u
), 0, 0);
480 f
= sym_find(&l
->v
.t
, r
->v
.s
, -1, 0, 0);
493 for (sym_mkiter(&i
, &l
->v
.t
); (b
= sym_next(&i
)) != 0; ) {
494 if (!sym_find(&r
->v
.t
, b
->name
, b
->len
, 0, 0))
495 sym_remove(&l
->v
.t
, b
);
501 /* --- Now trim the @l@ table to size --- *
503 * It may have lost a load of elements. Maybe it can be represented
504 * better as an immediate or even as @class_none@.
513 sym_mkiter(&i
, &l
->v
.t
);
514 if ((b
= sym_next(&i
)) == 0) {
519 if (type
& clType_user
) {
520 uid_t u
= *(uid_t
*)b
->name
;
521 sym_destroy(&l
->v
.t
);
522 l
->type
= (l
->type
& ~clNode_mask
) | clNode_immed
;
525 char *s
= xstrdup(b
->name
);
526 sym_destroy(&l
->v
.t
);
527 l
->type
= (l
->type
& ~clNode_mask
) | clNode_immed
;
538 /* --- Unfriendly nodes --- *
540 * Create a binop node and return that. If @l@ is a binop node, and @r@
541 * isn't, and the operation isn't set difference (i.e., it's commutative)
542 * then swap the two over to lessen the depth of recursion later.
546 class_node
*c
= xmalloc(sizeof(*c
));
550 if (lnode
>= clNode_binop
&& rnode
< clNode_binop
&& op
!= clNode_diff
) {
561 /* --- @class_union@ --- *
563 * Arguments: @class_node *l@ = left argument
564 * @class_node *r@ = right argument
566 * Returns: A class node representing the union of the two classes.
568 * Use: Performs the union operation on classes. If the types don't
569 * match, then a null pointer is returned. Both @l@ and @r@
570 * may be modified, and will be decremented before they get
571 * returned to you. If you don't want that to happen, ensure
572 * that you've claimed a reference to the original versions.
575 class_node
*class_union(class_node
*l
, class_node
*r
)
577 /* --- Check for the really simple cases --- */
579 if (l
== class_all
|| r
== class_all
) {
590 /* --- Do the job --- */
592 return (class__binop(l
, r
, clNode_union
));
595 /* --- @class_diff@ --- *
597 * Arguments: @class_node *l@ = left argument
598 * @class_node *r@ = right argument
600 * Returns: A class node representing the difference of the two classes.
602 * Use: Performs the set difference operation on classes. If the
603 * types don't match, then a null pointer is returned. Both
604 * @l@ and @r@ may be modified, and will be decremented before
605 * they get returned to you. If you don't want that to happen,
606 * ensure that you've claimed a reference to the original
610 class_node
*class_diff(class_node
*l
, class_node
*r
)
612 /* --- Check for the really simple cases --- */
614 if (l
== class_none
|| r
== class_all
) {
623 /* --- Do the job --- */
625 return (class__binop(l
, r
, clNode_diff
));
628 /* --- @class_isect@ --- *
630 * Arguments: @class_node *l@ = left argument
631 * @class_node *r@ = right argument
633 * Returns: A class node representing the intersection of the two
636 * Use: Performs the intersecion operation on classes. If the types
637 * don't match, then a null pointer is returned. Both @l@ and
638 * @r@ may be modified, and will be decremented before they get
639 * returned to you. If you don't want that to happen, ensure
640 * that you've claimed a reference to the original versions.
643 class_node
*class_isect(class_node
*l
, class_node
*r
)
645 /* --- Check for the really simple cases --- */
647 if (l
== class_none
|| r
== class_none
) {
658 /* --- Do the job --- */
660 return (class__binop(l
, r
, clNode_isect
));
663 /*----- Building the predefined classes -----------------------------------*/
665 /* --- @class_addUser@ --- *
667 * Arguments: @class_node *c@ = pointer to a class node (may be null)
668 * @uid_t u@ = user id number
670 * Returns: Pointer to the combined node.
672 * Use: Adds a user to a node, maybe hashifying it.
675 class_node
*class_addUser(class_node
*c
, uid_t u
)
678 return (class_fromUser(clType_user
, u
));
679 if ((c
->type
& clNode_mask
) == clNode_immed
)
680 c
= class__hashify(c
);
681 sym_find(&c
->v
.t
, (char *)&u
, sizeof(u
), sizeof(sym_base
), 0);
685 /* --- @class_addString@ --- *
687 * Arguments: @class_node *c@ = pointer to a class node (may be null)
688 * @const char *s@ = pointer to a string
690 * Returns: Pointer to the combined node.
692 * Use: Adds a user to a node, maybe hashifying it.
695 class_node
*class_addString(class_node
*c
, const char *s
)
697 class_node
*n
= class_fromString(clType_host
, s
); /* hack */
699 return (class_union(c
, n
));
704 /*----- Matching functions ------------------------------------------------*/
706 /* --- @class_matchUser@ --- *
708 * Arguments: @class_node *c@ = pointer to root class node
709 * @uid_t u@ = user id number
711 * Returns: Nonzero if it matches, zero if it doesn't.
713 * Use: Determines whether a user is matched by a class. Assumes
714 * that the types are correct.
717 int class_matchUser(class_node
*c
, uid_t u
)
721 for (cc
= 0; c
; c
= cc
, cc
= 0) {
726 switch (c
->type
& clNode_mask
) {
728 return (u
== c
->v
.u
);
731 return (sym_find(&c
->v
.t
, (char *)&u
, sizeof(u
), 0, 0) != 0);
734 if (class_matchUser(c
->v
.c
.l
, u
))
739 if (!class_matchUser(c
->v
.c
.l
, u
))
744 return (class_matchUser(c
->v
.c
.l
, u
) &&
745 !class_matchUser(c
->v
.c
.r
, u
));
750 die(1, "internal: can't get here in class_matchUser");
754 /* --- @class_matchCommand@ --- *
756 * Arguments: @class_node *c@ = pointer to root class node
757 * @const char *s@ = pointer to a string
759 * Returns: Nonzero if it matches, zero if it doesn't.
761 * Use: Determines whether a string is matched by a class. Assumes
762 * that the types are correct.
765 int class_matchCommand(class_node
*c
, const char *s
)
769 for (cc
= 0; c
; c
= cc
, cc
= 0) {
774 switch (c
->type
& clNode_mask
) {
776 return (class__wildMatch(c
->v
.s
, s
));
779 return (sym_find(&c
->v
.t
, s
, -1, 0, 0) != 0);
782 if (class_matchCommand(c
->v
.c
.l
, s
))
787 if (!class_matchCommand(c
->v
.c
.l
, s
))
792 return (class_matchCommand(c
->v
.c
.l
, s
) &&
793 !class_matchCommand(c
->v
.c
.r
, s
));
798 die(1, "internal: can't get here in class_matchCommand");
802 /* --- @class_matchHost@ --- *
804 * Arguments: @class_node *c@ = pointer to root class node
805 * @struct in_addr a@ = IP address to match
807 * Returns: Nonzero if it matches, zero if it doesn't.
809 * Use: Determines whether a host matches a host class. Assumes
810 * that the types are correct. The actual mechanism is a bit
811 * odd here, but I think this is the Right Thing. At each stage
812 * I try to match %%@/all/%% of the possible names for the host.
813 * Thus host `splat' with address 1.2.3.4 would fail to match
814 * the class "1.2.*" - "splat". This seems to be what the
815 * author intuitively expects. It's just a bit weird.
818 static int class__doMatchHost(class_node
*c
, const char *ip
,
819 const char *name
, char **aliases
)
823 for (cc
= 0; c
; c
= cc
, cc
= 0) {
828 switch (c
->type
& clNode_mask
) {
830 if ((ip
&& class__wildMatch(c
->v
.s
, ip
)) ||
831 (name
&& class__wildMatch(c
->v
.s
, name
)))
833 if (aliases
) for (; *aliases
; aliases
++) {
834 if (class__wildMatch(c
->v
.s
, *aliases
))
840 if ((ip
&& sym_find(&c
->v
.t
, ip
, -1, 0, 0)) ||
841 (name
&& sym_find(&c
->v
.t
, name
, -1, 0, 0)))
843 if (aliases
) for (; *aliases
; aliases
++) {
844 if (sym_find(&c
->v
.t
, *aliases
, -1, 0, 0))
850 if (class__doMatchHost(c
->v
.c
.l
, ip
, name
, aliases
))
855 if (!class__doMatchHost(c
->v
.c
.l
, ip
, name
, aliases
))
860 return (class__doMatchHost(c
->v
.c
.l
, ip
, name
, aliases
) &&
861 !class__doMatchHost(c
->v
.c
.r
, ip
, name
, aliases
));
866 die(1, "internal: can't get here in class_matchUser");
870 int class_matchHost(class_node
*c
, struct in_addr a
)
872 char *ip
, *name
, **aliases
;
876 if ((h
= gethostbyaddr((char *)&a
, sizeof(a
), AF_INET
)) != 0) {
878 aliases
= h
->h_aliases
;
884 return (class__doMatchHost(c
, ip
, name
, aliases
));
887 /*----- Debugging code ----------------------------------------------------*/
889 /* --- @class_dump@ --- *
891 * Argumemnts: @class_node *c@ = pointer to root node
892 * @int indent@ = indent depth
896 * Use: Dumps a class to the trace output.
899 void class_dump(class_node
*c
, int indent
)
903 static char *types
[] = {
911 static char *nodes
[] = {
918 "binop: intersection"
921 /* --- Handle some magical cases --- */
923 if (c
== class_all
) {
924 trace(TRACE_RULE
, "rule:%*s class ALL", indent
* 2, "");
927 if (c
== class_none
) {
928 trace(TRACE_RULE
, "rule:%*s class NONE", indent
* 2, "");
932 /* --- Dump basic type information --- */
934 trace(TRACE_RULE
, "rule:%*s type == [%s], node type == [%s]%s",
936 types
[c
->type
& clType_mask
],
937 nodes
[(c
->type
& clNode_mask
) >> 4],
938 (c
->type
& clFlag_friendly
) ?
" Friendly" : "");
940 /* --- Now trace the contents --- */
942 switch (c
->type
& clNode_mask
) {
944 if (c
->type
& clType_user
) {
945 trace(TRACE_RULE
, "rule:%*s user %lu",
946 indent
* 2, "", (unsigned long)c
->v
.u
);
948 trace(TRACE_RULE
, "rule:%*s `%s'", indent
* 2, "", c
->v
.s
);
954 for (sym_mkiter(&i
, &c
->v
.t
); (b
= sym_next(&i
)) != 0; ) {
955 if (c
->type
& clType_user
) {
956 trace(TRACE_RULE
, "rule:%*s user %lu",
957 indent
* 2, "", (unsigned long)*(uid_t
*)b
->name
);
959 trace(TRACE_RULE
, "rule:%*s `%s'", indent
* 2, "", b
->name
);
965 class_dump(c
->v
.c
.l
, indent
+ 1);
966 class_dump(c
->v
.c
.r
, indent
+ 1);
973 /*----- That's all, folks -------------------------------------------------*/