1/*
2  File: __acl_reorder_obj_p.c
3  (Linux Access Control List Management, Posix Library Functions)
4
5  Copyright (C) 1999, 2000
6  Andreas Gruenbacher, <a.gruenbacher@computer.org>
7
8  This program is free software; you can redistribute it and/or
9  modify it under the terms of the GNU Library General Public
10  License as published by the Free Software Foundation; either
11  version 2 of the License, or (at your option) any later version.
12
13  This program is distributed in the hope that it will be useful,
14  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  Library General Public License for more details.
17
18  You should have received a copy of the GNU Library General Public
19  License along with this library; if not, write to the Free Software
20  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21*/
22
23#include <alloca.h>
24#include "libacl.h"
25
26
27static inline int
28__acl_entry_p_compare(const acl_entry_obj *a_p, const acl_entry_obj *b_p)
29{
30	if (a_p->etag < b_p->etag)
31		return -1;
32	else if (a_p->etag > b_p->etag)
33		return 1;
34
35	if (a_p->eid.qid < b_p->eid.qid)
36		return -1;
37	else if (a_p->eid.qid > b_p->eid.qid)
38		return 1;
39	else
40		return 0;
41}
42
43
44static int
45__acl_entry_pp_compare(const void *a, const void *b)
46{
47	return __acl_entry_p_compare(*(const acl_entry_obj **)a,
48				   *(const acl_entry_obj **)b);
49}
50
51
52/*
53  Take an ACL entry form its current place in the entry ring,
54  and insert it at its proper place. Entries that are not valid
55  (yet) are not reordered.
56*/
57int
58__acl_reorder_entry_obj_p(acl_entry_obj *entry_obj_p)
59{
60	acl_obj *acl_obj_p = entry_obj_p->econtainer;
61	acl_entry_obj *here_obj_p;
62
63	if (acl_obj_p->aused <= 1)
64		return 0;
65	switch(entry_obj_p->etag) {
66		case ACL_UNDEFINED_TAG:
67			return 1;
68		case ACL_USER:
69		case ACL_GROUP:
70			if (qualifier_obj_id(entry_obj_p->eid) ==
71			    ACL_UNDEFINED_ID)
72				return 1;
73	}
74
75	/* Remove entry from ring */
76	entry_obj_p->eprev->enext = entry_obj_p->enext;
77	entry_obj_p->enext->eprev = entry_obj_p->eprev;
78
79	/* Search for next greater entry */
80	FOREACH_ACL_ENTRY(here_obj_p, acl_obj_p) {
81		if (__acl_entry_p_compare(here_obj_p, entry_obj_p) > 0)
82			break;
83	}
84
85	/* Re-insert entry into ring */
86	entry_obj_p->eprev = here_obj_p->eprev;
87	entry_obj_p->enext = here_obj_p;
88	entry_obj_p->eprev->enext = entry_obj_p;
89	entry_obj_p->enext->eprev = entry_obj_p;
90
91	return 0;
92}
93
94
95/*
96  Sort all ACL entries at once, after initializing them. This function is
97  only used when converting complete ACLs from external formats to ACLs;
98  the ACL entries are always kept in canonical order while an ACL is
99  manipulated.
100*/
101int
102__acl_reorder_obj_p(acl_obj *acl_obj_p)
103{
104	acl_entry_obj **vector = alloca(sizeof(acl_entry_obj *) *
105					acl_obj_p->aused), **v, *x;
106	acl_entry_obj *entry_obj_p;
107
108	if (acl_obj_p->aused <= 1)
109		return 0;
110
111	v = vector;
112	FOREACH_ACL_ENTRY(entry_obj_p, acl_obj_p) {
113		*v++ = entry_obj_p;
114	}
115
116	qsort(vector, acl_obj_p->aused, sizeof(acl_entry_obj *),
117	       __acl_entry_pp_compare);
118
119	x = (acl_entry_obj *)acl_obj_p;
120	for (v = vector; v != vector + acl_obj_p->aused; v++) {
121		(*v)->eprev = x;
122		x = *v;
123	}
124	acl_obj_p->aprev = *(vector + acl_obj_p->aused - 1);
125
126	x = (acl_entry_obj *)acl_obj_p;
127	for (v = vector + acl_obj_p->aused - 1; v != vector - 1; v--) {
128		(*v)->enext = x;
129		x = *v;
130	}
131	acl_obj_p->anext = *vector;
132	return 0;
133}
134
135