1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright (c) 1997-2001 by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28/*	  All Rights Reserved  	*/
29
30
31#pragma ident	"%Z%%M%	%I%	%E% SMI"	/* SVr4.0 1.5 */
32
33#include <sys/types.h>
34#include <stdio.h>
35#include <userdefs.h>
36#include <pwd.h>
37
38#include <sys/param.h>
39#ifndef	MAXUID
40#include <limits.h>
41#ifdef UID_MAX
42#define	MAXUID	UID_MAX
43#else
44#define	MAXUID	60000
45#endif
46#endif
47
48static uid_t getrangeboundid(uid_t start, uid_t stop);
49static int isreserveduid(uid_t uid);
50
51/*
52 * Find the highest uid currently in use and return it. If the highest unused
53 * uid is MAXUID, then attempt to find a hole in the range. If there are no
54 * more unused uids, then return -1.
55 */
56uid_t
57findnextuid(void)
58{
59	uid_t uid = DEFRID + 1;
60	struct passwd *pwd;
61	uchar_t overflow = 0;
62
63	setpwent();
64	for (pwd = getpwent(); pwd != NULL; pwd = getpwent()) {
65		if (isreserveduid(pwd->pw_uid))		/* Skip reserved IDs */
66			continue;
67		if (pwd->pw_uid >= uid) {
68			if (pwd->pw_uid == MAXUID) {	/* Overflow check */
69				overflow = 1;
70				break;
71			}
72			uid = pwd->pw_uid + 1;
73			while (isreserveduid(uid) &&
74			    uid < MAXUID) {		/* Skip reserved IDs */
75				uid++;
76			}
77		}
78	}
79	endpwent();
80	if (overflow == 1)				/* Find a hole */
81		return (getrangeboundid(DEFRID + 1, MAXUID));
82	return (uid);
83}
84
85/*
86 * Check to see that the uid is a reserved uid
87 * -- nobody, noaccess or nobody4
88 */
89static int
90isreserveduid(uid_t uid)
91{
92	return (uid == 60001 || uid == 60002 || uid == 65534);
93}
94
95
96/*
97 * getrangeboundid() attempts to return the next valid usable id between the
98 * supplied upper and lower limits. If these limits exceed the system
99 * boundaries of DEFRID +1 and MAXUID (lower and upper bound respectively),
100 * then they are ignored and DEFRID + 1 and MAXUID are used.
101 *
102 * Returns a valid uid_t between DEFRID +1 and MAXUID, -1 is returned on fail
103 */
104static uid_t
105getrangeboundid(uid_t start, uid_t stop)
106{
107	uid_t low = (start <= DEFRID) ? DEFRID + 1 : start;
108	uid_t high = (stop < MAXUID) ? stop : MAXUID;
109	uid_t uid;
110
111	for (uid = low; uid <= high; uid++) {
112		if (isreserveduid(uid))
113			continue;
114		if (getpwuid(uid) == NULL)
115			break;
116	}
117	return ((uid > high) ? -1 : uid);
118}
119